A 566989
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ELECTRICAL
RAILROADING
AS APPLIED TO
STEAM RAILWAYS
AYLMER-SMALL
TY

ARTES
LIBRARY
SCIENTIA
VERITAS
OF THE
UNIVERSITY OF MICHIGAN
-QUAERIS PENINSULAM AMOENAME
IRCUMSPICE
DEPARTMENT
OF
ENGINEERING
:
TF
855
564

Electrical Railroading
OR
ELECTRICITY AS APPLIED TO
RAILROAD TRANSPORTATION
BY
SIDNEY ALYMER-SMALL
ILLUSTRATED
CHICAGO
FREDERICK J. DRAKE & CO., PUBLISHERS
1908

Copyright, 1908
BY FREDERICK J. DRAKE & Co.
CHICAGO
YAZAQKX1000MIN) 48
Moloza, 5-4-42
PREFACE.
This book is written principally for railroad men who
are or may some day be in contact with the electrical
machinery and apparatus, which is today installed on all
steam roads, and with the machinery and apparatus which
is being or will be installed by many roads with the in-
tention of using electricity as a motive power on branches.
or even sections of their main line.
Nearly all roads use both telegraph and telephone in
controlling train movement; all use telegraph and elec-
tric bells. Many roads are using electrically controlled
block signals, and the use of automatic electric signals
is rapidly increasing.
It will not be long before electricity will become the
motive power in use by the roads entering the large cities
on all their urban and suburban lines. The electric loco-
motive and motor car will supersede the steam locomo-
tive.
No railroad man, engineer, conductor, fireman, bag-
gageman, switchman, brakeman, towerman or any other,
can afford to be ignorant of the subject of electricity. The
men who know most about it will stand the best chance.
The men who study will possess knowledge of elec-
tricity that can not fail to be of immense advantage to
them in the next few years.
It will make them more valuable to the companies, and
keep them abreast of their rapidly developing profession.
It would be impossible to exaggerate the importance
7
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191031
8
PREFACE
of such preparation being made by the men who wish to
succeed. To be content to be ignorant of electricity and
its application to motive power, is to be doomed, or to
doom yourself to failure.
There are, however, many other men who are inter-
ested in electricity as applied to railroads and for such
the book is also written.
Considering the recent date of the adaptation of elec-
trical power to steam roads, all descriptions of old-fash-
ioned machinery and apparatus which we would find in
many electric light or street railway plants are omitted
and the descriptions of apparatus to be found in large
traction plants, whether inter-urban, branch or main line
stations, will be described in full, and in such a way that
it is hoped that any still newer types of machinery and
apparatus, will be understood because of the fundamental
knowledge gained by study of this book.
METHOD OF THE BOOK,
The author has endeavored to be honest as to what we
know about electricity and what we think we know; also
to tell the things a railroad man should know plainly.
The book consists of a series of lessons, each one of
which should be learned before studying the next.
Each lesson is short enough to be studied at one time.
When a reference is given to a lesson ahead it is to be
simply read, not studied. In fact, the student need not
look up the reference if he is in a hurry to finish the
lesson.
These references will, however, be an extra help in
making the lessons easily understood. Whenever a word
or term is used for the first time it will be explained at
once, in the text or by foot note, or else a reference ahead
will be given. After a word has been used and explained
no reference will be given.
The style is a series of questions and answers.
The questions are those which would be asked by a
person seeking information about electricity and electric.
railroads, and the answers are those which would be
given by one teaching electricity to the questioner.
Thus by learning the answers a person gains a knowl-
edge of electricity and also the art of explaining things
to other people. This is of inestimable value to any man,
because when we are compelled to tell a friend "I know
it but I can't explain it," we are apt to fall in that per-
son's estimation. He either thinks that we do not know
or will not tell.
⭑
9
10
ELECTRIC RAILROADING
Many of the questions in these lessons are ones which
have actually been asked the author by acquaintances
and students. He feels greatly indebted to the railroad.
men of one of the large terminals who, while receiving
instructions from him in Electricity as Applied to Rail-
road Transportation, helped him wonderfully by their
readiness to ask questions until they understood what was
told them.
The book is not offered with a faint hope that it may
succeed, but knowing that what it contains has helped
a group of railroad men, it is hoped that, put in a book,
it will reach more men and be of use to them.
The introductions to the lessons are those parts which
prepare the student's mind for the lesson, and they con-
tain information which can be told better in that way
than by questions and answers.
Descriptions of apparatus and machinery are often
given between lessons. These not only make the student
familiar with the things described, but serve to fix the
knowledge already attained. The study of these descrip-
tions also reviews the knowledge previously acquired.
LESSON 1.
INTRODUCTION.
Exactly what electricity is we do not know, and indeed
a practical man always dealing with the useful effects
of electricity, applying these to the necessities and for
the comfort of mankind, finds little time to wonder what
electricity is.
We will omit the almost unanswerable question:-
"What is electricity?"-and proceed to the question.
Question 1. What is meant when a person talks about
electricity?
Answer. There are certain effects which we believe
to be due to electricity, so that when a person observes.
any one of these things, he at once declares that there is
electricity present.
Question 2. What are some of these effects?
Answer. Lightning during a thunder storm. Light-
ing gas with a spark from the finger tip.
Question 3. Are these effects due to electricity?
Answer. Yes, but by a kind which is different enough
from other electricity to be called Static Electricity.
Question 4. Why is it called static electricity?
Answer. Because a quantity of this kind of electricity
will remain on a body provided it is hung up by a dry
silk thread. This electricity is at rest or stands still.
Static means standing.
Question 5. What other effects are due to electricity?
11
12
ELECTRIC RAILROADING
Answer. Ringing of an electric bell. Operation of an
electric motor.
Question 6. Are these effects due to static electricity?
Answer. No, the bell and motor are operated by
Dynamic Electricity.
Question 7. What is méant by dynamic electricity?
Answer. Electricity in motion, because the word
dynamic means force, giving the idea of motion.
Question 8. What is meant by a current of electricity?
Answer. Dynamic electricity is usually referred to as
a current of electricity.
Question 9. Are there any other effects said to be due
to electricity?
Answer. Yes; the working of a wireless telegraphy
instrument.
Question 10. What kind of electricity operates this in-
strument?
Answer. Electrical waves.
Question 11. Are there still other kinds of electricity?
Answer. Practically no. All the effects we observe
may be explained as being caused by either static elec-
tricity, a current of electricity or electrical waves.
Question 12. What is static electricity?
Answer. It is electricity at rest.
Question 13. What is current electricity?
Answer. It is electricity in motion along a conductor.
Question 14. What are electrical waves?
Answer. They are electricity moving through the air,
no conductor being required.
Question 15. Does the word electricity in the last
three answers mean the same thing in each?
Answer. Yes; in each case it is electricity, either at
INTRODUCTION
13
rest, moving along a wire, or moving through the air
without a wire.
Question 16. Give an example of static electricity.
Answer. If a brass ball be suspended by a silk thread
and touched to one knob of an electrical machine (see
Lesson 6) and then removed, it will be covered with a
charge (see Lesson 2) of electricity. This electricity
will be at rest and so is called a charge of static elec-
tricity.
Question 17. Give an example of a current of elec-
tricity.
Answer. If quantities of electricity are supplied at the
end of a metal wire, they will quickly flow to the other
end. Here the electricity is in motion and a current of
electricity is flowing.
Question 18. Give an example of electrical waves.
Answer. If electricity is forced by a high pressure as
in an electric machine or in an induction coil (see Lesson
27) to jump a spark across an air space, while doing so,
it will send out in every direction a series of electrical
waves which will travel long distances without the aid
of wires.
Question 19. What are some of the common effects
of current electricity?
Answer. Heat, light, magnetism, metal plating and
refining, and medical effects.
Question 20. Explain about the heat effect.
Answer. If large quantities of electricity are forced
through a conductor in a short time the wire is heated.
The poorer the conductor the more heat is produced.
Question 21. Is there always some heat produced?
Answer. Yes. Electricity cannot flow through a con-
ductor without producing some heat.
14
ELECTRIC RAILROADING
Question 22. Are the wires in a building heated, while
carrying electricity?
Answer. Yes; but the wire is large compared with the
current carried; the material is copper, a good conduc-
tor, so that the heating is too small to be detected by feel-
ing the wire.
Question 23. Does electricity produce light?
Answer. Yes. The heat produced in a very poor con-
ductor by the current may be so great as to burn the con-
ductor and the flame gives light; or it may make the
conductor white or yellow hot, thus giving light.
The arc lamp gives light from flame and white hot car-
bon, while the incandescent lamp has no flame only the
yellow hot carbon.
Question 24. Does electricity produce magnetism?
Answer. Yes. Electricity in motion will always affect
the needle of a compass, usually pulling it aside from the
north and south line, and keeping it out. This is de-
scribed as "deflecting the needle" and whenever the
"magnetic needle" is spoken of we mean a magnet of
small weight and fairly long, pivoted so as to move freely
in a horizontal direction. We speak of this effect as
electro-magnetism.
Question 25. How does electricity plate metal?
Answer. Electricity in passing through solutions of
chemicals takes the metal out of the solution and turns it
into the solid form, thus making a layer of metal on the
object placed in the solution. (See Lesson 17.)
Question 26. How does electricity refine metals?
I
Answer. If a lot of metals and other chemicals are in
a solution, by passing electricity through the solution the
Imetals will be solidified and may be removed while the
other chemicals remain dissolved in the solution.
INTRODUCTION
15
Question 27. What are the medical effects of elec-
tricity?
Answer. They are not well understood; but the pas-
sage of current through the body seems to have a curative
effect on some diseases.
1
1
INTRODUCTION TO STATIC ELECTRICITY.
Static electricity is of importance to the railroad man
in many ways.
In power houses and machine shops the belts often
produce static electricity so that a person going near or
under them will receive a rather unpleasant shock.
A locomotive blowing off steam through the safety
valve becomes electrified but the charge is much too
small to give any one a shock.
Lightning is static electricity and consists of such large
charges that electrical machinery is usually badly dam-
aged if lightning passes through it.
The telegraph, telephone and signal circuits, the power
lines, and all buildings into which wires enter must be
protected by lightning arresters.
Motor cars and electrical locomotives must be equipped
with lightning arresters to protect their wiring, appa-
ratus and motors.
A great many of the cables distributing electricity,
especially at large railroad terminals, or along the right
of way in the city limits are carried in conduits under-
ground. To protect them from moisture they are covered
with lead. This lead sheathing often collects electricity
and heavy static discharges take place.
The discharge may injure instruments and apparatus
connected to the cables or may even injure the power
house or line, men while handling the cables or switches
attached to them.
A proper arrangement of lightning arresters and static
dischargers will prevent this.
16
INTRODUCTION TO STATIC ELECTRICITY
17
It will be seen that a thorough understanding of static
electricity is a good thing for a railroad man.
There are three pieces of apparatus which are easily
made, and the use of which will help one to readily under-
stand the action of static electricity.
They are the Electrophorous, to produce static elec-
tricity; the Leyden Jar, to store electric charges in; and
the Electroscope, to detect the presence of an electric
charge and its polarity.

← Glass Bottle
Wood Plug
Smaller Tin Pie Plate
Wood Screw
Tin Pie Plate
Resin Cake
Fig. 1.
Construction of an Electrophorous.
THE ELECTROPHOROUS.
Melt a mixture of two-thirds rosin and one-third gum
shellac or some common red sealing wax,* by setting the
dish on hot water. This is to avoid the danger of its
catching fire.
*Sealing wax is a mixture of rosin or other resins with
vermilion or some other powdered color.
18
ELECTRIC RAILROADING
Pour the melted stuff into a large tin pie plate and
allow to cool into a solid cake. Slow cooling will pre-
vent cracks, but they really do no harm.
Get a tin pie plate or tin layer cake pan a little smaller
in diameter than the resin* cake. Make a wood cone.
Screw a large flat head wood screw into the thick end
of cone, and then solder it to the tin plate. Fasten it to
the inside of bottom of plate.
Whittle the small end of the
neck of a small glass bottle.
but firmly.
cone to a driving fit to the
Press the bottle on gently
We now have a glass-handled tin dish to rest on the
resin cake, touching it all over, but the two tin plates not
touching anywhere.
A piece of flannel or woolen cloth is needed for a rub-
ber.
LEYDEN JAR.
A large plain beaker should be purchased from a chem-
ists' or druggists' supply house. The "plain" means that
there is no lip on the edge. It should be large enough
to hold a quart and a half of water. It will be a very
thin glass and must be handled carefully to avoid break-
ing.
Cut tinfoil to fit the inside and outside of the bottom
and dry the beaker over a stove or radiator. While dry
and warm paste the tinfoil on. Warm it again and paste
* Resin means any gum that flows from a tree as a sticky
liquid and hardens on contact with air. Gum arabic and gum
shellac are resins. Rosin is a resin from a pine tree. It is
left in the bottom of the stills when the spirits of turpentine
are boiled off.

INTRODUCTION TO STATIC ELECTRICITY
19
tinfoil over the outside up to about two-thirds its height.
Let the side foil lap over the bottom foil.
Cut a piece to fit the inside and roll it around a pencil.
Coat the inside with paste to about two-thirds its
height with paste or mucilage and stick one end of the
tinfoil down. Unwind the foil from the pencil and press
it down on paste with fingers or another pencil.
If the side and bottom foils do not connect, paste a
strip across the seam.
Take a thin board larger than the mouth of the beaker
and dry over a stove and shellac varnish it while hot.
Fig. 2. Leyden Jar.
Warm the beaker and while warm and dry shellac
all the glass not covered with foil.
Drill a small hole in the board and insert a short metal
rod. Fit to its lower end a piece of chain long enough to
touch the foil on the bottom of beaker, when the board
rests on its top. Fit the upper end with a metal ball.
Any size, solid or hollow makes no difference.
20
ELECTRIC RAILROADING
Put a circle of shellac varnish on the under side of
board and lay board on beaker so that chain touches bot-
tom.
When shellac dries the board will stick and keep inside
of jar dry.
DISCHARGER FOR LEYDEN JAR.
Bend a piece of wire like this and stick the doubled
part in a cork, put cork in a glass bottle and the result is
as good as Fig. 3.

1
1
Fig. 3. Discharger or Discharging Tongs for Leyden Jar.
ELECTROSCOPE.
A wide-mouthed fruit jar is taken and a cork or wood
stopper made to a loose fit.
Drill a hole through the stopper and insert a glass tube
about four inches long projecting equally on both sides.
Take a small metal rod or heavy wire which will go
through the glass tube and hammer one end flat for about
half an inch from the end. The thinner and flatter it is
made the better.

INTRODUCTION TO STATIC ELECTRICITY
21
Insert wire in tube so that the flattened end is about
one-third the way down the jar when cork is in place.
Cut off surplus wire at other end, leaving about half an
inch projecting from the glass tube.
Fix a small metal ball or plate on end of rod and let it
drop down and rest on the end of glass tube.
Fig. 4. Gold Leaf Electroscope.
Hold ball up against tube and turn it upside down,
pouring shellac varnish into the tube till it is filled. Give
the cork a coat of shellac* also.
When dry the metal rod will be cemented in the tube
and the tube into the cork.
Give outside of glass rod, the cork, the neck of bottle
*A pure shellac varnish is meant, made by dissolving or
"cutting," as it is called, flakes of gum shellac in alcohol. Wood
or grain alcohol are equally good. Orange or brown shellac
refer to the color of gum. Either will do.
22
ELECTRIC RAILROADING
inside and out two coats of shellac, allowing time for
perfect drying between coats.
The cork will now be a good tight fit.
Scrape any shellac off the flattened end of the rod and
paste on two strips of gold leaf, silver leaf, dutch metal -
or aluminum foil; as broad as the flat end itself is wide
and long enough so as to just not hit the sides of the jar
if they should stand out straight apart.
Cover the bottom of the jar an inch deep with fresh
dry calcium chloride. Buy it the day you are going to
put it in jar.
Give a last coat of shellac to the outside edge of the
cork and putting it in jar press down firmly, seeing that
the rod with its foil leaves hangs straight.
LESSON 2.
STATIC ELECTRICITY.
Question 1. What is static electricity?
Answer. I think it is a very small quantity of elec-
tricity at a very great pressure.
Question 2. Why do you think the quantity is small?
Answer. Because we cannot get any steady power out
of static electricity.
Question 3. Lightning often does considerable dam-
age. How do you account for that?
Answer. The damage done by lightning is like a blow
or an explosion, and seems to be the result of great pres-
sure.
Question 4. A static machine gives steady power, i. e.,
a steady stream of sparks.
Answer. No, it doesn't. The sparks follow each other
rapidly but are really intermittent. There is more time.
between sparks than the time of a single spark.
Question 5. Why do you think it has such a great
pressure?
Answer. Because it will jump across distances which
current electricity will not.
In all that we see of static electricity we are constantly
reminded of the fact that it possesses a power to escape
which enables it to cross a considerable space of one of
the best insulators known-dry air. This must mean
that static electricity is at a high pressure.
23
24
ELECTRIC RAILROADING
Question 6. Make this clearer.
Answer. A switch in an electric circuit can be almost
closed and yet no current will pass till the switch is
closed. Static electricity would have jumped across.
when the opening between the switch blades became
small.
Question 7. Mention some easy ways of producing
static electricity.
Answer.
I.
If you will rub a fountain pen on your
coat sleeve it will attract small pieces of paper.
2. A piece of glass rubbed with a silk necktie will do
the same.
3. A spark will be produced by shuffling your feet.
along the carpet and then touching a gas jet. This is in
miniature the same effect as lightning during a thunder
shower.
Question 8. Are there still other ways to produce
static electricity?
Answer. Yes. I. Friction between two different
substances will always produce electricity unless the
dampness is excessive. A leather belt on a rotating pul-
ley will become charged and give you a severe shock if
you walk under it.
2. Percussion. A violent blow struck by one sub-
stance on another produces positive and negative charges.
3. Breakage. Tear a playing or a visiting card, or
even a linen paper shipping tag suddenly across, and you
will charge the two pieces. Crunching a lump of sugar
quickly between the teeth does the same. Split a sheet of
mica with a sudden motion and you will also charge the
pieces.
Any of these tests done in a very dark room will show

STATIC ELECTRICITY
25
faint sparks. The hard rubber slides of the plate holder
of a camera, if pulled out suddenly on a dry day may
make such a spark that you can hear the crackling noise
above the sound made by the slide itself.
4. Solidification. When melted chocolate is poured
into moulds, upon cooling and hardening it becomes
electrified.
5. Combustion. The burning of a joss stick to keep
away mosquitos causes it to become electrified.
Fig. 5. Attraction due to Static Electricity.
6. Evaporation. The evaporation of a liquid from its
surface, when that surface is roughened by waves, pro-
duces electrification. This is one of the ways that the
atmosphere is kept charged relatively to the earth. In
fair weather it is always positive to the earth and during
rains and storms it is sometimes negative.
Question 9. Mention some other ways of showing
static electricity.
Answer. Briskly rub a sheet of paper which is lying
on a polished desk, with a rubber eraser, or even the
hand. If the room is cool and dry the sheet will stick
to the table.
26
ELECTRIC RAILROADING
嘗
​If two sheets are laid down together and rubbed and
both pulled away together; then when these are pulled
apart they will forcibly repel each other.
Lay a glass rod on a table, one end of which extends
over the edge a few inches. Attach to this a silk thread,*
fastened to the lower end of which is a small ball of pitht
from an elder or corn stalk.
Rub a second glass rod with a silk handkerchief and
bring it near the pith ball. It will be strongly attracted,
but almost immediately repelled, and it will not approach
the glass rod again.
Now rub a stick of sealing wax or a piece of wood
highly polished with shellac varnish, with a woolen rag
or piece of flannel and bring this near the pith ball. It
will be attracted and then repelled. We may repeat
this attraction and repulsion as often as we please.
Question 10. I do not understand the repulsion. What
causes it?
Answer. It is explained by saying that there are two
kinds of static electricity or at least two states of it.
Question II. Why does it seem that there are two
kinds of static electricity?
Answer. The fact that under one set of circumstances
an electrified body will be drawn to another body, and at
other times will be repulsed by the same body, plainly
indicates that there are two electrical states, one of attrac-
tion and the other of repulsion.
Question 12. Explain this further.
* À single thread drawn from a piece of embroidery silk is
best because it is very light and flexible.
† Any pith will do, and it may be purchased at a drug store,
STATIC ELECTRICITY
27
Answer. The glass rod in A9* attracted the pith ball
and then repelled it. Since it acted differently towards
the same charge of static electricity, there must have been
a charge on the pith ball which had two conditions, one
where it attracted and one where it repelled.
Question 13. How can these different states be pro-
duced or induced, as it is called?
Answer. Different electrical conditions are produced
by different treatment of the bodies electrified. The glass
rod rubbed by a silk handkerchief induced a condition
which is unlike that induced by the flannel's friction on
the sealing wax or shellac of the varnished wood.
Question 14. But this does not explain about the re-
pulsion or the cause of it.
Answer. With the knowledge gained in this experi-
ment and what we already know, we can find an explana-
tion.
Lay two glass rods over the edge of the table and as
far apart as possible and attach pith balls to each by
silk threads.
To one present a glass rod rubbed with silk. It is first
attracted and then repelled.
To the other present a stick of sealing wax that has
been rubbed with flannel. It will be attracted and then
repelled.
Take away the glass rod, the stick of wax, the silk
and flannel to a distance. Pick up one of the glass rods
and slowly bring its pith ball up towards the other. They
will be attracted.
*References to Answers in same Lesson will be made in this
way.
28
ELECTRIC RAILROADING
Handle the pith balls with the fingers a few seconds to
dissipate their charges. Replace them as before.
Rub the glass rod with silk and present to each pith
ball. They will be attracted and repelled.
Now as before bring the pith balls together and they
will repel each other.
Discharge the pith balls and repeat this last part, using
the sealing wax rubbed with flannel.
The balls are attracted and repelled, and when brought
near together they repel each other.
We already know from 49 that an unelectrified body.
is always attracted to an electric charge before being re-
pelled.
From these demonstrated facts we deduce the follow-
ing:
Similar electric charges repel each other. Dissimilar
charges attract each other. Either electrical condition
may show attraction for an unelectrified body.
In short:-
Like charges repel.
Unlike charges attract.
Charges attract neutral bodies.
Question 15. This explains why the two pith balls
were first attracted when one was charged by glass rod
and the other by sealing wax.
It explains why they repelled each other when both
were charged by glass rods.
Explain why a neutral or unelectrified body is attracted
and then repelled.
Answer. We have come to the conclusion that all
bodies contain equal amounts of the two kinds of static
electricity.
*
STATIC ELECTRICITY
29
When a body rests undisturbed the opposite qualities
of the parts neutralize each other and no outside effect
is observed; indeed one is tempted to say that there is
no electricity in the substance.
In a similar manner drinking a glassful of a solution
of caustic soda or of diluted muriatic acid would corrode
the lining of your stomach, and perhaps cause death.
Mixing the two would, if the chemicals were clean and
pure, and present in the right quantities, produce a large
glassful of a solution of table salt in water. I would
have no fear in drinking this, except for the excessive
thirst sure to follow such a salty beverage.
So the question is answered in this way-
at
B
-b
Fig. 6. State of a body B, having a charge induced in it due to the
action of C.
An unelectrified pith ball is really only an uncharged
one, for the two kinds of electricity are in it in equal
quantities and neutralize each other.
When the glass rod charged with glass electricity was
brought near the pith ball, the glass electricity of the
glass rod repelled the glass electricity of the pith ball to
the far side, and attracted the other kind (resinous) to
the near side. See Fig. 6.
The attraction being nearer than the repulsion the
whole pith ball with its separated electricities is pulled
toward the glass rod.
When the pith ball gets very near the glass rod the
t


30
ELECTRIC RAILROADING
attraction of the glass electricity on the rod actually pulls
the other kind (resinous) off the pith ball, leaving only
the glass electricity. The glass rod now repels the pith
ball even more strongly than it attracted it before.
When the stick of sealing wax was presented to a pith
ball the same thing is done by the resinous electricity of
the stick, it repels the resinous kind and attracts the glass.
kind. The same things occur and the ball is first at-
tracted, then repelled.
Question 16. Are these names, glass and resinous,
actually used?
Answer. Vitreous and resinous have been used, but
these names are out of date and they are now known as
positive and negative electricities.
The names are usually abbreviated by using the sign +
for the positive, and for the negative.
Question 17. Then an electric charge can induce a
charge in another body, that is, cause its electricities to
separate, without actually touching it?
Answer. Yes, as is shown in this experiment.
A sphere of metal, or wood covered with tinfoil is
mounted on an insulating stand-a wooden stand with a
glass rod for its support. A second similar stand has a
horizontal cylinder of conducting material, or wood coy-
ered with foil, hanging from which are double threads of
silk; and to these two or three inches below the cylinder
are fastened little pith balls. See Fig. 30, on page 78.
These double threads, four or five in number, are dis-
tributed along the cylinder at regular intervals.
The little cylinder, say an inch in diameter and six
inches long, is now insulated from the ground.
If the sphere is now charged and brought near one.
end of the cylinder, each pair of pith balls will show re-
*
STATIC ELECTRICITY
31
pulsion and remain standing apart. Those at the two
ends of the cylinder will show the greater repulsion and
remain further apart than the pairs near its center.
If we now electrify a rubber comb or glass rod by rub-
bing it, we will see that, on approaching the pith balls, it
will attract those at one end and repel those at the other;
thus showing the ends of the cylinder to be oppositely
electrified.
This proves conclusively that the approach of the
charged sphere separated the two electrical conditions on
the cylinders, attracting the opposite kind and repelling
the same kind.
It also gives another proof that "Like charges repel,"
because each of the pith balls in a pair had the same kind
of electricity in them, and repelled each other.
Question 18. Does the same charge always induce the
same quantity of electricity?
Answer. Yes, as is shown in the following experi-
ment.
As shown in Fig. 7, insulate a tin can by standing on a
glass tumbler. Connect it to an electroscope.*
Charge a metal ball and lower into the can by a silk
string, being careful not to let it touch the sides.
1
As the ball is lowered a charge is induced in the tin
pail and the gold leaves of the electroscope diverge, show-
ing it.
When the ball is well down into the pail the leaves
will diverge no further, even if the ball is touched to the
bottom.
This proves that the ball induced an equal and opposite
*Turn back and read description of Electroscope.
32
ELECTRIC RAILROADING
charge in the pail because touching the pail with the ball
added no more electricity.
Furthermore, after the ball has touched the pail pull it
out and it will be found perfectly neutral.
It was neutralized by the equal and opposite charge
which it induced.

t
a
Fig. 7. Showing that the induced charge is equal and opposite to t
inducing charge,
The electroscope was operated by the equal ar li
charge left free by the induction of the opposite cha re
Question 19. What is the usual trouble when ext
ments such as have been described won't work?
1
STATIC ELECTRICITY
33
Answer. The things used are not perfectly dry or the
air is too moist.
Question 20. What other things might cause trouble?
Answer. If the table used were set over a hot-air
register, the current of hot air will carry away the elec-
charges, perhaps as fast as produced.
thus
elect
T
char
the
the
I
bec
of t
Ç
sar
m
gl:
st:
T
1
LESSON 3.
STATIC ELECTRICITY (CONTINUED).
Question 1. Can you induce a + charge without at the
same time inducing an equal
Answer. No.
charge?
Question 2. But when you rubbed the fountain pen,
or the glass, or the carpet, as in A7, Lesson 2, only the
pen, glass or body seemed to have charges.
Answer. Careful investigation will prove that the coat
sleeve, necktie and the carpet under foot contain electrical
charges as well as the pen, glass, and your body.
Question 3. Why careful investigation?
Answer. Because it is very easy to be deceived by ap-
pearances in any electrical test. Care must be taken that
real effects are observed and to properly understand what
we see.
Question 4. What test is usually applied to the coat
sleeve, necktie and carpet to see if they are electrified,
i. e., if they contain a charge of static electricity?
Answer. A trial is made to see if they will attract pith
balls or affect an electroscope.
Question 5. But they won't and therefore there is no
charge on them.
Answer. No, not at the time they were tested, but
while being rubbed or rubbing they were electrified.
Question 6. Where did the charge go?
Answer. To the ground. You see the pen and glass
rod were insulators and insulated (Lesson 2) so that
34
STATIC ELECTRICITY
35
•
the electrification produced by the friction remained on
them, but the coat sleeve and silk necktie were not such
good insulators and were grounded, so that the charge
flowed away.
Question 7. But the glass rod and silk necktie were
both held in the hands. How could one be insulated and
the other not?
Answer. The glass rod being fairly long its lower
part acts as an insulator for the upper part. The hand,
which is a good conductor, makes a contact of small area
with the lower end of the glass rod. Hence the charge
on the other end, say three inches away, is insulated.
The necktie makes a contact of large area with the
hand and the charge being on the other side of the silk,
say a few thousandths of an inch away, is not properly
insulated and leaks away.
Question 8. But the charge on your body when you
drew a spark from the gas jet, did not flow away.
Answer. No; because the carpet was the better
grounded of the two and, moreover, the charge in the car-
pet, while being rubbed, was actually there and repelled a
charge into the body and held it there.
After the spark to the gas jet the charge. in the carpet
flowed away to the ground, and any excess charge on the
body also flowed away to ground.
Question 9. How can you prove that the coat sleeve
and necktie had charges while being rubbed?
Answer. By mounting a piece of woolen cloth to rep-
resent the coat sleeve on a glass rod and using this rod
as a handle, rub the cloth on the fountain pen.
Both the cloth and the pen will become charged, as
the charge on the cloth can not flow away, it remains, can
be tested and proved to exist.
ELECTRIC RAILROADING
36
The same idea may be carried out with a scrap of silk
and a glass rod.
Question 10. How do you test to prove a charge ex-
ists?
A
Answer. By using an electroscope.
Question II. Describe an electroscope.
Answer. As shown in Fig. 4 and in Fig. 8, it consists.
of a glass jar sealed up, practically moisture proof, with
two leaves of metal foil hanging from a metal rod in the
jar, the other end of the metal rod in the air terminates
in a metal ball. i

Fig. 8. Charging an Electroscope by Influence.
Two strips of foil are often pasted on the sides of the
jar to discharge the foil leaves if they swing out too far.
Question 12. How do you prepare an electroscope for
a test?
Answer. Rub a glass rod with a piece of silk and hold
rod near the ball of the electroscope, but do not touch it.
See Fig. 8. The leaves will diverge and remain apart.
While keeping the glass rod near the ball touch the
ball with the other hand and remove hand. The leaves
STATIC ELECTRICITY
37
fall together. Remove the glass rod to a distance and
the leaves will diverge again.
Question 13. Why does the electroscope act this way
while being charged?
Answer. When the charge of
electricity on the
glass rod is held near the neutral electroscope it separates.
the electricities and attracts the to the ball at the top
and repels all the + to the leaves at the bottom of the
metal rod.
The leaves being now both positively charged repel
each other and diverge.
When the ball is touched with the finger the elec-
tricity is held "bound" by the glass rod. Any which
would run in from the earth through the hand, is kept
out by the + of the glass rod, while more is attracted
from the earth. This charge combines with the + in the
leaves and neutralizes so that the leaves are no longer
charged. They therefore stop repelling each other and
fall together.
The in the ball is still held "bound" by the + of the
glass rod and can do nothing.
The finger being removed, and then the glass rod being
taken away, the charge which was in the ball spreads
all over the ball, rod and leaves.
The leaves being now each charged with
each other and diverge.
they repel
Notice that the final charge of the electroscope is op-
posite to the charge of the charging body.
Question 14. How do you test for a charge?
Answer. Bring the body on which a charge is sus-
pected near the ball and if the leaves diverge further or
fall together there is a charge on the body; if they are
not affected there is no charge on the body.
38
!
ELECTRIC RAILROADING
}
Question 15. How do you determine the kind of elec-
tricity on the body?
Answer. If the leaves diverge further when a body is
brought near the ball its charge is the same kind as is in
the electroscope, if they come together it is charged with
the opposite kind.
Question 16. What electricity is the electroscope usual-
ly charged with?
Answer. Usually a glass rod carrying a + charge is
used, which induces a charge in the electroscope.
Then a further divergence of the leaves means a and
a collapse of the leaves means a + charge on the tested
body.
Question 17. What is the general rule for determin-
ing the kind of electricity with an electroscope?
Answer. Collapse of leaves means same kind of
electricity as was used to charge the electroscope. Di-
vergence of leaves means different kind.
Question 18. How can you charge any body so as to
have only one kind of electricity in it?
Answer. By inducing a separation of the electricities
by means of a charged body and then drawing off the
"free" charge by touching the body with the finger.
Question 19. What does bound and free charges
mean?.
J
Answer. A bound charge means a charge which is at
tracted and held by a charge of the opposite kind.
Touching a body with a bound charge has no effect
upon it, because it is not free to neutralize with any elec-
tricity that might flow in, nor can it flow away, since it is
held by the other charge.
A free charge is a charge which is under no influence
or under the influence of a charge of the same kind,

STATIC ELECTRICITY
39
When a body is touched the free charge is either neu-
tralized by the inflowing charge or flows away itself to
the earth. Probably both of these actions take place.
Question 20. What is the best way to get a fairly large
charge of electricity?
Answer. By the Electrophorous.
Question 21. Describe the Electrophorous.
Answer. As shown in Figs. 1 and 9 it consists of a
plate of resin resting on a metal plate, and a second metal
plate with an insulated handle, rests on the resin.
Fig. 9. Using an electrophorous.
Question 22. How is the Electrophorous used?
Answer. The upper plate or cover is removed and the
cake of resin is rubbed or beaten with a piece of warm
dry flannel or cat's skin.
The cover is then taken up by the glass handle and
placed lightly on the cake. With thumb and forefinger
touch the metal plate containing the resin cake and the
metal cover at the same time,
40
ELECTRIC RAILROADING
Lift the cover off by the handle and it will be charged.
Question 23. How can you prove it?
Answer. By drawing a spark fro.n it by the finger.
Question' 24. Do you rub the resin cake each time
you want a spark?

A
B
+

+
+
+ +A
1B
Fig. 10. The Electrical State of an Electrophorous when cover is on,
and then after being touched and cover lifted.
Answer. No. The cover may be replaced, touched as
before, removed, and a spark drawn, over and over
again. If left after being used the charge on the cake
will leak away and rubbing will be necessary.
Question 25. Explain how the Electrophorous works.
Answer. When the resinous cake is first beaten its.
surface is -ly electrified and the+driven into the metal
pan. See Fig. 10. When the metal cover is placed light-
ly on the cake it does not touch at all points and is
really an insulated conductor.
The charge on the resin cake acts by influence on
the cover and induces a + charge on its under side and
repels the
charge to the upper side,
५
STATIC ELECTRICITY
41
When the cover and the bottom pan are touched by the
finger, several things happen. From the earth the resin
cake attracts more + charge to the lower side of the
cover and repels the on the upper side of cover out to
the earth through the finger. This gives the cover a
larger charge than before. This charge is bound
and cannot escape.
-
The connection of the bottom pan to earth allows its
+ charge to be increased, which in turn helps to "bind"
the charge on the resin.
If the cover is now lifted by the insulated handle the +
charge on it spreads over it and it is charged ready to
give a spark.
Question 26. Will the Electrophorous work if only
the cover is touched with the finger?
Answer. Yes, but the spark is stronger when both
cover and pan are touched.
Question 27. Is the original charge used up in draw-
ing several sparks in succession?
Answer. No, because the electricity which gives the
spark is really drawn from the earth each time.
Question 28. You have obtained energy without any
cost, have you not? This is contrary to nature's laws.
Answer. No. The cost of the spark is the muscular
effort of the first rubbing, and the subsequent touching
and liftings.
Question 29. How can a larger charge be obtained?
Answer. By accumulating the small charges given by
the electrophorous.
Question 30. What is used to accumulate charges?
Answer. A Leyden Jar.
Question 31. What is a Leyden Jar?
Answer. It is a glass jar lined inside and outside with
42
ELECTRIC RAILROADING
tinfoil with a conductor passing through an insulated
cork touching the inside foil. See Fig. 2.
Question 32. How is the Leyden jar used?
Answer. To get the best results connect the outer coat-
ing of tinfoil with a wire or chain to a gas or water
pipe, thus giving a good connection with the earth.
When the cover of the electrophorous is lifted, present
it to the knob of the jar and let the spark jump to it.
Repeat this a dozen times, and the jar will be charged.
Question 33. How do you show this charge?
Answer. Connect the ball with the outer coating using
the discharger (Fig. 3) and a heavy spark will be ob-
tained.
Question 34. Will it be twelve times as large as the
electrophorous spark?
Answer. No. It will be much larger than the electro-
phorous spark, but not twelve times as large, for there
are leaks and other losses which will reduce its size.
Question 35. Explain the main leak.
Answer. Glass is a hygroscopic substance. This
means that moisture collects on its surface very easily.
A china tea cup will have a dry surface in a room, while
a glass tumbler alongside of it will have a very damp
surface.
The charge leaks from one coating of tin foil to the
other over this film of moisture.
The shellac varnish on the glass is to prevent this
film of moisture forming. It does this very well.
Question 36. What is another cause of leakage?
Answer. There is the leakage from the coatings to
the air, because particles of air become electrified and
are then repelled.
Question 37. Why does not all the charge leak away?
1
STATIC ELECTRICITY
43
Answer. In a poorly made jar it will; but with well
shellaced glass, used in a dry atmosphere the leakage is
slow, and the binding influence of the inner and outer
charges on each other retains the charge.
Question 38. Is there any other leakage?
Answer. Yes there is leakage through the glass.
While glass is principally sand and soda yet there are
other ingredients added according to the grade of glass.
The cheaper kinds have accidental ingredients, really im-
purities, which lessen its value for electrical purposes. A
general rule is that the more expensive the glass the bet-
ter for electrical work.
A leyden jar to approach nearest to electrical perfec-
tion should be of glass containing no lead or other con-
ducting material.
For simple experimenting a cheap glass such as bottles
or fruit jars are made of will do.
In such cases it is absolutely necessary to coat the
glass with shellac varnish before putting on the tin foil.
Question 39. How can a larger spark be obtained?
Answer. By accumulating
sparks.
more
electrophorous
Question 40. Is there any limit to the size?
Answer. Yes; in time the pressure of the charge to
escape will be so great that the charge will either leak
as fast as it is added to or the pressure will flash a spark
over the edge of the glass.
Question 41. Will a larger leyden jar give a larger
spark?
Answer. Yes, a jar large enough to have twice the
amount of tin foil put on will give twice as large a spark.
Question 42. What do you mean by "twice as large
a spark?"
t

44
ELECTRIC RAILROADING
Answer. Either twice as long a spark, the same
length but twice as thick or some combination like this.
Twice as long and twice as thick, would be a spark four
times as large.
Fig. 11. A Leyden Jar with Removable Coatings.
Question 43. Can several leyden jars be used at once?
Answer. Yes, stand them all on a sheet of metal, and
connect all the knobs together with a piece of wire. This
is now the same as one big jar. Fig. 27, page 75.
Question 44. How does a leyden jar work?
Answer. The theory of the leyden jar is best explained
through the aid of an experiment, which requires a pe-
culiar form of jar, but which is easily constructed.
STATIC ELECTRICITY
45
Take a large glass tumbler, and varnish inside and out
with shellac. Arrange the inner and outer coatings so
as to be removable. Fig. 1I shows one where the coat-
ings have been made thick and stiff to facilitate their re-
moval.
A jar may be arranged more simply by attaching a ball
of tin foil refuse to the lower end of the rod so that it
will rest on the bottom of the jar and form the inner
coating.
For the outer coating thin sheet metal or foil may be
wrapped around the jar and tied with thread.
Place a board on several glass tumblers thus making
an insulated stand. Place jar on stand.
Charge the jar. Lift out the rod and inner coating-
being careful not to come within sparking distance of
the outer coating-and place on board. Now lift the
jar from the outer coating and place on board.
In each of these contacts a very slight shock will be re-
ceived by the hand.
A test of the two coatings will show that they are
neutral, as is natural since any charge on them would
be neutralized by touching them by the hand.
1
Replace the jar in its coating, and put the inner coat-
ing in place. Discharge the jar by making contact be-
tween the coatings, and it will be seen that there is nearly
as much electricity in the jar now as if the coatings had
not been disturbed.
It is evident then that when the inner and outer coat-
ings were removed that the electricity in the jar was not.
disturbed, for the outer charge remained bound after
the inner coating was removed.
We explain this by saying that the charges are really
46
ELECTRIC RAILROADING
on the inner and outer surfaces of the glass and that the
tin foil is only a means of getting the charge to the glass.
When we took the jar apart the slight shocks were due
to leaks, but the main charges stayed on the glass.
Question 45. Could the glass be discharged while out
of its coatings?
Answer. Yes, by connecting inside and outside by a
broad strip of tin foil. Doing this as if you were trying
to wipe off the charge.
Holding the glass under a tap and running water over
it will instantly discharge it.
Question 46. Will you get a spark by this discharge?
Answer. It depends. If you make a broad contact at
first you will not, because the charge flows over such a
large surface. If you get a spark it is a feeble one for
the glass being an insulator it cannot rush to the point of
discharge quickly enough to make a heavy spark.
Question 47. Do the foil coatings enable a spark to be
obtained?
Answer. Yes, without them the discharge is a fast
leak; with them the charge can rush through the con-
ducting coatings to the discharging tongs and the dis-
charge is a quick snappy one.
Question 48. Why will a leyden jar give a second
spark a few seconds after being discharged?
Answer. We believe that the charges penetrate the
glass to a certain extent and the first spark discharges all
the charge on the surface of the glass, but it is over be-
fore the charge which soaked into the glass has time to
escape.
The second time the jar is discharged we allow this
residual charge, which has come back to the surface, a
STATIC ELECTRICITY
47
chance to escape. This second spark is very much weaker
than the first one.
Question 49. What is meant by saying that the dis-
charge of a leyden jar is oscillatory?
Answer. In the first place the spark or discharge is
not instantaneous although very quick. This can be
shown by flashing a spark at some gunpowder, it will not
explode, but insert a piece of wet string about a foot long
in the wire leading up to the spark gap and the spark
will be forced to travel slower. It will then in its slower
movement heat up the gunpowder and ignite it.
But this is not all. The spark as we call it, whether it
be a fast or slow one, is not a single spark, but a series
of sparks.
There are always a great number of them jumping
in alternate directions, each weaker than the last until
they are too feeble to jump across the gap. The electric-
ity which forms the spark surges or oscillates between the
sparking points.
The sudden emptying of a barrel of water in a tank.
will cause the water in tank to surge back and forth, in
waves, each successive one being smaller, until the whole
mass settles down and becomes quiet.*
The action of a pendulum set in motion and gradually
coming to rest illustrates the action also, provided you
imagine the pendulum moving at a furious speed.
LESSON 4.
CONDENSERS.
Question 1. Why is a leyden jar often referred to as
a condenser ?
Answer. Because that is the general name for ap-
paratus designed to collect charges of electricity.
Question 2. What is a condenser?
Answer. A condenser consists of two metal plates
separated by an insulator.
Question 3. What is the dielectric of a condenser?
Answer. It is the special name given to the insulator
of a condenser.
Question 4. Explain the action of a condenser.
Answer. If a pane of glass be set on edge and a
piece of tin foil pasted on one side it will have a certain
capacity for electricity, but if another piece is pasted on
the other side and charged with the opposite kind of
electricity then the first piece will have a greater capac-
ity. It is as if this arrangement could condense elec-
tricity, that is get more in the same space.
Question 5. What is meant by capacity?
Answer. A piece of tin foil could have its charge in-
creased until the leakage equalled the amount put on, then
we might say that it was full, and that the amount on it
was its capacity. Since this amount would vary with the
dampness of the air, the temperature of the tin foil, and
the rate at which you added electricity, a more definite
way has been adopted to define Capacity,
48
CONDENSERS
49
A certain pressure is called a volt. We apply electric-
ity to the condenser increasing the pressure until it be-
comes one volt, then we say the condenser is full enough
and the charge then in it is said to be the capacity of the
condenser.
Question 6. On what does the capacity of a condenser
depend?'
Answer. On three things:-
I. The area of the metal part.
2. The thinness of the dielectric.
3. The kind of dielectric.
Question 7. Does not the kind of metal used or its
thickness affect the capacity?
Answer. No, only the area. The greater the area the
greater the capacity.
Question 8. Why is it that the thinness of the dielec-
tric affects the capacity?
Answer.
Because the thinner the dielectric the nearer
the metal portions are to each other and so the electri-
cal action between the charges is greater.
Question 9. Why should the material used as a
dielectric affect the capacity?
Answer. Exactly why is not known, but it is a fact
that the electric action takes place through the same
thickness of different materials with more or less strength
according to the material.
Question 10.
What is the metal portion of a condenser
usually made of?
Answer. It is always made of tin foil, for it is thin
and hence light in weight for large areas.
Question II. What is used generally as a dielectric?
Answer. For condensers used in commercial work,
paper soaked in paraffin is used while for standard con-

50
ELECTRIC RAILROADING
densers used in laboratories to test others, mica split into
thin sheets is used.
Question 12. What are the advantages of the paper
condensers, as they are called?
Answer. They are cheap to make, light in weight
and good enough for many purposes.
Question 13. What are the objections to paper con-
densers?
Fig. 12. Paper Condenser.
Fig. 13. Mica Condenser.
Answer. They cannot hold a charge as long as a mical
condenser, as the insulation is not so good. They leak
considerably, that is the charge leaks from foil to foil,
thus discharging the condenser. If rapidly charged and
discharged the paraffin is heated and may soften or even
melt.
Question 14. What are the advantages of the mica
condensers?
Answer. They hold their charge without leaking for
a long time, rapid charge and discharge does not heat
them much, and even so mica is not affected by tempera-
tures at which paraffin would liquefy. Their capacity
is great, so a mica condenser is smaller than a paper
one of the same capacity.
Question 15. What are the objections to mica con-
densers?
CONDENSERS
51
1
Answer. They are expensive, and while small in size
are very heavy.
Question 16. How would the capacities of three simi-
lar condensers of mica, paraffined paper, and glass com-
pare?
Answer. Selecting a condenser with air for a dielec-
tric as a standard because it is the poorest condenser of
all, the mica is the best being six to eight times as good
as the air condenser. The glass one would be three
times as good as the air one. The paraffined paper
dielectric makes the poorest condenser being only twice
as good as air.
It must be remembered that some mica, such as used
in oil and gas stoves is worthless as a dielectric, as it
has fine lines of metal running through it, and hence is a
conductor.
Some grades of glass are also almost useless for a con-
denser.
Question 17. What is the standard capacity?
Answer. The scientists' standard was a metal sphere
of 1 cm radius perfectly isolated and insulated.
This capacity is so absurdly large that all electricians
used as a standard a unit which is 1-900000 of the other.
This unit is called a microfarad (abbreviated m. f.) and
is now used by scientists and electricians.
Question 18. How big a condenser is a microfarad?
Answer. A mica condenser containing 3600 square
inches of tin foil.
Question 19. How is a paper condenser made?
*The centimeter (abbreviated cm) is the 1/100 part of the
French standard length called the meter. A meter is approxi-
mately 39.3 inches, so a centimeter is about 0.4 inches and
there are roughly 2½ cm. to one inch.
52
ELECTRIC RAILROADING
Answer. The finest and thinnest linen paper is ex-
amined to be sure that it is free from small holes, the
tiniest hole causes a sheet to be rejected.
They are then dried and warmed, dipped in a bath of
melted paraffin, from which all water has been extracted,
and allowed to drain and cool.
A pile is made of alternate sheets of tin foil and paper.
The papers are placed with all their edges even, but each
alternate foil projects on the same side of the pile. The
first, third, fifth foils project to the right and all the even
numbered foils project to the left.
Each set are all connected together, and the whole mass
clamped tightly and put in a case for. protection.
Binding posts are connected to each set of foils.
Question 20. What name is given to the quality of
a dielectric?
Answer. Dielectric capacity or specific inductive
capacity is the name used.
Question 21. What is the standard of dielectric ca-
pacity?
Answer. Perfectly dry air at normal pressure and
temperature of o° Centigrade is said to have a dielec-
tric capacity of 1.
Question 22.
terials measured?
How is the dielectric capacity of ma-
Answer. By comparing them with air. Air has the
least value as a dielectric, so other materials are said to
*The Fahrenheit thermometer is the standard throughout the
business and social life of the United States and Great Britain.
The temperature of freezing water is called 32 degrees and
that of boiling water 212 degrees. The range between these
temperatures is divided into 180 equal parts, numbered con-
secutively from 33 to 211, and as far below 32 and above 212
CONDENSERS
53
as is needed these equal divisions are carried. If carried below
o, we read the temperatures as minus 1, minus 2, or 1 below
zero, 2 below zero; and we write them -1, -2.
In scientific work all over the world, the thermometers are
marked differently.
The freezing point of water is marked o and the boiling
point of water 100, and the space between into 100 equal parts.
These divisions are carried down below the zero and above.
the 100 mark.
This thermometer was introduced by a man named Celcius,
but is named Centigrade because it has 100 steps between
freezing and boiling points. (Centum is 100 in Latin and
gradus means step.)
Since 100° Cent. 212° Fah.
and 。° Cent. =
then 100° Cent. =
:
32° Fah.
180° Fah.
and I Cent. degree 1.8 Fah. degree.
To change Centigrade readings to Fahrenheit:
Multiply by 1.8 and add 32.
Ex.-A room whose temperature is 21° C. is 69°.2 Fah.
21 X 1.8 37.2 + 32 = 69.2.
=
To change from Fahrenheit to Centigrade:
Subtract 32. Multiply by 5 and divide by 9.
A room which is 70° Fah. is also 21° (approx.) Cent.
70—32=38
The mark
38 X 5190
190921°.1 Cent..
means degree and the abbreviation C. or Fah.
after it tells the kind of degree.
When a decimal fraction is written it is always thus: 7°.2,
so that should the decimal point be forgotten or not written
clearly it can not be mistaken for 72°.
Also when a fraction of a degree is written it is thus: 0°.5,
so that we may know that it is five-tenths of a degree and not
5 degrees even if decimal point is not there.
The o is placed there to show that it really is five-tenths and
that some figure has not been forgotten.
It might be that 2°.5 was meant and °.5 written by an omis-
sion. By writing o°.5 the writer shows he has not forgotten a
figure.
54
ELECTRIC RAILROADING
have a dielectric capacity of 2 or 3 as the case may be, if
they are twice or three times as good as air, when used
in a condenser.
Question 23. Has capacity any effect on commercial
work?
Answer. Yes a great deal.
Question 24. Mention some effects.
Answer. In sending alternating currents through a
long line the presence of capacity may help to neutral-
ize some of the bad effects of coils of wire in the circuit.*
Also in telephone lines the presence of much capacity
is exceedingly bad, making the transmission of the voice.
difficult and producing a tinny tone.
For this reason paper insulation is used in telephone
cables, rather than rubber. The latter has a much higher
dielectric capacity, making the cable a better condenser
and a worse telephone line.
Question 25. Are there any other effects?
Answer. Yes. The capacity of long telegraph lines
makes signalling very slow; for the line has to be filled.
up each time before the signal will be transmitted, and
it has to empty itself before the next signal can begin.
Long submarine cables are especially troubled this
way.
The wire inside and the water outside are the two
conductors and the gutta percha† insulation is the
dielectric. This makes a condenser.
* A circuit is the path of the current from the battery or
generator out and back again to the starting point. By line
we often mean the same thing.
† Gutta percha is a gum something like rubber but a better
insulator, less dielectric capacity, less likely to deteriorate
with age, and can stand more moisture. It is injured by light,
and should never be used in a light, hot, dry place. It is
CONDENSERS
55
}

ell
To Circuit
To Circuit
1
Fig. 14. Two Condensers wired so as to be in Parallel.
One of the Atlantic cables has a capacity of about
1000 m. f. (microfarads). This makes the signalling
very slow and limits the amount of business that can be
transacted per hour.
easily softened by placing in hot water.
rubber and a piece of it will usually float.
It is lighter than
It is used chiefly as an insulator in ocean cables.
56
ELECTRIC RAILROADING
The operators can send faster than the cable can take;
that is if the operators went as fast as they could, the
signals would jumble up and be unintelligible at receiving
end.
Question 26. How are condensers used in commercial
work?
Answer. In ocean cable telegraphy a condenser is
often put in at each end, which by absorbing the electric-
ity on the opening of the circuit and giving it out on the
closing of the circuit, help the battery to fill the cable on
the close of the telegraph key, and help to stop the elec-
trical flow when key is opened.

+
Kr
K₂
2
Fig. 15. Diagram of Two Condensers connected in Parallel. The
black lines represent the sheets of tin foil.
In ordinary telegraphy when sending two or four mes-
sages over the same wire at the same time, an artificial
line must be formed which is electrically exactly like the
real line. Coils of wire give the resistance of the actual
line, and condensers its capacity.
Question 27. How can two condensers be used as one
large condenser?
Answer. As in Fig. 14, connect a wire from one bind-
ing post of the first condenser to either binding post of
the other condenser. Connect the other two posts by a
wire. Connect the wires of the circuit, one to each of
the wires joining the condensers.
CONDENSERS
57
A convenient way of attaching the wires of the circuit
is to loosen up both binding posts on the one condenser;
slip the circuit wires under and tighten up again.
To Circuit

еее
To Circuit
مود
Fig. 16. Two Condensers in Series.
Question 28. What is the actual capacity of two con-
densers connected in parallel?
Answer. The capacity of this arrangement is the
sum of the two capacities.
Fig. 17.
-V---

K₂
K₂
Diagram of Two Condensers in Series. K, is supposed to
have a greater capacity than K The dotted lines
show where to connect voltmeters V, & V₂ 2
to read pressure of condensers.
Question 29. Suppose you connect the circuit (or
line) through the two condensers?
Answer. If as shown in Fig. 16 you bring a line wire
to one binding post of the first condenser, and the other
58
ELECTRIC RAILROADING
line wire to a post of the other condenser, and join the
other two posts with a wire you will have them in series.
Question 30. What is the capacity of two condensers
in series?
Answer. The actual capacity of the two in series will be
the product of the two divided by their sum.
Calling C, and C, the capacities of the condensers, the
C₁XC2
joint or combined capacity will be expressed as C₁+C₂
Ex.:-A 2 m f and a 3 m f condenser are connected in
series. What is capacity of combination?
C₁XC2 2X8 6
C₁+C₂ 2+3 5
-1.2 m f.
You will notice that the capacity of the two wired up
in this way is less than the capacity of either.
Question 31. Suppose you connect three condensers or
even more in parallel. What is their joint capacity?
Answer. The sum of their separate capacities.
Question 32. Suppose you connect three or more con-
densers in series, or as it is sometimes called in cascade.
What is their joint capacity?
Answer. Divide each separate capacity into I add the
answers and divide this into 1. Result is joint capacity.
Suppose three condensers have capacities of ½, 3 and
5 mf.
½ into 1 goes 2 equals
30
5
3 into 1 goes
equals TT
5 into 1 goes
equals r
Sum
38
15
&
1 5
Τ into 1 goes 3 times.
5
1 or 0.4 (approx) m f.
Question 33. Describe an experiment showing how a
condenser works,
CONDENSERS
59
Answer. Suppose as in Fig. 18 we have two metal
disks A and B insulated by glass supports, with a sheet
of glass or mica between them.
Let B be connected by a wire to the knob of an electric
machine and let A be joined to a gas or water pipe by a
wire; thus connecting it to ground or earth.
The charge from machine will act by induction
across the dielectric C, on A and repel + to earth, leav-
ing the disk Aly charged.
This
charge will react on B and draw more + from
the machine.
B
H|H


Fig. 18. A Condenser arranged so as to use different dielectrics at
C, and with plates A & B movable.
The nearer A and B are together the better the in-
duction acts and the more electricity will be condensed.
If the wires be removed from A and B and the disks
drawn apart, the pith balls will fly out showing that there.
is more electricity "free" to act than before.
We ought not to say more electricity is present, it is
simply more "free"; for the two charges will not hold
each other so "bound" at the greater distance. This
freed electricity spreads over the plate and balls. When
the disks approach each other again this free electricity is
drawn back to the plates and held bound. Hence the
pith balls become discharged or nearly so and fall,
LESSON 5.
ELECTRICAL MACHINES.
Question 1. What is an electrical machine?
Answer. Used in this sense the words mean any of
the machines capable of producing static electricity.
Question 2. Describe the simplest machine.
Answer. The simplest machine is a friction machine.
A circular glass plate is mounted on an axle and arranged.
so as to be turned rapidly by belt and pulley. See Fig. 19.
At the top and bottom of plate a cushion of curled hair
covered with leather is bent around so as to squeeze the
plate. Light springs keep these cushions in firm contact.
At both sides of the plate is a set of spikes nearly
touching the plate both on the back and the front. A con-
ductor connects the two sets of spikes. A wire from this
conductor leads to a metal knob or club which is called
the prime conductor.
The two cushions are connected by a wire, and this in
turn to the ground.
A silk bag or flap runs from the cushion or rubber to
the spikes or comb. Both the rubber and the comb are
insulated by glass supports.
The rubber has a thin layer of tallow spread on it and
some powdered electrical amalgam sprinkled on. They
are then pressed against the glass and the springs ad-
justed to keep them there.
When the plate is rapidly revolved the friction between
the glass and the amalgam coated surface of the rubber
60

ELECTRICAL MACHINES
61
produces electrification; a + charge on the glass and a
charge on the rubber.
Positive electricity flows from earth to the rubber and
neutralizes its charge. In fact the ground wire keeps the
rubber continually neutral.
*
Fig. 19. Simple Electrical Machine.
The charge is carried around on the glass in front
of the comb which is connected with the prime conductor
repelling a charge to the knob of the conductor and
attracting the into the comb. The effect of the spikes
is to emit a -ly charged electrical wind which neutral-
izes the glass plate and prepares it for the action of the
next rubber and at the same time leaves the prime con
ductor +ly charged.
Question 3. What is electrical amalgam?
Answer. One ounce of tin and one ounce of zinc are

62
ELECTRIC RAILROADING
melted together and while melted four ounces of mercury
are stirred in. When cool the mass is powdered and
sifted. It may be sprinkled on the rubber from a salt
shaker.
Question 4. Why is this amalgam used?
Answer. It produces a better charge than any other
substance and moreover, by being a conductor helps the
prompt neutralization of the rubber, which also tends to
make the charge on the glass plate larger.
Fig. 20. Electrical Winds.
Question 5. Is the use of this amalgam necessary?
Answer. No. Powdered graphite will work very well.
Simply rub it into the leather of the cushion. Of course
omit the tallowing.
Question 6. What is an electrical wind?
Answer. It has been found that electricity leaks from
sharp cornered bodies like a cube faster than from
rounded ones like a ball. From sharp pointed bodies it
leaks so fast as to actually produce a brisk air current.
If a needle be fastened to the prime conductor and a
lighted candle held near the needle the wind rushing off
the needle will blow the candle flame aside. See Fig. 20.
The wind can also be plainly felt by the hand.
ELECTRICAL MACHINES-
63
Question 7. Why does the candle on the knob get
blown in the opposite direction?
Answer. Because now the wind is caused by the op-
posite kind of electricity flowing off the needle to the
knob.
The wind is always blowing off the point.
Question 8. What are the silk bags for?
Answer. The silk being an insulator prevents the +
charge on the glass from leaking off into the air before
it arrives at the comb.
It is believed by many that the air currents produced
by the swiftly moving plate, electrifying the silk nega-
tively and being a non-conductor, it is imperfectly neu-
tralized by any ground connection that may happen to
exist, so there is always a charge on the silk to "bind"
the charge on the glass.
This action is not strong enough to interfere with the
effect of the negative wind at the comb.
Question 9. Are not frictional machines generally un-
reliable?
Answer. Yes. Dampness and dust may prevent them
from working. Glass attracts moisture so that the ma-
chines always have to be heated to dry them before use.
The amalgam will need renewing before use if the
machine has been standing idle for a couple of months.
Question 10. Is there another type of electrical ma-
chine more reliable?
Answer. Yes, the influence machine.
reliable.
These are very
Question II. What principle do they involve?
Answer. The principle of charging induction or in-
fluence, and of doubling up charges.
64
ELECTRIC RAILROADING
Question 12. Explain what is meant by charging by
influence?
Answer. A body touched while under the influence of
a charge acquires a charge of the opposite kind.
Question 13. What is meant by doubling up charge?
Answer. Suppose one (A) of two insulated conduc-
tors (A and B) is charged ever so little with say + elec-
tricity. Let a third insulated conductor, which we will
call a carrier be arranged so as to move back and forth
between A and B.
Let C be touched with finger while near A.
It will acquire a small
charge. Move it over and
make contact with B which will receive some elec-
tricity. Move C a short distance from B and touch it.
C will acquire a + charge by influence.
Move C over to A and let them make contact which
will give some more + electricity to A. Move C away a
short distance and touch it. This charges C with elec-
tricity. Move C over to B and make contact which in-
creases the charge on B.
Keep this up and the charges on A and B keep increas-
ing and by acting more strongly on C they make the in-
crease a rapid one.
Question 14. What machines work on these princi-
ples?
Answer. The Toepler machine which has been per-
fected by Holtz and Voss, and the Wimshurst machine.
Question 15. Describe the Toepler machine.
Answer. The principle of the machine is described by
Silvanus Thompson.
Before describing some special forms we will deal with
a generalized type of machine having two fixed field-
ELECTRICAL MACHINES
65
plates, A and B, which are to become respectively + and
, and a set of carriers, attached to a rotating disk or
armature. Figure 21 gives in a diagrammatic way a view
of the essential parts. For convenience of drawing it is
shown as if the metal field-plates A and B were affixed
to the outside of an outer stationary cylinder of glass;

X
X
n
αι q
B
Fig. 21.
+
A
+
Cr
น
X
×
X
ta
D
72
S
Diagram to show the principles upon which the Toepler
Machine operates.
the six carriers p, q, r, s, t, and u being attached to the
inside of an inner rotating cylinder. The essential parts.
then are as follows:
(1)
A pair of field-plates A and B.
(II) A set of rotating carriers p, q, r, s, t, and u.
(III) A pair of neutralizing brushes n,, n, made
of flexible metal wires, the function of
which is to touch the carriers while they
are under the influence of the field-plates.
They are connected together by a diagonal
conductor, which need not be insulated.
66
ELECTRIC RAILROADING
(IV) A pair of appropriating brushes a,, a,, which
reach over from the field-plates to appro-
that are conveyed
priate the charges that
around by the carriers, and impart them to
the field-plates.
(V) In addition to the above, which are sufficient
to constitute a complete self-exciting ma-
1
chine, it is usual to add a discharging ap-
paratus, consisting of two combs c₁, c₂, to
collect any unappropriated charges from
the carriers after they have passed the ap-
propriating brushes; these combs being
.connected to the adjustable discharging
balls at D.
The operation of the machine is as follows. The neu-
tralizing brushes are set so as to touch the moving car-
riers just before they pass out of the influence of the field-'
plates. Suppose the field-plate A to be charged ever so
little positively, then the carrier p, touched by n, just as it
passes, will acquire a slight negative charge, which it will
convey forward to the appropriating brush a₁, and will
thus make B slightly negative. Each of the carriers as it
passes to the right over the top will do the same thing..
Similarly each of the carriers as it passes from right to
left at the lower side will be touched by n, while under
the influence of the charge on B, and will convey a
small charge to A through the appropriating brush a,.
In this way A will rapidly become more and more +,
and B more and more ; and the more highly charged
they become, the more do the collecting combs c₁ and c₂
receive of unappropriated charges. Sparks will snap
across between the discharging knobs at D.
ELECTRICAL MACHINES
ст
2
The machine will not be self-exciting unless there is a
good metallic contact made by the neutralizing brushes
and by the appropriating brushes. If the discharging
apparatus were fitted at C₁, C₂ with contact brushes in-
stead of spiked combs, the machine would be liable to lose
the charge of the field-plates, or even to have their
charges reversed in sign whenever a large spark was
taken from the knobs.
It will be noticed that there are two thicknesses of glass
between the fixed field-plates and the rotating carriers.
The glass serves not only to hold the metal parts, but
prevents the possibility of back-discharges (by sparks or
winds) from the carriers to the field-plates as they pass.
Toepler's Influence Machine.-In this machine, as con-
structed by Voss, are embodied various points due to
Holtz and others. Its construction follows almost literally
the diagram already explained, but instead of having two
cylinders, one inside the other, it has two flat disks of
varnished glass, one fixed, the other slightly smaller ro-
tating in front of it (Fig. 22). The field-plates A and B
consist of pieces of tinfoil, cemented on the back of the
back disk, each protected by a coating of varnished paper.
The carriers are small disks or sectors of tinfoil, to the
number of six or eight, cemented to the front of the front
disk. To prevent them from being worn away by rubbing
against the brushes a small metallic button is attached to
the middle of each. The neutralizing brushes n,, n, are
small whisps of fine springy brass wire, and are mounted
on the ends of a diagonal conductor Z. The appropriat-
ing brushes a₁, a, are also of thin brass wire, and are
fastened to clamps projecting from the edge of the fixed
disk, so that they communicate metallically with the two

68
ELECTRIC RAILROADING
field-plates. The collecting combs, which have brass spikes
so short as not to touch the carriers, are mounted on in-
sulating pillars and are connected to the adjustable dis-
charging knobs D₁, D. These also communicate with
J₁
J
S
E
2
155
Ja
B
BACK FIXED DISK WITH
FIELD PLATES ON BACK.
FRONT ROTATING DISK
WITH CARRIERS ON FRONT.
Fig. 22. A Toepler Electrical Machine.
the two small Leyden jars J, J2, the function of which
is to accumulate the charges before any discharge takes
place. These jars are separately depicted in Fig. 22.
Without them, the discharges between the knobs take
ELECTRICAL MACHINES
69
place in frequent thin blue sparks. With them the sparks
are less numerous, but more brilliant and noisy.-
To use the Toepler (Voss) machine first see that all the
four brushes are so set as to make good metallic contact
with the carriers as they move past, and that the neutral-
izing brushes are set so as to touch the carriers while
under influence. Then see that the discharging knobs
are drawn widely apart. If it is clean it should excite
itself after a couple of turns, and will emit a gentle hiss-
ing sound, due to internal discharges (visible as blue
glimmers in the dark), and will offer more resistance to
turning. If then the knobs are pushed nearer together
sparks will pass across between them. The jars (the ad-
dition of which we owe to Holtz) should be kept free
from dust. Sometimes a pair of terminal screws are
added at S₁, S₂ (Fig. 22) connected respectively with the
outer coatings of the jars. These are convenient for at-
taching wires to lead away discharges for experiments at
a distance. If not so used they should be joined together
by a short wire, as the two jars will not work properly
unless their outer coatings are connected.
Question 16. Describe the Wimshurst machine.
Answer. Silvanus Thompson describes it as follows:
In this, the most widely used of influence machines,
there are no fixed field-plates. In its simplest form it con-
sists of (Fig. 23) two circular plates of varnished glass,
which are geared to rotate in opposite directions. A num-
ber of sectors of metal foil are cemented to the front of
the front plate and to the back of the back plate; these
sectors serve both as carriers and as inductors. Across
the front is fixed an uninsulated diagonal conductor,
carrying at its ends neutralizing brushes, which

70
ELECTRIC RAILROADING
touch the front sectors as they pass. Across the
back, but sloping the other way, is a second diag-
onal conductor, with brushes that touch the sec-
FRIMBAULT
Fig. 23. A Wimshurst Electrical Machine.
tors on the hinder plate. Nothing more than this is
needed for the 'machine to excite itself when set in rota-
tion; but for convenience there is added a collecting and
discharging apparatus. This consists of two pairs of in-
sulated combs, each pair having its spikes turned inwards
ELECTRICAL MACHINES
71
toward the revolving disks, but not touching them; one
pair being on the right, the other on the left, mounted
each on an insulating pillar of ebonite. These collectors
are furnished with a pair of adjustable discharging knobs
overhead; and sometimes a pair of Leyden jars is added,
to prevent the sparks from passing until considerable
quantities of charge have been collected.

ДАЛДА
++
+
گ
Fig. 24.
*
123
+
The Wimshurst Machine laid out in diagrammatic way, to
show principle of its operation.
The processes that occur in this machine are best ex-
plained by aid of a diagram (Fig. 24), in which, for
greater clearness, the two rotating plates are represented
as though they were two cylinders of glass, rotating op-
posite ways, one inside the other. The inner cylinder will
72
ELECTRIC RAILROADING
•
represent the front plate, the outer the back plate. In
Figs. 23 and 24 the front plate rotates right-handedly, the
back plate left-handedly. The neutralizing brushes n₁,
n, touch the front sectors, while n,, n, touch against the
back sectors.
Now suppose any one of the back sectors represented
near the top of the diagram to receive a slight positive
charge. As it is moved onward toward the left it will
come opposite the place where one of the front sectors.
is moving past the brush n₁. The result will be that the
sector so touched while under influence by n, will acquire
a slight negative charge, which it will carry onward
toward the right. When this negatively-charged front
sector arrives at a point opposite n, it acts inductively on
the back sector which is being touched by n,; hence this
back sector will in turn acquire a positive charge, which
it will carry over to the left. In this way all the sectors
will become more and more highly charged, the front
sectors carrying over negative charges from left to right,
and the back sectors carrying over positive charges from
right to left. At the lower half of the diagram a similar
but inverse set of operations will be taking place. For
when n₁ touches a. front sector under the influence of a
positive back sector, a repelled charge will travel along
the diagonal conductor to n,, helping to charge positively
the sector which it touches. The front sectors, as they
pass from right to left (in the lower half), will carry
positive charges, while the back sectors, after touching n,,
will carry negative charges from left to right. The
metal sectors then act both as carriers and as inductors.
It is clear that there will be a continual carrying of posi-
tive charges toward the right, and of negative charges to
the left. At these points, toward which the opposite kind

ELECTRICAL MACHINES
73
of charges travel, are placed the collecting combs com-
municating with the discharging knobs. The latter ought
to be opened wide apart when starting the machine, and
moved together after it has excited itself.
Fig. 25. Electrical Wheel.
In larger Wimshurst influence machines two, three, or
more pairs of oppositely-rotating plates are mounted
within a glass case to keep off the dust. If the neutraliz-
ing brushes make good metallic contact these machines
are all self-exciting in all weathers. Machines with only
six or eight sectors on each plate give longer sparks, but
less frequently than those that have a greater number.
Mr. Wimshurst has designed many influence machines,
from small ones with disks 2 inches across up to that at
South Kensington which has plates 7 feet in diameter.

74
ELECTRIC RAILROADING
Prior to Wimshurst's machine Holtz had constructed
one with two oppositely-rotating glass disks; but they had
no metal carriers upon them. It was not self-exciting.
Question 17. Give some experiments showing the ac-
tion of electricity.
Answer. Example 1. If a pivot be erected on the
knob of an electric machine and a small wheel with wire
spokes bent as shown in Fig. 25 is balanced on the pivot,
the electrical winds coming from the pointed ends will
drive the wheel around.
Fig. 26. Puncturing a Card with Spark from a Leyden Jar.
Example 2. A card may be punctured as shown in
Fig. 26. There will be a burr on both sides of the hole in
the card as if the material were pulled out from the card
on both sides at the same time.

ELECTRICAL MACHINES
75
Example 3. A fine wire melted as shown in Fig. 27.
Example 4. When an electrical machine is actuated in
the dark, accompanying the slight crackling which indi-
cates leaking, at several points on the frame may be seen
luminous appearances, called brushes; and if a conductor,
a wire, or the hand, be presented toward the terminal of
NAMBERT.
Fig. 27. Melting a Wire with a Battery of Leyden Jars.
the machine, just beyond the striking distance of a spark,
one of these brushes will reach for the object so pre-
sented. The brush discharge consists of a short stalk,
from which spreads a shape not unlike a palm leaf fan,
consisting of rays which become thinner and lighter
towards their outer extremity.
76
ELECTRIC RAILROADING
1
Example 5. If a doll's head having hair, be placed on
the terminal of the machine, and the machine actuated,
the hair will tend to straighten out in all directions, and
will reach for the hand or other conductor presented.
Discharging the machine by placing its terminals in con-
tact, will restore the hair to its normal condition.
-
Example 6. A human leyden jar may be made by a
person occupying a stool or chair, the legs of which are
standing in dry India rubber overshoes, in tumblers, or in
telegraph insulators. In this position the human leyden
jar is capable of being charged, and of giving shocks to
parties standing on the floor or ground. The hair of the
human jar will stand on end if the charge is considerable,
and be attracted by the approach of any conductor. The
charge may be silently discharged through a fork or
needle held in the hand.
Example 7. Attach a rod or heavy wire to the terminal
of the machine, having the curved shape of a shower bath
standard, and terminating in a metal band, the lower edge
of which is fitted with points like an inverted crown. One
sitting or standing beneath such an attachment will feel a
very perceptible breeze.
Example 8. Approach the knob of a machine with a
sharp needle held in the hand, and the discharge will be
noiseless and not unpleasant. If in a darkened room, the
discharge will be seen to resemble a blue flame.
Question 18. It is said that static electricity is only
on the surface of charged bodies. Is this true?
Answer. Yes, as is shown by this experiment.
On the top of a rod of glass which is fastened to a
sufficiently heavy base, a brass ring is fixed in a vertical
position. To this ring, much like a minnow or landing or

ELECTRICAL MACHINES
77
butterfly net frame, is attached a fine linen bag, which
runs down to a point-like an elongated cone. A silk
thread extends from the apex or point of the cone, in
each direction, so that the bag may be reversed at will by
pulling on the one thread and loosing the other. Now,
when this bag is charged a test shows electricity on the
outside, and none on the inside of the net, in all cases.
Reversing the bag reverses the surface electrified, no
matter how often or how suddenly the change is made.
See Fig. 28.
Fig. 28. Static Electricity always stays on Outside of Body.
Question 19. Is the charge spread evenly over the
whole surface?
Answer. No. The density of electricity residing on
the surface of a conductor sufficiently removed from
bodies affecting it as to be uninfluenced by them, is ma-
terially dependent as to distribution, on the shape of the
charged body. For instance, a perfect metallic sphere

78
ELECTRIC RAILROADING
shows the same electrical density over all portions of its
surface, and while the charge of a metallic disc is hardly
appreciable on the two surfaces, yet close to the edges
it increases rapidly to the outer limit of the body. See
Fig. 29.
1
2
Fig. 29. Distribution of Electrical Charge over the surface of a body,
showing influence of edges and points.
A A A
ΙΛΛ
Fig. 30. Charge on a Conductor.
Shows Density at Different Points.
This density increases at all pointed as well as rounded
extremities. The density is greatest on the most pro-
ELECTRICAL MACHINES
79
jecting parts of the surface, or those which have the
sharpest convexity, while hollows and indentations show
little or no charge. In consequence of this strain, at a
sharp projection on a charged conductor, or still more
markedly, at a point, as in a sharpened wire, the con-
densation of such an amount of force within such small
space produces a very rapid escape of electricity from
such points. For this reason conductors which it is de-
sired should retain their charge should have no edges or
points, and must be very smooth. This is why the termi-
nals of leyden jars and other similar apparatus are in the
form of knobs and the combs of electrical machines are,
like lightning rods, pointed, to facilitate silent, rapid
leaking.
The density of the charge is also shown by the relative
repulsion of the pith balls at different points on the sur-
face, as in Fig. 30.
LESSON 6.
LIGHTNING.
ATMOSPHERIC ELECTRICITY.
The similarity in the effects of lightning and those of
the electric spark enlisted the minds of the earliest phys-
ical investigators. Lightning ruptures and disintegrates
substances opposing its passage, and where these are com-
bustible, often ignites them. It is capable of producing all
the effects of heat in melting metals, and volatilizing them,
, and leaves behind it, in many instances, the odor which
we recognize as that pertaining to ozone. This odor is
the same that is observed when an electrical machine has
been working a few minutes. To Franklin is given the
credit of thoroughly identifying the phenomena of prov-
ing experimentally with his historic kite, and the aid of
leyden jars, that, excepting the factors of quantity and
intensity, the two were one.
Franklin enumerated the following specific character-
istics pertaining to, and tending to show that lightning
and the spark were but different manifestations of static
electricity: "Giving light; color of the light; crooked di-
rection; swift motion; being conducted by metals; noise
in exploding; conductivity in water and ice; rending im-
perfect conductors; destroying animals; melting metals;
firing inflammable substances; sulphureous smell (ozone);
and similarity of appearance between the brush discharge
from the tips of masts and spars sometimes seen at sea,
80

LIGHTNING
81
called St. Elmo's fire by the sailors, and the slow escape
from points on an electrical machine or a leyden jar."
The cause of electrical charges in the atmosphere is un-
known, there are half a dozen explanations any one of
which or all may be correct.
A Brush Discharge of Lightning.
It is generally agreed, however, that the cause of light-
ning is the condensation of water vapor in clouds.
Thunder Storms.-One of the most interesting mani-
festations of statical electricity is the thunder shower
which is brought about in this way. Although bodies can-
82
ELECTRIC RAILROADING
not be charged throughout their substance, the electricity
being always on the surface of the body; yet clouds seem
to be electrified all the way through. This is because a
collection of little particles of water, like a rain cloud, can
have a charge on the surface of each particle.
As the particles of water fall by gravitation many touch
and unite, so that the charges of say eight small drops
are now in a drop weighing eight times as much, but
which has only half the surface of the eight, hence the
pressure is four times as large. This occurs in the follow-
ing manner:
Since the surface of a sphere is equal to the product of
the square of its diameter and the fraction twenty-two
sevenths and the volume of a sphere is equal to one-sixth
of the product of twenty-two sevenths and the cube of the
diameter, we can calculate as follows:
Eight spherical rain drops each 1 mil* in diameter have
a total surface of 25 sq. mils. They have a total volume
*NOTE. A mil is the name given in machine shops and in all
electrical work to one-thousandth of an inch.
The mathematical work of the above is here given in full.
Twenty-two sevenths is a convenient and quite accurate way
of expressing the number 3.1416.
Total surface of eight spheres
8 X 3.1416 X 1 X 1 = 25 sq. mils.
I
Total volume of eight spheres
8 × 0.166 X 3.1416 × 1 × 1 × 1 = 4.2 cu. mils.
X I X I X
Volume of the large sphere 4.2 cu. mils.
Diameter of large sphere is the cube root of
4.2 X 63.1416=8 mils.
Cube root of 82 mils.
Surface of large sphere
3.1416 X 2 X 2 = 12.5 sq. mils.
=
25 12.5 = 2.
So large sphere has only half surface of
eight small ones,
LIGHTNING
83
of 4.2 cu. mils. Now the sphere composed of the eight
drops has the same volume i. e. 4.2 cu. mils and we can
find its diameter from the rule: The diameter of a sphere
is the cube root of the continued product of its volume,
six, and seven twenty-seconds. Applying this we find the
diameter to be 2 mils, hence its surface is 12.5 sq. inils.
That is exactly one-half the surface of the eight separate
drops.
Therefore the eight charges having been squeezed into
the surface where only two were before, the pressure
must be four times as great.
By the repeated union of these larger drops, the pres-
sure becomes very high, and meanwhile the influence of
the charged cloud is to accumulate a charge of the oppo-
site name in the earth under the cloud. This in turn in-
creases the pressure. When finally the pressure gets high
enough the air is punctured, and the spark jumps between
earth and cloud. It literally punches a hole in the atmos-
phere and the inrush of air to fill the hole causes the loud
sounding thunder.
There are two kinds of atmospheric electricity different
enough to need different devices to guard against their
effects. Some forms of lightning arresters combine both
devices in the one piece of apparatus.
Lines are sometimes struck by lightning. This means
that an accumulation of electricity suddenly makes con-
nection with the line, discharging through it, its machin-
ery and instruments.
A stroke discharges violently and cannot be discharged
by degrees, for the line is not strained until the lightning
strikes.
Lines are often affected by "static," which means that
84
ELECTRIC RAILROADING
electricity has accumulated on the line until its pressure is
high enough to do damage when discharging along the
line through machinery, etc.
Static changes can accumulate on long open air lines as
well as on lead sheathed cables.
The cable insulator makes a dielectric and the lead
cover and copper conductor the two plates of a con-
denser.
In the open air line the two wires of the circuit form
the plates and the air between the dielectric. Also the
two wires together and the earth form two plates with
air as the dielectirc.
A transmission line 150 miles long may have a capacity
of 3 mf, i. e. I mf per 50 miles.
Both these effects, static and strokes are summed up in
the one word "lightning."
Static charges may be discharged little by little as they
accumulate, so that when properly protected a line never
´has a static charge on it great enough to do any damage.
STATIC EFFECTS ON CIRCUITS,
On high voltage alternating current lines not only light-
ning makes trouble but accidental grounds, and switching
operations some times cause "static effects."
This use of the word static is hardly a good one as
these effects are all due to a wave of electricity flowing
over the circuit. This wave is the flow of an electro-
static charge from one point of the circuit to another.
When a disturbance is created at any point of an elec-
tric circuit as the sudden opening of a field circuit, an arc
jumping across the lines, the release of a large "bound"
static charge, or the striking of lightning, etc., a set of
LIGHTNING
85
waves of electricity are started just as when a stone is
thrown into a narrow stream of smooth water.
Our troubles are caused by "static" electricity, but are
actually produced by the wave or surge following the dis-
turbance.
The damage done by a surge depends on the condition
of the circuit, whether dead,* live or loaded, the excel-
lence of its arresters in design and state of repair.
We will make this distinction between lightning and
other static troubles.
When we say lightning we mean an actual stroke and
its effects at the point of striking.
When we say surge we mean any or all static electrical
troubles on the lines at points where the lightning did not
strike.
Lightning can do damage by striking and producing
a surge at the same time.
A surge is electricity at very high pressure and very
great frequency; the normal current on a line is of mod-
erate pressure and low frequency.
The normal current is produced by the generators.
Surges may be produced by
I.
Switching off live lines from a station.
2. Switching on dead transmission lines, branch lines,
transformers, or underground cables to a station or to a
live line.
3. Short circuits which are sudden.
*A dead line is one not connected to any source of electricity.
A live line is one connected to a generator in operation or
another circuit and has pressure on it ready to deliver power.
When lamps, motors, etc., are connected to a live line it car-
ries the current to operate them and is called a loaded line.
{
86
ELECTRIC RAILROADING
4. Grounds or partial short circuits which occur sud-
denly.
5. Lightning stroke.
By high pressure we mean any pressure over 50%
greater than the line voltage.
Frequency is best explained as follows:
If the feed wire of a city trolley line be cut and a pres-
sure indicator inserted the pointer will stand rather steady
at about 500 volts. This shows a steady current.
If, however a feed cable from one of the main power
stations to a sub-station be cut and a pressure indicator
inserted (called an oscilligraph), the instrument will
show that the pressure is constantly and very rapidly
changing from a high value to a low one, then reversing
and going down to a high negative value and coming
back to zero.
The pressure keeps rising and falling and alternating
positive and negative.
It will make from 15 to 33 of these complete changes,
called cycles, every second. The frequency with which
these changes occur is called the frequency.
Frequency is then the number of cycles per second.
Take a transmission line delivering power at the dis-
tant end where the capacity is about 3 mf.
While this line is in operation supplying power, the cur-
rent varies, according to the load. When all the motors.
it supplies are stopped and all the transformers at the
other end are cut off there is no load but still about 50
amperes flow into the line.
This current is charging the line, that is, keeping up
the voltage of the line; for the line is a condenser and
takes current to charge it.

LIGHTNING
87
If a switch is opened when the line is loaded there
would be an arc formed at the switch blades on account
of the large current broken and the discharge of the line
itself.
A Lightning Stroke.
If a switch is opened when the line is simply alive, that
is, charged but not loaded, there is a slight arc at the
switch due to the discharge of the line.
If the generators are stopped and the line is "dead" of
course there is then no arc at the switch opening.
The arc formed by the opening of a loaded line allows
88
ELECTRIC RAILROADING
the line to discharge itself across the arc, but when the
switch to a live line is opened quickly the small arc dies
out, leaving the line lightly charged. The line will now
discharge itself at the weakest point along its insulation
unless provided with arresters to discharge it in a harm-
less manner.
The surge of the charge may raise the pressure on this
cut out* line to double the pressure of the generators. A
22000 volt line may rise to 44000 volts when suddenly
cut out.
When a single phase generator (See Lesson 28) is
grounded at one terminal and a "live" branch line con-
nected to its other terminal is cut at the switch-board the
pressure caused by the surge may rise to four times the
original pressure. So a 40000 volt line might have one of
its branch lines rise to 120000 volts.
The two cables from a single phase generator to the
switch board are called its terminals.
When a dead line is "cut in"* its capacity must be filled
up and there is a sudden rush of current into it. This
produces a surge along the line and when the line is
short the pressure may rise to double the normal pres-
sure. When the line is long it hardly ever rises to quite
double pressure.
It is interesting to know that the first dead line switched
on to the generators has the least rise in pressure, and the
last switched on the greatest. So the line with the weak-
est insulation or poorest arresters may be switched on
first.
*To cut in a line is to connect it to the generator or to the
main transmission line; to cut out is to disconnect it. A cut
out line is one which has been disconnected.
LIGHTNING
89
When a "dead" transformer is connected to a live line
there is a surge, and due to the choking effect of the coils
in the transformer, this surge only penetrates a short dis-
tance. The turns of wire near the end of a transformer
are insulated with extra thickness of material to protect
them, and arresters should be placed near each transform-
er to rid the line of the surge.
PROTECTION FROM LIGHTNING.
Persons.
Question 1. What precautions should people take dur-
ing lightning discharges?
Answer. Do not stand in the open doorway of a build-
ing or under a single tree in a field. Standing under a
group of trees is not so bad. Do not stand near a wire
fence.
Question 2. Won't steel articles attract lightning?
Answer. No, nothing attracts lightning, it merely goes
by the shortest path whose resistance is fairly low.
Question 3. Is not staying in a locomotive dangerous,
especially electric ones?
Answer. No, it is the safest place you can be, as the
metal is all around and acts as a shield, carrying the dis-
charge safely past the person.
Question 4. What is to be done to a person struck by
lightning?
Answer. Treated like a person who has been suffo-
cated, and artificial breathing begun at once, as follows:
Howard's method of producing artificial respiration.
has this advantage over other methods in that it can be
successfully practiced by a single person, instead of two,
and at the same time is equally efficacious,
!
90
ELECTRIC RAILROADING
"Place the subject on his back, head down and bent
backward, arms folded under the head (under no condi-
tions raise the head from the ground or floor). Place a
hard roll of clothing beneath the body, with the shoulders.
declining slightly over it. Open the mouth, pull the
tongue forward, and with a cloth wipe out saliva or
mucus. Thoroughly loosen the clothing from the neck to
the waist, but do not leave the subject's body exposed, for
it is essential to keep the body warm; kneel astride the
subject's hips, with your hands well opened upon his
chest, thumbs pointing toward each other and resting cn.
the lower end of the breastbone; little fingers upon the
margin of the ribs and the other fingers dipping into the
spaces between the ribs. Place your elbows firmly against
your hips, and using your knees as a pivot press upward
and inward toward the heart and lungs, throwing your
weight slowly forward for two or three seconds, until
your face almost touches that of your patient, ending with
a sharp push which helps to jerk back to your first posi-
tion. At the same time relax the pressure of your hands
so that the ribs, springing back to their original position,
will cause the air to rush into the subject's lungs. Pause
for two or three seconds, and then repeat these motions.
at the rate of about ten a minute, until your patient.
breathes naturally, or until satisfied that life is extinct.
If there is no response to your efforts persistently and
tirelessly maintained for a full hour, you may assume that
life is gone.
"Hot flannels, water bottles, bricks, and warm clothing
will aid in recovery. Warmth should be maintained, but
nothing must prevent persistent effort as above described.
Stimulants in small quantities may be administered after
swallowing is possible, and sleep must be encouraged, as
LIGHTNING
91
one of the best recuperatives. Get a physician as early as
possible.
The treatment of persons shocked by electric light or
power currents is identical with that for lightning stroke.
Buildings.
Question 5. Are lightning rods of any use?
Answer. Yes, if properly installed they offer a great
protection.
Question 6. What material is best for lightning rods?
Answer. Copper, as its conductivity is high, and so is
much lighter, smaller and neater in appearance than an
iron rod.
Question 7. What should they weigh?
Answer. A copper rod six ounces to the lineal foot
and an iron rod two pounds per lineal foot.
Question 8. What kind of rod should be used?
Answer. We really do not mean a rod, the word being
used in a general sense. The best form is a tape or flat
thin bar.
Question 9. What kind of tips should be used?
Answer. They should be pointed.
Question 10. Why is this?
Answer. The points tend to discharge the electricity
of the earth to the air and thus relieve the tension in the
atmosphere.
Question 11. Where should the rods be placed?
Answer. Tips should be erected on all parts of build-
ing projecting above the roof, such as cupolas, chimneys,
gables.
Question 12. What should be done to cornices, orna-
mental iron work, etc.?
<
L
92
ELECTRIC RAILROADING
!
Answer. They should all be connected by a soldered.
joint to a "rod."
Question 13. Should the rod be insulated from build-
ing?
Answer. No. It is certainly unnecessary from an elec-
trical point of view and is troublesome and expensive.
Question 14. Can the "rod" be run inside the building?
Answer. Never. This would be very dangerous, as
lightning if it jumped from rod would surely cause great
damage.
Question 15. Must the "rods" be run straight?
Answer. It is better to run from each point on the
roof as straight to the ground as possible, avoiding all
sharp bends, as these give the lightning a chance to jump
off.
Question 16. Does each point protect a certain area?
Answer. No. The amount of space protected by a
point varies. A sudden rush or disruptive lightning dis-
charge may strike a building very near a point. Hence
the more points the greater safety.
Question 17. How are the lower ends of "rods" con-
nected to earth?
Answer. By being well soldered to water pipes or to a
plate of copper about 3x3 ft. buried in moist earth.
Question 18. If the rods pass near metal work gas
pipes, etc., what should be done?
Answer. Connect them to the rod by wires whose
joints are well soldered.
Question 19. Why should the joints be soldered?
Answer. Because the resistance of an old or badly
made joint will sometimes cause the lightning to jump off
the rod. Every joint in the rod and connections should
be soldered,
LIGHTNING
· 93
Question 20. How should lightning be prevented from
entering buildings by the line wires?
Answer. Use lightning arresters at the point where
they enter the building.
Question 21. What is a lightning arrester?
Answer. It is a device designed to protect electrical
apparatus from lightning or atmospheric electricity.
Question 22. Does it stop the lightning?
Answer. No, the name arresters is misleading. They
do not stop the discharges, but turn them aside to a con-
ductor which leads to the ground.
Question 23. What circuits need protection?
Anster. Any circuit which has a part running out
doors, or any circuit connected to one running into the
open air.
Question 24. What kinds of circuits need protection
most?
Answer. Long lines, lines running over hills or moun-
tains.
Question 25. Does the kind of power on the line af-
fect the liability of lightning discharge?
Answer. No, any kind of line from telegraph to power
transmission is equally liable to be struck.
Question 26. Do the station men sometimes disconnect
the dynamos from the line to prevent the line being
struck?
Answer. No, they do it when they mistrust the light-
ning arresters' ability to protect the dynamos. Cutting
the dynamos off puts them in safety, but the line is not
protected. A dead line is just as apt to be struck as a
live one.
Question 27. Are some parts of the country troubled
with lightning more than others?
94
ELECTRIC RAILROADING
Answer. Yes. In the Rocky Mountains lightning dis-
charges are very numerous and severe.
Question 28. What trouble may result from lightning
striking a line?
Answer (1) Burning of insulation on wires in instru-
ments and machines.
(2) Puncturing insulation of machinery, like
dynamos or transformers. Either of these destroys the
insulating value of the material.
(3) Melting of wires or fusing together met-
al parts which are in contact.
(4) Dangerous injuries to persons.
(5) Fire caused by an arc jumping across in-
flammable material.
(6)
even splintered.
tered.
The insulators are sometimes cracked or
(7) Poles are splintered or sometimes shat-
(8) A cable forming a part of the current is
more likely to have its insulator punctured than any other
part of the circuit. This is a very troublesome and costly
thing to repair.
This applies to underground or underwater cables more.
than to those strung on poles.
Question 29. Does lightning follow the shortest path
or the path of least resistance?
Answer. Unlike ordinary current electricity, lightning
usually follows the straight, short path even if of enor-
mous resistance.
Question 30. Does a break in the circuit stop light-
ning?
Answer. No, it will jump across and go on.
LIGHTNING
95
Question 31. Do coils have any effect on lightning?
Answer. Yes. Lightning cannot pass readily through
a coil of wire. It will do so if this is the only path open to
it, but if there is any other path not containing coils the
lightning will usually take the path without coils. It
sometimes jumps from turn to turn of a coil, thus getting
past without going through.
Errata :—Illustration on page 102 should read Shunt
Circuit in lower part instead of Short Circuit.
LESSON 7.
Lightning Arresters.
LOW VOLTAGE.
Question 1. What is the oldest form of arrester?
Answer. The saw tooth spark gap of the telegraph of-
fices.

LINE
A
I
Fig. 31.
GROUND'
The Saw-tooth Lightning Arrester as used on Telegraph
Circuits. I and I are the Instruments and A the Arrester.
Question 2. Describe it.
Answer. Two brass plates with V-shaped points are
set close to each other on an insulating base, one plate is
connected to the line and the other to a ground plate.
buried in the earth. (See Fig. 31.)
Question 3. How does it operate?
Answer. The lightning being of an electrostatic na-
1
96
LIGHTNING ARRESTERS-LOW VOLTAGE
97
ture discharges from points readily, and being of an enor-
mous pressure is able to jump the air gap between the
points. The telegraph instruments contain electro mag-
nets whose coils act as choke coils.
The lightning has the choice of the path through the in-
strument coils or across the air gap. It practically always
takes the air gap and runs to the earth through the
ground wire.
Question 4. What objection is there to this type of ar-
rester when power circuits are to be protected?
Answer. The spark caused by the lightning in leaping
across the air gap forms a conducting path between the
plates.
The pressure on the line due to the generators sends.
the current across this path which forms an arc melting
the edges of the plates.
This arc grows larger until it conducts enough current
to "blow"* the fuses in the circuit, which interrupts the
service.
The arcing of an arrester is always caused by the cur-
rent of the line following the sparks due to lightning dis-
charge.
Question 5. What is the easiest way of stopping the
working current from following the lightning discharge?
Answer. Place small fuses (as in Fig. 32) in the
ground wires of the arresters before they join to the com-
mont ground wire. Then any working current following
the lightning discharge will blow these fuses instantly,
}
*Melt.
A wire acting as a ground wire for several others is called
a "common" ground wire.
98
ELECTRIC RAILROADING
leaving the main fuses unharmed. This will not inter-
rupt the service.
Question 6. What is the objection to the arrangement?
Answer. Often the two fuses are blown, the arrester
is useless and machinery left unprotected, there being no
ground connection to conduct the discharge away.

DYNAMO
F
LL
F
LINES
A www
mi
A
D
D
GROUND
F, F are
Fig. 32. The Saw-tooth arrester applied to a Dynamo.
the regular fuses. D, D are the fuses for Arrester Circuit.
Question 7. But the fuses can be replaced?
1
Answer. Perhaps not before the next discharge has
come. Moreover, a lightning arrester should allow the
static charges which accumulate even in clear, dry weath-
er to escape. These discharges sometimes snap across an
arrester in the steady stream.
Question 8. What are some of the better ways of stop-
ping the passage of the current after the discharge?
Answer. There are various ways, some methods put
out the arc which is conducting the working current, and
LIGHTNING ARRESTERS-LOW VOLTAGE
99
some try to prevent an arc or at least make arc very small.
Question 9. How is the arc put out?
Answer. By air blast, electromagnetic action, mechan-
isms for lengthening the gap momentarily as the dis-
charge passes, also use of non-arcing metals.
Question 10. How are arcs prevented?
Answer. Smothering the arc so that it doesn't form
for lack of air; insertion of resistance into the discharge.
circuit which weakens the current following discharge so
that it cannot hold an arc.
Question II. What should be done if an arrester in a
station holds its arc?
Answer. The arc should be beaten out with a cloth or
broom, or it should be smothered with sand.
Dry powder fire extinguishers are very useful for this
purpose, but water or liquid extinguishers should never
be used.
Question 12. Where should arresters be placed?
Answer. At the point where lines enter or leave any
building, and at intervals along the line.
Question 13. Why should they be placed along the
line? Will not the protectors at the buildings protect the
machinery?
Answer. It seems to be generally believed now that
lightning runs along the lines in waves and that at one
point it may be so weak that it will not jump to ground
through a certain arrester but pass on, and the same
charge a few miles further on, will either be discharged
through an arrester there or if there is no arrester, do
considerable damage.
Hence all the most exposed places on the line should
certainly have arresters and a few strung along the line
will not be wasted.
100
ELECTRIC RAILROADING
Question 14. What is the best arrester?
Answer. Each kind has its good points, some will not
work on low pressures, others will not stand the severe
test of Rocky Mountain use, but are reasonable in price
and satisfactory in action in the more open and level parts
of the country.
Ground Wire
Arresters
To Ground
Connection.
Fig. 33. Bank of Lightning Arresters.
Line

Any arrester is hardly a complete protection unless
combined with choke coils. (See Lesson 9.)
Question 15. Into what classes may arresters be di-
vided as regards to the circuits and apparatus they pro-
tect?
Answer. (1) For use when currents are very small
and voltages moderate as in telephone lines. The instru-
ments are very delicate and need absolute protection.
(2) When currents are small and voltage
moderate as in telegraph and signalling lines. Here the
apparatus is heavier and less liable to damage.
LIGHTNING ARRESTERS-LOW VOLTAGE
101
(3) Power lines and lightning circuits where
currents are heavy and voltage moderate, say up to 2500
volts.
(4) Power lines, transmission lines where the
voltage is very high, say from 11000 up to 50000 or 60000
volts.
Question 16. Into what classes may arresters be di-
vided as regards to the design of the arrester?
Answer. (1) Single gap arresters where one place is
provided for the lightning to jump across.
Single gap arresters are often installed in banks in par-
allel so that many places are provided at once.
The old saw tooth arrester is really a bank of single
gaps.
(2) Multigap arresters, in which we have a
number of single gaps in series.
These are sometimes simply a set of arresters in series.
Each arrester being designed for say 2500 volts, using
four in a series will protect a 10000 volt circuit.
*The words series, parallel, and shunt will be more fully
explained in Lesson 18, but it will be sufficient now to state
that if a current goes through all of a number of instruments or
resistances, they are in series. If the current splits and part
goes through one set of instruments or resistances and the
rest goes through another set then these two sets are in par-
allel.
Each set while in parallel with the other set may of course
consist of several pieces of apparatus in series.
When a circuit is cut and a new piece of apparatus is inserted,
this piece is in series with the other.
When a circuit has a new piece of apparatus attached by
soldering on the wires without cutting the original circuit the
new piece is a shunt circuit and the part of the old circuit is
said to be shunted,
102
ELECTRIC RAILROADING
Usually they are so designed that a single arrester con-
sists of a set of gaps in series. These arresters can be
placed in series for high voltage.
100 Amperes
Series Circuit

100
1
Parallel Circuits
60
100.

100 Amperes
40
Short Gircuit
90
100 Amperes
Main Line
100

100
10
Shunt
The part of the main line which carries
go amp. is shunted by the shunt which
carries. 10 amperes.
(3) Arresters with series. resistances. The
idea being that lightning will pass through the resistance
without being obstructed much while the normal line
pressure cannot send enough current through the resist-
ance to hold an arc between the discharge points,
LIGHTNING ARRESTERS LOW VOLTAGE
103
(4) Shunted resistances. In this type a re-
sistance is put in parallel with the spark gaps. Experi-
ment has shown that by proper design this is very effect-
ive in preventing an arc across the discharge points.
(5)
Fixed gap length. In some arresters the
gap length is fixed, and resistance (series or shunt), also,
and the kind of metal used for the points, is used to sup-
press the arc.
(6) Lengthened gaps. The gap points are
shaped like horns and the heat of the arc lengthens it by
the uprush of hot air or the arc is forced up by magnet-
ism.

S.C.
A
PI
(T.
F
Fig. 34. Lightning Arrester and Stray Current Protector for Telephone,
Bell and Signalling Circuits.
In other types the gap points are drawn apart by mag-
netism.
Question 17. What type of arrester is used for tele-
phone circuits?
Answer. The protector is shown in Figs. 34 and 35.
The line current enters at binding post A and passing
along the spring B goes through the pin P through the
wire of the coil SC on to post E, where the instrument
wire is attached.
Each side of the apparatus is just alike, there being one
piece for each line wire.
On the left of post A are two carbon blocks, C and C₁,
104
ELECTRIC RAILROADING
ļ
separated by a slip of mica M with a circular hole in it.
The upper carbon block has a drop of fusible metal let
into its lower face, but it is flush with the carbon.
The upper block is in contact with post A by a spring
which holds it in position. The lower block rests on a
metal plate, which is connected to the ground wire D.
When lightning or any pressure over 300 volts comes
on the line it jumps across the air gap between the carbon
blocks (whose length is equal to the thickness of the mica
strip) and goes to ground. It at the same time melts the
drop of metal, making a complete ground. The instru-
ments are then absolutely short circuited and protected.

·
·
D
G
B
S. C.
DE
Fig. 35. Top view of Arrester shown in Fig. 34.
This means that there is a short and low resistance path
for the current, which lightning will follow instead of go-
ing through the instruments.
Should there be a cross connection with other lines or a
leak to the telephone line, the instruments could be dam-
aged by the amount of current, while the pressure was far
below 300 volts.
In this case the "sneak current," as it is called, goes
from A along the german silver spring B, up through P
and through the sneak çoil SC,

LIGHTNING ARRESTERS-LOW VOLTAGE
105
The sneak coil is of very fine german silver wire, about
30 ohms resistance and in a few seconds this coil gener-
ates enough heat to melt a plug of fusible metal which
holds the pin P in place.
The spring B then moves up and touches the ground
strip G, thus grounding the line and protecting the in-
struments.
Fig. 36. Lightning Arrester with Magnetic Blow-out
Question 18. What type of arrester is used on moder-
ate voltage lines?
Answer. One type is shown in Fig. 36. The air gap is
between the curved plates. The magnet below is excited
from the dynamo and the arc when formed is blown up-
wards until the space at the upper end of the curved
plates is too long for the pressure to maintain the arc.

106
ELECTRIC RAILROADING
The instrument acts as if the arc were blown out by a
puff of wind.
Another form of this arrester has two flat plates so sur-
rounded by the magnetism that the blow out effect is
stronger, and it is relied on, there being no horns to help.
Both of these are used on direct current circuits.
Question 19. Describe an arrester for alternating cur-
rents at moderate voltage.
Answer.
There is a non-arcing arrester for A. C.*
work. It consists of seven cylinders, each one inch in di-
ameter and three inches high. They are made of white.

Fig. 37. Wurtz Non-arcing Lightning Arrester.
Alternating Current.
Used with
brass with a large percentage of zinc, and very little cop-
per, in it. They are knurled or checkered so that the sur-
face is covered with little points.
These cylinders are held in insulating strips so as to be
about 1-64 of an inch apart. For low voltages the center
*Abbreviation for alternating current.
LIGHTNING ARRESTERS-LOW VOLTAGE
107
cylinder is grounded and the end ones connected to the
lines.
When used on A C circuits the discharges which, spark
across do not cause arcs.
The probable reason is that the cylinders being close
together, the spark makes a little explosion which blows.
— 1000 VOLTS

GENERATOR
I
GROUND
LINE
LINE
Fig. 38. Wiring diagram for 1000 volt circuits.
One Arrester used.
the arc out, and the boiling of the metal where the spark
jumps carries the heat away in the vapor and the spot is
too cool to hold an arc.
The cylinders must be turned after each storm to pre-
sent fresh surfaces for the next discharge.
A single arrester is shown in Figs. 37 and 38.
Figs. 39 and 40 show the arrangements for higher volt-
ages.
It will be noticed that this is of the multigap type.
108
ELECTRIC RAILROADING
[In Fig. 40 is shown the beginning of the "new idea"
in lightning arresters which will be discussed at length
further on.]
{
Question 20. How does the non-arcing arrester in Fig.
40 operate?
LINE
2000 VOLTS

GENERATOR
GROUND
LINE
Fig. 39. Wiring diagram for 2000 volt circuits. Two Arresters used.
Answer. The operation of this arrester is as follows:
The number of series gaps is adjusted to the voltage at
which the arrester is desired to discharge. This is the
real lightning discharger. The series resistance is small
and so wound that it is as little like a coil in its choking
action as possible. Its presence will prevent a large cur-
rent flowing through the arrester while it is discharging.
If only as few series gaps as are shown were there, with
à small series resistance, the dynamo current which fol-
LIGHTNING ARRESTERS-LOW VOLTAGE
109
TO LINE
The lightning followed by the line current passes
through the series gaps. Then the lightning due to the
choking action of the shunt resistance, sparks through the
SERIES
GAPS
Fig. 40.
SHUNTED
GAPS
SHUNT RESISTANCE
SERIES RES.
lows the lightning discharge will cause an arc and burn
the cylinders.
When shunted gaps are used the result is:

GROUND
Arrangement of Arresters and Resistances for High Voltages.
This forms a Multigap Arrester.
110
ELECTRIC RAILROADING
I
shunted gaps, while the line current on account of the
high resistance of the shunted gaps, passes through the
shunt resistance.
There is then no line current in the shunted gaps to
hold an arc. The lightning having now discharged the
line current finds a series circuit, composed of the series.
gaps, the shunt resistance and the series resistance.
The shunt resistance being large, the total resistance of
the arrester is large enough to shut off the line current en-
tirely.
Had such a large resistance been in series with the
series gaps at first the arrester would not have started to
discharge and of course afforded no protection.
Question 21. Is there a non-arcing direct current ar-
rester?
Answer. Yes, the non arcing direct current arrester is
based on these facts.
(1) Lightning will pass over a non-conducting sur-
face more readily than across an equal air gap.
(2) It will pass even more readily if the surface is
covered with carbon.
(3). An arc cannot form where there is no air to help
the material burn.
A lignum-vitæ block is charred in its center for about
half an inch in width. Two metal plates are set flush in
the block on each side of the charred strip.
A second block is screwed tightly over the first to keep
out the air.
This arrester works on direct current up to 700 volts.
The lightning passes easily from plate to plate; while the
charred strip of about 50000 ohms resistance prevents the
passage of current from the line.
The lightning cannot start an arc in this small space.
LIGHTNING ARRESTERS--LOW VOLTAGE
111
r
One plate is connected to a line wire and the other to
the ground. Two should be used, one on positive wire
and the other on the negative.
These arresters have been used with "smooth cored"
alternating current generators furnishing 1000 volts pres-
sure.
Question 22. Is there a small, cheap arrester for single
instruments and small buildings, as switch men's cabins,
tool houses, etc., and for use on electric light circuits?
Answer. Yes. A lightning arrester designed for alter-
nating current (abbreviated A. C.) up to 350 volts pres-
sure is shown in Fig. 41.
Where long secondaries are run from transformers, a
necessity has been found for the use of lightning arrest-
ers. The demand for a low priced but effective and reli-
able arrester for this service has resulted in the arrester
shown.
This device is for use on any A. C. circuit of 350 volts
or less, and is suitable for protection of individual series.
A. C. arc lamps, as well as on incandescent lighting cir-
cuits. Its effectiveness when placed on wires at the en-
trance to buildings, store-houses, signal towers, etc., rec-
ommends its general adoption.
A detailed description of construction is given later.
The general plan is shown in Fig. 41, where will be seen
the two large circular discharge plates separated by an
air-space of 1/50 (.020) inch at their beaded edges. Over
this air-gap a heavy discharge may pass, while light dis-
charges and static surges will pass to earth, more slowly,
through the high resistance disc that separates the larger
metallic discs. This disc is of permanent resistance and
allows the passage of but an infinitesimal normal current,
while permitting the escape of the high voltage static dis-

112.
ELECTRIC RAILROADING
charges. In the event of the discharge being heavy, it
will jump the spark gap, but the low voltage of the nor-
mal current will not maintain an arc, owing to the cooling
effect of the heavily beaded disc.
ARRESTER
ARRESTER
CUT NO 15.
Fig. 41. Small Arrester
for Alternating Current
up to 350 volts.
Fixed gap type.
DIAGRAM of CONNECTIONS
GARTON-DANIELS LIGHTNING ARRESTERS
TYPE T. No. 300
-FOR-
SECONDARIES OF TRANSFORMERS
UP TO 350 VOLTS, A.C.
GARTON-DANIELS COMPANY
KEOKUK, IOWA. U.S.A.
Fig. 42.
It will be seen that this device offers a choice of either
of two paths, one highly efficient as an outlet for static
surges, and the other (the spark-gap of 1/50 inch) a
highly efficient path for lightning discharges.
When used on the secondaries of transformers, one ar-
rester is necessary on each leg of the circuit. Same should
be connected in a shunt path to earth as shown in Fig. 42.
As an arc lamp protector it is connected directly across
LIGHTNING ARRESTERS--LOW VOLTAGE
113
the terminals of the lamp as shown in Fig. 43, thus offer-
ing a path around the lamp, to the standard pole
arresters, which should be distributed along the line at
intervals. These standard pole arresters are, of course,
connected between line and ground, and thus offer an easy
escape for the discharges.
TYPE T. 300
GARTON-DANIELS-LIGHTNING ÅRRESTER

UNE
LINE
DIAGRAM of CONNECTIONS
GARTON-DANIELS
LIGHTNING ARRESTERS
TYPE TN? 300
FOR ALT, CURRENT SERIES
ARC LAMPS
UP TO 350 VOLTS
GARTON-DANIELS COMPANY.
KEOKUKIOWA. USA.
Fig. 43.
It has been customary in many cases to use standard:
forms of arresters in the same service for which this de-
vice is designed. These standard forms have the objec-.
tion of higher cost, larger size, and, as all employ a
much greater spark-gap distance, are not nearly so effi-
cient as this Type T. arrester. Furthermore, the auxiliary
path through the high resistance disc increases the effi-
ciency of this arrester many times,

114
ELECTRIC RAILROADING
The device consists of the parts illustrated in Fig. 44
assembled as shown in side view Fig. 41. Parts Nos. 309
are two metallic discs, formed with a heavy bead around
the circumference, the center being flat to make contact
with the high resistance disc, No. 311. These parts are
TYPE T 800
VARTON-DANIELS
ALTERNATING CURRENTS
FLIGHTNING ABRESTR
FOR 350 VOLTS OR LESS
PATENTS PENDING
MED BY
GARTON DANIELS
CO.
KEOKUROWA
301
309
309
307
308
311
308
313
100
CUT No314
302
306
312
303
--304
310
310
--305
Fig. 44a. Parts of Arrester shown in Fig 41.
assembled on the insulating tube, 312. The high resist-
ance disc separates the metallic discs so that the heavy
beaded circles are separated by 1/50 (.020) inch. Parts
Nos. 308 are insulating discs, also mounted on 312. The
screw, No. 306, passes through steel washer, 307, tube,
312, and asbestos disc, 313, so as to clamp them together
when screwed into weather-proof box, 302. The flexible
leads, No. 310, pass through porcelain insulator, No.

LIGHTNING ARRESTERS-LOW VOLTAGE
115
303. The cover, 301, hooks over the top of box, 302, and
is fastened in place by but one screw, 305. This cover is
perfectly weather-proof. Complete, the arrester measures
3½ inches from center to center of supporting holes.
TYPE T 300
GARTON DANIELS
ALTERNATING CURRENT
LIGHTRING ARRESTER
FOR 350 VOLTS OR LESS
BATENTS PENDING
MFO BY
GARTON DANIELS
CO.
KECKUK IOWA
CUT No.300.
Fig. 44b. Arrester parts as shown in 44a assembled ready to
screw cover on.
PROTECTION OF LINES.
Question 23. How should signal lines be protected?
Answer. When on pole lines an arrester should be
placed on pole about every half mile; when run in con-
duits or tunnels one should be placed at each end of con-
duit or tunnel.
Question 24. How should telegraph lines be pro-
tected?
Answer. As the instruments are only placed in sta-
tions, an arrester at point where wires enter station is
sufficient.
Question 25. How should telephone lines be pro-
tected?
Answer. A protector which contains a "sneak cur-
rent" device should be placed in every line where it enters
a building.
116
ELECTRIC RAILROADING
Question 26. How should feeders to trolley wire or
third rail be protected?
Answer. Such lines are usually fairly short and not
much exposed to lightning being carried on low poles.
The arrester on the feeder at the station and one where
the feeder connects to trolley or third rail should give
ample protection.
Question 27. How should trolley wires or third rails
be protected?
Answer. The arresters at the ends of the feeders
ought to be sufficient for the trolley wire also.
If there are very few feeders it would be well to see
that there is an arrester every half or three quarters of a
mile. One to the mile will do, as trolley construction is
very strong and not liable to damage.
The third rail lies along the ground and is seldom
struck. If it were the mechanical strength of the rail it-
self and its insulators would protect them, although the
lightning did side flash to the ground.
Question 28. What protection should motor cars or
locomotives have?
Answer. There should be an arrester in the main cir-
cuits which furnish the power, and an arrester in the
control circuits which control the motors. These two
arresters should be of different styles. That for power
circuits should discharge at 1,000 volts and that in the
control circuits at 250 volts.
Question 29. What protection should be given to a
trolley car?
Answer. An arrester should be placed on roof or un-
der hood of such a capacity that there can be no chance
of its failing to operate.
LESSON 8.
LIGHTNING ARRESTERS.
HIGH VOLTAGE.
An arrester of the two gap type with a magnetically
lengthened gap to break arc is shown in Fig. 45, and its
construction in Fig. 46. It is made for alternating or
direct current work.
In order to increase the surface distance, so as to pre-
vent breakdown between current carrying parts of con-
siderable difference of potential, one of the discharge
points is mounted on the end of the resistance rod B.
This rod is held in position by the clamps at C and D.
The distance from clamp C to upper discharge point A is
234 inches. The solenoid cut-out coil H is supported by
brackets I and K, bracket K being so designed that it
gives a surface distance on the porcelain base of 24
inches between K and lower discharge point bracket L.
This is a total of 5 inches, which is a liberally safe sur-
face distance on porcelain for 2500 volts.
To still further reduce the possibility of current jump-
ing between parts, the line connection is at the top of the
Arrester, from which the discharge passes downward in a
practically straight path to ground connection. This path
is indicated by the round dots in Fig. 46, the dashes show-
ing the path of the normal current. It will be noted that
the discharge goes through the section of the resistance.
rod C-D, the normal current being shunted through the
117

118
ELECTRIC RAILROADING
solenoid coil H. This energizes the iron armature J,
which raises upward in the coil, opening the circuit be-
tween the discharge point M and lower end of armature.
The discharge point M is stationary, so that the air-gap
110
LINE
M
21
GROUND
Fig. 45. 2500 volt Alternating
Current Arrester. Mechanically
lengthened gap type.
Fig. 46. Diagram of Arrester
shown in Fig. 45.
at N is not changed by the operation of the Arrester. The
arc is thus drawn out until broken inside the tube, which
is practically air tight and prevents flying sparks or seri-
ous arcing. The upper end of discharge point M is car-
LIGHTNING ARRESTERS HIGH VOLTAGE
119
bon, so the arc is drawn out between the same and the
iron armature. This combination prevents sticking or
welding together.
3500 volt arresters are designed along the same lines as
the 2500 type. They differ in width and length of base to
accommodate the higher voltage rating per arrester unit.
In the 3500 volt arresters is provided an additional air-
gap near the line binding-post. This construction has
proven in extended service to be perfectly safe, and satis-
factory for the higher voltage rating of 3500 volts.
As the circuit is opened inside the tube and the air-gap
adjustment is always the same, it is possible to use the
small air-gap space. In this 2500 volt arrester, the air-
gap distance is 3-32 inch, which is as small as can be used
safely.
The cut-out is entirely automatic, restores itself by
gravity, is instantaneous in operation, and prevents
grounding the line, whether the discharge points are dirty
from repeated operation or not. If the normal current
follows the lightning over the air-gaps, it is shunted ·
through the coil. The coil immediately cuts it off and the
normal dielectric of the air-gap is restored.
To limit the flow of normal current that can follow the
discharge to ground, the upper section of the resistance
rod B is employed, there being approximately 250 ohms
between discharge point A and clamp C in the 2500 volt
arrester. This keeps the current down to a value that is
broken readily by the cut-out, and is not enough resist-
ance to impede the passage of the discharge.
This feature is particularly effective where a part of
the circuit is grounded, or where the circuit is temporarily
or accidentally grounded. This series resistance prevents
a heavy short-circuit through the arrester. The cut-out

120
ELECTRIC RAILROADING
Fig. 47. 10 000 volt Arrangement of Four 3000 volt Arresters.
LIGHTNING ARRESTERS-HIGH VOLTAGE
121
readily interrupts the flow of normal current, and the ar-
rester is again ready for another discharge.
The positive action of the cut-out renders the arrester
independent of the condition of the discharge points, and
they require no more than an occasional inspection.
When protection for higher pressures is desired a num-
ber of these arresters are often mounted in series as
shown in Fig. 47.
The multigap arrester with graded shunt resistance for
alternating current.
If a series of knurled cylinders of zinc alloy about 1/64
of an inch apart has the first one connected to a line and
the last one grounded, there will be an electric strain
all along the series due to the tendency of the pressure
on the line to force electricity through the series to the
earth.
Suppose a single gap between two cylinders will al-
ways prevent 400 to 600 volts from jumping across, but
that 800 volts will be sure to jump.
Suppose you have a 22000 volt line and place 56 cyl-
inders in line making 55 gaps, each gap will stand 400
so the 22000 volts will never spark across.
Suppose a lightning discharge increases the pressure
on the line to 33000 volts, which makes 600 volts per
gap. One would think that the gap will not be jumped,
and that the insulation of the machines, etc., will be
The frequent occurrence of this will finally
break down the insulation and a burnt out generator be
the result.
However, an arrester of a large number of gaps works
in a peculiar manner.
When the normal 22000 volts is on the arrester the
122
ELECTRIC RAILROADING
first gap has a pressure on it of 600 to 700 volts and each
successive gap less and less on to the end.
The pressure does not distribute itself evenly over all
the gap but piles up on the first few.
It is clear then that when the abnormal 33000 comes
on the line that the first few gaps of the arrester have a
pressure of 900 to 1000 on them, and the spark jumps
across.
The state of affairs is now as if 52 gaps were placed
as an arrester on a 31500 voltage. The first few gaps
getting the highest pressure are sparked across.
This action takes place all along the 55 gaps, each gap
nearest the line being sparked across by the concentra-
tion of pressure upon it, until all the 55 gaps are spark-
ing. The discharge passes to the earth and the line is re-
lieved.
Another peculiar thing now happens. When all the
gaps are sparking the voltage distributes itself evenly
over the arrester; so that now only 600 volts are across
each gap and the sparks go out before any of the current
of the line can flow through and cause arcs.
If line current should follow the lightning discharge
this current by its action brings the arrester more quickly
to the even distribution state, and the arcs go out.
If the discharge did not completely relieve the line a
second one would immediately occur, or a succession of
them until the pressure was down to 22000. At that pres-
sure there would be 600 to 700 volts on the first gap and
very little on the last.
It is evident that in designing a multigap arrester you
cannot divide the line voltage by 400 and put in that many
gaps in series and be positive that 22000 volts won't dis-
charge through it under all conditions of regular use,
LIGHTNING ARRESTERS-HIGH VOLTAGE
123
You must remember that extra gaps are needed as you
increase the number in the arrester. Three gaps will hold
1200 volts while 120000 volts will go right through 300
gaps. Ten times as many gaps will not hold back ten
times the pressure.
This arrangement of a large number of gaps called the
multigap arrester has three excellent features.
(1) It will discharge at a very slight increase of pres-
sure above the normal.
(2) It automatically stops discharging when pressure
on line falls to nearly the normal pressure.
(3) Line current going through the arrester carries
its own cure.
This condition of high pressure existing at the end of
a series of gaps may be illustrated by connecting ten in-
candescent lamps (110 volt type) suddenly to a 1000 volt
circuit. There will then be a surge which will generally
burn out a lamp or two at each end of the series. Those
lamps at the center of series. will never be damaged.
Remember this is not a proof of the high pressure at
the first gaps because the lamps are broken by a surge,
but it does prove that pressures can pile up at a point in
a circuit far above normal, and makes one willing to be-
lieve that the gaps might do a similar thing.
The objection to the multigap arrester is as peculiar as
its action.
A static discharge is of low frequency and a lightning
stroke discharge of high frequency.
A high frequency pressure causes a greater pressure cn.
the first gap than a low frequency pressure.
Hence, an arrester discharges at a lower pressure for
l'ghtning-stroke, than for static accumulations,
124
ELECTRIC RAILROADING
If then enough cylinders are used so that the regular
voltage on line won't break down the gaps, there will be
often static accumulations of higher voltages than is safe.
for line but of such low frequency that enough pressure
will not be exerted on the first gap to start the arrester
into action.
It is the multigap arrester with graded shunt resist-
ances that solves this problem.
Low frequency pressures can only break down a few
gaps as compared with a high frequency pressure of same
voltage.
0000000000000000000-


0000000000000-
LOW RESISTANCE
ООООО
MEDIUM RESISTANCE
HIGH RESISTANCE
Fig. 48. Diagram of a Multigap Arrester in Imperfect Form.
Suppose as in Fig. 48 there are arranged between line.
and ground four circuits, one of 18 gaps, another of 12
gaps and a low resistance, a third of 8 gaps and a me-
dium resistance, while the last has 4 gaps and a high re-
sistance.
It will be seen that the opposition offered by any of the
four circuits to 6600 volts will be perfect and no line cur-
rent will pass through the arrester.
A lightning stroke of high frequency will pass through
*The words "break down" used with lightning arresters do
not mean any damage to apparatus but merely refer to the dis-
charge,
LIGHTNING ARRESTERS-HIGH VOLTAGE
125
the 18 gaps quite easily. Surges will perhaps be unable
to pass the 18 gaps, the frequency being too low, but will
find their way through one of the other circuits. Static
accumulations being of very low frequency will pass.
through the 4 gaps and high resistance while they could
not get through any of the other three. Remember that
any of these must be above the normal pressure to dis-
charge. In fact, unless they were above normal voltage
we would not care about them.
The objection to this arrangement of gaps and resist-
ances is that a static charge of very high pressure and
very low frequency might occur.

-0000000000000000000-
DOOT
MEDIUM RESISTANCE
LOW RESISTANCE
HIGH RESISTANCE
Fig. 49. Perfected Form of Multigap Arrester with Graded Shunt
Resistances.
This could only break down the 4 gap high resistance
leg* of the arrester on account of low frequency. It
would discharge so slowly through the high resistance
that the line would not be freed from the high pressure
quickly enough to prevent damage.
The arrangement of gaps and resistances actually used
is shown in Fig. 49. The multigaps are put in series and
the three resistances are put in as shunts.
*Parts of circuits which have the same starting and ending
points are often called legs.
126
ELECTRIC RAILROADING
This removes the objection just mentioned and inci-
dentally uses far less cylinders in an arrester.
The action is just the same, each frequency selecting its
own path. In addition to this each time the arrester acts
no matter what the frequency, the whole line of gaps
from end to end breaks down and relieves the line
quickly.
In fact, with this arrangement we might say that the
resistances are merely a device to enable a low frequency
to break down more gaps than it usually can.
This action takes place as follows: When a low fre-
quency discharge passes through the high resistance and
sparks across the last 4 gaps; at the same time, part of
it passes through the medium resistance, and as the last
4 gaps are sparking it is able to break through the 4 in
front of it to them. This action occurs all the way up
the arrester.
The action can also be explained in this way: The low
frequency pressure passes through the three resistances
and exerts its pressure at different points along the gaps.
At only one place does it find few enough gaps between
itself and the ground. This place is the last 4 gaps. It
breaks these down and begins to discharge to earth. But
now at the end of the medium resistance connection it
finds only 4 unbroken gaps, and is able to break them
down and it does so.
In this way the whole arrester breaks down in sections,
even for low frequency discharges.
In Fig. 50 is shown a 2300 volt arrester with two re-
sistances and in Fig. 51 is shown a set of cylinders
mounted on slate base. These sets of cylinders are used
in building up the 6600 volt up to 60000 volt arresters.
1

LIGHTNING ARRESTERS-HIGH VOLTAGE
127
ARRE
Fig. 50. A 2300 volt Multigap Shunt Resistance Arrester for
Alternating Current.
With these high voltages a long spark gap shunted
by a fuse is placed in series with the arrester. Then on
a heavy short circuit the fuse blows and puts the spark
gap in series with the arrester.

128
ELECTRIC RAILROADING
This prevents the destruction of the arrester and does
not put it completely out of action. The fuse should be
replaced as soon as possible. Frequent inspections should
be made to see that cylinders are clean and the fuse in
working order.
Fig. 51. Set of Cylinders on Slate Base. These are used as units
to make up complete arresters.
PROTECTION OF LINES.
Transmission Lines.
Question 1. What is one of the simplest methods of
protecting an overhead line?
Answer. Using a ground wire.
Question 2. What is a ground wire?
Answer. It is one or more wires strung parallel to the
line and grounded at every pole. One is about as good as
more and very much cheaper.
LIGHTNING ARRESTERS-
129
-HIGH VOLTAGE
Question 3. In what position are they placed?
Answer. When there are two line wires one ground
wire should be run on the top of the pole, or two ground
wires run; one at each end of the cross arm or another
cross arm below the main arm.
When there are three line wires, one ground wire
should run on top of pole or in the center of the triangle
formed by the line wires, or three ground wires should
be installed, one on top of the pole and one at each end of
a cross arm under the main cross arm.
Question 4. Why are they run on glass insulators?
Answer. They must be tied to something and a cheap
glass insulator is less expensive than some special device
which is not an insulator. The fact that the glass is an
insulator is not harmful, because a ground connection is.
made by a wire at every pole.
Question 5. Are the ground wires copper?
Answer. They are usually galvanized iron about No.
4 size but a stranded 3% "cable" is better.
Question 6. Is the iron wire as good as copper for a
ground wire?
Answer. Yes, for electrostatic charges the size of the
wire is of far greater importance than the material.
Question 7. Barbed wire is generally used, is it not?
Answer. Formerly it was, but engineers are now be-
lieving that the plain wire is as good, and being cheaper
and much easier to handle is much more used than the
barbed.
!
Question 8. What was the reason for originally using
barbed wire?
Answer. It was thought that the barbs acted as dis-
charge points to let the free charges escape quickly into
the air.
130.
ELECTRIC RAILROADING
Question 9. Do they not act that way?
Answer. They probably would if the free charge was.
not neutralized by the earth connection so quickly.
A plain grounded wire well connected to earth is suf-
ficient protection.
Barbed wire is not as strong as a plain wire of equal
weight per foot.
Question 10. Why are not ground wires always put.
above the line wire?
Answer. They used to be put above, because engi-
neers thought the ground wire was a protection from a
direct lightning stroke.
We now think that they are not much use in that case,
so do not always put them above so as to have them
struck first.
We often put them below believing that, in the way
that they protect, they can do so as well from there as
from above.
Furthermore, being below should they break they can-
not cause short circuits by falling on the line wires.
A single ground wire is often put on the top of the pole
for convenience, but a single ground wire with three
line wires is sometimes put in the center so as to be
equally distant from all three.
Question II. How does a ground wire protect the
line?
Answer. It seems to be a fact that lines are not often
struck by lightning, but that thunder or electrical storms
affect the lines by static charges very frequently.
This is done as follows: A cloud heavily charged with
say positive electricity blows up over the line. There
will be induced in the line a bound negative charge and
LIGHTNING ARRESTERS-HIGH VOLTAGE
131
a free positive charge. This free charge will have a
tendency to go to the earth. It may do so by leakage
over and through the insulators of the line if the approach
of the cloud is slow enough to allow it to do so, if not it
jumps through the insulator puncturing it, or it may
side flash over the insulators from wire to cross arm.
If a ground wire is present a bound negative and a
free positive charge is induced in it.

Cloud
++++++
Line
+++ A
B
·Tendency to
puncture or side flash
Wire
1++
+++ G
Tendency to punc-
ture or side flash
Fig. 52. Electrostatic Charges on a Line under a Thunder Cloud
Without a Ground Wire.
This bound negative charge prevents as great an elec-
trical separation on the line as the cloud alone would
make and so the line does not become so highly charged.
This is shown in Figs. 52 and 53.
In Fig. 52 suppose the cloud to cause an electrical sep-
aration in the line as shown. There will be a tendency
to puncture or side flash at points A and C.
Now suppose the charge on the cloud to be neutralized.
by a lightning flash from cloud to earth. If it does not
132
ELECTRIC RAILROADING
strike the line at B and neutralize the negative charge
there, it will leave this charge free and there will be a
tendency to puncture or side flash at B. After this the
charge at A and B will spread over the line with a surge.

Cloud
++++++
Line +
D
++
++
+
Wire
E
F
G
H

Ground
Fig. 53.
Earth
++
Earth
++
Wire
Earth
++
Electrostatic Charges on a Line having a Ground Wire.
When the ground wire is there as in Fig. 53 the cloud
induces a negative charge on the ground wire which is
smaller than that on the line. It is smaller because the
capacity of the ground wire is less than that of the line
wires. It would be far too expensive to make the ground
wire capacity nearly equal to the line itself.
The free positive charge on the ground wire goes to
earth and the bound negative charge acts inductively on
the free positive charge of the line. This causes the dis-
LIGHTNING ARRESTERS-HIGH VOLTAGE
133
tribution of charge to be as is shown and the tendency
to have static troubles at E and G is less than it would be
without the ground wire.
Suppose now the cloud is discharged. The charge at
F on line will not act as violently as that at B did, because
the repelling effect of the negative charge on the ground
line at F tends to spread out the negative charge on the
line at F. Thus the tendency to static discharge at F is
less than if ground wire were not there.
Question 12. What are the objections to a ground
wire?
Answer. It is expensive to install. It is only a partial
protection and other devices must be used with it.
Question 13. What is its chief value?
Answer. It prevents the splitting of the poles, and
damaging of insulators.
Question 14. Does it protect the station?
Answer. No, it is a line protection.
Question 15. What other simple protectors are there?
Answer. The horn arrester is an extremely simple
device.
Question 16. What is a horn arrester.
Answer. A horn arrester is as shown in Fig. 54. A
single spark gap whose length is regulated by the pres-
sure it is designed to withstand (say 64 inches for 90000
volts) has a wide spreading pair of horns attached, the
ends being perhaps twelve feet apart.
Question 17. How are they attached to line?
Answer. One side is attached to a line wire and the
other side of gap is grounded. A fuse is placed in the
ground wire. Each line wire has its own horn,
Question 18. How do they work?
134
ELECTRIC RAILROADING
K
- 10′0″
त्रै
8'6"
61/4"
All of
#000 Copper Wire
To Line
Wire
I
6'0"
-18".
20 Ampere Fuse
Ꮕ
Shows loca-
tion of
insulators
18" high.
Wire *00 Copper
Ground
Fig. 54. Horn Lightning Arrester arranged with Fuse.
To Earth



LIGHTNING ARRESTERS-HIGH VOLTAGE
135
Answer. The discharge jumps across the gap form-
ing an arc. The heat of the arc causes it to rise and as
its ends are in the horns it is stretched out long and thin.
This cools the arc down and it goes out. While the arc
holds the charge on the line runs across it to the earth.
If the arc does not go out the normal current on the line
flows across the arc and blows the fuse. The fuse is
made very long so that an arc cannot jump across be-
tween the terminals which hold it. -
Question 19. What are the advantages of the horn
arrester?
Answer. Fairly cheap. They cannot get out of ad-
justment and discharge at wrong pressure. They cannot
produce an accidental ground by getting out of repair
or through defects in manufacture. They are mechani-
cally strong and will stand the most severe strokes.
Question 20. What are the objections?
Answer. Any time they discharge the line the fuse.
may blow.
The arrester is then useless until fuse is re-
placed.
The discharge is a vicious arc which sends a surge
through line.
Some engineers think the surge is worse than the origi-
nal trouble.
Question 21. What is the general opinion about them?
Answer. That they are an excellent thing to use at
points on the circuit especially exposed to lightning.
Question 22. What are single or side horns?
Answer. As shown in Fig. 55, the ground wire of
each pole is extended up beyond the top insulator and a
branch run up outside of each side insulator.
This construction is to protect the insulators by allow-
136
ELECTRIC RAILROADING

GROUND WIRE
PIPE FLATTENED
TO THIS POINT TO
EXCLUDE WATER
AND TO SUPPORT
GROUND WIRE.
CLAMP FOR LIGHTNING ROD
►LIGHTNING ROO
2″GAS PIPE.
GUARD.
WIRE.
TO GROUND
Fig. 55. Side Horns.
ing the discharge to jump to the ground wire instead of
flashing around insulator to the cross arm.
This Fig. does not show a ground wire strung from
pole to pole,
LIGHTNING ARRESTERS-HIGH VOLTAGE
137
But horn arresters and side horns can be installed
whether there is a line ground wire or not.
Side horns are installed at every pole.
Question 23. What is the lowest voltage used on
transmission lines?
Answer. 22000 volts, because at lower voltages the
wires have to be so large that expense is too great.
MAINS, FEEDERS.
Question 24. What is the highest voltage used on
mains and feeders?
Answer. 11000 volts. Any voltage higher than this
needs such special protection, that it should be run on a
high pole line, off to one side of the right of way.
The mains from power house or the feeders from sub-
stations to the third rail or trolley wire can be run at 11,-
000 with safety.
Question 25. How should mains and feeders be pro-
tected?
Answer. When on pole lines an arrester every half
mile is the best practice. When underground, one at eaclı
end of the section.
Question 26. Are choke coils used with these line ar-
resters?
Answer. No. Choke coils are only used with station
arresters.
Unless an arrester is protecting machinery or instru-
rents no choke coil is used.

LESSON 9.
LIGHTNING ARRESTERS.
AUXILIARY APPARATUS.
Question 1. What is a choke coil?
Answer. It is a coil specially designed to insert in a
line between the apparatus to be protected and the light-
ning arrester.
Question 2.
How are they made?
Answer. For low voltage they are simple coils of in-
sulated wire mounted on a slate bases as shown in Fig.
56.
Fig. 56. Low Voltage Choke Coil.
For high voltage (over 600) the wire is bare and the
turns are wound in an hour glass fashion, so that air
forms the insulation between turns.
Question 3. How do choke coils act?
Answer. A surge or stroke encountering a choke, re-
active, or kicking coil in its path is momentarily held
back,* practically stopped. The coil then begins to con-
duct the charge. It will be seen that the choke coil offers
*Throttled, choked off, kicked back, are some of the terms
used.
138

ARRESTERS-AUXILIARY APPARATUS
139
protection for an instant only, but during this time the
arrester on the line side of the coil can free the line of
the charge.
The damming up of the surge by the choke coil pro-
duces an enormous pressure which helps to force the
charge through the arrester.
Question 4. What is the objection to a choke coil?
Answer. It has resistance, and so wastes energy, it
will also retard a little the flow of the normal current. In
order to prevent their interference with normal operation
they are large and expensive.
Fig. 57. Hour glass Type of High Voltage Choke Coil.
Question 5. What are the advantages?
Answer. They increase the protection offered by the
arrester and even if arrester fails to act the choke coil
protects to some extent by causing a side flash on the
line where damage is less expensive than should it occur
in the station.
Question 6. How are lightning arresters installed?
Answer. They are placed in between line and ground
and the two arresters which are attached to the line wires
at a certain point are all connected to the same ground
140
ELECTRIC RAILROADING
¿
wire, so that there may be a free discharge between line.
and line, as well as between line and ground.
Question 7. What precautions must be taken when in-
stalling arresters in buildings?
Answer. The National Electric Code gives the fol-
lowing rules for the construction and installation of ar-
resters in buildings:
1. Lightning arresters must be mounted on non-com-
bustible bases, and must be so constructed as not to main-
tain an arc after discharge has passed, and must have no
moving parts.
[The arrester shown in Fig. 45 has been tested and
approved by the National Board of Fire Underwriters.
although it has a moving part.]
2. Must be attached to each side of every overhead
circuit connected with the station.
It is recommended to all electric light and power com-
panies that arresters be connected at intervals over sys-
tems in such numbers and so located as to prevent ordi-
nary discharges entering (over the wires) buildings con-
nected to the lines.
Must be located in readily accessible places away
from combustible materials, and as near as practicable to
the point where the wires enter the building.
Station arresters should generally be placed in plain
sight on the switch-board.
In all cases, kinks, coils, and sharp bends in the wires
between the arresters and the outdoor lines must be
avoided as far as possible.
4. Must be connected with a thoroughly good and
permanent ground connection by metallic strips or wires
having a conductivity not less than that of a No. 6 B. & S.
ARRESTERS-AUXILIARY APPARATUS •
141
copper wire, which must be run as nearly in a straight
line as possible from the arresters to the earth connec-
tion.
Ground wires for lightning arresters must not be at-
tached to gas-pipes within the buildings.
It is often desirable to introduce a choke coil in circuit
between the arresters and the dynamo. In no case should
the ground wire from a lightning arrester be put into
iron pipes, as these would tend to impede the discharge.
Question 8. How should arresters be grounded?
Answer. For station arresters there are many ways of
getting a good ground.
Copper sheets approximately 1 inch thick and of 4 to
6 square feet surface are suitable. A piece of cast iron
of large surface, with brass or copper plug tapped into it
for connections, is preferable. Cast iron does not waste
away as rapidly, and, when completely oxidized, still af-
fords a good ground path.
The ground wire must be carefully riveted or soldered
to the plate and the connection coated with a preserva-
tive paint.
The plate should be buried deep enough to be in damp
soil the year through. The bottom of the hole should be
covered with broken charcoal, coke or carbon to a depth
of 2 or 3 inches. After the plate is put in position, it
should be covered with another layer of charcoal, coke or
carbon, and the hole filled with earth. It is well to use
running water to settle.
Ground connections may be made to plates placed in
the mud at the edge of a stream. Where water or gas
pipes are available, the ground wires should be soldered
to a brass plug screwed into the pipe in addition to the

142
ELECTRIC RAILROADING
connection with the ground plate provided. In ground-
ing arresters on electric railway circuits, a connection
with the rails, as well as with the ground plate, should
always be employed.
Where an iron pipe is used to protect the ground wire,
the wire should be soldered to a cap on the upper end
of pipe. This avoids the choking effect of the pipe upon
a wire passing through it.
For pole arresters a cheaper arrangement is necessary.
The ground pipe is perhaps the best.
G.P.
G.P
100
G.P.
102
101
Fig. 58. Ground Pipe Fittings.
These may be driven into the earth, or if the soil will
not permit driving, a hole may be dug at the foot of the
pole to receive same. The pipe should extend upward
along the pole for eight to twelve feet above the ground,
to prevent cutting or removing the wire, and the ground
wire soldered to a cap on the upper end of the pipe. The
pipe should extend eight or ten feet below the surface
where it will be in damp earth the year round.
For this purpose are manufactured the fittings illus-
trated in Fig. 58. These are tapped for use with 3/4 inch
iron pipe and consist of the brass cap GP 100, with lug

ARRESTERS-AUXILIARY APPARATUS
143
for soldering in ground wire from the arrester. GP IOI
is a brass coupling for connecting upper and lower sec-
tions. (It being more convenient to drive an 8 or 10 feet
length and then couple on another length, than to drive
a 16 or 20 feet length.) This brass coupling GP 101 is
also provided with a lug for soldering in wire to rail,
when used on electric railway circuits. The driving point
GP 102 is of malleable iron, with dipped galvanized
finish.
G.P.
103.
Fig. 59. Ground Plate for Pole Arresters.
The pipe may be driven by placing an iron cap on upper
end, to protect the threads, or the method used by well-
drivers may be used to advantage. This is to start the
hole, fill with water and "churn" the hole to the required
depth with the pipe. This method is of particular advan-
tage where the soil is very hard.
In Fig. 50 is shown a cast iron plate, 12 inches in di-
ameter (total surface 450 sq. in.), with hole near edge
tapped for 3/4 inch pipe. This plate may be used in
place of the driving point and should be buried at the
foot of pole, and the necessary length of pipe attached.
144
ELECTRIC RAILROADING
It may be buried at the bottom of pole before the pole is
set, but if this is done, it should be made certain that the
surrounding soil will be damp the year through.
In electric railway circuits the rails should be connected
to the ground wire as is shown in Fig. 60.

SOLDERED
TO FEED
WIDE OR
TROLLET FAR
1
Urete
SOLDERED
TO CAP
DIAGRAM SHOWING
METHOD OF GROUNDING
POLE ARRESTERS
ON
ELECTRIC RAILWAYS
GARTON-DANIELS CO
KEO KUK, IA.
U.S. A GROUND
POINT
GAL-PIPE
PLATE-NOTO
Fig. 60.
FRED
The rail alone will not suffice, as it may be up on a
rock road-bed, or buried in cement or a soil that does not
provide a low resistance path for the lightning. With a
connection to both rail and ground point, any danger due

ARRESTERS-AUXILIARY APPARATUS
145
to difference of static potential between rail and earth is
avoided. Should either one of the connections be broken
or fail from any cause, the other one probably will be in
order and afford a degree of protection.
COUPL
SOLDERED
SOLDERED
C
SOLDERED
SOLDERED
TO
CAP
GROUND POINT
Fig. 61.
Fig. 61 shows manner of grounding a two wire or un-
grounded circuit.
All ground wires should be No. 6 gauge or larger.

146
ELECTRIC RAILROADING
Question 9. What inspection is necessary for light-
ning arresters?
Answer. Frequent inspection (once a month) and
cleaning with a bellows for dust is necessary.
f
Fig. 62. Low Voltage Arrester Disconnecting Switches.
Railroad work. Double for Electric Lighting.
Single for
Question 10. Is there not danger in the men inspect-
ing the arresters?
Answer. Disconnecting switches as shown in Figs. 62
and 63 are installed in places where some other switch
will not serve to disconnect the arresters.
Fig. 63. High Voltage Disconnecting Switch for Arrester.

LESSON 10.
MAGNETISM.
INTRODUCTION.
The natural magnet has been known for ages. The
Egyptians and Greeks in their writings long before the
Christian era mentioned that a certain mineral attracted
iron and steel. They also knew that a piece of steel be-
ing rubbed or rather stroked with the mineral, acted
Fig. 64. Natural Magnet: A piece of Magnetite or Black Oxide of Iron.
just as if it had become a piece of the mineral. Fig. 64.
Who first discovered that the mineral would point to
the north, we do not know, but in the year 1200 A. D.
Arabs brought compasses to Europe.
The mineral was called lode stone because it was a
leading stone i. e. it lead you to the north.
The name magnet was also given to it because most of
it came from a part of Greece called Magnesia.
Besides the quantity in Greece large quantities of mag-
netite are found in Sweden, Spain, also in states of Ar-
kansas and New Jersey.
147
148
ELECTRIC RAILROADING
Question 1. What is a magnet?
Answer. A magnet is a piece of material which will
turn into a north and south position when suspended so
as to be free to turn.
Question 2. Can it be any material?
Answer. No. It can only be of iron, steel or nickel,
or a few other substances which are feebly magnetic.
Question 3. But the mineral mentioned is a magnet?
Answer. Yes, because it is iron ore.
Question 4. Then copper, zinc, etc., cannot be mag-
netized?
Answer. No.


S
N
N
8
N
S
N'
Fig. 65. Making a Magnet by use of a Permanent Magnet.
}
Question 5. How can a magnet be made?
Answer. Produce two pieces of Jessup's steel about
6x4x4 or 12X1X3-16 inches. Machinery steel, man-
ganese steel, and some cast steels are useless. Heat
them moderately bright red and plunge sidewise and
edgewise into water or oil. They will become very hard
and brittle, or as we say "glass hard."
I. Lay one down on the table and stroke one-half of
the bar from the center out to the end.. Fig. 65. · Do
this ten times with the S-pole of a permanent magnet,
MAGNETISM--INTRODUCTION
149
and turning the bar over repeat this on the same end.
You now have an N-pole. Then using the N-pole of the
magnet stroke the other end of the bar in the same man-
ner. You now have the complete magnet with two
strong poles. You have made 40 strokes in all and you
need that many, but sitting there stroking for a 100 or
more times is wasted energy, for the bar soon becomes
saturated and will take up no more magnetism. Then treat
the second piece in the same way. Always make two
at the same time and keep them by laying them with an
N and an S-pole at the same end of the box, separating
the magnets lengthwise by a strip of card board, and
placing a strip of tinned iron or strap iron across the
ends. Laid away separately or with two N-poles side
by side they lose strength. Fig. 66.

FTTTIZAL
LE
Fig. 66. Two Bar Magnets with Keepers across ends. A represents
north pole and B, south pole.
As shown in Fig. 67 wrap insulated wire around the
bar or on a spool in which the bar will be placed. Con-
nect the wire to a battery, dynamo or electric light cir-
cuit, and while the current is flowing in the coil tap the
bar with a hammer. Stop tapping before the current is
turned off. No one unskilled in the handling of elec-
trical machinery should do this, as one can cause con-
siderable damage to himself and to the electrical wiring.
Correct management of this process will produce the
strongest possible magnet.
150
ELECTRIC RAILROADING
Question 6. Do magnets need to be handled care-
fully?
Answer. Yes. Dont: Heat, drop hammer, or file
your magnet, for it will lose strength.
Question 7. How should magnets be kept when not
in use?
EM
N
-Direction
T+
B
of Moving Bar.

EM
-WB
Fig. 67. Making a Magnet by means of an Electro-magnet.
Answer. Bar magnets should be laid side by side,
separated by a thin strip of wood, the north end of one
and south end of the other at same end. Strips of iron
should be laid across the ends so as to touch both mag-
nets as in Fig. 66.
Horse-shoe magnets should have a strip of iron laid
across the ends as in Fig. 68.
Question 8. What is a magnetic needle?
MAGNETISM-INTRODUCTION
151
Answer. It is a long slender magnet, as compared
with its own width and thickness, fitted with a cap in
the center so that it may be balanced on a pivot or hung
from a thread. This allows it to turn freely. Fig. 69.

•
{
A
N
Fig. 63. A Horseshoe Magnet with its Keeper or Armature A.
Question 9. How may you determine whether a bar
is a magnet or not?
Answer. To decide the question whether the bar in
our hand is a magnet or not we put it to test in this way.

152
ELECTRIC RAILROADING
Remember, however, that should the bar be of wood,
fibre, copper, zinc, etc., there is no need of a test since
only steel, iron and nickel have enough magnetism in
them to be worth calling magnets.
A
B
...S
Fig. 69. Magnetic Needle.
I. Bend a stirrup of copper or brass wire and sus-
pend the bar in it. Hang the whole by a single thread
that has been untwisted and soaked in water long
enough to take out all the twist. If the bar persistently
returns to the north and south line after being moved
out of it; then it is a magnet.
2. As a further precaution procure a magnet needle
from some dealer and suspend it as in Test 1. If it sat-
isfies this test proceed to take your bar in hand and cau-
tiously approach one end of the magnet. Should it at-
MAGNETISM-INTRODUCTION
153
tract it reverse the piece in your hand, and it should now
repel. If it does all right, it is a magnet; if it does not,
it is not a magnet.
Question 10. Why is the repulsion test more impor-
tant than the attraction?
Answer. Because any piece of iron or steel will be
attracted to a magnet but only a magnet will ever be re-
pelled.
Question II. Is this rule absolute?
Answer. Hitherto only iron, steel and nickel have
been mentioned as capable of being made magnets. Co-
balt and manganese possess, limitedly, the same capabil-
ity. Metals of this character are called Paramagnetic,
and are attracted by the poles of magnets. There are
other substances, among which are phosphorous, bis-
muth, zinc and antimony, which act in a contrary man-
ner, being repulsed by magnets. These substances are
known as Diamagnetic substances.
This repulsion is so weak that it can never be mis-
taken for the repulsion of a magnet by a magnet. Fur-
thermore, these diamagnetic metals are repelled by either
end of a magnet.
Question 12. What are the poles of a magnet?
Answer. The ends of a magnet are called its poles.
Question 13. How are the poles named?
Answer. The end which points to the north geo-
graphical pole is called the north pole of the magnet,
the other end is called the south pole of the magnet.
Question 14. How are the poles marked?
Answer. The north pole with an N or a line cut in
the steel, the other end is left unmarked.
Question 15. What is the polarity of a magnet?
Answer. By polarity we mean the nature of the mag-
}
154
ELECTRIC RAILROADING
netism at a particular point, whether it is north or south
magnetism.
Question 16. What are consequent poles?
Answer. In long magnets extra poles may be found
besides the poles at the ends. These extra poles always
come in pairs. Such a magnet is shown in Fig. 70.
Question 17. What rule gives the results of magnetic
attraction and repulsion?

N
S
Fig. 70. A Magnet with Consequent Poles.
Answer. Either pole of a magnet attracts a magnet-
izable metal. Like poles repel, unlike poles attract.
If you take a magnet a foot long and brutally jab it at a
tiny compass needle this rule may not work and the rea-
son is this: The great power of the large magnet sweeps
out the private magnetism of the compass and. replaces
it by magnetism whose poles are just the opposite to
that which was formerly there. When the poles are re-
versed, then where there was repulsion there will now
be attraction.
Question 18. But the end of the magnet which points
to the north geographical pole is called the north pole of
the magnet?
MAGNETISM-INTRODUCTION
155
Answer. Yes, for convenience we do say this and
then to get out of the difficulty we say that the south
magnetic pole of the earth is up at the north geographic
pole.
It must be definitely understood that when we speak
of the "magnetic north pole" we mean that spot on the
earth's surface which exhibits "south polarity."
When we speak of the north pole of a magnet we can
avoid any confusion by saying the "north seeking pole."
Question 19. Has the earth polarity?
Answer. Yes, the region around the north geograph-
ic pole has south pole magnetic polarity. Around the
south geographic pole there is north pole magnetic po-
larity.
Question 20. Is not the north magnetic pole exactly
at the north geographic pole?
Answer. No. Standing in Chicago the compass
points a little east of the geographic north. At San
Francisco it points 16 degrees* east and in New York
10 degrees west of the true north.
Question 21. Why is this?
Answer. The magnetic north pole is about 1400 miles
south of the north pole and looking from New York
about 10 degrees west of it. Why the magnetic pole
should be here instead of at the north pole we do not
know.
Question 22. Are there any places where the compass
points to the north pole?
*If the circumference of any circle is divided into 360 equal
portions, each is called a degree. A right angle embraces 90°
(° is abbreviation for degree).
All degrees are not of the same size unless the circles happen to
be the same size.

156
ELECTRIC RAILROADING
Answer. Yes. There is a ring around the earth
where the compass points north. This ring is an irreg-
ular line. In the United States, Charleston, S. C., the
east end of Tennessee, Columbus, Ohio, and Lansing,
Mich., are on this Agonic line. It crosses Russia, Per-
sia and Australia.
90
Sto
N
120
NIE
90
Fig. 71. A Compass marked with Degrees as well as the Points of the
Compass.
Question 23. Is the magnetic north pole fixed?,
Answer. No. In 1580 in London the needle pointed
II° east of north, it gradually swung over till in 1657
pointed true north, it kept on till in 1816 it pointed 24°
west of north and then it swung back so that in 1907 it
points about 15° west of north. It seems as if it took
about 320 years to make a complete swing.
Question 24. What name is given to this peculiarity
of the compass?

MAGNETISM-INTRODUCTION
157
Answer. It is called the Declination of the compass.
It may be easily remembered because the compass de-
clines to point true north.
Fig. 72. Dipping Needle.
Question 25. What is a compass?
Answer. The usual compass is a magnetic needle sus-
pended over a card bearing the names of the points of
the compass and sometimes the 360° of the circle are
marked out. Fig. 71.
158
ELECTRIC RAILROADING
Question 26. Why do home made compasses balance.
badly? One end seems too heavy.
Answer. Near the equator of the earth a needle may
be balanced and then magnetized, but in other places.
if the needle is balanced and then magnetized one end
of the needle will dip. Fig. 69 shows this. If the needle
is mounted so that it can turn with perfect freedom ver-
tically as in Fig. 72 it will in Chicago incline from the
horizontal line about 70°.

Fig. 73.
Showing Dip or Inclination of Needle at Magnetic north pole,
Magnetic equator, Magnetic south pole.
Question 27. Is this Inclination of the needle the
same all over the world?
Answer. No. In Fig. 73 is shown the Dip or Inclina-
tion of the needle at the magnetic north pole, magnetic
equator and magnetic south pole. As you leave the
equator going either way the dip increases until you
reach the poles.
Question 28. How is the dip neutralized in com-
passes.
Answer. By balancing the needle after magnetizing,
or if the compass must be used all over the world by at-
taching a tiny sliding weight.
North of magnetic equator the weight is put on south
end of needle and south of it it is put on the north
end of needle.
MAGNETISM-INTRODUCTION
159
J
Question 29. What is the magnetic equator?
Answer. It is an irregular line running around the
world, being north of the geographic equator on Atlan-
tic ocean and south of it on Pacific ocean.
line there is no dip to the needle.
Along this
Question 30. Do you consider the earth a huge spher-
ical magnet?
Answer. Yes. These experiments tend to show that
the‍earth is a magnet, for it magnetizes objects.
Experiment 1. Procure a small pocket compass, and
hold this so that the needle will move freely, against an
iron stovepipe. Raise and lower it past the joints in the
pipe, and as a rule the action of the needle will show
that there is a change of polarity at each joint, the ends
of the needle being alternately attracted in passing.
Experiment 2. With the same compass explore the
polarity of any permanent piece of iron, such as a bal-
cony, an iron safe, a gas or water pipe which lies in a
north and south position, and it will generally be found
that the north and south extremities between joints will
show different polarities.
Experiment 3. Explore the polarity of a street car
rail lying in a north and south street. Its polarity will
be found to be lengthwise of the rail. Now try a rail.
lying in an east and west position, and it will generally
show a polarity at right angles to the length of the rail—
the north side will show one polarity, while the south
will show the other.
Experiment 4. Take a fine cambric needle from a
package which has been lying in a north and south po-
sition, and drop it carefully on a glass of water. In the
majority of cases, if properly handled, it will float, and
generally show polarity by settling in a north and south
position.
160
ELECTRIC RAILROADING
Experiment 5. If now, while this needle is lying on
the surface of the water we approach it carefully with
the compass, one pole will be attracted, and the other
pole will be repelled. That is, the two ends of the com-
pass needle will repel the like ends of the floating needle,
but will attract the dissimilar ends. This experiment may
be made still easier by floating the needle with a tiny bit.
of cork through which it has been thrust.
Question 31. Can the earth's magnetism be shown in
any other way?
J
Answer. Yes, if a bar of hard steel or even hard iron
and some iron filings are procured.
Hold the bar level in an east and west position and
strike one end a smart blow with a hammer. Now dip
it in the iron filings and we shall find it has little or no
magnetism, at least in its length. Now point it down-
ward at an angle corresponding to the latitude where.
you are, so as to point to the actual north magnetic pole
as nearly as possible, and strike the end of the bar, as
before. You will find that the bar has acquired a quite
perceptible amount of magnetism; that either end will
attract the iron filings, tacks or other bits of iron, and
that the phenomena of attraction and repulsion will be
shown by bringing it near the compass needle.
Now, having marked the end which attracts the south
end of the needle with paint or chalk as the N polę, we
again point it to the north pole of the earth, but in a re-
versed position, and strike it again as before. On test-
ing for magnetism we will find that the particles of iron
adhere as before, but what we marked as the N pole of
our magnet has become the S pole, and repels the end of
the needle it attracted before.
}
LESSON II.
MAGNETISM-CONTINUED.
Question 1. For the experiment in A. 31 of Lesson
10 why is it necessary to take hard steel to get best
results?
Answer. We know that wrought iron becomes a mag-
net readily, steel castings are easily magnetized, cast iron
less easily and hard steel is the most difficult of all to
magnetize. The more difficult it is to magnetize a sub-
stance, the better it retains its magnetism. If you want
a permanent magnet use hard steel. If you want a tem-
porary magnet use iron or steel castings..
Question 2. Do you mean steel castings or cast steel?
Answer. I mean steel castings which are made of
Bessemer steel. Cast steel is a high grade steel which is
expensive and is used for tools, etc.
Question 3. Does magnetism permeate some metals
better than others?
Answer. Yes. We say that some metals have greater
permeability than others.
Wrought iron is the most permeable, cast iron the
least permeable, of the cheaper metals. Hard steel has
small permeability.
Question 4. Do some metals retain magnetism better
than others?
Answer: Yes. The retentivity of wrought iron is
least, and that of cast iron the greatest of the commonly
used metals, Hard steel has great retentivity.
་
161
162
ELECTRIC RAILROADING
Question 5. How can you explain the facts`of differ-
ent permeability and retentivity?
Answer. We know the following facts, and from
these we have thought out an explanation which we
think is correct.
Facts:
(1) The softest iron is the most permeable.
(2) Soft grey cast iron has greater permeability than
hard white cast iron.
(3) The harder the steel the less permeability.
(4) When a bar of iron or steel is suddenly mag-
netized there is a faint click and the bar lengthens slight-
ly. If magnetized and demagnetized rapidly the clicks
will merge into a hum or buzz. Keeping this up for a
length of time heats the bar.
+
+
Fig. 74. The result of Breaking a Magnet is Several Short Magnets,
(5) Pounding or jarring a permanent magnet
weakens it. So does heating it red hot.
(6) If a magnet is broken, each piece is a perfect
magnet with two poles. No matter into how many
pieces you break a magnet, each is still a magnet. See
Fig. 74.
(7) If a thick piece of steel is magnetized and then
laid in nitric acid for some time, when the outer surface
has been eaten off, a test for magnetism will show that
the bar has lost almost all its polarity. Magnetism is
evidently only skin deep.
(8) Four bars 6x1x14 inches magnetized and
MAGNETISM-CONTINUED
163
bound together make a much stronger magnet than one
bar 6x IXI magnetized from as powerful a source.
Theory:-
From the above facts we have concluded that a piece.
of iron or steel is not solid but comprised of innumera-
ble small particles which are each a perfect magnet.
In ordinary iron or steel these are all jumbled up as
in Fig. 75, and do not show any magnetism.

A
Fig. 75. A Bar of Iron Unmagnetized.
There being about as many north and south poles
pointing the same way, they neutralize each other.
Now suppose this bar be stroked by a magnet as in
Fig. 65. The influence of the magnet will be strongest
at the surface and weaker as it penetrates. In fact, after
-inch under surface the action is practically nothing.

B
Fig. 76. A Bar of Iron while magnetized.
What this magnet does is to pull all the little particles
around into line with the north poles pointing one way
and the south poles the other. This movement of the
particles causes a slight noise if they move all at once,
but the gradual movement due to the stroking does not
produce a sound that we can hear. If the rod is iron it
lengthens a tiny bit; if it is a nickel rod it shortens a
little (about 1-700000 of its own length).
164
ELECTRIC RAILROADING
The rapid magnetizing and demagnetizing pulls them
around so fast that the internal friction heats the bar.
Fig. 76 shows the bar with the particles all in line, and
as each particle is a miniature magnet, Fig. 77 shows
why the whole bar becomes a magnet.
If now the magnet be pounded the vibrations shake
up the particles and they get jumbled up and the bar
ceases to show its magnetism.
The harder the iron or steel the more difficult it be-
comes to pull the particles into line and make a magnet.
In the same way once magnetized the better they stay
in position.

Fig. 77. Internal Structure of a magnetized Bar.
Very soft wrought iron may be magnetized easily, but
as soon as the magnetizing force is removed the parti-
cles slip back to the jumbled condition.
A glass tube filled with cast iron filings may be mag-
netized by a coil of wire. On examination the filings
will be seen all arranged, end for end.
Handled carefully it will act as a magnet, but when
shaken so as to jumble up the filings it loses its polarity.
You notice we do not say it loses its magnetism, for
it does not. It ceases to have magnetic poles at each
end, i. e., it has lost its polarity.
When we say demagnetize a bar, it would be more
accurate to say depolarize.
We use this word, however, for a different thing and
say demagnetize, for every one understands what we
mean.
MAGNETISM-CONTINUED
165
Question 6. Will a magnet floated on water by corks
be drawn to north or south?
Answer. No. The force that the earth exerts on a
magnet will only turn it into the north and south line.
The poles of the earth are so far away and the magnet
so small that the distance between the two poles of the
magnet is practically nothing as compared with the dis-
tance from magnet to either pole.
The south magnetic pole of the earth attracts one end
and repels the other end of the magnet. The forces are
equal because distances are equal. The same thing hap-
pens at other end of the magnet. The result is no mo-
tion.
Question 7. Can the earth's tendency to turn a com-
pass needle be neutralized?
Answer. Yes. Take a bar magnet and hold it high.
above and parallel with the compass needle. Let its
north pole point in the same direction as the north pole
of the compass needle.
Slowly lower the magnet until the compass needle
starts to waver. If the magnet is fastened in this posi-
tion the compass needle will stay in any position it is
placed.
Question 8. Is this of any practical use?
Answer. Yes. If surrounding iron objects or mag-
netized things are interfering with the earth's effect on
the compass, then by means of extra magnets these dis-
turbing influences may be neutralized and the earth's
magnetism alone left free to turn the compass.
This must be done with compasses on iron or steei
ships.
Question 9. What is meant by magnetic force?
Answer. The force exerted by one magnet on an-
C
166
ELECTRIC RAILROADING
other to attract it or to repel it, or to attract iron filings
or pieces of iron is termed magnetic force.
Question 10. Does this force act all over the magnet?
Answer. There is almost none in the center, and most
at the ends. Plunging the end of a magnet into a box
of iron filings shows this.
Question II. What are the relative magnetic forces
at different points from the center to the end of a mag-
net?

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Hegneticwdzia
Hextral
L
Fig. 78. Strength of Magnetism as roughly Tested by Lifting Power.
Answer. Fig. 78 shows approximately the magnetic
force at different points. It shows that the pole of a
magnet is not at the tip end, but a little way back.
*
An accurate test of a six-inch bar magnet has shown
these results:
LOCATION OF POINT.
Center
½" away
MAGNETIC STRENGTH.
1
1/2
2
21/2
234 Pole
None
9 units
20
33
Other end gave
48
same results
}
65
84
80
3 Tip end

MAGNETISM-CONTINUED
167
Question 12. What are the magnetic lines of force?
Answer. These words are used in several different
ways. The word magnetic is usually dropped for the
sake of shortness and "lines of force" spoken about.
Engineers usually say "lines."
(1) The magnetic force of a magnet seems to lie
along certain lines and these lines are called "lines of
force." Perhaps "direction of force" would be a better
name.
(2) When a magnetic pole exerts a certain force of
repulsion on the same named pole of a magnet of equai
Fig. 79. Lines of Magnetic Action around a Bar Magnet.
strength we say that there are 10,000 "lines of force"
to the square inch in that magnet pole. If it exerted
twice that force we would say there were 20,000 lines to
the square inch.
Perhaps "units of force" would be a better name for
this,
168
ELECTRIC RAILROADING
It has been proposed to drop the expression "line of
force" when used as "units of force," and say 10,000
gausses. Whether this word will be adopted or not re-
mains to be seen.
Question 13. How may the direction of force be
ascertained?
Answer. Place the bar magnet on a table (Fig. 79)
and lay over it a sheet of glass.

N
Fig. 80. The Magnetic Field of a Bar Magnet as shown by
Iron Filings.
Lift iron filings over the glass and tap very gently.
The filings will arrange themselves and show the direc-
tion of the magnetic force at all points.
Many different combinations of poles should be tried.
Figs. 80 and 81 show two magnetic spectrums.
MAGNETIC INDUCTION
169
Question 14. What is a magnetic field?
Answer. The space around a magnet under its in-
fluence is called a magnetic field.
The spectrum made with iron filings shows the direc-
tions of the magnetic forces in the magnetic field.

Fig. 81. The Magnetic Field of a Magnet Pole. Magnet at Right
Angles to Observer.
Question 15. What is magnetic induction?
Answer. When a piece of soft iron free from mag-
netism is placed in a magnetic field it becomes a magnet
by induction.
Fig. 82 shows this. The part of the iron under the
north pole of the magnet becomes a south pole.
It may be difficult to find a piece of iron which is not
slightly magnetized.
170
ELECTRIC RAILROADING
Question 16. How can you demagnetize?
Answer. Heat to a cherry red and cool very slowly.
The piece may be now hardened and tempered and no
magnetism will appear.
Question 17. Explain magnetic induction more fully.
Answer. (1) Hold a magnet horizontally and at-
tach to its north pole a soft iron nail. To this nail at-

Fig. 82.
Magnel
NI
Soft Tron
-11'ood
Soft Tran
Iron Filings
The Induction of Magnetism in Iron without Contact.
tach another until three or four are adhering to the mag-
net. The end of the first nail which is in contact with
the north pole of the magnet becomes a south pole by
induction. This temporary polarity of the first nail acts
on the other, and so on down the line of nails. The po-
larity of the nails is shown by small letters on the left
side of the nails in Fig. 83.
Now slide the south pole of a similar magnet (the
other one of the pair) over the north of the first magnet.
This magnet will act inductively on the nails, and the
MAGNETIC INDUCTION
171
small letters on the right side of the nails show the polar-
ities induced.
The result of the two effects is to render the nails
neutral, and they drop off.
(2) Attach nail to one magnet as before and then as
in Fig. 84 place the other magnet below. The effect of
the upper magnet is the same as before. The lower mag-
net acts inductively on the nails, but the south pole of
the magnet acts on the lower end of the last nail, so
that the polarities induced are the same as those induced
by the upper magnet. The result is a stronger magnetic

S
IN
∞ g* 78
S
S
N
Fig. 83.
Demagnetizing Inductive
Fig. 84.
Effect of Unlike Poles.
Increased Magnetizing
Effect of Unlike Poles.
action than before. It will be seen by experiment that
more nails can be supported.
Only one set of small letters is used because both mag-
nets induce the same polarities.
(3) If, as in Fig. 85, the two magnets are held to-
gether, we have the same effect as if a stronger magnet
were used.
(4) Placing the second magnet below as in Fig. 86
results in demagnetizing the nails. The left-hand let-
ters show effect of upper magnet, the right-hand letters
172
ELECTRIC RAILROADING
the effect of the lower magnet. Net effect, no mag-
netism.
A slightly different explanation of these four facts.
will be given in Lesson 13. This explanation will be no
better, but merely telling the same thing in a different.
way.
Question 18. Is there any material which will in-
sulate from magnetism?
Answer. No. Deflect a compass needle slightly by
a bar magnet. Slip in between them thick sheets of
cardboard, copper, wood, glass, rubber, in fact anything
but iron or steel, or perhaps a thick slab of nickel, and
the deflection of the needle is not affected.

N
N
S
N
n
S
20%
n
8
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15
S
Fig. 85. Increased Magnetizing
Effect of Like Poles.
N
S
Fig. 86. Demagnetizing Inductive
Effect of Like Poles.
This shows that magnetism passes through anything.
Question 19. What would be the result if a piece of
iron or steel were placed between needle and magnet?
Answer. If a sheet of steel, iron (wrought or cast),
is interposed the deflection will become much less.
Question 20. How do you explain this?
V
Answer. It seems that everything conducts mag-
netism equally well, but perhaps equally poorly would
be more accurate, except iron or steel. Therefore the
magnet does not care or even know that something else
瞽
​MAGNETIC SCREENING
173
has been put in place of part of the air through which
it must send its force or effect. But when the iron is
put in place it is so much better a conductor that, the
magnetic effect prefers the easy path through the iron off
to the side, instead of going on into the air beyond.
Hence only a little effect passes on to the compass. In-
deed, if the iron screen were thick enough in proportion
to the strength of the magnetism present, none would
pass through.

Lines To Magnetic S.Pole
N
Non
Magnetic Body
Lines
From Earth's
N. Pole
"Ztro Line
Lines
To Earth's
S. Pole
Fig. 87. Needle Deflected Through a Non-Magnetic Body.
These effects are shown in Figs. 87 and 88. The lines
along which the magnetic force acts are also shown.
Question 21. Are there any practical uses of the
screening action?
Answer. Yes, several uses are made of it.
(1) Advantage is taken of this fact by putting an ex-
tra hunting case of soft iron on a watch to screen it from
the magnetism of electrical machinery.
(2) Measuring instruments used on switchboards or
near dynamos are enclosed in heavy cast-iron cases..
174
ELECTRIC RAILROADING
(3) Galvanometers are sometimes surrounded by a
cylinder of wrought iron, or a piece of heavy iron pipe.
A small hole is cut in the side, so as to observe the de-
flection of the needle.
Question 22. To what practical use are permanent
magnets put?

S
N
Thick Wrought Iron Plute
Lines
From Earth's
N.Pole
Zero Line
-Lines
To Earth'
S. Pulc
Fig. 88. Needle Screened from Action of a Magnet by a Magnetic
Body.
Answer. They are used in the receivers of tele-
phones; in magneto bells for telephone calling and gen-
eral signalling; in the magnetos used for ignition pur-
poses in gas, gasolene and oil engines; as magnets in
measuring instruments.
Question 23. How are magnets named?
Answer. When an engineer or electrician speaks of
a magnet he means an electro-magnet; when he says per-
manent magnet he means a piece of hard steel which
has been magnetized. In referring to a piece of iron
temporarily magnetized he calls it an armaturę or a core.
LESSON 12.
ELECTRO-MAGNETISM.
It is well known that all the effects due to a natural
magnet or an artificial magnet, can be produced by a
current of electricity.
The effects produced by the electric current are so
much more powerful than natural magnetism, and the
cost is so much less that they are almost universally used.

}
Fig. 89. Magnetic Field due to Electric Current.
Question I. What is electro-magnetism?
Answer. It is the magnetic effect produced by a flow
of electric current.
Question 2. Does a wire carrying current have a
magnetic field?
175

176
ELECTRIC RAILROADING
Answer. Yes. Pass a straight wire carrying a large
current through the center of a sheet of cardboard as
shown in Fig. 89. If iron filings are sprinkled on the
board they will arrange themselves in circles around the
wire, thus showing the magnetic field.
Question 3. Will the wire affect a magnetic needle?
Answer. Yes. If a small compass be placed on the
cardboard and pushed around the wire it will be seen
that the needle is being moved by the magnetic action of
the current in the wire.
B
Fig. 90. Action of Electric Current on Magnetic Needle.
It is also easily shown by holding a wire carrying
current over a magnetic needle. The needle will be
turned and stand at an angle to the wire. Fig. 90 shows
this.
Question 4. Does the wire exhibit north and south
polarity like a bar magnet?
Answer. No, not like a bar magnet. It moves the
magnetic needle in the following way: When the cur-
SNOW RULE
177
rent flows from the South to North Over the needle
the N-end turns West.
This is called the SNOW rule, so called from the first
letters of the important words of the rule.
To test this rule arrange things as in Fig. 91. Turn
the cell so that a line through the copper and zinc
plates will be north and south, and have the copper plate
to the south. Bend your wire circuit into a loop stand-
ing vertically in the N. and S. line. Stand behind the
zinc plate facing south; put a small compass in this
loop with the N. mark on the box pointing to the north.

N
T
Z
Fig. 91. The S-N-O-W Rule.
If the circuit is open, i. e. the dry ends of the plates
not touching, and the connecting wires cut and the ends
held apart, then the N-end of the needle will as usual
point to the north.
Close the circuit by touching the ends of the wire,
and the N-end of the compass will move to the west
Since we say the current flows
(to your right hand).
from carbon to zinc plates, this proves our rule cor-
rect..
178
ELECTRIC RAILROADING
Question. 5. Give a further proof that although the
current acts magnetically it does not act like a bar mag-
net.
Answer. If the wire were a simple bar magnet put-
ting the current under the needle would not change the
direction of the deflection, but it does change the direc-
tion of the deflection. Further if the wire were like a
bar magnet when the current was reversed it would
change in polarity and attract the needle holding it in
the north and south line, but it does not do this. When
the current is reversed it deflects the needle the other
way.
Question 6. Why does the current act in this way
on a magnetic needle?
Answer. We do not know. The current acts as if
it had a paddle wheel of magnetism rotating on the
wire as an axle and in the opposite direction to the
hands of a watch when the current is flowing towards
you.
Standing in the position shown in Fig. 91, when the
current is over the needle flowing towards us (north),
the part of the whirls (paddle wheels) of magnetism
on the under side of the wire are turning towards the
west and knock the N-end of the needle in that direc-·
tion, and since the S-end always does the opposite thing
it goes east.
But moving the wire under the needle the parts of
the whirls on top of the wire are moving east and push
the N-end of the needle in that direction.
Fig. 92 shows the magnetic whirls around the wire,
and the effect of the SNOW rule. For since the cur-
rent runs in the opposite direction from the rule, we
should expect to find the N-end of the needle move in
RIGHT HAND RULE
179
the opposite direction. This is exactly what it does.
The N-end of the needle moves East.
This may be made into a rule and called the NOSE
rule.
When a current flows from North Over a needle to
the South the N-end is deflected East.
Question 7. For what is the extra hand in Fig. 92?
Answer. The extra right hand shown in the illus-
tration is another way of remembering the SNOW rule,
and is especially adapted to discover in which direction
the current flows.

Battery
Right Hand
N₁
Wire
Dotted Circles and Arrows
thereon indicate direction
of Current's Field of Fore
Fig. 92. Action of Current on a Magnet.
Arrange the wire ABOVE the needle in a N and S line
placing the palm of RIGHT HAND OVER the wire with the
THUMB Stretched out at right angles to the hand and
pointing towards the N-END of the needle. The FINGERS
point IN THE DIRECTION the current flows.
Question 8. What is an electro-magnet?
Answer. An electro-magnet consists of a coil of wire,
180
ELECTRIC RAILROADING
a piece of soft iron to fill the hollow of the coil and a
current to pass through the wire.
Fig. 93 shows this, as well as the lines of magnetic
action.
Question 9. What are the technical names of the
parts of an electro-magnet?
Answer (1)
The iron is called the core.
(2)
The coil of wire is called a helix.
(3) The helix carrying current (without a
core) is called a solenoid.
*

N
Battery
Fig. 93. An Electro-Magnet with its Magnetic Field.
(4) A core placed in a solenoid makes it an
electro-magnet.
Remember plugs of brass, fiber or other materials
placed in a solenoid are not cores in the technical sense
of the word.
(5) The helix or coil is usually not wound on
the core but on a spool of brass or bronze. The ends
of this spool are called the flanges and show in Fig. 93.
(6) On horse shoe magnets the iron connecting
the two cores is called the yoke.
POLARITY OF MAGNET
181
Question 10. Why is the left end an N-pole and the
right end a S-pole. (In Fig. 93).
Answer. The polarity of a magnet depends on the
direction of the current flow through the helix.
In Figs. 94 and 95 the current enters at the right hand
end of the helix, but being wound, one right handed and
the other left handed the polarities developed are as
shown.
N
5

愛愛​愛愛
​+
Fig. 94.
Electro-Magnet with Right-handed Helix.
Question II. What rule will give you the polarity of
a magnet?
Answer. Hold the magnet so that the current flows
through the helix away from you. If the current flows.
round the core in the direction that the hands of a watch
or clock move, the pole you are looking at is an S-
S
N

+
Fig. 95.
Electro-Magnet with Left-handed Helix.
pole. If the current went counter-clock wise around the
core, the pole is an N-pole.
Question 12. Is there any other rule?
Answer. Yes. It is a rule especially applicable to
winding horse shoe magnets so that both legs of the
182
ELECTRIC RAILROADING
magnet will not be accidentally made of the same po-
larity.
Write on the pole piece the letter S or N as the case
may be and put arrow heads on the ends of the letters
as in Fig. 96. These arrow heads show the direction
the current must flow around the core to give the po-
larity indicated by the letter.

S
N
Fig. 96. Rule for Proper Winding of Horse-shoe Magnets.
Question 13. What is the strength of a magnet?
Answer. The term "the strength of a magnet"
is used very carelessly. Some people mean its lifting
power, while engineers and electricians mean the actual
quantity of magnetism flowing from a pole piece.* The
expression "strength of a magnet" should only be used
as engineers or electricians use it.
Question 14. What is the lifting power of a mag-
net?
Answer. It is the number of pounds the magnet will
hold up, when things are arranged as in Figs. 97 and
98.
*In electro-magnets when we say pole we generally mean the
end of the core. Usually we say pole piece, meaning the surface
at the end of the core, or the piece of iron which is screwed,
bolted or even cast on the core to make the actual pole larger
than the core.

LIFTING POWER
183
There are some very curious things about lifting
power. It depends upon the shape of the magnet, and
the actual quantity of magnetism. A horse shoe mag-
net will lift three or four times as much as a bar magnet
of equal strength. A long bar magnet will lift more
than a short one; the actual quantity of magnetism be-
ing the same.
A
B
Fig. 97. Horse-shoe Magnet
Arranged for Test of Lifting
Power.
Fig. 98.
Testing Lifting
Power of a Solenoid.
A magnet with round or pointed pole pieces will lift
more than the same magnet with flat or broadened pole
pieces. The same magnet may have its lifting power
changed by unscrewing its pole pieces and screwing on
a flatter set.
It is an excellent joke to wind a horse shoe magnet
with one pole piece flat and the other rounded. If one
will hold 5 pounds the rounded one will hold 6 pounds.
184
ELECTRIC RAILROADING
A magnet having its armature loaded almost to the
pulling off point, may have its load increased slightly
the next day. This gradual increase of the load may be
attempted every day until finally the armature will be
torn off.
It will be found that the last day the magnet was
holding up a load that it could not have held had it
been applied all at once. This may be easily proved by
trying a load a little less than that which tore the arma-
ture away. The magnet will not be able to hold it.
Doubling the strength of the same magnet more than
doubles its lifting power, but a magnet will not pull
twice as strongly if you move up twice as close to it.
A test made with the armature in contact with the
poles of the magnet with increases in the magnets'
strength gives practically the following results for lift-
ing power.
Do not forget that doubling the current in an electro
magnets coil does not double the strength. This will
be fully explained later.
Test I.
Relative strength of Magnet.
I
2
Relative lifting power.
I
4
3
9
4
16
5
25
6
36
7
49
8
64
9
81
ΙΟ
100
LIFTING POWER
185
Test 2.
A test made with a horse shoe magnet to determine its
lifting power at different distances from its poles shows
the following results:
Distance away from poles.
O
I
2
3
4
Lifting power.
82.0
35.0
25.0
20.0
567
8
9
10
15.1
12.1
11.3
9.3
7.4
6.5
5.5
LAW OF DIRECT AND INVERSE SQUARES.
The results of Test I are not the actual figures in the
test. They have been increased or diminished a little
in order to illustrate what is called the Law of Direct
Squares.
By looking at the table of results you will notice that
the lifting power is always the strength of the magnet.
multiplied by itself. For instance when the magnet was.
5 times as strong as before it lifted 5x5 or 25 times as
much.
When the magnet strength was increased from 1 to 2
the lifting power was increased from 1 to 4. Doubling
the strength quadrupled (2x2) the lifting power.
186
ELECTRIC RAILROADING
With a magnet 5 units strength, doubling its strength,
quadrupled its lifting power; increased it from 25 to
100.
We call a number multiplied by itself a square. The
number which is multiplied we call the square root.
To find the lifting power of a magnet square its
strength.
Having found this rule we could go farther than the
results of the test and predict that if the magnet had
been increased in strength to 12 times the original
value, the lifting power would be 12x12 or 144.
The greater the strength of the magnet the greater
the lifting power. This is called a direct relation.
The complete rule as stated in text books is:
The lifting power of a magnet varies directly as the
square of its strength.
Varies means changes.
Directly means they both increase.
Square means multiply strength by itself.
The results in Test 2 do not seem to follow any rule.
Even if the figures were changed a little as in Test I
they could not be made so as to get a rule from them.
It is stated in nearly all text books that the lifting
power of a magnet decreases according to the square
of the distance from the magnet. They state the rule
thus:
The attraction of a magnet varies inversely as the
square of the distance.
This rule is true with very tiny magnets at small dis-
tances and in a space absolutely neutral, free from any
magnetism, even the earth's effect.
Under the circumstances of ordinary life this rule is
worthless,
1
LAW OF INVERSE SQUARE
187
What the test shows is this:-As you recede from a
magnet the lifting power decreases at first rapidly and
then more slowly.
The word inversely in the rule means the greater
the distance the less the lifting power.
The inverse square of a number is found by squaring
the number and placing it in the denominator of a frac-
tion whose numerator is I.
Example:
Numbers
1 2 3 4 5 6 etc.
1 4 9 16 25 36 et..
Direct Squares
Inverse Squares
1
1
1
to
121555
36 etc.
The peculiar thing about I is that IXI is still I and
that the fraction I-1 is still 1.
The importance of these laws of direct and inverse
squares is greatly magnified. At the best magnets do
not follow the first rule closely, and they do not follow
second rule at all,
LESSON 13.
ELECTRO-MAGNETISM-CONTINUED.
Question 1. What is the "strength" of a magnet,
speaking in a correct manner?
Answer. The actual quantity of magnetism flowing
through one square inch of the surface of the pole piece.
Question 2. How is this quantity of magnetism meas-
ured?
Answer. Scientists have selected for a unit of mag-
netism a quantity they call a "line."
Their tests for the presence of "lines" and the deter-
mination of how many "lines" there are in a magnet,
need not worry us, as the engineer's job is usually to
produce "lines."
Take a stick of wood one inch square, wrap around it
a piece of wire making one complete turn and no more.
Pass a current of one ampere through this turn of wire
and you will produce a flux of a little over 3 lines.
Question 3. What does Flux mean?
Answer. The term flux is used to speak about the
total quantity of magnetism. For example, a designer
will say that the flux from a magnet is 3½ million lines.
Question 4. What is meant by Density?
Answer. By density we mean the flux per square
inch. A designer may say that both these magnets have
a flux of 2 million lines; but this one having a density
of 10 thousand lines has a smaller core than the other,
the density of which is 5 thousand lines,
188
FLUX OF MAGnet
189
To get the flux of a magnet multiply the density by
the area of the pole piece in square inches.
Knowing the flux we find the density of any part by
dividing the flux by the area of that part in square
inches.
Question 5. What is meant by Intensity of magneti-
zation?
Answer. It is an out of date term among engineers.
A man using the expression probably means density.
Question 6. What is meant by Magnetizing Force?
Answer. Magnetizing force or Magneto-motive force,
means the force that is causing magnetism to flow out
of the pole piece. In other words magnetizing force is
the cause of flux.
Question 7. How is magnetizing force measured?
Answer. Since one turn of wire carrying one ampere
current causes a definite flux, we use this as the unit to
measure magnetizing force. It is called the Ampere
turn.
Experiment shows that half a turn of wire and two
amperes cause the same flux as three turns and one
third of an ampere. In fact, an ampere turn is any com-
bination of turns and currents arranged so that the num-
ber of turns multiplied by the current in amperes gives.
a product of one.
Question 8. Upon what does the flux from a magnet.
depend?
Answer. (1) Material of core.
(2) Length of core.
(3) Number of turns of wire in coil.
(4) Current in coil..
(5) Shape of magnet. .
190
ELECTRIC RAILROADING
Question 9. Why does the material of the core affect.
the magnet?
Answer. To answer this clearly let us go back a little.
A solenoid such as shown in Fig. 99 has a certain flux
whose density is calculated by the following rule.
The density is equal to the number of Ampere-turns
multiplied by 0.313 and divided by the length of the
solenoid in inches.

0000000
Fig. 99. Flux in a Solenoid.
If the solenoid is very short the density at the ends
may be much less than in the middle.
Let us assume that we have a solenoid with a central
space one square inch in area and of such a number of
turns and carrying such a current that it has 3133 A. T.
(ampere-turns) to each inch of its length.
Since one A. T. gives a flux of about 3 lines per
square inch (see A 2), these 3133 A. T. will give a flux
of 10,000 lines.
Let us take a solenoid like Fig. 99 and slip a wrought
iron core into it making a magnet as in Fig. 100. Have
the area of the bars' end one square inch (a bar 1%
inches in diameter has a cross section of practically I
square inch).
Let the magnet have such a helix and carry such a
current that there are 2.2 A. T. per inch of its length.
EFFECT OF CORE
191
The flux of this magnet will be 10,000 lines.
This experiment can be completed by making a magnet
of 1% inch diameter cast iron rod with 18.5 A. T. per
inch, and the flux will again be 10,000 lines.
It is quite evident then that the core has great in-
fluence on the strength of the magnet.

CC G C C C C
Fig. 100.
Flux in a Magnet: i. e., a Solenoid with Iron Core.
The explanation is that wrought iron has far greater
permeability than air and so 2.2 A. T. per inch can in-
duce in the wrought iron as much flux as 3133 A. T. per
inch could induce in air.
The permeability of cast iron being less than wrought
iron it takes 18.5 A. T. to do the work that 2.2 A. T.
did before.
Question 10. How does the length of the core affect
the flux?
I
Answer. In this way 500 A. T. wrapped on an 1%
inch round iron* bar one inch long would give a flux of
*When we speak of iron we mean in general wrought iron or
Bessemer steel. When we mean cast iron we generally say so.
Bessemer steel is cast iron with the extra carbon burnt out. It
is nearer to wrought iron than any other metal.
192
ELECTRIC RAILROADING
115,000 lines; while if the bar was 10 inches long there
would only be a flux of 90,000 lines.
Question 11. Why does not the same number of A. T.
give the same flux?
Answer. Because the iron although a good conductor
of magnetism, offers some opposition to the flux. So if
500 A. T. can induce in a core one inch long, a flux of
11,500 lines, in a longer core it is to be expected that
the flux will be less.
The magnetizing force of 500 A. T. can only do a cer-
tain amount of work and the longer the path the flux
must be forced through, the less flux there will be.
To get the same flux through different lengths of cir-
cuit the A. T. per inch of circuit must be the same.
Question 12. Well then, if 500 A. T. give a flux of
115,000 lines through 1 inch of iron, why did they not
give 11,500 or 1/10 of 115,000 through the 10 inch piece?
Instead of that you say 500 A. T. on a 10 inch piece give
a flux of 90,000 lines.
Answer. The reason is that while iron is more per-
meable than air the exact degree of permeability depends
on the density.
500 A. T. on a 1 inch piece is 500 A. T. per inch.
500 A. T. on a 10 inch piece is 50 A. T. per inch.
Five hundred A. T. per inch can only create a flux of
11,500 per square inch because the density is so high that
the iron offers a great deal of opposition to the flux,
while 50 A. T. per inch, not being strong enough to
create a great flux, finds the iron offering less opposition
and is able to create a flux per square inch of 90,000, or
nearly eight times what you would expect.
Question 13. Why does iron offer different opposi-
tion at different degrees of magnetization?
EFFECT OF DENSITY
193
Answer. Why iron should need greater and greater
increases of magnetic force to produce the same increases
of density (flux per square inch) we do not know. It
does not even act in any regular manner.
It is easy to show that this, does occur, and perhaps we
can understand the peculiar action a little from the fol-
lowing experiment:
Procure a thick short elastic band and a bunch of
butcher's wooden skewers.
Place a dozen skewers inside the band points down.
No effort is required; they practically fall in. Place an-
other dozen in. Perhaps a gentle pressure is necessary
as you begin to feel the pressure of the band.
The next dozen must be pushed in. The following
dozen you have to push in one at a time. At last you will
have to drive the skewers in, one at a time, with a block
of wood or a light hammer.
Evidently the ease with which the skewers can be
placed inside the band depends on the number of skewers.
per square inch you are trying to get in. As the density
increases the difficulty of insertion increases.
The iron acts in the same manner. The more flux in
a core the greater a magnetizing force is necessary to
place additional lines in it.
Question 14. Do all magnetic materials act in this
way?
Answer. Every magnetic material acts in this way in
its own peculiar fashion.
Question 15. How do the non-magnetic materials
such as brass, air, fibre, etc., act?
Answer. Non-magnetic materials act in an ordinary
manner. Twice the magnetizing force produces twice
the density.
194
ELECTRIC RAILROADING
Question 16. What statement can be made about per-
meability of materials?
Answer.
(1) The materials which are in common
use are here arranged according to their permeability at
a density of 10,000 lines. The first has the greatest
permeability.
(a) Annealed wrought iron.
(b) Soft steel castings.
practically equal.
(c) Cast iron with a little aluminum.
(d) Ordinary grey cast iron.
(e) Air, fibre, brass, zinc, copper: (All practically
equal and very low.)
(2) At first the magnetic materials (mentioned in a,
b, c, d) give more than twice the density for twice the
magnetizing force. Then they change and act regularly
for a short time. After this they give rapidly decreas-
ing increase of density for equal increases in the mag-
netizing force, till at last a doubling of the A. T. per
inch hardly increases the density. We then say the ma-
terial is saturated.
(3) They keep the same order of degree of perme-
ability but their actual permeabilities change in different
manners.
At 10,000 density a steel casting is 5 times as permeable
as grey cast iron, while at 60,000 density steel castings
have 18 times the permeability of iron castings.
(4) The permeabilities of all non-magnetic materials.
may be taken the same as air without much error, and
their permeabilities at all densities are the same.
Question 17. How can definite information as to the
permeability of a metal be obtained?
Answer. A specimen is cut and tested in a laboratory.
For all ordinary use the average results as published in
TABLE
195
AMPERE TURNS REQUIRED PER INCH LENGTH
TO INDUCE THE FOLLOWING DENSITIES:
A T per Inch.
Density.
Soft Iron.
Soft Steel
Castings.
Cast Iron.
Air.
5000
1.7
1
10000
15000
હેં હેં
2.2
2.7
aż að ti
2.
13.
1566
3.7
1-
18.5
3133
4.3
00
24.1
4700
20000
3.5
5.
30.5
6266
25000
4.5
5.8
39.
7833
30000
5.5
6.6
50.
9400
35000
6.5
7.6
65.
10966
40000
7.5
8.8
88.
12532
45000
8.5
10.1
116.
14100
50000
9.6
11.8
160.
15665
55000
11.1
13.9
222.
17233
60000
13.
16.4
295.
18800
65000
15.7
19.3
400.
*
70000
19.6
22.7
570.
75000
24.7
27.
*
80000
31.2
34.
85000
39.7
44.
90000
50.7
57.
95000
67.
75.
100000
91.
100.
105000
137.
159.
110000
290.
325.
115000
500.
550.
120000
*
*
125000
*The figures are not given when the number of A T becomes
excessively large or beyond the usual limits of density.
Air gaps are generally worked at a density below 50,000.
A density of over 105,000 is rarely used in iron or soft steel.
To find the A T corresponding to a density not given:-
How many AT per inch are required for soft steel at den-
sity of 37,000.
1
40000
takes
8.8
35000
takes
7.6
Subtract
5000
1.2
Divide by 5
1000
0.24
Multiply by 2
2000
0.48 Add in
35000
7.6
37000
takes
8.08 A T per inch.
This scheme is called interpolation and can be applied to any table.
196
ELECTRIC RAILROADING
books and magazines can be used. This table is taken
from A. E. Wiener's book on dynamo designing.
Question 18. What is Reluctance?
Answer. The name reluctance is given to the total
opposition offered by a piece of material to the passage
of flux.
Question 19. What is Reluctivity?
Answer. Reluctivity is the reluctance of a piece of
material one inch long and one square inch in cross sec-
tion.
Question 20. Why are the two words necessary?
Answer. Because it is necessary to express the reluc-
tances of magnetic circuits. It is equally necessary to
express the reluctances of exactly similar pieces of dif-
ferent materials. To do this we would have to use the
expression "reluctance per cubic inch" unless we use
"reluctivity."
Question 21. Why do we not hear the word reluc-
tivity used more frequently?
Answer. Because we usually are thinking about the
conductivity per cubic inch instead of the opposition per
cubic inch.
The conductivity of a piece of material one inch long
and one square inch in cross section is called its permea-
bility. It is this latter word which we use.
Question 22. What is Permeance?
Answer. The name permeance is given to the total
conductivity of a piece of material for flux.
Question 23. What is meant by saying that reluc-
tivity is the reciprocal of permeability?
Answer. When two things are opposite in sense, as
reluctivity and permeability, one being the opposition,
RESIDUAL MAGNETISM
197
the other the conductivity, of the same piece of metal, we
call them reciprocals of each other.
If the permeability of iron is 200, its reluctivity is
1/200, for the greater the permeability the less the re-
luctance.
Question 24. What is Retentivity?
Answer. A piece of iron becomes a magnet temporar-
ily under the influence of ampere turns but loses nearly
all its magnetism when the current is cut off from the
helix.
What remains is called Residual magnetism. The re-
sidual magnetism per cubic inch is called the retentivity
of the iron.
Iron or soft steel has very little retaining power; hard
steel has great retentivity.
Question 25. Is residual magnetism a good or bad
thing?
Answer. It depends. In dynamo armatures we would
rather not have it; in the yokes of the magnets we are
very glad of it.
In telegraph relays we try to reduce it as much as
possible.
A peculiar thing about residual magnetism is that a
piece of soft iron which has been under the influence of a
magnet only a thousandth of an inch away will show less
residual magnetism than if it had been in actual con-
tact.
Telegraphers take advantage of this and paste tissue
paper on the armatures of relays and sounders so that
they may come very close to the magnetic cores and yet
never come accidentally in actual contact.
Question 26. The word saturated was used in A 16.
What does supersaturated mean?
198
ELECTRIC RAILROADING
Answer. It is possible to magnetize a piece of steel so
strongly that when tested instantly after magnetizing, it
shows a strength in excess of what it will show four or
five hours after.
This second strength is its permanent strength. It can
be magnetized permanently no stronger than this second
strength, so this is called saturation.
Question 27. What is a magnetic circuit?
Answer. From experiments which were first made.
with permanent magnets it seemed as if the flux of a
magnet simply came out of each end. Later when the
result of breaking a magnet was discovered, it was rec-
ognized that the flux must also pass through the middle.
of the bar.
What became of the flux after it left the poles was for
a long time unknown. Experiments like Fig. 80 made
electricians suspect that the flux which left one pole went
around through the air and entered the other pole.
In fact people soon began to believe that magnetism
flows around a circuit just as electricity does.
In the case of the electric circuit it is all copper wire,
while the magnetic circuit is usually composed of iron
and air.
Question 28. Can you give other reasons for believ-
ing that flux flows around a circuit?
Answer. Yes. Make an electro-magnet of a ring of
iron and a coil wound on as in Fig. 101 A. It will
show no polarity at all, and be only slightly magnetic.
Saw out a piece of the metal and the ring will develop
polarity at N. and S. as shown in B.
This shows that the magnetism flowed around the
ring and also across the air gap when one was made,
POLARITY
199
Question 29. Why was there no polarity in Fig.
IOI A?
Answer. Because the iron being a good conductor the
flux passes through it and practically none is in the air
where the testing needle was put.
But if a hole should be bored in the ring and the
compass dropped into it, then the polarity would show,
because flux would pass through the compass.



Solid Iron Ring
with wo external
Polea
Split Ring
with Two
Polea
Sell Rin
200
with
·Polez
Fig. 101. Magnetic Polarity of an Iron Ring.
Question 30. Why did Fig. 101 B show polarity?
Answer. Because the air gap being a poor conductor,
the flux spread out as indicated and affected a compass
needle brought near it.
Question 31. Why should Fig. 101 C develop poles
at opposite sides of the ring and why should it show so
much magnetism in the air around it.
Answer. The left hand part of the winding produces
a N-pole at top of ring. The right hand portion does
the same thing. These North polarities oppose each other
and force the flux out of the iron on both sides.
Part of the flux passes directly across inside of ring to
the S-pole and the rest curves around the outside of the
ring through the air,
200
ELECTRIC RAILROADING
Question 32. What are closed and open magnetic cir-
cuits.
Answer. A circuit composed entirely of iron or mag-
netic metals is called a closed circuit, while a circuit with
an air gap in it is called an open circuit. Even if the air
gap is filled with brass, fibre, etc., the circuit is still an
open one.
Figs. 101 B and C show open circuits. In C the iron
is a continuous ring but there are two magnetic circuits
each composed of a half ring of iron and an air space
across which the flux passes.
The results shown in Figs. 83, 84, 85 and 86 can be
explained by magnetic flux and magnetic circuits, remem-
bering that the permeability of even hard steel is many
times higher than air, which means that its reluctivity is.
many times less.
Suppose that in Fig. 83 only the first magnet with the
nails hanging to its N-pole is present. The flux from the
N-pole passes around the magnet to its S-pole. The su-
perior permeability of the iron nails makes most of the
flux pass to the S-pole through them. This makes them
temporary magnets and they stick together.
Now suppose the top magnet to be slid over the under
one. The permeance of the magnetic circuit composed of
the two magnets lying side by side is much greater than
that of the circuit composed of one magnet, the nails and
all the air from the end of the last to the S-pole of the
first magnet.
Naturally the greater part of the flux goes through the
new path and the part of the flux through the nails is too
small to strongly magnetize them. Their magnetism be-
ing reduced they cease to adhere and drop off.
The second magnet acts as a shunt circuit for the flux
4
MAGNETIC CIRCUITS
201
}
and being of great permeance robs the nails of the flux
that magnetized them.
In Fig. 84, when only the first magnet was there, we
had rather a poor magnetic circuit-a piece of steel, the
nails and a long air gap from last nail to S-pole of
magnet.
When the second magnet is put in position, the perme-
ance of the circuit is improved because the air gap has
been shortened. (Measure it and see.) Furthermore, in
a circuit of greater permeance we have double the mag-
netizing force:
In Fig. 85, the adding of the second magnet increases
the permeance and the magnetizing force. In Fig. 84 we
reduced the air gap, while in Fig. 85 the air gap is left
the same; hence the increase in inductive effect in Fig.
84 is greater than in Fig. 85.
In Fig. 86 the addition of the second magnet gives a
result something like that shown in Fig. 101 C. The flux
from the two N-poles which passes between the magnets
is very weak and does not magnetize the nails sufficiently.
The greater part of the flux goes back outside of the
magnets.
1
1
·
LESSON 14.
LAW OF MAGNETIC CIRCUITS.
It is natural to suppose that there is some direct con-
nection between the value of the magnetizing force and
the flux induced. Also between the reluctance of the
circuit and the flux induced.
These three things: the magnetizing force, reluctance,
and flux are connected in the following way:
Flux=
Magnetizing force,
Reluctance.
This formula while not of much practical use is of the
highest importance theoretically. By that I mean: It is
only by learning this formula by heart and understand-
ing what it means that we can get a clear idea of how the
flux in a circuit changes with the changes of magnetizing
force, and how the changes of reluctance affect the flux.
Let us once more be sure that we know what the terms
used mean.
Flux is the total amount of magnetism in the core, ex-
pressed as so many lines.
Magnetizing Force or Magneto-motive Force is the to-
tal pressure trying to send flux through the circuit. It
is expressed by ampere turns multiplied by 1.25.
Reluctance is the total opposition offered by the circuit
to the passage of flux.
The greater the magnetizing force the more flux; the
greater the reluctance the less flux.
202
MAGNETIC LAW
203
Let us see how this formula could be applied to a prob-
lem in a designer's office.
He would generally know what flux he wanted and he
would know what kind of a circuit he intended to use, so
he would want to find out how many ampere turns must
be wound on the spools.
He must find the reluctance of the circuit. Then know-
ing two things he can twist the formula into this shape:
Magnetizing force Flux X Reluctance.*
Ampere turns =
Flux X Reluctance
1.25
The reluctance of a circuit is equal to the reluctivity of
the material multiplied by the length and divided by the
cross section of the circuit.
This must be so because the reluctivity is the opposi-
tion per cubic inch. The longer the circuit the greater
the reluctance and the greater the area of the cross sec-
tion the less the reluctance.
In the first case the flux has further to travel and in
the second case has more room to travel in.
Calling L length of circuit in inches and a its area, the
formula becomes:
Ampere turns =
Flux X reluctivity X L
1.25 X a
This designer will not find any tables of reluctivity in
books, but he can find tables or curvest of permeability.
Reluctivity is the reciprocal of permeability.
*The way these formulas are changed will be more fully ex-
plained at the end of the lesson.
Curves and their use will be explained at the end of this lesson.
204
ELECTRIC RAILROADING
If a man can do a job in 6 days he can do 1/6 of it in
one day.
The part he can do in one day is the reciprocal of the
number of days needed to do the whole job.
I
Reluctivity =
Permeability
The formula he is using now becomes
Flux
Ampere turns —
Х
L
1.25 a X permeability
To make this formula more compact letters are used for
the words.
Different books use different letters, some even using
German or Greek letters for the names.
We will use A T for ampere turns. X (the last
letter) for flux; and p (the first letter) for permeability.
The formula now looks like this:
A T
X X L
1.25 X a Xp
This is a short way of saying:
The ampere turns required to excite a magnet so as to
produce a flux X are found in this way.
(1) Find the product of the flux and the length of the
circuit.
(2) Find the continued product of 1.25, the area of
the cross section of the circuit, and the permeability of
the material.
(3) Divide the first product by the continued product.
By fussing with this formula the designer has obtained
a knowledge of magnetism that can be obtained in no
other way, but about this point he is apt to be disgusted
DESIGNING CIRCUITS
205
with the formula. He now on looking up the permeabil-
ity tables or curves finds that he must calculate the dens-
ity i. e. flux divided by area before he can find the perme-
ability he wants; for the permeability changes with the
change in density.
After doing this he can replace each letter in the
formula by the proper number and calculate the ampere
turns.
This formula may be changed to appear as:
X =
x=
1.25 X a X PXAT
L
This form is useless as a quick and accurate means of
calculation for you must know the answer before you
start. This is evident because p cannot be obtained until
density is known and density is unknown until the total
flux is determined.
The way to use this formula is to guess at an answer,
use a value of p accordingly and if the answer comes out
too far away from the guess, correct the value of þ and
solve again.
These formulas are not used in designing.
The designer proceeds as follows:
Suppose he has a magnetic circuit of type shown in
Fig. 102. Y is the yoke which measures 12 inches be-
tween centers of holes into which the poles P. are set.
The path of the flux through the poles is 14 inches long
in each.
The part marked a is of sheet iron (annealed wrought
iron sheets). The wires w are of copper. Between the
armature iron and the pole piece on either side is an air
gap of half an inch,
206
ELECTRIC RAILROADING
The magnetic circuit is through 2 X 14 = 28 plus
12 = 40 inches of steel casting. Through 10 inches of
sheet iron, and one inch of air gap.
The pole pieces are, roughly, square 6x6 inches. The
parts of P inside the coils or bobbins B are circular, 5
inches in diameter. The yoke is a slab 5x12 inches. Arma-
ture is 7 inches long and 7 inches wide.

W
*
P
α
a
B
C
B
B
B
Y
Fig. 102. The Magnetic Circuit of a Small Motor.
The flux required is 1,800,000 lines. How many am-
pere turns must the bobbins B contain?
From the laboratory connected with the factory he has
obtained a table as is given in Lesson 13. Ampere Turns
Required per Inch for Different Densities.
He figures the densities:
Yoke: 12x5
60 sq. in.
1,800,000-60
30,000 lines.
Poles: 5 inch circles 19.6 sq. in.
1,800,000 20 90,000 lines.
÷ —
=
Air gaps: 6x6 = 36 sq. in.
1,800,000 36 50,000 lines.
Armature: 7x7 = 49 sq. in.
Say 50 sq. in.
1,800,000 ÷ 50 = 36,000 lines.
DESIGNING CIRCUITS
207
1
Looking at the table he finds steel castings at density
of 30,000 lines take 6.6 A T per inch; at 90,000 lines
they require 57 A T per inch.
Air at a density of 50,000 requires 15,665 A T per
inch; while sheet iron at 36,000 density needs 6.7 A T
per inch.
Referring back to the lengths of the circuits and tabu-
lating the data he has:
Material. Density.
AT Length.
Total A T
per inch.
required.
Steel.
30,000
6.6
12
792
Steel. 90,000
57
28
1,596
Air. 50,000 15,665
I
.15,665
Iron.
36,000
Grand total
6.7
ΙΟ
67
..18,120
Since there are two coils there will be 9,060 A T on
each leg of the magnetic circuit.
With a current of 12 amperes 6,040 turns of wire will
be required.
In a similar manner when a designer wishes to know
the flux that a magnet will produce, he measures its area
and length. He then figures from the 'number of turns in
the coil and the current he intends it to carry what the
ampere turns are. Then he figures the ampere turns per
inch and looking up in the table finds the density induced.
Multiplying this by the area gives him the flux.
This latter calculation can only be made when the cir-
cuit is of one material and of the same size throughout,
but one makes this calculation only once to a thousand
calculations of the ampere turns required.
208
ELECTRIC RAILROADING
In cases where the circuit is of varying dimensions and
materials the ampere turns must be apportioned to each.
part of the circuit before the figuring is done.
Question 1. Suppose two pieces of Bessemer rod*
each a foot long, one 1% inch the other 334 inches in
diameter, were each to be magnetized to a density of
77,500 lines (per square inch). How many ampere
turns would each need?
Answer. Table says 30 A. T. per inch for density of
77,500 for soft steel. One foot is twelve inches.
12X30=360 A. T.
Question 2. But both will not require the same num-
ber of ampere turns? One is I sq. in. in area, the other
is II sq. in.
Answer. They both need the same magnetizing force.
because the lengths and densities are the same.
Question 3. But if 360 A. T. are placed in each rod
there will be a flux of IX77,500 77,500 in one, and
11X77,500=852,500 in the other. How can this be?
Answer. Because 360 A. T. on a 1 sq. in. rod pro-
duces 77,500 lines, but the 334 diameter rod having 11
times the area of the smaller rod offers only one-eleventh
the reluctance and hence the flux is eleven times as great
or 852,500 lines.
But as flux is II times as great and area II times
larger the density is the same.
Question 4. Can you explain this in a different way?
Answer. Suppose 36 turns of wire are made in one
end of a long piece; making the turns around a piece of
18-inch round wood, and a 10 ampere current is sent
* Bessemer rod is rolled from the same material that steel
castings are poured. They are almost like iron. When purchased
they have a plating of copper on them to prevent rusting.
RULE FOR DENSITY
209
through the whole wire. Suppose the turns are pulled
apart until they are evenly spaced and the first and last.
turns 12 inches apart. This solenoid has now
10X36÷12-30 A. T. per inch. This will produce à
density of 98 lines, say 100, in the air inside the solenoid.
Suppose now the whole wire is used to make the 36
turns. Keep the spacing the same but let the turns
be nearly 10 inches across, from side to side. There will
be an area of 78.5 sq. in. now under the influence of
the solenoid.
Each square inch is just as powerfully excited as be-
fore, since there are 30 A. T. per inch surrounding it.
Each of the square inches in the whole 78.5 will have
100 lines induced in it.
Question 5. Can you express this result as a rule?
Answer. No matter what the size of a core the flux
per square inch (density) depends on the number of
ampere turns on each inch of its length.
An expression
FORMULAS
Flux
Magnetizing force
Reluctance
(1)
when written
ATX 1.25
X
x =
(2)
Z
is called an algebraic formula.
These formulas are capable of assuming different
forms, but all these forms are brought about in a regular
manner.
Rules may be given to teach one how to make the
changes but the principle underlying the rule should be
understood.
To place a term such as Z on the other side of the equal
sign, remember that it must be moved either up or down.
If in the denominator on one side it must move to the
numerator on the other side. If in the numerator on one
side it must be placed in the denominator on the other.
Whole numbers are to be considered as in a numerator.
In (2) let us place Z on the left hand side of the equal
sign.
ZXX ATX 1.25.
(3)
The reason for this rule is: Formula (2) must be con-
The
sidered as an equation. The left side is equal to the right
side. Nothing must be done which will disturb this
equality.
210
FORMULAS
211
If we multiply both sides of (2) by Z, the equality will
not be affected, and the equation will look like
ZXATX 1.25
ZXX=
Z
(4)
But the two Z's on the right and side cancel, and we
have
ZXX=ATX 1.25.
(3)
Suppose that in (2) we wished to change the formula
so that the term A T would stand alone.
Z comes to the left numerator; 1.25 comes to the right
denominator, and we have.
Z XX
AT
1.25
(5)
Since these things are equal it makes no difference
which is written first, so we write
ZX X
AT=
1.25
(6)
To substitute for Z any other letter or expression, we
must first be sure that the thing we wish to substitute is
exactly equal to Z.
From the Lesson we know
I
Ꮓ
a X P
(7)
Substitute in (6) for Z its value as given in (7) by
writing in the space occupied by Z the other expression:
I
XX
a X P
AT=
1.25
(8)
The right hand side is now a complex fraction which
must be simplified.
↑
212
ELECTRIC RAILROADING
↑
Do so in this way: Copy the numerator of the com-
plex fraction down separately.
I
XXX
XX
a X P
(9)
Multiply the fraction by the whole number X in the
ordinary way of arithmetic:
IXX
a Xp
(10)
Go back to the complex fraction and copy its denom-
inator changing it to a fraction.
1.25
I
(II)
Now draw a heavy line; place (10) above it and (11)
below it.
IX X
a X P
1.25
I
(12)
Multiply the extreme top and bottom of (12) for a
numerator, and multiply together the middle parts for a
denominator, as shown by the brackets. This gives
IXX
a X PX 1.25
(13)
which we can put back in (8) and get
IXX
AT
(14)
a XpX 1.25
Rearranging the letters we get
XXI
AT
(15)
1.25 X a Xp
as we did in the Lesson.
CURVES.
The use of curves in engineering work was started
with an idea of showing results quickly and making them
easily understood.
Suppose you were trying to impress on a man's mind
the fact that the traffic on suburban trains varied in a
regular manner every morning and evening, and that
the through trains were evenly loaded all day. Also that
the weight of the passengers in the through trains aver-
aged 5% of the weight of the train, while the weight of
suburban passengers varied from 2% to 20% of the
train's weight, according to the time of day.
Hand him the following table and while the informa-
tion is there it will take him some time to get it into his
head. Ask him suddenly: "At what times are the sub-
urban and through trains equally loaded with passen-
gers ?"
See how long before he finds the information which
will enable him to answer.
Table of the Percentage of Passenger Weight to Light
Train Weight, Grand Central Station to Mott
Haven Junction, New York.
SUBURBAN TRAINS.
Per-
Per-
Time.
Time.
centage.
centage
Midnight
2.
6.
I
2.25 7
2
4
345
2.75
8
نب حب حب
9
3.5
IO
5.
II
•
Q
12.
18.
20.
..18.5
14.5
9.
213
214
ELECTRIC RAILROADING
Per-
Time.
Time.
centage.
Noon
8.25
6
Per-
centage.
.19.
I
8.5
7
•
19.25
2
8.75
8
..16.
345
9.5
9
.II.
ΙΟ
..10.5
6.5
..16.
ΙΙ
4.25
Midnight
2.
Per Cent
20
19
18
17
16
15
14
THROUGH TRAINS.
Five per cent at all hours.
Now hand him the following curve (Fig. 103):

13
Suburban
Trains
8
265
432
1
Through Trains
2 3
9
10 11 12
Noon
P.M.
Midnight
12 1 2 3 4 5 6 7 8 9 10 11 12 1 2
Midnight
A.M.
Fig. 103.
Percentage of Passenger Weight to Total Weight of Train.
DRAWING CURVES
215
1
How quickly he grasps the way in which the traffic
varies. He notices much more quickly than he would
by use of the table that from 5 to 8 in the morning there
is an abrupt rise in traffic, while from 6:30 to II in the
evening there is an equal decline in traffic at a much
slower rate. He notices the great changes in train
loads between 5 and 7 in the morning and the slight
change between 2 and 4 in the afternoon.
Ask him again the question, and see how quickly it is
answered.
A curve is certainly a great thing for imparting in-
formation.
The curve is drawn from the table in the following
way: Procure a piece of paper printed with lines run-
ning across at right angles in both directions and at
some convenient distance apart, say 1/10 of an inch, or
for finer work, I millimeter.* This is called cross-section
paper.
Determine which of the set of two numbers you are
most anxious to have show up strikingly, and number
each line up along the left edge accordingly.
Each space can be 1%, but if the percentages run up
very high, you might have to call each space 5%.
Number the lines along the bottom of the sheet ac-
cording to hours. Let one space represent 15 minutes
or one-quarter of an hour, or if there is not room for
this, let each space count one hour.
to
When the lines are
properly numbered, lay out the curve.
Place your pencil on the first vertical line (marked
midnight). Run pencil up along this line until you reach
*A millimeter is 1/10 of a centimeter, i. e. about 0.04 of an
inch.
216
ELECTRIC RAILROADING
DENSITY:-LINES PER SQUARE INCH
the horizontal line marked 2%. Make a dot where
these two lines meet.
On the next line, marked I a. m., run the pencil up
till opposite a point one quarter the way up between
the 2 and 3% lines. This represents 2.25. Make a
dot here.
PERMEABILITY CURVES FOR
STEEL CASTINGS
ORDINARY CAST IRON

120000
110000
100000
190000
STEE L CASTINGSI
18000
170000
60000
CAST IRON
50000
40000
20000
0
100 200 300 400 500 600 700 800 90
MAGNETIZING FORCE:- AMPERE-TURNS PER INCH LENGTH
Fig. 104. Permeability Curves.
With the figures from the table in this way make a
dot at the point where the vertical time line cuts the
horizontal per cent line.
There will be one dot for every set of figures in the
table. When all dots are placed, draw a line through
them and you have the desired curve.
PERMEABILITY CURVE
217
Figure 104 contains two curves drawn from data ob-
tained from the table of ampere turns per inch at dif-
ferent densities.
Certain information can be more easily gained and is
shown in a more impressive manner by these curves than
by the table.
Notice that as you steadily increase the A. T. per inch
on a steel casting at first the result is a great increase in
flux, and the density rapidly increases, but after a while
the density increases very slowly.
With cast iron this same statement is true, but the
effect is not so marked. At first you get a rapid increase
in density and later a slower increase.
The first and last parts of the steel curves are prac-
tically straight lines. Designers often speak of the
"straight line portion of the curve." The part between
these two is called the "knee" of the curve.
The cast iron curve has no definite straight line por-
tions and the knee is so large that it is difficult to ex-
actly locate it.
!
LESSON 15.
PRIMARY BATTERIES.
There are many places where we need a small amount
of electrical power, so little that running a line to the
point would not pay. In such cases we uses batteries.
A storage cell needs more attention than a primary
cell, so many automatic signals, call bells, and such are
operated by primary cells.
There is a deal of truth in the statement, "There is
electricity in everything." The hard job is to get it out.
Suppose you throw a dozen shovelfuls of fine damp
coal into the firebox, and forget to close the door. The
result you get is not the fault of the coal. It was full
of B. T. U.'s¹ and you gave them a chance to get out,
but not in the proper manner, and they failed to do the
work of making steam.
What a difference there is if this same kind of coal
in larger pieces is fired two shovelfuls at a time with
just the right quantity of air.
So it is with electricity; we must treat our materials
in exactly the correct manner if we expect a production
of current worth the money expended.
If one pound of zinc be placed in dilute sulphuric acid
1. B. T. U. is an abbreviation for a British Thermal Unit,
being the amount of heat required to raise one pound of water
from 39 to 40 degrees Fahrenheit (ordinary thermometer). One
pound of good coal contains 1,200 B. T. U.
2. Buy oil of vitriol and dilute by pouring the acid slowly
into 20 times as much water, stirring with a piece of glass. An
earthen ware pot is the safest thing to mix in as the great heat
generated will not crack it.
218
SIMPLE CELL
219
it will dissolve and give out 1,026 B. T. U., but no elec-
tricity. You will notice that there are bubbles of hydro-
gen gas coming up from the zinc and a thermometer
would show the increase in temperature. A certain part
of the energy liberated might have been obtained as
electricity if the zinc were treated in the following way:
Placing the zinc and a piece of copper in a jar of
dilute sulphuric acid, not allowing them to touch below
the liquid, allowing them to touch above it, or connect
them with a copper or iron wire. Now the thermometer
will rise very little, electricity will flow through the
wire and the wire exhibit magnetic qualities. We agree
to say that the current flows from the copper to the
zinc outside of the cell and from the zinc to the copper
in the liquid.
We have now started into action the simplest of the
primary batteries.
This same experiment made with a strong solution of
common salt in water will work as well.
If you attempt to use the current from such a simple
cell you will find that it is very quickly apparently ex-
· hausted.
To be a commercial success a cell should deliver cur-
rent more or less continuously until its zinc is all con-
sumed.
In the words "more or less continuously" lies the dis-
tinction made between cells. An "all around service"
cell is difficult to design, so that we have Open circuit,
Semi-closed and Closed circuit types of cells.
The main thing in any cell is to avoid the tendency of
the cell to "lay down" while there are yet plenty of
chemicals in the cell capable of, under proper circum-
stances, delivering electricity,
220
ELECTRIC RAILROADING
This stoppage of the cell's activity is called Polariza-
tion.
Return to the simple cell of copper, zinc and sulphuric
acid. If it has been used long enough to “lay down,”
examine the plates. The copper one is entirely covered
with bubbles. These are the cause of the cell's non-
action. The cell is polarized. The reason for this name
and the cause of the non-action will be best understood
by first learning this table:
TABLE OF VOLTAIC CELL MATERIALS,
Direction of current through the wire in external cir-
cuit.
Positive Ꮓ I L
C
S
C
Negative
i
r
e
О
i
a
Plates
n
O
a
P
1
H
Plates
с
n
d
P
V
b
e
е
O
1
1*
n
Direction of current through solution in cell.
This table is the result of experiments such as you can
perform yourself. In another glass of dilute sulphuric
acid place two pieces of zinc and connect them. They
dissolve but no electricity is delivered. Try two iron.
plates with the same result, with perhaps less corrosion
of the metal by the acid. Two pieces of lead give no elec-
tricity and are hardly affected by the acid, while two
sticks of carbon are not even attacked by the acid. With
zinc and iron you get a weak and almost useless cell, with
current flowing from the iron to the zinc. Zinc and cop-
per we know to be good, but we find that zinc and carbon
is better,
'
POLARIZATION
221
This table is evidently arranged so that the further
apart the metals stand in it the better a cell they make.
This should set you thinking. A zinc plate and a bub-
ble covered copper plate will not make a cell. Therefore
bubbles must make a positive plate.

POSITIVE
POLE
ELECTRODE
NEGATIVE
OR
POLE OR
ELECTRUDR
NEGATIVE
PLATE
}
CUPPER
1 1
LING
POSITIVE
+ PLATE
Fig. 105. Names of Parts of Cell.
You must find now what the bubbles are and how
they act electrically.
The things in the cells are:
Zinc: that is zinc and impurities.
Copper: that is copper, pure.
Sulphuric Acid: that is sulphur, hydrogen and oxygen.
Water: that is hydrogen and oxygen.
Since the bubbles are of gas they must be either hydro-
gen or oxygen.
Chemistry books will tell you that oxygen makes a
fine negative plate and hydrogen a fine positive plate;
just about as good as zinc.
222
ELECTRIC RAILROADING
t
The cell has then two positive plates in it, and has two
negative poles. (See Fig. 105.) The cell is polarized.
We have learned so far that a cell must have two dif-
ferent materials immersed in a solution and the more
rapidly it attacks one and the less it affects the other
the better the cell. For this reason zinc and carbon, be-
ing cheap commercial products, are almost universally
used in primary cells.
Also a cell to be a commercial success must either
not produce hydrogen gas or get rid of it after pro-
duction.
We will now describe some of the most used cells,
classifying them under headings as follows:
Open circuit: A cell designed for intermittent work.
Periods of work short, intervals of rest long. Usually
designed for small currents. When not in use these cells
must be left on open circuit.
Semi-closed: A cell designed for fairly steady work.
Periods of work long, intervals of rest short. Often de-
signed to produce heavy currents. When not in use
these cells must be left on open circuit.
Closed circuit: A cell designed for continuous work.
Periods of work long, intervals of rest very short. Usually
designed for very small currents. Almost impossible to
design so as to produce much current. When not in use
they must be left on closed circuit.
Polarization prevented: Cell so designed that no
hydrogen gas is produced by chemical action of cell.
Polarization cured: Cell produces hydrogen, but a
chemical placed in the cell turns the hydrogen to water,
which is harmless.
Polarization delayed: Cell has very large and ab-
sorbent negative plate.

DESCRIPTIONS
223
CELLS COMMONLY USED IN RAILROAD WORK.
The Carbon Cylinder Cell. These are sold under the
name of Law, Samson, Hercules, etc. It is an open cir-
cuit, polarization delayed type. They give a pressure of
1.5 volts and have a resistance of 1 to 2 ohms. Two of
them are shown in Fig. 106.
The carbon element is made with as large a surface
as possible. Carbon and charcoal have a remarkable
power of absorbing gases. A cubic inch of charcoal will
condense and absorb 20 to 30 cubic inches of gas.
Fig. 106. Carbon Cylinder Cell.
The zinc element is a rod and the fluid a strong solu-
tion of sal ammoniac in water. The scientific name of
this chemical is ammonium chloride.
The action of the cell dissolves the zinc, forming zinc
chloride, which dissolves in the water.
monia and hydrogen gases are set free.
A little am-
The ammonia
is dissolved by the water and the hydrogen absorbed by
the carbon.

224
ELECTRIC RAILROADING
In time the carbon gets soaked full of hydrogen, and.
to restore the cell it should be taken out and boiled in
water for an hour.
These should only be used for call bells in offices or
such unimportant work.
Leclanche Cell. This is an open-circuit, polarization
cured type. They are made in several forms. Voltage
1.5 and resistance 1 to 4 ohms. Uses sal ammoniac, zinc
and carbon.
Fig. 107. Carbon Cylinder Cell with Depolarizer.
The carbon cylinder cell is sometimes modified to the
Leclanche type by making the carbon element with a
bottom and no opening in the sides. This carbon can or
bucket is filled with lumps of black oxide of manganese
(manganese dioxide). The zinc is made in a cylindrical
This cell is shown in
form, surrounding the carbon.
Fig. 107.
The hydrogen is absorbed by the carbon but the man-
ganese dioxide, being in contact with the carbon, gives
up half of its oxygen to the hydrogen forming water,
while it is reduced to manganese monoxide.
This cell is useful for call bell work, operating mag-

OPEN CIRCUIT CELLS
225
nets on interlocking machines, running tell-tales on inter-
locking boards and such other intermittent light, work.
There is an older form of Leclanche cell shown in Fig.
108, where the carbon is placed in a cup of unglazed
earthen ware (like a yellow flower pot) called a porous
C
Fig. 108. Ordinary Leclanche Cell.
GONDA
NOV 16
Fig. 109. Elements of the
Gonda-Leclanche Cell.
cup. The manganese is packed around the carbon slab.
This form does not give such a large current as the
cell in Fig. 107 because its resistance is high, often as
much as four or five ohms.
A much used form of the Leclanche cell is the Gonda
cell. The elements are shown in Fig. 109.
Here the manganese is powdered, mixed with cheap
molasses. then by, heat and pressure formed into slabs.

226
ELECTRIC RAILROADING
These are attached to the carbon plates by rubber bands.
The bother and resistance of the porous cup is avoided.
The usual charge of a Leclanche type cell is a generous
quarter pound of sal ammoniac dissolved in sufficient
water to fill the jar two-thirds full after elements are in
place.
Fig. 110. Elements of Gravity Cell and Jar.
The Gravity Cell. This is a closed circuit cell with
polarization prevented. It is very much used for tele-
graph circuits, operating the electrical devices in the
lock and block signals, the motors in automatic signals
and generally around interlocking plants. Its pressure
is I volt and its current capacity rather low for its re-
sistance is 3 or 4 ohms.

CLOSED CIRCUIT CELLS
227
This cell is made in many forms called Bluestone cell,
crow-foot battery, Lockwood cell, etc.
The parts of a gravity cell are shown in Fig. 110, and
the assembled cell in Fig. III.
Fig. 111. Gravity Cell Ready for Use.
The glass jars should be about 7 inches high and 6
inches in diameter. The zinc is cast in a shape so as to
be easily suspended from the edge of the jar. The form
shown is called a crow-foot zinc. It weighs about 3
pounds.
The copper element shown on left of Fig. 110 is made
of three sheets riveted together at center and then spread
out as shown. The rubber covered wire must be at-
tached to the copper element by riveting. If soldered
the joint would be eaten away by electrical action.
228
ELECTRIC RAILROADING
1
To set up a cell of ordinary size which holds about 0.8
gallons of liquid make two solutions, one of copper, the
other of zinc.
Zinc solution: Pint and a half of pure soft water
and 10 oz. of crystallized sulphate of zinc (white vitriol).
Mix until dissolved and let it stand half a day in a glass
jar.
Copper solution: Two and a half pints of soft water,
4 ozs. of crystallized sulphate of zinc, 8 ozs. crystallized
sulphate of copper (blue vitriol). Mix and let stand a
few hours in a glass jar.
Dip edge of battery jar for an inch in melted paraffin
and let it cool.
Place the parts in jar as in Fig. 111 and pour jar nearly
three-fourths full of the zinc solution. Place it at once
in the spot where it is to be used and pour in the copper
solution."
}
Insert a glass funnel in the top of a piece of 3-inch
rubber tubing. Hold funnel so that lower end of the tube.
will be in the middle of the jar and just a little above
the bottom.
Pour in the copper solution slowly until the copper
element is completely covered. Place the cell into service.
immediately.
This cell will show a sharply defined line between the
blue copper solution and the colorless zinc solution. This
separation of solutions is essential to the cell's health.
Leaving the circuit open for any length of time will allow
the solutions to mix and spoil the cell.
The action of the cell is such that no hydrogen is per-
manently formed. The zinc is steadily dissolved into
the zinc solution, setting free some hydrogen. This
forms with the copper sulphate, sulphuric acid and me-
GRAVITY CELL
229
tallic copper. The sulphuric acid dissolves more, zinc,
while the copper plates itself on the copper element at the
bottom of jar.
The zinc is consumed and the copper plate grows
larger.
The effect of continued action is to increase the
strength of the zinc solution so that it tends to settle to
bottom of jar.

O
Fig. 112.
Long Service Copper Element for Gravity Cell.
The copper being taken out, bit by bit, from the copper
solution this latter gets lighter in weight and tends to
rise, being pushed up by the zinc solution.
If the blue solution of copper sulphate ever touches.
the zinc it will copper plate it at once. The cell will then
have two copper elements and stop working.
Cells should be given some attention, and clever man-
agement will keep a gravity cell working continuously
for an almost indefinite time,

230
ELECTRIC RAILROADING
As helps in the maintenance of cells two improvements
have been made.
Fig. 113. d'Infrevilles Wasteless Zinc.
The form of copper element shown in Fig. 112 is bet-
ter when heavy currents are not needed. It is a copper
ribbon 4 feet long and ½ an inch wide, coiled like a
Fig. 114. Using Up Old Zines.
clock spring. Zincs shaped like Fig. 113 are used until
the prongs are all eaten off. A new one is then put in
HYDROMETER
231
service and the old one jammed into the bottom of the
new one as shown in Fig. 114.
These zincs are hung from a spring clip shown in Fig.
115, which lays across the top of the jar. The stud on
the zinc makes a tight friction fit with the hole in the
hanger, due to the springiness of the metal.
To keep cells in order a hard rubber syringe with the
nozzle at right angles to barrel, holding about a pint, and
a hydrometer should be obtained.

Fig. 115.
The hydrometer (Fig. 116) is a hollow glass float
loaded with shot so as to float upright. The heavier a
liquid the more of the stem sticks up above the surface.
These hydrometers are graduated on stem in actual
specific gravities or in degrees Baume (pronounced
Bomay). One with a stem about two inches long gradu-
ated from 15° to 40° Baume, or from 1.11 to 1.40 specific.
gravity, is best for battery work.
The first signs of exhaustion in the cell will be a fading
of the deep blue color of the copper solution and a low-
ering of the line of separation between blue and white
liquids.
When this occurs drop in about an ounce of copper
sulphate in lumps. Be sure the lumps fall to the bottom,

232
ELECTRIC RAILROADING
There will always be a lot of fine powder at the bottom
of the copper sulphate barrel. Use this for making up
new cells when possible. If too much accumulates for
this purpose, make a saturated solution of it in water.
15
20
25
30
35
40
Fig. 116. Hydrometer with Baume Scale.
A saturated solution is one where the water has dis-
solved all it possibly can of the chemical and leaves some
yet undissolved on bottom of jar after repeated stirring.
Place this in cells showing signs of exhaustion in same
GRAVITY CELL
233
way as the copper solution was placed in a newly set up
cell.
The zinc solution should be tested as frequently as
possible. Once in two weeks is not too often. Drop the
hydrometer gently in. Should it read 115 draw some out
with syringe and replace by fresh water.
Do not let it go below 1.10. If you have a Baume
scale these numbers are 20 and 15 degrees. Throw all
the removed zinc in a wooden tub, whether from working
cells or from old cells, to be renewed.
Keep half a dozen pieces of metallic zinc in this tub.
Any copper in this solution, mixed by cell's action, will
turn to a reddish brown curd which can be filtered out.
Reduce the clear liquid to 1.10 and use in making up new
cells.
Watch your zinc. Should any brown hangers develop
on it, detach them with a bent wire and let them fall to
bottom of cell.
In time, in spite of all care, the zinc in a cell gets
reddish brown all over. It is now time to give a com-
plete overhauling.
Take the cell out of service. Syphon off zinc solution
into the tub. Lift zinc out carefully and at once scrub
clean with a wire brush. Wash and replace in another
cell at once or dry thoroughly and keep dry until needed.
Syphon off the rest of the liquid into another wooden
tub and use after filtering as copper solution to make up
new cells.
+
Any lumps of copper sulphate in the bottom take out,
rinse and put in other cells.
The mud in bottom of cells and in the zinc solution
tub should be dried and sold to brass founders as "bat-
tery mud."

234
ELECTRIC RAILROADING
The copper plates taken from cells should be kept
completely covered with water, wire and all, until needed
again.
When they get too heavy and cumbersome sell them,
as they are an especially pure form of copper.
Never leave gravity cell on open circuit; the liquids
will mix.
Fig. 117. Fuller Cell.
The Fuller Cell. Semi-closed circuit type, for heavy
duty. Long periods of work with little rest.
Polarization cured. Pressure 2 volts, resistance 0.5
ohms. Cell shown in Fig. 117.
These cells are carbon and zinc, and since the chemical
which converts the hydrogen to water will attack the
zinc, a porous cup is used.
The carbon or the zinc can be placed in the porous
cup, but the zinc usually is. A tablespoonful of mercury
is placed in bottom of porous cup, the zinc set in and
the cup filled with very dilute sulphuric acid (1 acid, 50
water). The carbon is then placed in the outer jar, the
EDISON CELL
235
porous cup being also in, and the outer jar filled three-
quarters full of battery fluid or electropoin.
This is composed of 4 ozs. of bichromate of soda, 14.
pints of boiling water, mixed and cooled; then while
slowly stirring add little by little 3 ozs. sulphuric acid ·
taken out of a carbon (not diluted). NEVER POUR
WATER INTO ACID.
The bichromate of soda has so much oxygen in it that
it will turn the hydrogen to water, changing itself to
chromate of soda.
When the interior of the porous cup gets dark green
colored a cup should be soaked in 1 to 50 acid for an
hour and then mercury placed in bottom and zinc set in.
Simply take out old cup and insert new one in its place.
The old zinc should be cleaned, porous cup washed
and then boiled in water and both placed in stock.
These cells should be left on open circuit when not in
use. They are very powerful, but nasty to handle and
not as cheap as the gravity cell. When the electropoin
gets greenish it soon becomes exhausted, then throw it
away. Cold battery rooms or pits affect this cell less than
the gravity cell.
Į
Edison-Lalande Cell. This is a semi-closed type with
polarization cured. It has a resistance of 0.2 ohms and
a very low voltage, o.7, but is a bull dog for holding on.
It will, when set up, start in to deliver a heavy current
and keep at it until all its chemicals are used up. It
needs no attention and is built so that you can not
give any.
When it stops take out the copper and sell it, throwing
everything else out. Clean up the jar and fit out again.
The cell uses zinc and oxide of copper plates immersed
in a solution of caustic potash. The oxide plate is shown

236
ELECTRIC RAILROADING
in Fig. 118 and the complete cell with a glass jar in Fig.
119. Porcelain jars are usually furnished.
The caustic potash comes in sticks sealed up in a tin
can.
Place the elements in jar and fill with water to about
one inch of the top. Take out the elements and put in
the sticks of potash.
Fig. 118. Oxide Plate of Edison-Lalande Cell.
Stir constantly while dissolving, for it gets very hot
and might crack the jar. Be very careful not to get
caustic potash on your flesh. It not only burns ter-
ribly, but makes a wound which is very hard to heal.
If you buy potash by bulk, make the solution up to
1.33 on specific gravity scale or 38° on the Baume
scale.

CAUSTIC POTASH CELL
237
Place the zinc and copper oxide elements in the jar,
seeing that they are properly separated by the hard
rubber buffers. Pour the bottle of oil over the top of
solution and place cover on.
Fig. 119. Edison-Lalande Cell.
215 57
If buying oil by bulk, get a heavy paraffin oil which
will read 1.46 specific gravity on 48° Baume and pour
a 1/4 inch layer on each cell.
These are good cells, but any sulphuric acid or caus-
tic potash cell is a nasty thing to handle.
The action of the cell dissolves the zinc, setting free
hydrogen, which is changed to water by the copper

238
ELECTRIC RAILROADING
oxide, which is reduced to pure copper by giving up the
oxygen in it.
The Dry Cell. Shown in Fig. 120 is really a moist
cell sealed up water tight with cement or glue.
The can is made of zinc and serves as one element,
while a carbon plate or rod is the other. Around the
carbon is packed a mixture of powdered manganese
dioxide, carbon and flour, while the rest of the can is
THE MESCO
DRY BATTER
Fig. 120. Dry Cell.
filled with a mixture of plaster, oxide of zinc and flour;
the whole being soaked with a solution of sal ammoniac
and zinc chloride. Pressure 1.4 volts.
These are very useful for testing, as they can be
carried around in a satchel or your overcoat pockets.
Whenever they are used in sets see that their rest-
ing place is dry, otherwise the moisture will connect all
the zinc cans together and cause them to run down.
The principles on which primary cells work are sim-
ple and well understood by most people; yet there are
men trying yet to design a cell to do more than is
possible.
LOCAL ACTÍON
239
The best that could be done with a cell using zinc.
as the dissolved metal is to get one horse-power-hour*
per pound of zinc.
There are inevitable wastes which prevent us doing
as well as that, so with coal at 4 cent a pound and zinc
at 16 cents it is evident that the primary battery will
only be used when circumstances force us to use it.
One great waste is Local Action:
Local Action. Commercial zinc or spelter contains
small particles of carbon and iron which with the zinc
they are imbedded in form small local cells producing
electricity where it cannot be gotten at for use, and the
zinc is continuously dissolved whether the cell is on
open or closed circuit. In the sal ammoniac batteries
sometimes the change in the strength of the solution.
will cause the zinc to be eaten through at or very near
the surface of the solution.
The remedy for this is
Amalgamation. Mercury forms a soft paste or amal-
gam with all the metals except iron, and will not dis-
solve carbon. Advantage is taken of this fact and local
action is prevented by cleaning the zinc with sand paper,
washing with dilute sulphuric acid, and while -wet rub-
bing on mercury (quicksilver) with an old brush or a
rag tied to a stick. N. B. Mercury is a poison. The
zinc becomes bright, covered with a layer of zinc-
mercury amalgam; and the particles of iron and carbon
are merely covered up and protected from the acid,
which cannot corrode the mercury. During the action
* An horse-power hour is the work done by a one horse-
power engine running at full load for an hour; or the work
done by a 10 H. P. engine running at half load for one-fifth of
an hour, etc.
240
ELECTRIC RAILROADING
of the cell the zinc dissolves out, and the mercury eats
its way into the zinc, reforming the amalgam. When
the zinc around the particles is eaten away they fall out
to the bottom of the battery jar and do no harm.
Zincs for batteries are sometimes cast with 5% of mer-
cury in them. When the zinc is in a porous cup it is a
good thing to pour a tablespoonful of mercury into the
cup and then set the amalgamated zinc in. With all the
precautions that can be taken about 3%
put in the cell is wasted in local action.
of the zinc
CATECHISM TO LESSON 15.
1. What is an open circuit cell?
2.
What is a closed circuit cell?
3. What is polarization?
4. What means are used to prevent polarization?
5. What ways are there of curing polarization?
6. What two materials of ordinary cost make the
best cell?
7. How good a cell would zinc and iron in sal am-
moniac make?
8. Would the results of a zinc silver combination
in sulphuric acid give results worth the cost?
9. What is the name of the wet end of the zinc
element? The dry end?
IO.
10. What is the name of the wet end of the copper
or carbon element? The dry end?
II. Why would not a zinc-copper cell made like a
Law cell operate?
12. What cells would work well on a signal circuit
closed 98% of the time?
CATECHISM
241
13. What cell would work well on the motor of a
signal, current closed 1% of the time?
14. What is Local Action?
15. What is amalgamation of zinc?
16. How are zincs amalgamated?
17. What is a hydrometer?
LESSON 16.
STORAGE BATTERIES.
The storage cell is rapidly pushing the primary bat-
tery aside in signal and fire alarm work on account of:
(1) Its high voltage.
(2) Its great current capacity.
(3) The lowering of total battery expense if used for
several years.
(4) Its steadiness of action.
Storage cells are used in train lighting to furnish light
when train is not in motion and to steady the supply of
current.
They are used in some cases to furnish the power to
operate switches on locomotives and motor cars.
In power houses they offer a reserve supply of power
and act as a steadier of the load on the generators.
The simplest storage cell would be two strips of lead
immersed in dilute sulphuric acid. When current is sent
through them one plate turns a dark brown color and
the other a grey color. After an hour's passage of cur-
rent reverse the connection and charge the other way.
The plates will change color-the grey one becoming
brown and the other one grey.
If this charging first in one direction and then in the
other be kept up, you will notice that after each reversal
of the current through the cell the acid is quiet but soon
begins to gas or boil. This is the signal to reverse the
current as the cell is charged.
242

STORAGE BATTERIES
243
When the cell takes several hours to gas it is in condi-
tion to use.
After one of the reversals continue to charge until cell
has gassed about fifteen minutes. Remove the charging
wires and connect to anything you wish to run. About
70% of the power you put into the cell can now be taken
out.
Fig. 121. Lead Grid.
You may now use this as a storage cell, charging it up
till it gasses and then using the accumulated electricity as
you please.
You always lose 30% but you have the advantages of
portability and ability to work when engines are shut
down.
In time you will notice that the lead plates become
spongy and should the cell be used long enough the plates
will finally crumble and break. You will notice that the
more spongy the plates become the greater a charge they
are capable of holding.
In fact, just before your battery goes to pieces its ca-
pacity is the greatest.
244
ELECTRIC RAILROADING
To make a commercially practical cell we would pro-
ceed thus:
The lead plates would be replaced by grids as shown in
Fig. 121 or by grooved plates as in Fig. 122.
Litharge and sulphuric acid is mixed to a stiff paste
and the grids or grooved plates plastered with the paste
and stood up to dry. This makes a negative plate.


Fig. 122. Grooved Lead Plates.
Using a paste of red lead and sulphuric acid the posi-
tive plates are formed in the same way.
The objection to a storage cell'using these plates is
that after very little use they go to pieces. The changing
of the red lead to the brown oxide, and the changing of
the litharge to spongy lead is accompanied by a swelling

STORAGE BATTERIES
245
and shrinking of the material. This loosens up the
pasted mass and it begins to fall out.
Most of the ingenuity of inventors has been concen-
trated on making plates which would hold the active ma-
terials firmly and continually.
Perhaps one of the best lead-lead (i. e. lead for both
plates) is the Electric Storage Battery Company's Chlor-
ide Cell.
Fig. 123. Chloride Accumulator.
This cell is shown in Fig. 123. Its method of manufac-
ture is interesting and is practically as follows:
The first thing is to get finely divided lead which is
made by directing a blast of air against a stream of the
molten metal, producing a spray of lead which upon cool-
ing falls as a powder. This powder is dissolved in nitric
acid and precipitated* as lead chloride on the addition of
*Turned back to a solid.
246
ELECTRIC RAILROADING
hydrochloric acid. This chloride washed and dried forms.
the basis of the material which afterwards becomes active
in the negative plate. The lead chloride is mixed with
zinc chloride, and melted in crucibles, then cast into small.
blocks or tablets about 3/4 inch square and of the thickness.
of the negative plate, which according to the size of the
battery varies from 14 inch to 5/16 inch. These tablets
are then put in molds and held in place by pins, so that
they clear each other 0.2 inch and are at the same dis-
tance from the edges of the mold. Molten lead is then.
forced into the mold under about seventy-five pounds.
pressure, completely filling the space between the tab-
lets. The result is a solid lead grid holding small
squares of active material. The lead chloride is then
reduced by stacking the plates in a tank containing a
dilute solution of zinc chloride, slabs of zinc being al-
ternated with them. The assemblage of plates consti-
tutes a short-circuited cell, the lead chloride being re-
duced to metallic lead. The plates are then thoroughly
washed to remove all traces of zinc chloride.
A later form of negative plate consists of a "pocketed"
grid, the opening being filled with a litharge paste; this
is then covered with perforated lead sheets, which are
soldered to the grid. The positive plate is a firm grid.
composed of lead alloyed with about 5% of antimony.
about 7/16 inch thick, with circular holes 25/32 inch
in diameter, staggered so that the nearest points are
.2 inch apart. Corrugated lead ribbons 25/32 inch wide
are then rolled into close spirals of 25/32 inch in diam-
eter, which are forced into the circular holes of the
plate. By electrochemical action these spirals are formed
into active material, the process requiring about thirty
hours; at the same time the spirals expand so that they

STORAGE BATTERIES
247
fit still more closely in the grids. This form of posi-
tive is known as the Manchester Plate.
In setting up the cells the plates are separated from
each other by special cherry wood partitions, the per-
forations being connected by vertical grooves to facili-
tate the rising of the gases. Sometimes glass rods are
used as separators.
There are ten sizes of cell, the smallest containing
three plates 3 by 3 inches, and the largest having seventy-
five plates 152 by 3034 inches, ranging in capacity from
5 to 12,000 ampere-hours, and in weight from 5½ to
Fig. 124. Lead-Zine Storage Battery.
5,800 lbs. The smaller sizes are provided with either
rubber or glass jars, and the larger one with lead-lined
tanks.
In the lead-lead cells the negative plates deteriorate
in capacity, while the positive plates increase in capacity,
with continued use.
To even things up the two end plates are made nega-
tive and they then alternate, thus giving one more nega-
tive plate per cell.
248
". ELECTRIC RAILROADING
1
A lead-zinc cell is made by the United States Battery
Co. It is shown in Fig. 124.
The positive plate is of perforated lead sheets riveted
together with lead rivets and formed by the slow proc-
ess of charging and reversal as described. in first part
of lesson. The negative element is a zinc amalgam which
swells up when charged.
This amalgam lies on bottom of jar while the lead
element hangs over it.
The pressure given by these cells is a little higher
than a lead-lead cell and they weigh less for the same
capacity. For signal work they are excellent, while for
reserve power use the lead-lead cell is preferred as being
better under such severe conditions.
The Edison Cell uses grids of nickel plated iron, the
grids being filled with small nickel plated steel boxes
which are perforated with very small holes.
The boxes in positive plate are filled with oxide of
nickel and pulverized carbon, the negative boxes being.
filled with oxide of iron and pulverized carbon.
The carbon in each case is merely to render material
a better conductor.
A 20% solution of caustic potash is used in a nickel
plated steel vessel.
The advantage of this cell is its lightness and ability
to stand the most reckless abuse. For railway work it is
no better than any other cell and its price puts it out of
consideration.

STORAGE BATTERIES
249
Fig. 125. Top and Inside
View of a Concrete Battery Well.
Fig. 126.
Battery Chute.
250
ELECTRIC RAILROADING
CATECHISM.
Question I. What is a storage battery?
Answer. It is a cell somewhat resembling a primary
cell, used to store electricity.
Question 2. Does the cell produce electricity or sim-
ply store it?
Answer. The chemicals in the cell are not normally
capable of producing electricity but by treating them
with electric current for some hours they become changed
so that they can produce electricity like a primary cell.
In fact we might say that a storage battery is a pri-
mary cell which, when exhausted, is restored to its
original power by application of electric current which
renews the chemicals, whereas in the ordinary primary
cell we have to buy new chemicals. The gravity cell
can be renewed a few times by passage of current, but
soon gets in a condition where purchase of fresh chemi-
cals is absolutely necessary.
Question 3. Of what material is the positive plate
made?
Answer. Red lead is the real plate, but it is supported
by a lead grid.
Question 4. What material is used for the negative
plate?
Answer. Spongy lead or litharge, held in a lead grid.
Zinc in form of amalgam lying on a copper plate.
Question 5. What fluid is used in jars?
Answer. Dilute sulphuric acid.
Question 6. What is sulphuric acid?
Answer, It is an oily liquid either colorless or with
STORAGE BATTERIES
251
F
a very faint yellow tinge. It is sold in carboys* as
Oil of Vitriol and should test by hydrometer (Lesson
15) to 1.842 specific gravity or 66 degrees Baume.
To avoid the constant use of the decimal point battéry
attendants call the strong acid 1842 acid and call water
1000 specific gravity.
-Question 7. What is dilute acid?
Answer. It is acid of 1842 strength mixed with pure
water. To make 1200 acid take I measure of acid and
pour into 3 measures of water. For 1400 acid take 1
measure acid and pour into an equal quantity of water.
1200 acid is most used and corresponds to 25° Baume.
Question 8. Is pure water necessary?
Answer. For best results, yes. Distilled water is not
so very expensive to make and it pays. Half of the
battery troubles are caused by filling up cells with any
clean water that is handy.
Even clean water contains chemicals that should not
get into the storage battery.
Question 9. Should the diluted acid be cooled before
putting in cells?
Answer. It should be thoroughly cooled. Acid should
always be diluted the day before you intend to use it.
The specific gravity should be taken after acid has cooled
at least twelve hours.
Question 10. Does it make any difference whether
1200 or 1400 acid is used?
Answer. Yes. Acid from 1150 to 1230 is generally
used. The stronger the acid the greater the capacity
of the battery and the more liable it is to get the disease
of Sulphate.
*Carboys are large glass bottles several feet high and about the
same diameter, They are securely boxed to prevent breaking.
252
ELECTRIC RAILROADING
}
•
Question 11. Why is it that the acid tested in cells.
is sometimes so high?
Answer. The acid is weakest when cell is discharged
and strongest when cell is charged. This is because.
the acid goes in and out of the plates on discharge and
charge.
Question 12. What is meant by a 180 ampere-hour
cell?
Answer. It means that the cell in question will give
I ampere for 180 hours, if it has been fully and prop-
erly charged. It might give 30 amperes for 6 hours if
it was designed for allowing the flow of such a cur-
rent.
It certainly would not give 180 amperes for 1 hour
as the heat generated would buckle the plates and ruin
the battery before the end of the hour.
Question 13. What is the normal rate of a battery?
Answer. As batteries are usually made we may draw
I ampere from every 10 square inches of positive plate,
counting both sides, without over heating.
A cell of 5 positives and 4 negatives, has plates 5x7
inches. What current is it safe to draw? 7x5=35=one
side of a plate. Both sides 70 sq. in. 5 plates gives 350
sq. in. Dividing by 10 gives 35 as safe current. This
is called the normal rate. In actual practice we usually
discharge at about normal rate and hurry the charge by
exceeding the normal rate.
Question 14. What harm does this do?
Answer. Wastes money. It costs more to put in 180
A H (ampere hours) quickly than it does slowly.
Question 15. What is an 8 hour rate?
Answer. It means taking 8 hours to charge or dis-
charge the battery. If battery is worked twice as hard it
STORAGE BATTERIES
253
}
will charge or discharge in half the time or at a 4 hour
rate.
Question 16. What precaution should be taken in a
battery room?
Answer. The room must be dry and well ventilated
to get rid of the acid fumes. Walls and floors should.
be of enameled brick and ceiling of white cement. Win-
dows should be white-washed on outside or of ground
glass to prevent sun shining on cells and heating them.
The benches cells stand on should be soaked in paraffin.
The cells should stand on insulators.
Question 17. How are signal batteries installed?
Answer. In wells like Fig. 125 when there are many.
These wells are of sheet steel and concrete, and are
about 10 feet high. They are heated when necessary by
small oil stoves or by being packed over the top with
manure.
When only two or three cells are used the battery
chute of Fig. 126 is installed. The chute is of iron
pipe and goes down below the frost line. The cells are
hauled up by the rope for renewal or charging.
Question 18. Of what material are battery jars made?
Answer. Glass, hard rubber, celluloid, wood with
sheet lead lining.
Small cells usually have glass jars as in Fig. 127.
Large cells have the lead lined wooden tank as in Fig.
128. Hard rubber and celluloid are expensive. Neither
is transparent.
Question 19. How should cells be put in service?
Answer. As soon as electrolyte (acid) is put in the
cell it should be charged with one-third its normal
rate for 4 hours, then increase to normal rate and con-
tinue 20 hours. Cells will now be up to 2.6 volts each.

254
ELECTRIC RAILROADING
rate. The voltage of
Drop back to one-quarter normal rate.
each cell will drop a little. Continue charging up to
2.6 volts again.
EST
Fig. 127. Form of Storage Battery for Signal Work. Glass Jar.
Question 20.
How should cells in service be treated?
Answer. Never discharge below 1.7 volts and 1.8 is
better. Charge up to 2.5 volts usually at normal rate.

STORAGE BATTERIES
255
Once a week give a charge at one-third normal rate
till cells read 2.6 volts.
Never let them stand idle with less than 30% of their
capacity in them. The fuller a cell the safer it is when
idle. When cells are idle charge up to boiling once a
week.
ESACE
1957
Fig 128. Storage Battery in Lead Lined Wooden Tank. Tank Rests
on an Insulated Frame.
Do not habitually overcharge cells; it is a waste of
money.
The cell is charged when the specific gravity of elec-
trolyte is about 0.025 higher than when discharged.
Bubbles of gas are given off freely when cell is fully
charged, because material of plate is no longer able to
take up the oxygen and hydrogen which tend to be set
256
ELECTRIC RAILROADING
free by the electrolysis;* these bubbles give the elec-
trolyte the appearance of boiling, and often they are so
fine that the liquid looks almost milky-white, particu-
larly in a cell which has not been very long in use.
↓
The color of the positive plates varies from a light
brown on active parts to a chocolate color when fully
charged, and to nearly black when overcharged. The
negatives vary from pale to dark slate color, but they
always differ in color from the positives. This indica-
tion of the amount of charge is learned by experience,
but is quite definite after one becomes familiar with a
particular battery.
Do not discharge too rapidly, it wastes money. A cell
whose normal rate of discharge is 100 amperes for 8
hours, can be discharged at the rate of 400' amperes in
one hour, but never at the rate of 400 amperes for 2
hours. You see the rapid discharge is inefficient and
you only get half as much energy out of cell as you
could have obtained at a slower rate.
}
Question 21. Do storage batteries wear out or de-
preciate?
Answer. Yes, it will take 10% of the cost of a
battery every year to keep it in repair.
Question 22. How should a battery be put out of
commission or laid up?
Answer. If, for any reason, the battery is to be but
occasionally used, or the discharge is to be at a very
low rate, a weekly freshening charge to full capacity at
normal rate should be given. It sometimes happens that
a storage battery is put out of commission for a long
period. In such cases the procedure is as follows:
First the battery is given a complete charge at normal
*Lesson 17.
STORAGE BATTERIES
257
1
rate, then the electrolyte is siphoned off into carefully
cleaned carboys (as it may be used again), and as each
cell is emptied it is immediately refilled with pure water.
When the acid has been drawn from all cells and re-
placed with water, the battery is discharged until the
voltage falls to or below one volt per cell at normal cur-
rent; when this point has been reached the water should
be drawn off. In this condition the battery may stand
without further attention until it is again put into service,
which is accomplished in the same manner as when the
battery was originally started. If during the discharge,
when the water has replaced the electrolyte, the battery
shows a tendency to get hot (100 F.) colder water should
be added.
Question 23. What troubles occur in batteries and
what are their remedies?
Answer. The most serious troubles which occur in
storage batteries are sulphating, buckling, disintegration,
and short-circuiting of the plates. These can usually
be avoided, or cured by proper treatment if they have
not gone too far.
SULPHATING.-The normal chemical reaction
which takes place in storage batteries is supposed to
produce lead sulphate on both plates when they are dis-
charged, their color being usually light brown and gray,
due to the presence of lead oxide, on the positive plate.
But under certain circumstances a whitish scale forms
on the plates. Plates thus coated are said to be "sul-
phated." This term is, however, somewhat ambiguous,
the formation of a certain portion of ordinary lead
sulphate being perfectly legitimate, but the word has
acquired a special significance in this connection. A plate
is inactive, and practically incapable of being charged,
258
ELECTRIC RAILROADING
when covered with this white sulphate, as it is a non-
conductor.
The conditions under which this objectional sulphat-
ing is likely to occur are as follows:
(a) A storage battery may be left discharged for
some time, even though the limits have not been ex-
ceeded.
(b) A storage battery may be overdischarged, that is,
run below the limits of voltage specified, and left in that
condition for several hours.
(c) The electrolyte may be too strong.
(d) The electrolyte may be too hot (above 125 F.).
(e) A short circuit may cause "sulphating" because
the cell becomes discharged (on open circuit) and dur-
ing charging it receives only a low charge compared
with the other cells of the series. A battery may be-
come overdischarged or remain discharged a long time
on account of leakage of current due to defective insu-
lation of the cells or circuit, or the plates may become
short-circuited by particles of the active or foreign sub-
stances falling between them.
(f) By charging at a very low rate, for example,
one-thirtieth of normal.
Sulphating may be removed by carefully scraping the
plates. The faulty cells should then be charged at a low
rate (about one-half normal) for a long period. In this
way, by fully charging and only partially discharging
the cells to about 1.9 volts at the 8-hour rate, for a
number of times the unhealthy sulphate is gradually elim-
inated. When the cells are only slightly sulphated, the
latter treatment is sufficient without scraping; but with
cells that are very badly sulphated, the charge should be
at about one-quarter the normal rate for three days.
KA
STORAGE BATTERIES
259
*
Adding to the electrolyte a small quantity of sodium
sulphate, or carbonate, which later is immediately con-
verted into sodium sulphate, tends to hasten the cure of
sulphated plates by decomposing or dissolving the white
sulphate. This is not often used, as a cell should be
emptied, thoroughly washed, and fresh electrolyte added
before the cell can be used again.
Sulphating not only reduces the capacity of lead stor-
age batteries, but also uses up the active material by
forming a scale which falls off or has to be removed.
It also produces the following trouble:
BUCKLING, or warping of a plate, may be caused by
too great expansion of the active material, which strains
the ribs of the containing grid: or by uneven action on
the two surfaces, for example, a patch of white sulphate
on one side of a plate will prevent the action from tak-
ing place there, so that the expansion and contraction
of the active material on the other side, which occurs
in normal working, will cause the plate to buckle. This
might be so serious that it would be impossible to
straighten the plate without breaking or cracking it;
but, if taken in time, it may be accomplished by placing
the warped plate between boards, and subjecting it to
pressure in a screw or lever press. Striking the plate
is objectionable, because it cracks or loosens the active
material; but, if it should be necessary to straighten a
plate when no press is available, a wooden mallet may be
used very carefully, with flat boards laid under and over
the plate. Buckling is caused by an excessive rate of
charging or discharging, as well as by sulphating.
DISINTEGRATION.-Some of the material may be-
come loosened or entirely separated from the plates, as
*Sal-soda; common washing soda..
260
ELECTRIC RAILROADING
a result of various causes. The chief of these is sulphat-
ing, which forms scales or blisters that are likely to
fall off, thus gradually reducing the amount of active.
material and the capacity of the cell. Buckling also tends
to disintegrate the plates. Contraction and expansion of
the active material may take place in normal working,
and are increased by excessive rates or limits of charg-
ing and discharging. This constitutes another cause of
disintegration, particularly in plates of the Faure type,
containing plugs or pellets of lead parts. The fragments
which fall from the plates not only involve a loss of
active material, but are also likely to extend across or
gather between the plates and cause a short circuit.
The positive plates are far more susceptible to and
injured by these troubles than the negatives. The former
are also more expensive to make, therefore it is to them.
that special attention should be directed in the manage-
ment of storage batteries.
SHORT-CIRCUITING may be caused by conditions
previously stated, and also by the collection of sediment
at the bottom of the containing well. The short-cir-
cuiting caused by the dropping in of foreign matter, or
bridging by the active materials, is prevented by the
use of glass, rubber, or wooden separators. The short-
circuiting of plates by the formation of sediment is pre-
vented, or the chances of it are decreased, by raising
the plates so that they clear the bottom of the contain-
ing cell. In small batteries this clearance is about an
inch; in large cells it is considerable, being about 6 inches,
and on account of the weight of large-sized plates they
are supported at the bottom by glass frames running
lengthwise through the cell.
The sediment should be watched carefully, and when
STORAGE BATTERIES
261
it reaches a depth of an inch or more at the center of the
cells it should be removed. The usual method is to take
out the plates, syphon the electrolyte off carefully, and
then flush out the tanks until all the sediment is re-
moved. If syphoning cannot be resorted to, a pump may
be used, either of glass or of the bronze rotary type.
TROUBLES FROM ACID SPRAY.-A battery will
give off occasional bubbles of the gas at almost any time;
but when nearly charged the evolution becomes more rap-
id. These bubbles, as they break at the surface, throw
minute particles of acid into the air, forming a fine spray
which floats about. This spray not only corrodes the
metallic connections and fittings in the battery room,
but is also very irritating to the throat and lungs, caus-
ing an extremely disagreeable cough. Glass covers are
sometimes placed over cells to prevent the escape of
fumes, but this is not advisable as the glass becomes
moist and will collect dust, thus forming a conducting
surface over the battery.
Attempts have been made to do away with the spray
by having an oil film over the electrolyte, but this inter-
feres with the use of hydrometers, and sticks to the sur-
face of the plates when they are removed, thus increasing
the resistance when they are replaced. Another plan
consists in spreading a layer of finely granulated cork
over the surface of the liquid, but while this does not
interfere with the hydrometer, it makes the cell look
dirty. The general practice is to depend almost entirely
upon ventilation to get rid of the acid fumes, in fact,
even forced ventilation is used. A blower forces fresh
air into the room, which is provided with a free ex-
haust. In connecting up the cells, it is advisable to use
lead-covered copper cables, as this covering protects the
262
ELECTRIC RAILROADING
}
copper, and prevents the formation of copper salts which
might drop into the cell and contaminate the electro-
lyte.
THE PURITY OF THE ELECTROLYTE is very
important, and great care should be taken to insure it.
The electrolyte may have nitric acid present when
"formed" (Plante) plates are used, and some chlorine,
when "Chloride" negatives are used. In addition, iron
may be present due to the water or acid, if the sulphuric
acid is made from iron pyrites; it may also be present,
owing to the corrosion of iron fittings near the cells,
some of the scale falling into the electrolyte. Similarly,
the copper salt formed from the connections by cor-
rosive action may fall into the cell. Mercury may also
be present due to the breakage of hydrometers or
thermometers. Other foreign substance might be present,
but those named are the most harmful.
Nitric acid, even in exceedingly small quantities, causes
disintegration, as the supporting metal grid of the plate
is destroyed.
Chlorine has a similar effect.
Iron, mercury, and copper produce local action, and
thus decrease the efficiency and ultimately the life of the
cell.
The electrolyte should be tested about once a week for
these impurities, and if any of them are present, it should
be drawn off and renewed. When nitric acid is found,
it is advisable to flush the cell with pure water.
Question 24. How are batteries connected to line?
Answer. Usually they are "floated" on line, meaning
that the battery is always connected and charged when
load is light and discharged when load is heavy. This
gives the battery the least possible work to do and keeps
1
STORAGE BATTERIES
263
it well charged at all times. Fig. 129 shows this.
Switches are provided to cut off battery or to cut off
dynamo and let battery run the lights. Usually both
switches are closed as shown.
Question 25. What is end cell regulation?
Answer. If 700 volts are wanted at station 300 cells
would give 750 volts when fully charged and 510 volts
when at their lowest safe limit.
V
A
1

Fig. 129. Diagram of Connections for a Storage Battery to Float on Line.
If 280 cells were connected permanently and 130 extra
cells arranged so as to be cut in at the end of the string
of 300 cells a few at a time, then when cells were down
to 1.7 volts we would have 410 in service and have full
voltage.
Question 26. What is booster regulation?
Answer. A booster is a dynamo whose field magnets.
are excited by the current going out to the lines. Hence
when the battery is being worked the hardest the booster
lynamo furnishes the highest voltage which is added to
that of the battery,
264
ELECTRIC RAILROADING
As the battery voltage drops the attendant regulates the
field rheostat of the booster so as to add enough voltage
to keep the combined voltage up to the regular voltage.
Question 27. Are batteries much used in railroad
work?
Answer. Yes. Every electrically lighted train has a
storage battery to run things when the train is still.
Many motor cars have storage batteries to operate the
controlling devices.
Power houses have batteries to run things in case of
accident.
The New York Central has five batteries, each giving
2,250 amperes for one hour and others give 3,000, 3,750
and 4,000 amperes each. The whole set can run the
entire electrical division of the railroad for an hour in
case of a mechanical break down.
ELECTRICALLY OPERATED TURN TABLES.
In the yards of all our large railroads the hand oper-
ated turn table has gone out of use or ought to go at once.
Locomotives are so heavy, some weighing 175 tons and
a few even 200 tons, that it requires too many men to
turn, especially in winter.
In busy junctions and terminals the hand turning, being
so slow, is a great source of congestion and delay,
A steam "donkey" or single wheeled locomotive is oc-
casionally used to turn the table, being attached to one
end and running on the same rails as the wheels of the
turn table.
The equipment consists of a small vertical boiler, a
steam engine, a water tank and a coal bin. Water and
coal must be brought to the table and ashes taken away.
TURN TABLES
265
In many places a licensed engineer is required by law.
If some old locomotive engineer has the job, it is wasting
a valuable man on a poor job, as his knowledge of rail-
roading and the road should be utilized where they will
be of service.
It has often been suggested that a pipe be run from
the station heating plant or the shop boilers. Steam from
this pipe, which should run underground to the center of,
the table pit, would be taken through a pivoted slip joint'
to the "donkey."
In this case, owing to the length of pipe, the engine
would have to run on hot water most of the time.
The electric motor is just the thing to operate a turn
table and they are rapidly coming into general use.
Where a terminal has been electrified the electric turn
table goes without saying, but it will pay any road to
install an electric turn table even if they must buy power
from the local electric light company.
The same dynamos which furnished 125 or 250 volts
for lighting the station or shops can operate the turn table
motor.
The regular equipment would be a small railroad motor
with the ordinary gearing, a rheostatic controller and a
circuit breaker, the whole being mounted on a single
wheeled truck. This constitutes an electrical "donkey."
Such a turn table is shown in Fig. 130.
Where a large number of engines must be handled
quickly, a regular turn table operator should be employed
and a cab built over the "donkey" for his protection.
There are many cases, however, where it is feasible for
the locomotive fireman to operate the turn table. In such
a case the controller should be installed in middle of table
at one side, and the cab is not essential.

266
ELECTRIC RAILROADING
Fig. 130.
Turn Table with Donkey.
TURN TABLES
267
The details of the "donkey" are well shown in Fig. 131,
while Figs. 132, 133, 134 give all the information of the
equipment that would be required. Note that the rails
can be sanded in both directions.
The cost of a turn table "donkey" as in Fig. 130 is
about $1,000.
Single wheel truck.
Electrical equipment
Installation ;..
...$ 350
500
150
$1,000
This is based on the assumption that the railroad buy
the truck from a truck builder, do the mechanical work
in their own shops and let the electricians install the
electrical equipment when received from the manufac-
turers.
The turn table shown in Fig. 135 is of the "draw
bridge" type. The table rests on a heavy cradle which
turns on a train of small wheels.
A large stationary gear as shown is engaged by the
pinion of the vertical motor shaft.
You will notice that a "donkey" drives by friction like
a locomotive so that ice on rails, or oil will reduce trac-
tion and make sand necessary. The "draw bridge" type
drives positively by a gear.
Whatever type is used the ordinary street railway
motor is best adapted to the purpose. It is completely
enclosed and water and dust proof.
The conditions of frequent starting and large momen-
tary overloads makes the direct current series motor the
best. If only alternating current is obtainable the com-
pensated series motor will give good service. If only

268
ELECTRIC RAILROADING
Fig. 131.
Under Part of Donkey.
TURN TABLES
269

Fig. 132.
SANDING DEVICE
раст
BRAKE
TRAP
PLAN OF CAB
SAND APt
Side View of Donkey and Plan of Interior of Cab.

COSTAN
Fig. 133. Plan of Under Part of Donkey.
MOTOR
an அடிக்கு
270
ELECTRIC RAILROADING
multiphase alternating current can be obtained an induc-
tion motor will do the work better than hand or steam.
The induction motor should be of the definite wound
armature, collector ring, external resistance type, and be
designed for speed variation. (See Lesson 27.)
!
In any case the motor must be designed and constructed
to stand rough use and even positive abuse.

Fig. 134.
#
End View of Under Part of Donkey, Gear Wheel of Motor
on Right, Single Drive Wheel in Center.
The motor is usually provided with feet, and in place
of the car axle an intermediate-shaft is substituted so that
there is a double reduction gearing. Both sets of gears
run in a gear case filled with oil or soft grease.
The armature shaft of motor is extended at the end
opposite the pinion and a hand brake fitted. Sometimes
this is set by a wheel and sometimes by a weight or a
spring and is released by a foot lever.
The controller is like a street car controller except that
it has no separate reverse wrench.

TURN TABLES
271
10
369
Fig. 135. Draw Bridge Type of Turn Table.
272
ELECTRIC RAILROADING
they
The handle being in center, power is off; moving it to
right turns table to right, to the left turns table to left.
The resistances are like those on a street car.
The circuit breaker serves as a switch and protects
from serious overloads.
The advantages of electrically operated tables are:
Low cost of maintenance and operation; speeds up, moves:
and stops quickly; perfect control of speed; consumes.
power only when work is done.
Perhaps time saving is its greatest advantage. In a
certain terminal the new round house was built to ac-
commodate twice as many locomotives as the old one. The
electrical turn table served this round house with less
delays than the hand table caused when serving the old
house.
The actual power to turn a 60-foot table with a 100-ton
engine on, is from 8 to 12 H. P. The speed of operation
was one turn in 40 seconds. At the moment of starting
the power ran up to about 20 H. P.
It is for this reason that a 20 H. P. railway motor is
installed.
A 10 H. P. motor of regular type would operate the
table, but not as well. The reason is not because the 20
H. P. railway is more powerful than à 10 H. P. regular
motor, for strange to say they are of about equal power.
(See Lesson 27.)
The railway motor is best suited to the work and should
be installed.
No time should be wasted in trying to balance engines
on the table; in fact, the 8. H. P result was obtained
with engine slightly out of balance; 9 H. P. was when
engine was balanced and 12 H. P. when much out of
balance.
TURN TABLES
273
In one yard where the electric table turned 300 locomo-
tives a day, the cost of the power used was less than
the cost of hauling the coal to the steam donkey pre-
viously employed. It would have been utterly foolish to'
waste time in balancing engines to try to save a little.
power.*
In this yard the actual cost of turning a locomotive by
electric power from their own shop, was 1.4 cents. This
was obtained by averaging the total expense for six
months' use of the table. Had this power been purchased
from the local electric light company, it would have cost
them 1.9 cents per locomotive.
There are three good ways of bringing the power into
the turn table:
The best way is to lead the wires from underground
up to a pair of cast iron rings and have brushes in the
table to collect the current.
When center pivots are solid and the under bracing
complicated this cannot be done.
For a turn table of this description the method shown.
in Fig. 131 is good.
Two trolley wires, in spans of 6 or 8 feet, are placed
around the wall of the pit, supported by trolley hangers of
the "toggle" type, ordinarily used in electric mine haulage.
Short trolley poles are flexibly attached to the "donkey,”
so as to allow a horizontal movement on account of the
variation in the trolley wires and a vertical movement to
accommodate the tilting of the table. This scheme is
}
*While extravagance is to be deplored, false economy is
equally foolish, spending a dollar to save 93 cents is not business
nor religion. Railroad officials are not the only ones gone crazy
on "economy" or "efficiency." I shall refer to this at other
places.
274
ELECTRIC RAILROADING
simple and inexpensive, and in practice has operated in
a very satisfactory manner.
In some places, on account of the possibility of the pit
being flooded, neither of the arrangements described

о
О
Point of Contact-
Oil level
·Point of Contact
Fig. 136.
Overhead Contact for Turn Table.
1
above is practicable and it becomes necessary to collect
the current from above the turn table. A very ingenious
arrangernent for this purpose has been used on a turn
TURN TABLES
275
}
table where the pit occasionally fills with sea water. A
light arch was built over the center of table to support
directly over pivoted point the device shown in Fig. 136.
The case is a piece of 8-inch steam pipe with a regular
cap fitting screwed on each end. A bearing is set in at
the top and a stuffing box at the bottom.
The case is held stationary by wire rope guys attached
to regular trolley road insulators and the two electric
wires enter the case and end in copper brushes insulated
by a hard wood shell.
A piece of 1-inch gas pipe turned smooth on the out-
side at one end is fastened to the table. Its upper end
revolves in the bearing of the case and takes most of the
weight of it. The guys merely steady it and prevent rota-
tion. The gas pipe revolves in the oil tight stuffing box
at bottom of case. A hard wood spool on the gas pipe
carries two copper rings which collect current and from
which the two wires run down inside the pipe to the turn
table.
The case is filled with oil which serves a triple purpose:
it lubricates, insulates, and prevents the gases and steam
from the locomotive from running contacts and insulation.
1
LESSON 17.
ELECTROLYSIS.
The word electrolysis means a loosening up by elec-
tricity done in a liquid.
There are three classes of liquids:
(1) Do not conduct electricity, as oils, petroleum
products.
(2) Simply conduct like mercury, melted metals.
(3) Conduct and are loosened up so that the different
constituents separate and the constituents of the same
kind collect together.
Dilute acids (I part acid and 20 parts water); solutions
of metallic salts (copper sulphate, àmmonium chloride);
melted chemicals; are in the third class.
Liquids of the third class are called Electrolytes and
the process Electrolysis.
Now when an electric current is passed through these
solutions, they split up into parts, one part being liberated
at the point where the current enters, and the other part.
where it leaves the liquid. If, for instance, we pass a
current through water, we find oxygen gas being liber-
ated where the current enters the water, and hydrogen gas
where it leaves. The conductors that lead the current
into and out of the liquid have been called the electrodes
(or electricity doors). The leading-in electrode is called
the anode (or entering door), and the leading-out one the
cathode (or exit). Therefore we say oxygen is liberated
276
ELECTROLYSIS
277
at the anode, and hydrogen at the cathode. If the solu-
tion contains a metal it is always liberated at the cathode.
The plus wire of circuit is attached to anode and nega-
tive wire to the cathode.
When a metal is dissolved in a dilute acid and the water
boiled away the solid substance left is called a salt.
If the metal sodium is dissolved in weak muriatic acid
and the water boiled away common table salt is left
behind. If this is dissolved in water again we can by
electrolysis separate it into the soda and muriatic acid
again.
Cryolite is a compound with a great deal of aluminum
in it. By melting it and while liquid passing current
through it the aluminum is collected at the cathode.
The pieces of the electrolyte produced by electrolysis
are called ions.
HOW ELECTROLYSIS TAKES PLACE.
Electricity is an invisible something known only by its
effects. It can be moved from place to place through
the air as Marconi has shown, or it can be more accurately
and more cheaply transferred by copper wires. How the
air or the copper wire conducts the electricity we do not
know.
When electricity is transferred through a liquid we
know that certain kinds of little particles of the sub-
stances in the liquid carry the electricity across from the
anode to the cathode and stay there and certain other
kinds of particles collect about the anode, for there is a
transfer of electricity in both directions.
Unless these little particles are present the liquid will
not conduct. If they are present the liquid conducts and
278
ELECTRIC RAILROADING.
while conducting the loosening process goes on and more.
particles (ions) are produced to keep up the conductivity
of the liquid.
ELECTROLYSIS OF WATER.
Take a glass of boiled and filtered water (it would be
better if it were distilled water). Bring the + and
wires from a 3-cell battery to the glass and fasten strips
of platinum foil to the ends by wrapping on wires. Bend
the wires up and over the edge of glass and let platinum
strips hang in water. Do not let the copper wires get
even wet, much less in the water. An ammeter would
show no current passing because the pure water has no
ions in it. Now pour in a teaspoonful of sulphuric acid
and the water begins to conduct (due to presence of ions)
and electrolysis commences.
The water is composed of hydrogen and oxygen in the
proportion of 2 to 1, and the electrolysis allows these
gases to escape into the air so that after a while all the
water will be turned to gas.
To a railroad man electro plating and destruction of
water and gas pipes are the two important things.
ELECTRO PLATING.
Electro-plating and chemical-plating are often mixed
up in people's minds.
If you thrust a pen knife blade or a key into the copper
sulphate solution used in a gravity cell, the knife is in-
stantly copper plated by chemical action. If a sheet of
iron, sprinkled with sal ammoniac is dipped in a bath of
melted zinc it is chemically plated and is called galvanized
ELECTRO PLATING
279
iron. Electricity had nothing to do with either of these
platings.
As we know that the metals are dissolved into the
solution at the anode and deposited at the cathode, we'
may electroplate an article with copper in the following
way:

Fig. 137. Electro-plating Cell.
Make a bath of 1 gallon water, 10 oz. potassium cyanide
(deadly poison), 5 oz. of copper carbonate, and 2 oz.
potassium carbonate.
Place in a glass or wooden tub, connect to positive
wire a slab of copper (Fig. 137), and to negative wire
the thoroughly cleaned articles. The passage of a cur-
rent of low voltage will plate copper on the articles.
280
ELECTRIC RAILROADING
Brass may be electro-plated on iron castings. This is
a cheap and nasty substitute for a solid brass casting.
Impure ores of copper, scrap copper, old telegraph and
electric light wires in which there is always more or less
solder, and copper mixed with other impurities, may be
purified by electrolysis, the cathode being a plate of pure
copper, the bath a solution of sulphate of copper, and
the anode the impure metal. The pure copper replaces
the exhaust from the bath, and the impurities fall to the
bottom of the tank. Recovered copper thus deposited is
extremely free from impurities, and is used for electrical
conductors where low resistance is required.
ELECTROLYTIC CORROSION.
When the current has passed through motors it returns
to the power house by many paths, some of which are:
Rails of the track, return feeders between rails, elevated
railway structures, waterpipes, gaspipes, cables of tele-
phone wires, Edison tubes, adjacent streams of water.
Let us consider the water and gaspipes and the cables.
The current going into these is positive and when finally
the current leaves them to go to the earth plates of the
power house, if the ground is the least bit moist, metal
is dissolved and taken away. In this way holes have been
eaten in gas and water mains, and the sheathing of cables
destroyed. The return current has a habit of leaving the
pipes at each joint and coming back into pipe on the
other side. This causes corrosion at every joint.
This electrolytic corrosion is frequently the cause of
law suits against the railroad companies.
To reduce the evil and to be able to show in case of
ELECTROLYTIC CORROSION
281
suit that every possible precaution has been taken the
company should:
Thoroughly bond the track rails at every joint.
Run a bare copper wire along between the rails and
connect each rail of the track to it.
Whenever a pipe or cable is found to be in danger of
corrosion, run a wire from negative pole of station to
the pipe and make a well soldered connection.
It is evident that alternating current will not cause
corrosion for it is rapidly reversing in direction.
Main line tracks will have far less trouble with corro-
sion than branches, and city extensions, belt lines, etc.,
which run through streets crowded with pipes and cables.
}
F
CIRCUITS.
An electric current is so called because it is the thing
through which the electricity passes or makes its circuit
around through the different pieces of apparatus and
machinery.
The word circuit is used in connection with many
other words as: series circuit, parallel circuit, short cir-
cuit, A. C. circuit, etc. These will all be explained in the
following lessons.
A dead circuit must be made live before it can deliver
power, and where so delivering it is called a loaded cir-
cuit.
Every loaded circuit has Conductance, Resistance, In-
sulation, Pressure and Current which are explained in
the following lessons.
The habit of referring to circuits as lines has grown
so that the words are almost interchangeable.
We ought to be more accurate and use the words in
this manner.
When a wire starts from the power house and returns
again we have a circuit. When we speak of a part of
this circuit we say "the line between Chicago and Hins-
dale.'
When the wires run. from a power house to a sub-sta-
tion we may call it "the line." Of course there is an
electric circuit there but we are always thinking of it as
if current only flowed from power house to sub-station,
and speak accordingly.
282
CIRCUITS
283
When one side of the circuit is composed of rails,
earth, etc., we always speak of the copper part as the
"line" and the rest of it as the "ground."
Fig. 138 shows several kinds of circuits and corre-
sponding effects.
Taking the top part of the figure with the solid lines.
Starting from the terminal of the battery we have a
series circuit through the magnet, lamp, resistance, elec-
trolytic tank and back to the terminal of the battery.

+
R
a
Z
Battery
2
Fig. 138. Diagram of Circuits.
In such a series circuit the same current must pass
through each of the pieces of apparatus. If the circuit.
had all lamps, or all electro-plating tanks this would per-
haps be satisfactory, but since a lamp takes one-half to
one ampere and the plating bath 10 amperes and up-
wards, it is evident that such a circuit will not work at
all when different kinds of apparatus are in it. Either
the plating bath won't work or the lamp will be burnt out
in a few minutes.
284
ELECTRIC RAILROADING
!
Another objection to a series circuit is that should we.
wish to stop the flow of current through the resistance.
R, we cannot open the circuit by a switch as that would
cut the current off from all the rest of the apparatus. A
short-circuiting switch must be installed as shown at a, b.
When the ends of these wires are connected by a switch,
a shunt circuit is formed around R and the shunt will
carry the current when R is removed. The shunt cir-
cuit must be made of large enough wire to carry the cur-
rent formerly carried by R without over heating.
Such a short circuit of a part of a series circuit causes
no trouble at all but a short circuit of the whole of a
series circuit must be made more carefully. The re-
sistance of the wires x, and y forming the short circuit
should be very low when a series dynamo is used and
verv high when a battery is used.
A very low resistance short circuit on a series dynamo
stops the generation of current, and a very high re-
sistance short circuit on a battery stops it generating
current.
A high resistance short circuit is always referred to
as a shunt, and the words short circuit reserved for
low resistance ones.
Looking at the dotted part in Fig. 138 we have two,
mains running from the battery and branches running
across between mains; the branches containing the ap-
paratus.
The mains and branches form parallel circuits and
the apparatus is said to be installed in parallel or mul-
tiple.
Several distinct advantages are gained by the par-
allel system,
CIRCUITS
285
Each piece of apparatus can draw as much current
as it needs without interfering with other apparatus.
The current may be cut off from any of them by
opening a switch in its branch without affecting the
remaining branches.
Short circuits (i. e. low resistance) anywhere in a
parallel circuit will cause considerable damage.
Parallel circuits are fed by shunt dynamos or alter-
nators. A short circuit on a shunt dynamo causes it
to generate an enormous current and may destroy the
apparatus short circuited and the dynamo's armature.
Alternators do not produce such large currents when
short circuited so in this case it is the apparatus short
circuited that suffers most.
When each branch of a parallel circuit contains sev-
eral pieces of apparatus in series, the whole is called a
series parallel circuit.
Suppose we now learn how electricity flows through
circuits.
In hydraulic, pneumatic or steam engineering, the in-
dications of the pressure gauge are of the utmost im-
portance to the engineer; in fact, he is always consid-
ering and asking about the pressure, and does not trouble
himself about the water, air, or steam, for none of these
would be of any use to him unless they existed under
a certain head or pressure. It is simply the pressure.
under which they exist that gives to them their working
power.
In a similar way the electrical engineer is always
concerned about the electrical pressure; he does not
talk or think much about the electricity, but the elec-
trical pressure is always in his mind as being of the
first importance.
286
ELECTRIC RAILROADING
The hydraulic engineer measures his pressure in
pounds per square inch, that is to say, his unit of pres-
sure is that exerted by a pound weight. The electri-
cal engineer's unit of pressure is called the volt (from
Volta, an Italian electrician), the consideration of which
we will leave for a future lesson. It is owing to this.
pressure that a current of electricity flows around a con-
ducting circuit. No current could possibly flow unless.
there was a difference of electrical pressure in the cir-
cuit, in the same way that no water would possibly flow
through a water conductor unless there existed a dif-
ference of pressure.
Instead of calling it the electrical pressure, we might
call it the electricity-moving force, or the electro-motive.
force, or, for brevity, the E. M. F., which is the term
most commonly applied to the electrical pressure; thus
we speak of the E. M. F. of a circuit as being equal to
so many volts.
It would perhaps be well to point out here the en-
gineer's meaning of pressure.*
We may exert a pressure and still have no resultant
motion; as, for example, suppose a man applies a pres-
sure (a moving force) at one end of a table, which
would of itself be able to move the table along the
floor; if now a boy pushes at the opposite end and in the
opposite direction, it is certain that the table would not
be moved as rapidly as before, providing the man pushes
with the same force throughout, while if another man
takes the place of the boy and pushes with equal force
to the man opposite to him, the table would not be moved
at all, although there is now a greater pressure being
*This illustration is taken from Mr. Tyson Sewall.
ELECTRO-MOTIVE FORCE
287
applied to the table than in the original case. It will
therefore be seen that the result obtained does not de-
pend on the pressure, but on the difference of pressure,
and in all cases where pressure is spoken of it is the
difference of pressure that is meant.
Returning to the experiment with the table, we have
just seen that before the table can be moved we must
provide a table-moving force, but when this is provided
it does not follow that the table will move even then-
it all depends on the resistance offered. We can imag-
ine a very heavy table, with rough feet, standing on
two rough boards, and the man applying a moving force
to it but producing no movement; whereas when the
floor has been smoothly planed he may be able to move
it slowly, and by fitting wheels or casters to the feet of
the table he may be able to move it rapidly with the
same moving force.
We see that the rate of movement of the table depends
partly upon the table-moving force applied and also in
part upon the resistance offered by the boards on which
the table stands. It is directly proportional to the
former and inversely proportional to the latter. That is
to say, if we double the moving force while the resistance.
remains the same, the rate of movement of the table will
be doubled, and if we keep the moving force the same
and halve the resistance, the rate of movement of the
table will be doubled. This could be stated thus:
Rate of move-
ment of table
is proportional to
table-moving force
resistance.
Therefore the rate of movement of the table is a
thing entirely dependent on two other things, and in try-
288
ELECTRIC RAILROADING
ing to find its value we have to ask, first, what is the
moving force available? and second, what is the resist-
ance offered? The same applies to water moving in
pipes and this is perhaps a better analogy to the elec-
trical case. We say there is a current of water flowing
through the pipes, but this current is flowing simply be-
cause there is a difference of pressure between the two
ends of the pipes, and as the pipes offer a certain resist-
ance, while these two things remain constant, the
strength of the current will remain constant also. If we
desire to alter the rate of flow (the current), we must
alter either the water-moving force (the head) or the
resistance (the tap). We can now see why the engineer
is not concerned so much about the current; he may
want a certain current to flow, but he gets it by seeing
either to the water-moving force, or to the resistances,
or to both.
If we now apply this electricity we find the same ideas
in the mind of the electrical engineer. If he desires a
certain current he asks himself, "What E. M. F. (elec-
tro-motive force) have I available?" and then, "What re-
sistance must I have in the circuit?" and he makes all
alterations in the current strength by adjusting the one
or the other, or both, to suit. If the circuit has a fixed
resistance then he cannot alter the current flowing round
it except by proportionally altering the E. M. F., that is
to say, if he wishes to have twice the current strength he
must put twice the E. M. F. into the circuit. If the E.
M. F. has a fixed value, then he cannot alter the current
without altering the resistance of the circuit, thus-if he
wishes to double the current strength he must halve the
total resistance of the circuit.
سم
t
FLOW OF CURRENT
289
All the so-called generators of electricity, dynamos,
batteries, etc., are simply
maintaining an E. M. F.
E. M. F.'s from 2000 to
while battery cells produce low E. M. F.'s from 1 to 2
volts only.
devices for producing and
Some dynamos produce high
10000 volts and even higher,
To make the analogy between the water system and
the electrical system more correct, we should suppose a
closed circuit of pipes, as shown in Fig. 139, completely
filled with water, having a rotary pump P in the cir-
cuit, and furnished with a tap R a pressure gauge PG,
and a current gauge C G.

@
C.G
L
Fig. 139. Simple Hydraulic Circuit with Gauges.
Suppose now we turn on tap T and start the pump
working, the pressure gauge will indicate a difference of
pressure in the circuit, and the current gauge will indi-
cate a current, flowing round the circuit.
In this case we are not generating water, we are sim-
ply putting into motion the water that was already there,
and this is done by creating a difference of pressure by
means of the pump, and by providing a conducting cir-
cuit. If we stop the pump, the two indicators will point
again to zero, but there is just the same amount of water
there as we started with, there has been no consumption
of water.
290
ELECTRIC RAILROADING
In the same way we have to think of an electrical cir-
cuit (Fig. 140). The dynamo D is simply a device for
producing a difference of electrical pressure, and is put
into the circuit to act exactly as the pump does in Fig.
139 if we switch on S, which is comparable with turning
on the tap in Fig. 139, and start the dynamo working,
the pressure gauge (called the voltmeter) VM will indi-
cate a difference of electrical pressure or an E. M. F.,
and the current gauge (called an ampere-meter, or for
brevity an ammeter) will indicate a current flowing
round the circuit. In this case we are not generating
electricity, but simply putting into motion electricity that
was already there.
Going back to Fig. 139, suppose we turn off the tap T
and keep the pump working, then the current meter will
indicate no current, but the pressure gauge will indicate
a slightly higher pressure than before. Here we have a
water-moving force, but the resistance in the circuit is
now exceedingly great, consequently no current can flow.
Similarly in Fig. 140 if we switch off, still keeping the
dynamo running, the voltmeter will show a slightly
higher pressure, while the ammeter will indicate no cur-
rent. Here again we have the one essential for a flow
of electricity round the circuit, but not the other, for in
switching off we have introduced into the circuit an
enormous resistance.
It will be noticed that we have referred throughout to
the current as being not the movement of the table, or
the flow of water or electricity, nor yet the quantity of
water or electricity moved, but as the rate of movement.
Fifty gallons of water is not a current of water, but 50
gallons per minute is a statement of the rate of flow, and
FLOW OF CURRENT
291
consequently is a statement of the current strength. A
current is the rate of flow.
Let us return again to our water circuit (Fig. 139)
and examine it more closely. Imagine the system to be
quite full of water, and remember that water is a practi-
cally incompressible fluid. If now we have our pump at
work with the tap turned off, we shall have a difference
of pressure between the two sides of the pump but no
The moment we turn the tap on the current
current.

}
S
о
D
VM
AM
Fig. 140. A Simple Series Circuit, with Instruments..
will flow, but this current will be everywhere in the cir-
cuit of the same strength, it will not be strongest at the
pump and get weaker as we go round the circuit, but
will instantly have the same strength everywhere, and
the current does not get used up in going round the cir-·
cuit.
This is exactly the case with the current in Fig. 140,
If the dynamo be at work we have an E. M. F. in the
circuit, but while the switch is off no current can flow.
The moment we switch on there is a current in the cir-
292
ELECTRIC RAILROADING
cuit which is everywhere of the same strength, not
stronger near the dynamo, and getting used up as it goes
round the circuit, but of the same strength everywhere
in the circuit.
It is evident that flow of current is regulated by pres-
sure and resistance of circuit so that
Resistance
Current=
Pressure
using the principles taught in Formulas Page 210 we
get two other forms of this rule
Pressure
Current X Resistance
Resistance
Pressure
Current
A man named Ohm first noticed this rule and it is
called Ohm's Law in his honor.
Let us now consider a few problems on the Ohm's
Law.
I. The E. M. F. in a simple circuit (Fig. 140) is 100
volts, the resistance of the whole circuit is 50 Ohms.
What current will flow through the circuit?
Ohm's law says, current
Therefore in this case C =
E. M. F.
Resistance
100
50
14
2 amperes.
It must be fully realized by the student that while the
E. M. F. remains at 100 volts, and the resistance re-
mains at 50 ohms, the current in that circuit will be 2.
amperes, no more and no less. It is impossible for any
other strength current to flow.
OHM'S LAW
293
2. The resistance of the circuit being reduced to 10
ohms, while the E. M. F. is kept at 100 volts, what is
now the strength of the current?
Again current
E. M. F.
Resistance
ΙΟΟ
Therefore C=
10 amperes.
IO
3. It is found that when an E. M. F. of 100 volts is
applied to a circuit, a current of 25 amperes flows. What
is the total resistance of the circuit?
E. M. F.
Resistance=
current
100 volts
Therefore resistance
4 ohms.
25 amperes
4.
In the same circuit we find that by twisting upon.
itself some of the wire of which it is composed, the cur-
rent increased to 50 amperes. What is now the resistance
of the circuit, and how much resistance has been cut out
by so twisting up the wire?
Again by Ohm's law-
E. M. F.
Resistance
current
100
Therefore resistance
2 ohms.
50
It had four ohms previously; we have therefore cut out
4-2-2 ohms.
294
ELECTRIC RAILROADING
5. In a circuit of 20 ohms resistance, a current of 5
amperes is flowing. What is the E. M. F. in the circuit?
By Ohm's law-
The E. M. F. Current X Resistance.
Therefore E. M. F.5X20-100 volts.
6. What is the E. M. F. in a circuit whose resistance.
is equal to 10 ohms when a current of 20 amperes flows
through it?
E. M. F. Current X Resistance.
E. M. F. 20 X 10200 volts.
We have now to consider circuits other than the simple
circuits just described, known as divided circuits or par-
allel circuits.
Fig. 141 represents a simple circuit in which the prin-
cipal resistance consists of a conductor A of 50 ohms re-
sistance; the remainder of the circuit consists of a dyna-
mo capable of generating the E. M. F. of 100 volts, and
thick connecting wires joining it to the ends of A.
If we neglect for the present the small resistances of
the dynamo and connecting wires, then the current flow-
ing is
C =
E 100
R
50
2 amperes.
Suppose we now join the points C and D with another
conductor B exactly similar to A, as in Fig. 142. Will
the current through the dynamo be greater or less than
before? And will it make any difference to the current
flowing through A?
Let us see. The circuit B having the same resistance.
as circuit A conducts just as well, hence twice as much
current can flow between C and D, as flowed before. It is
evident that the resistance offered is now half what it
OHM'S LAW
295
was. In Fig. 141 it was 50 ohms, in Fig. 142 it must be
25 ohms, by Ohm's law the current through the dynamo
Ε
100
has doubled, for C=
4 amperes; 2 amperes
R
25
through A, and 2 amperes through B.
To make this quite clear, let us take our water analogy
again. Fig. 143 represents a water circuit similar to our
last electrical circuit. If the pump be working con-
tinuously, maintaining a difference of pressure between'
its ends, then with T turned on and t turned off, we

Am
Vm
= 100
о
D
A = 50 Ohms
Fig. 141. A Series Circuit.
should have a flow of water round the circuit through A,
which would offer the principal resistance of the circuit,
and the current gauge would indicate a certain current
flowing through the pump. If now we turn on tap t, we
open up another path for the water to flow in, and con-
sequently, as water will flow in B just as easily as in A,
296.
ELECTRIC RAILROADING
the resistance to the passage of water from C to D would
be halved, and the current gauge would immediately in-
dicate twice the former current. The two pipes in paral-
lel are really equivalent to one pipe of twice the internal
sectional area. The same thing would apply to 3, 4, 10,
or any number of similar pipes joined between C and D;
the resistance would be reduced to 2, 4, or 1/10 its
former value, with a corresponding increase in the cur-
rent flowing through the pump.

V
=100
о
Dy
Am
00000000
B = 50 Ohms
·A-50 Ohrs
2 d o O o O o O o O o O o ÿ ÿ d d r d ə o d
Fig. 142.
Parallel Circuits.
It must be understood that there is no increase in
the current flowing through any individual pipe when
others are connected across. The current in A, Fig.
143, for instance, would remain practically constant
throughout providing the pump maintained the same
difference of pressure.
It is in this way that we must look upon the electrical
current in Fig. 142. The more similar wires we join
between C and D, the more are we increasing the con-
PARALLEL CIRCUITS
297
}
ductivity between these two points, and the less is the
resistance becoming, but providing the dynamo main-
tains the pressure, no alteration would take place in the
value of the current in any individual conductor. Each
separate conductor would act according to Ohm's law,
and each being joined to points, maintained the same
difference of potential, and each being of the same re-
sistance, each must have the same strength of current
flowing through it.

P
ao
C
a
Fig. 143. Hydraulic Circuit with By-pass.
Effects of Current.
Imagine a circuit like Fig. 144 containing in order:
1. A galvanometer or current meter.
2. An electromagnet.
3. An apparatus for electrolysing water or a gas volt-
ameter.
4. A copper plating bath or copper voltameter.
298
ELECTRIC RAILROADING
+
5. A vessel containing a coil of wire submerged in
water, and surrounded with a box of sawdust to pre-
vent the radiation of the heat.
6. An incandescent lamp.

Bounds
Bull
Copar
Нублюден
Sulphater
AHMHICLE
Coppass
Salvanometer
Elutiomagnet.
Das Voltameter
Thurmometer
Coppes
Copper
Voltametest
Heater
Switch
Sawdust
Cells in series.
Calorimeter
Incandescent Lamp
Fig. 144. The Different Effects of Current.
When the current is flowing you will observe the fol-
lowing effects:
1. The needle is deflected.
2. Armature of magnet is attracted and held.
3. Water is turned to oxygen and hydrogen gases.
4. The cathode is copper plated.
5. The thermometer rises.
6. The lamp gives light.
EFFECTS འ
299
OF CURRENT
Now let us examine the size of each of these effects,
measuring them in the most suitable units, and then let
the current be changed from its original value to say
twice and then three times that value and see how the
size of the effect varies.
The Galvanometer gives readings of 10, 15, 17 de-
grees, so that the effect of a given current varies ac-
cording to whether it is the only current passing or one
of many equal currents.
The Electro-magnet gives 9 lbs. pull, then 11 lbs., and
finally 11½ lbs.; so that evidently the attraction of a
magnet does not increase in the same proportion as the
increase of current in its coils.
In the Gas Voltameter we find that double the current
electrolyses double the quantity of water, and three times.
the current, treble the water. The same is true of the
Copper Plating Bath. The amount of metal deposited
is exactly proportional to the current and the time. A
given current deposits 0.0026 pounds of copper per hour;
double the current will deposit 0.0052 pounds, treble the
current 0.0078 pounds.
The thermometer in the Calorimeter has risen very
rapidly. The original current made it rise 1/10 of a
degree a second, twice the current gave a rise of 4/10
degrees and thrice the current gave 9/10 degrees rise.
Since I XI equals 1
and 2 x 2
and 3x3
CC
4
9
And since the numbers 1, 2 and 3 represent the cur-
rents; and 1, 4, 9 the heat produced, we say that the
heating is proportional to the square of the current.
}
300
ELECTRIC RAILROADING
(The product obtained by multiplying a number by itself
is called the square of that number).
The extra amount of Light obtained by increasing
the current is small and does not increase regularly.
The first increase in current adding 3 candle power, and
the next increase added 4 candle power, while the next
would have probably added 6 candle power.
Looking back over these current effects it will be seen
that the electrolysis or electro-chemical effect is the only
one that is regular in a simple manner, so we choose the
amount of copper or silver plating done as the test for
the size of the current flowing. We decide that the unit
of current shall be called an
AMPERE, which is the current depositing 0.0026
pounds of copper or 0.00887 pounds of silver per hour.
Although a certain current may be lighting a lamp, if
that current were made to silver plate and deposited
0.00443 pounds in ½ hour, we should call it an ampere.
The original Edison Meters were nothing but zinc
plating baths put into the customers line and by the
amount of plating done the amount of current drawn by
the lamps was known.
Modern meters are either galvanometers marked to
show amperes or are small motors with a cyclometer
attachment to record the ampere-hours.
An ampere-hour is one ampere for one hour, half an
ampere for two hours, etc.
LESSON 18.
RESISTANCE.
Every conductor offers more or less opposition to the
flow of electricity and we call the opposition Resistance.
In order to compare the resistance of different ma-
terials some standard of resistance must be agreed upon.
All electricians and engineers have settled on the
OHM. The unit of resistance is the ohm, which is
the same resistance as is offered by a mercury conductor
nade in this way: Take 0.0318 of a pound of pure
mercury and pour it into a glass tube which is exactly
41.88 inches long, and of uniform size of bore. The
mercury must exactly fill the tube when both are at a
temperature of 32 degrees Fah. Try different sized
tubes of the same length (41.88 inches) until one is
found to be exactly filled. Then the resistance offered
by this conductor to the passage of electric current is
called one ohm. Remember that the temperature must
always be 32 degrees.
Mercury is selected because it is a liquid and because
its resistance is high and so the tube is not inconveniently
long.
To measure all resistances the ohm is used, but to
express very small resistances the microhm is used. It
is one millionth of an ohm.
To express very high resistances the megohm is used,
It is one million ohms. It is abbreviated meg,
301
302
ELECTRIC RAILROADING
A telephone engineer would refer to a resistance of
0.00385 ohms as 3850 microhms. OhmsX1,000,000—
microhms.
In speaking of the resistance between the two track
rails measured across the ties an engineer would proba-
bly say 47.5 megs instead of 47,500,000 ohms.
1
Ohms÷÷÷1,000,000-megohms.
Laws of Resistance.
The resistance varies with the nature of the material.
The metals are good conductors, cotton and dry goods
very poor conductors, while silk, porcelain, shellac, oils,
mica, paraffin, and dry air are so poor that we call them
insulators.
}
If we take a piece of wire having a known resistance,
and cut it into two equal lengths, we find on measuring
that each piece has just half the resistance of the former
piece, hence the law is twice the length, twice the re-
sistance.
Stated mathematically it is—
ཝཱ་
The resistance of a given wire of uniform section is
proportional to its length.
But the resistance also depends on the cross section.
of the wire. If we take three wires of the same ma-
terial, but with cross sections, of 1, 2 and 3 circular
mills,* if the first one has 1 ohm resistance, the others.
will have 2 and 3 of an ohm resistance.
Hence the greater the area of wire's cross section the
less the resistance.
The resistances are inversely proportional to their
cross sectional areas..
*See further on in Lesson.
RESISTANCE
303
It must be remembered that the cross sectional area
is obtained by squaring the diameter. If the diameters
of two wires are 3 and 6 mils, their areas are 9 and 36°
circular mils and the resistance of the first wire is 4
times as great as the second, because the area is only
4 of the second.
The resistance of conductors also varies very largely
with the nature of the material used. For instance, if
we take three different wires, all the same length, and
the same sectional area, but one made of copper, an-
other of iron, and the third of german silver, their re-
sistances would be in the ratio of 1:6:13. It is useful
to remember these figures as being approximately cor-
rect, for the three metals named are in great demand.
in electrical engineering.
German silver made of 2 parts copper, I of zinc and
I of nickel, is an extra high resistance metal, and is
useful when we need a lot of resistance in a small space.
The resistances used to aid in the starting of traction
motors are usually of cast iron.
Stated briefly, the longer the piece of material the
higher is the resistance, and the greater its cross section
the lower the resistance. The rule being:
Resistance in ohms-
Material x Length
Cross Section.
The number representing the materials are the ohms
resistance of a piece I foot long and I mil in diameter.
Copper 10.8
Aluminum 17.2
Iron 63.4
Mercury 128.3
German Silver 586.2
304
ELECTRIC RAILROADING
For Length insert the number of feet and for Cross
Section put the square of the diameter in mils (thou-
sandths of an inch).
For example: Find the resistance of 9000 ft. of iron
wire 0.2 inch in diameter.
→
Material: Iron 63.4. Length in feet 9000
Diameter in mils 200. Squared 40000
63.4 x 90000
Resistance in ohms=
14.26
40000
This rule only applies to round wires but may be
changed so as to apply to rectangular conductors.
Resistance=
Material x Length
Area X 1.27
:
Area being the area of the cross section of rod in
square mils.
An increase in the temperature increases the resist-
ance of the metals, but they each have their own way
of increasing, some faster than others.
The resistance of copper increases a little less than 4
of 1% for every degree Fahr. and iron increases a little
more than copper. Mercury increases about 1/40 of
1% per degree.
Wire Measurement.
The diameter of a round wire or bar is always meas-
ured in mils. A mil is a thousandth of an inch.
The area of round wires is measured in Circular mils.
The number of circular mils is found by squaring the
diameter measured in mils..
RESISTANCE
305
This is a far better way of measuring than the me-
chanics way of square inches, but cannot be applied to
rectangular pieces of material.
To make matters as simple as possible the electrician
measures the two dimensions of the cross section in mils
and obtains the area (by multiplying them together) in
square mils. This he converts at once to circular mils.
by multiplying by 1.27. Then having circular mils he
can apply formulas.
The mil-foot is used in formulas and is handy as a
comparison of resistances.
A piece of round material I foot long and 1 mil in
diameter is a mil-foot.
G
Resistance and Conductivity.
If we take a piece of wire whose resistance is 1 ohm,
and apply an E. M. F. to the ends of it, we find that it
is able to conduct electricity. We might say that this
piece of wire has unit conducting power, or unit con-
ductivity, as well as unit resistance. If we take another
piece of the same wire, but twice the length of the former
piece, it will have twice the resistance, that is, it will con-
duct electricity only half as well as the former piece, con-
sequently we should say this piece of wire has resistance
of 2 ohms and a conductivity of ½. Again, if we take a
wire having a resistance of 10 ohms, then it will conduct
electricity only 1/10 as well as the piece having 1 ohm.
Therefore we should say its conductivity is 1/10, and so
on.
We thus see that the conductivity of a substance is the
reciprocal or the reverse of its resistance. If the resist-
306
ELECTRIC RAILROADING
TABLE OF DIMENSIONS OF PURE COPPER WIRE.*

Area.
Weight and Length,
Sp. Gr. 8.9.
No.
Diam.
B. & S.
Mils.
Circular
Mils.
Square
Mils:
Lbs. per
Lbs. per
Feet per
1000 feet.
Mile.
Pound.
0000
460.000
211600.0
166190.2
640.73
3383.04
1.56
000
409.640
167805.0
131793.7
508.12
2682.85
1.97
00
364.800
133079.0
104520.0
102.97
2127.66
2.48
0
324.950
105592.5
82932.2
319.74
1688.20
3.13
1
289.300
83694.5
65733.5
253.43
1338.10
3.95
2
257.630
66373.2
52129.4
200.98
1061.17
4.98
3
229.420
52633.5
41338.3
159.38
841.50
6.28
4
204.310
41742.6
32784.5
126.40
667.38
7.91
5
181.940
33102.2
25998.4
100.23
529.23
9.98
6
162.020
26250.5
20617.1
79.49
419.69
12.58
789
144.280
20816.7
16349.4
63.03
332.82
15.86
128.490
16509.7
12966.7
49.99
263.96
20.00
114.480
13094.2
10284.2
39.65
209.35
25.22
10
101.890
10381.6
8153 67
31 44
165.98
31.81
11
90.742
8234.11
6467.06
24.93
137.65
40.11
12
80.808
6529.94
5128 60
19.77
104.40
50.58
13
71.961
5178.39
4067.07
15.68
82.792
63.78
14
64.084
4106.76
3225.44
12.44
65.658
80.42
15
57.068
3256.76
2557.85
9.86
52.069
101.40.
16
50.820
2582.67
2028.43
7.82
41.292
127.87
17
45.257
2048.20
1608.65
6.20
32.746
161.24
18
40.303
1624.33
1275.75
4.92
25.970
203.31
19
35.890
1288.09
1011.66
3.90
20.594
256.39
20
31.961
1021.44
802.24
3.09
16.331
323.32
21
28.462
810.09
636.24
2.45
12.952
407.67
22
25.347
642.47
504.60
1.95
10.272
514.03
23
22.571
509.45
400.12
1.54
8.1450
648.25
24
20.100
404.01
317.31
1.22
6.4593
817.43
25
17.900
320.41
251.65
.97
5.1227
1030 71
26
15.940
254.08
199.56
27
14.195
201.50
158.26
28
12.641-
159.80
125.50
29
11.257
126.72
99.526
30
10.025
100.50
78.933
.30
31
8.928
79.71
62.603
32
7.950
63.20
49.639
.19
33
7.080
50.13
39.369
34
6.304
39.74
31.212
35
5.614
31.52
24.753
.10
36
5.000
25.00
19.635
.08
37
4.453
19.83
15.574
.06
38
3.965
15.72
12.347
.05
39
3.531
12.47
9.7923
.04
40
8.144
9.88
7.7635
.08
* 9988888
.77
4.0623
1299.77
.61
3.2215
1638.97
.48
2.5548
2066.71
.38
2.0260
2606.13
1.6068
3286.04
.24
1,2744
4143.18
1.0105
5225.26
.15
.8015
6588.33
.12
.6354
8310.17
.5039
10478.46
.8997
13209.98
.3170
16654.70
.2518
21006.60
.1993
26487.84
.1580
83410.05
* 1 mile pure copper wire
1-16 inch, diam.:
13.59 ohms at 15.5° O. or
59.9° F.
1 circular mil is .7854 square mil.
RESISTANCE
307
}
ance of a conductor be 50 ohms, its conductivity is 1/50.
A name has been given to the unit of conductivity which
is easy to remember. Seeing that the conductivity is the
reverse of resistance, the name of the unit of resistance
(ohm) has been reversed for that of conductivity. Thus
a wire of I ohm resistance has I mho conductivity. A
wire of 75 ohms resistance has a conductivity of 1/75
nho, while a wire of ½ ohm resistance has a conductiv-
ity of 2 mhos.
Of course it will be understood that if conductivity is
the reciprocal of resistance, then resistance is also the re-
ciprocal of conductivity, one the reverse or reciprocal
of the other. Therefore a wire of 1/50 mho conductiv-
ity has a resistance of
1
1
25
50 ohms.
Resistances in Series and in Parallel.
When resistances are in series we add their values to-
gether to get the total resistance but when they are in
parallel the resistance of the group, called joint resist-
ance, is less than the smallest and must be calculated in
a certain manner.
Turn back to Fig. 142. A can conduct electricity
across between A and D its conductivity being 1/50 mho,
that is, it will conduct electricity across only 1/50 as well
as a resistance of ohm. But we have now got two paths,
each with a conductivity of 1/50 mho, so the two to-
gether can conduct electricity across twice as well as one
of them, for now we have a conductivity of 1/50+1/50
=1/25 mho. We have already seen that resistance is the
reciprocal of conductivity, therefore the resistance be-
=25 ohms. But it was 50
tween C and D is now
1
1
25
308
ELECTRIC RAILROADING
chms before we joined the second wire across, so that we
have reduced the resistance to half its former value.
If there should be resistances in series with those in
parallel figure the joint resistance of the set in parallel
and then figure the rest as if that joint resistance took the
place of the parallel group and everything were in series.
Consider Fig. 145. Here we have C and D joined by
two wires, A having a resistance of 50 ohms, and B hav-
ing a resistance of 25 ohms.

Vm
= 100
о
D
Am
B = 250hms
r o d o o o o o o o ooo ooo ooo oo ot
A =50 Ohms
Fig. 145. À Divided Circuit.
Now we have seen that A has a conductivity or con-
ducting power 1/50, similarly B has a conductivity—
1/25, and therefore the two together have a conductivity.
of 1/50+1/25=3/50 mho. The resistance between C
and D being the reciprocal of the conductivity
1 50
is
16.6 ohms
3
50
3
(less than the smallest resistance).
RESISTANCE
309
}
The current flowing through the dynamo now is
E
100
R 16.6
6 amperes.
Again, imagine C and D to be connected by three
wires, A=50 ohms, B-25 ohms, and G=10 ohms. Then
the conductivity between
C and D=
{
1 1 1
+ +
50 25 10
1+2+5 8
50
mho,
50
and the resistance between
50
C and D
8
6.25 ohms
50
(again less than the smallest resistance joining C and D).
Of course the combined resistance must be less than
that of the smallest resistance between the points, for if
G were there alone, that part of the circuit would have 10
ohms resistance, and the addition of B and A, though
larger than G, is only diminishing the resistance between
these points by opening up other paths for the passage of
electricity.
Q. I. What is the resistance of four wires in par-
allel of 2, 5, 10, and 20 ohms respectively?
The combination has a conductivity of—
1 1 1 1 10+4+2+1
+ + +
2
5 10 20
20
and their combined resistance in parallel.
1 20
17
mho,
20
ohms.
1.7
20
곰곰 ​- 17
310
ELECTRIC RAILROADING
Q. 2. Two mains are carrying current for a group of
twenty lamps; each lamp has a resistance when incan-
descent (white hot) of 160 ohms, and they are all joined
in parallel. What is the resistance between the two
mains.
Here all the resistances are equal and the total resist-
ance is 1/20 of one of them or 160÷÷÷20=8 ohms.
If we have only to deal with two resistances in parallel,
it will be easier and quicker to make use of this rule:
The joint resistance of two resistances in parallel is
the product of the two divided by their sum.
Q. 3. Two resistances of 5 ohms and 20 ohms are in
parallel. What is their combined resistance?
product 5X20 100
R==
sum
4 ohms
5+20 25
Working by the first method we have:
1 1
5
Conductivity= +
5 20
20
20
Resistance: =4 ohms.
5
LESSON 19.
OHM'S LAW.
We have now stated what an ampere of current and
an ohm of resistance are. The unit of pressure is the
result of these two, for a volt is the pressure necessary
to send one ampere of current through one ohm of resist-
ance.
Knowing these three units of measurement and the
law of flow of current we can solve many electrical
problems.
Law of the Flow of Current.
With a given circuit the greater the pressure the
greater the current, or if the pressure (voltage) re-
mains the same, the less the resistance the more current
flows.
Hence Current equals Pressure divided by Resistance,
or Amperes=
volts
ohms
This is the regular form of Ohms Law and means:
The current in amperes in any conductor is equal to
the difference in pressure between the ends of the con-
ductor, in volts; divided by the resistance between the
ends, expressed in ohms.
311
312
ELECTRIC RAILROADING
Expressed as a formula, Ohms Law is
E*
R
C= or C
V
PD
or C:
R
Ꭱ
By E we mean the E. M. F., or electromotive force,
that is the total pressure in the circuit measured in volts.
By V we mean the pressure (in volts) in the part of
the circuit we are considering.
By P. D. we mean the Pressure Difference or differ-
ence in pressure (in volts) between the ends of the part.
of the circuit we are considering.
It is evident that V and PD are the same, while E is
the sum of all the V's in the circuit.
The form V=CR means:
(1) The voltage required to maintain a current flow
of C amperes through R ohms is given by the product of
C and R.
(2) The drop of pressure or voltage lost in any con-
ductor is equal to the product of the current C and
resistance R.
In fact, the loss in pressure which always occurs when
transmitting current is often called the CR loss. The
"drop" is the usual term.
The form R=
alu
C
is used to find what resistance
must be used in connection with a pressure E to limit
the current to C amperes.
*Electrical magazines and many text books use I for current,
reserving C for capacity. It will soon be generally adopted by
every one; but for a student C is more convenient and expressive.
OHM'S LAW
313
Problem 1. An incandescent lamp having a resist-
ance when hot of 240 ohms is connected to mains having
120 volts pressure between them. How much current
does the lamp draw?
V 120
C=
=12 ampere.
R 240
Problem 2.
What pressure will be required to force
7 amperes through an arc lamp whose resistance hot is
7 ohms?
V=CR=7X7=49 volts.
Problem 3. What drop will there be in transmitting
2000 amperes to a locomotive 2 miles from power house,
with a circuit whose resistance is 1/20 of an ohm per
mile?
2 miles=2/20=1/10 ohms.
Drop-V CR-2000X1/10=200 volts.
Problem 4. In a car heater enough heat is generated
when 10 amperes are flowing. Five of them are to be
placed in series in a car. Voltage between third rail
and track 500.
What must be the resistance of the
heater when hot?
500 volts÷5 heaters=100 volts per heater.
R=
V 100
C 10
10 ohms.
Problem 5. In Fig. 146 let the dynamo of 0.01 ohms
resistance be producing 100 volts as measured on the
volt meter V. This is not the E. M. F. of the dynamo,
because there is some drop in the dynamo. The 100
314
ELECTRIC RAILROADING
volts is the V. or P. D. at the ends of the external cir-
cuit.
This external circuit contains resistances as follows:
A in series 2 ohms. C and E together in parallel, yet
in series as a group with A. C is 100 ohms, E is 300
ohms. B is 3 ohms in series with A and the parallel
group.

V
* 100
A = 2 Ohms
о
01 Ohm
C = 100 Ohms
b=3Ohms
e=300Ohms
Fig. 146. Dynamo in a Series-Parallel Circuit.
What current flows through the dynamo?
The same current as through A or B for the circuit
is a series one. The resistance of external circuit is as
follows:
A=
7
2 ohms
C+E jointly=
product
30000
75 ohms
sum
400
·B=
3 ohms
Total 80 ohms
A circuit of 80 ohms has 100 volts pressure at its
ends, therefore,
V 100
C=
.25 ampere flows.
R 80
OHM'S LAW
315
The drop in the dynamo must be
V=CR=1.25X0.01 -0.0125 volts.
A trifling amount, it is true, but should the dynamo de-
liver 1000 amperes the drop becomes 10 volts, which is
large enough to be considered. If the voltmeter were
placed around A what would it read? It would read
the drop in A.
CR=1.25X2=2.5 volts.
Grouping Cells or Dynamos.
A cell or dynamo is a source of E. M. F. and is in
addition a source of resistance.
When we wish a higher voltage than one cell on ma-
chine will give, we connect several in series. This in-
creases the voltage and resistance and the result depends
on the resistances of the external and internal circuit.
The part of circuit in the cells or dynamos is the internal
circuit.
Problem 1. Six blue stone cells, each 1 volt E. M. F.
and 3 ohms resistance, are in series on a 100 ohm exter-
nal circuit. Add 6 more in series. Will the current be
doubled? Ri and Re are abbreviations for internal and '
external resistances.
Cell Ri= 3 ohms
6 cells Ri 18 ohms
Re=100 ohms
E M FI volt
E M F-6 volts
R-118 ohms
E 6
=0.05 (nearly) amperes,
R118
316
ELECTRIC RAILROADING
Add 6 more.
Ri
36 ohm's
Re=100 ohms
136 ohms
E M F 12 volts
C=12/136=0.09 (nearly) amperes.
Answer: The current is almost doubled.
Problem 2. The same cells as in Problem I are con-
nected to external circuit of 1 ohm and 6 more cells are.
added in series. Is the current doubled?
6 cells Ri=18 ohms
Re I
EMF-6 volts.
R=19
E
6
=0.32 (nearly) amperes.
R 19
Adding 6 in series
Ri=36 ohms
Re 1 ohm
R=37 ohms
E 12
EMF-12 volts
1
C=
=0.32+amperes.
R
37
Answer. No. Practically no increase of current.
Moral: With high external resistance add more E.
M. F. in series to increase current (the added resistance
does no harm). With low external resistance add noth-
ing in series unless it has a very low internal resistance.
OHM'S LAW
317
Suppose in Problem 2 we had added 3 storage bat-
teries at 2 volts and 0.33 ohms each.
Old Ri=18
New Ri= 0.99
Re I.
R=20 ohms
Old EMF=6
New EMF=6
E-12 volts
E 12
=0.6 amperes.
Ꭱ
20
Which is practically double the previous current.


+
او
Fig. 147. Batteries in Parallel.
In Problem 2 had there been nothing available except
6 more blue stone cells they should have been put in
parallel with the others, similar to Fig. 147.
Each set of 6 cells has Ri-18 but joint resistance of
two groups is 9 ohms.
Ri 9 ohms
Re
1 ohm
t
R=10 ohms
The E. M. F. of each set of 6 cells is 6 volts and
318
ELECTRIC RAILROADING
the E. M. F. of the two groups not adding together
makes E. M. F. of group, 6 volts as before.
C=
Ꭱ
E 6
10
=0.6 amperes,
which is practically double the previous current. Hence,
when external resistance is low, lower your internal re-
sistance by adding more cells in parallel.
There is a silly rule:
The best arrangement of cells is when the internal
and external resistances are equal.
This is an arrangement to force the battery to deliver
the greatest possible current. The efficiency will be 50%
because since Ri and Re are equal the drop in each is
the same, hence half the pressure is doing useless work
and half useful work.
For economy have internal resistance low as compared
with external resistance.
When a battery is at work on a high resistance.
line, add cells in series to increase current. When ex-
ternal resistance is low always add cells in parallel.
These rules do not apply to most dynamos because
their internal resistance is very low.
With dynamos to get more voltage place extra ma-
chines in series. You will then get more current also.
To get more current at same voltage place extra ma-
chines in parallel with the first one.
LESSON 20.
METERS.
Galvanometers.
We have already seen in Lesson 12 that a current
passing near a magnetic needle deflects it; also that a
current passing first over a magnetic needle and then
back under it in opposite direction deflects the needle
further.
By a few simple tests you can convince yourself that
increasing the current would increase the deflection.
An instrument consisting of a coil of wire carrying
the current to be tested, and a magnet; the two being so
arranged that one can be deflected, is called a galvan-
ometer.
There are two types, the Thompson and the D'Ar-
sonval.
The Thompson type has the coil of wire stationary
and the light magnetic needle suspended by a silk thread.
These can be made more sensitive than the other type,
but are not portable and external fields have a great influ-
ence on them, causing them to give false indications.
This is prevented by thick soft iron cases, much tool
heavy to be carried around.
The silk suspension makes the needle sensitive to vibra-
tion.
It is a fine laboratory instrument and with modified
319
320
ELECTRIC RAILROADING
construction has been used in the workshop and field,
but for this work the D'Arsonval is much better.
The D'Arsonval type has a very small light coil of
wire suspended by a fine bronze wire between the poles
of a stationary magnet. Since the movable part is not
a magnet except during the actual instant of the test,
outside magnetic fields have no influence on its motion.
To shield it during test a thin soft iron or steel case
is put on the instrument which does not affect its porta-
bility. These covers are usually copper, brass or nickel
plated for appearance sake, but the actual material is
iron for the purpose of shielding the instrument.
These D'Arsonval galvanometers are not so sensitive.
as the other type, which for ordinary work is a great
advantage.
Both of these types have the needle swinging over a
circular scale divided into degrees, or may have a small
mirror attached so that the deflection may be read by
the motion of a spot of light moving along a long ruler
supported about a yard away from galvanometer.
As mentioned before, twice the current does not give
twice the deflection but by sending known currents
through a galvanometer and marking a scale with pen
and ink we could make an ampere meter. This is called
Calibration.
Ammeters and Voltmeters.
}
The ammeters and voltmeters of commercial work are
all special adaptations of the D'Arsonval galvanometer
or for the least accurate work such as on switchboards;
they are of the magnetic vane type.
METERS
321
The Weston instruments are D'Arsonval galvano-
meters.
Fig. 148 shows an instrument with the cover removed.
A large permanent magnet of U shape is supported by a
gun-metal casting screwed to the ends of the limbs, and
the whole of the working part is built up on this mag-
net independent of the case, so that the movement can
be removed bodily from the case by simply taking out
one screw which holds the gun-metal casting in place.
The inside polar faces of the magnet are surfaced up so
as to come closely into contact with wrought-iron pole.
pieces which are bored out to about 1 in. diameter, and
fixed rigidly in their place with screws passing through
the limbs of the magnet. To these pole pieces a second.
gun-metal casting is screwed, which forms a support
for a soft iron cylinder 3/4 in. diameter inside the bored
out pole pieces, and also a support for the scale. The
soft iron cylinder fills up most of the space between the
pole pieces, allowing an air space at either side of %
in., and in this space a fairly strong, uniform, magnetic
field exists. A coil of fine insulated copper wire of
about twelve turns is wound on a thin brass frame, large
enough to embrace the soft iron cylinder, with freedom
to move in the space between it and the pole pieces.
This is pivoted in jewelled bearings which are screwed.
to the pole pieces, but insulated from them, forming lit-
tle bridges across, and the ends of the coil are connected
to these bridge pieces by spiral springs, one at the top
and the other at the bottom of the coil, the springs being
wound in opposite directions, so that when one is twisted
up by a movement of the coil the other is untwisted.
This arrangement corrects for any variation in tempera-
ture, for the effect on one spring would be counteracted
322
ELECTRIC RAILROADING

"
:
+3
Fig. 148., Interior of Weston Instrument.
Į
+
METERS
323
by the opposite effect on the other. The coil normally
lies at 45° to the line joining the poles of the magnet,
and consequently the magnetic field created by a cur-
rent in the coil will be displaced relatively to the field of
the horseshoe magnet as shown in Fig. 149, and the
lines twist the coil through a certain angle against the
action of the spiral springs, the angular movement of
the coil depending on the strength of the current in the
coil and the strength of the field in which it is placed.

N
О
S
Fig. 149. Diagram of Magnets, Flux, Coil and Inner Core of
Weston Instrument.
To the coil is attached a pointer of aluminum, the
whole being balanced so that the instrument can be read
in any position, and the pointer and scale are bent up
so as to come near the front of the case.
A perspective view of movement is shown in Fig. 150.
In this instrument the whole current does not go
through the coil, but only a small fraction of it. The

324
ELECTRIC RAILROADING
main part of the current crosses from one terminal to
the other by a broad strip of metal under the base of
the instrument, while the coil is placed as a shunt across
the terminals, or as a conductor in parallel with the
metal strip (Fig. 151), and consequently the ratio of
Fig. 150. View of Movement of Weston Instruments.
the currents in the strip and in the coil will be inversely
proportional to their resistances. Now with a given.
strength magnetic field due to the magnet, and a given
elasticity of the spiral springs, it will require a certain.
number of ampere turns in the coil to produce the full
deflection on the scale. This can be secured by adjust-
METERS
325
ing the resistance of the strip connecting the terminals
so that the same movement will do for any instrument.
Thus, suppose the instrument were required to read to
a maximum of 10 amperes, and we required 1 ampere in

Fig. 151. Magnet and Shunt of Weston Ammeter.
the coil to give the maximum deflection,* then the re-
sistance of the coil must be 9 times that of the strip,
so that the current will divide at the terminals, 9/10
*It actually takes 1/100 amperes,

326
ELECTRIC RAILROADING
going through the metal strip and 1/10 through the coil.
If the instrument is required to read to a maximum of
100 amperes, then the metal strip must have 99 times.
less resistance than the coil, and the current will then
Fig. 152.
External Shunts for Ammeters. 1000 and 5000 Ampere Sizes.
divide at the terminals, 99/100 going through the strip
and 1/100 going through the coil, which will give a
reading to the full range of the scale as before. By the
arrangement of the pole pieces and wrought iron cylin-
der the field due to the permanent magnet is practically
uniform over the range of movement of the coil, and so

METERS
327
the scale readings are the same size throughout. Should
the permanent magnet vary in strength, the instrument
would not read correctly, but the magnets are so treated
that the falling off in strength over a number of years is
inappreciable.
10 20 30 40 50 60
70 8
90
100 110 120 130 140 150
TYPE
VOLTMETER
AMERICAN
NO.
INSTRUMENT COMPANY.
PATENTS APPLIED FOR
NEWARK N.J.U.S.A.
Fig. 153. Switch Board Instrument.
The strip or shunt for portable instruments is always
inside the case, while for switchboard instruments the
shunt is too large (Fig. 152) and is placed separately on
the back of the board. Leads are run along the board
to the meter terminals which project through holes in
the board from the meter which is in front.
Such a switchboard instrument is shown in Fig. 153
and Fig. 154.
A voltmeter is made by removing the metal strip or
*Technical name for wires,

328
ELECTRIC RAILROADING
shunt connecting the terminals and placing a resistance
coil in series with the moving coil.
As it takes 1/100 amperes to swing the pointer over
full scale for every volt the instrument reads, it must
have 100 ohms in the resistance coil.
A 500 volt instrument will have 500,000 ohms resist-
ance, and hence 1/100 amperes will flow through the
moving coil.

THOMSON
ASTATIC AMMETER
NO
FATENTED LYRICSE NOV 3,96
GENERAL ELECTRIC CO
SCHENECTADY N
USA
Fig. 154. Switch Board Ammeter.

The moving coil is wound on a copper or aluminum
frame, which when it swings has current induced in it
by the magnets and stops vibrating very quickly; in fact
you cannot detect any vibration. The needle seems to
move to a certain spot and stop dead. This is called a
"dead beat" needle; a more scientific name is "ape-
riodic."
Some instruments have electro-magnets instead of per-
manent magnets. The Thomson Astatic instruments are

METERS
329
of this type. Two of these instruments are shown in
Figs. 154 and 155. This latter has a scale or dial of
opal glass with an electric light behind it. This makes
the instrument easily read from a distance or at night.
These are called "illuminated dial instruments."

100 200 300 400 500 600 700
THOMSON
ASTATIC VOLTMETER
NO
FATENTED AFR 16 95 NOV 3'35
GENERAL ELECTRIC CO.
SCHENECTADY NY
USA
Fig. 155. Illuminated Dial Instrument.
The instrument of Fig. 153 has an extra hand ending
in a ring. This can be set at the voltage you wish to
maintain. The most hasty glance will then tell you
whether your voltage is too high or too low.
In order to save space on switchboards some instru-
ments are made thin and broad and are set horizontally
or vertically.
Fig. 156 shows the exterior and interior of a Thom-
son Edgewise Ammeter.
The Thomson Inclined Coil instruments as shown in
Fig. 157 are portable instruments used for alternating


330
ELECTRIC RAILROADING
current only. In an emergency they can be used to
measure direct current by reading, reversing current,
reading again and averaging results.
THOMSON AMMETER
25
GENERAL ELECTRIC COMPANY
DCHENECTARY MY BA
Fig. 156. Thomson Horizontal Ammeter.
The action of the magnetism of the inclined coil is
twist the inclined sheet iron vane "a" around to the
dotted line position.
The Weston instruments described are for direct cur-
rent only. The company makes an alternating current
voltmeter but no ammeter. Thomson Astatic instruments
METERS
331
are for direct current. The Thomson Inclined Coil in
portable, or edgewise switchboard form is for alternating
current.

b
A
αν
Fig. 157. Thomson Inclined Coil Instrument.
Wattmeters.
By combining two coils, one movable, the other sta-
tionary, one attached as a voltmeter with series resist-
ance, the other attached as an ammeter, with a shunt,
we get an instrument whose needle indicates power or
watts. These are called indicating wattmeters.
The recording wattmeter records watt-hours. A watt-
hour is one watt of power used for an hour, or any com-
bination like one-quarter of a watt for four hours, etc.
The Thomson Recording Watt-Hour Meter is used
for direct or alternating current. It is shown with dust-
proof case removed in Fig. 158. The connections made
to it are shown in Fig. 159. By "light" in the figure
must be understood any load at all.
The meter consists of an electric motor whose arma-
ture A is supplied with current from the mains through
a high resistance P in the back of the instrument and a
small field coil on right-hand side.

332
ELECTRIC RAILROADING
This armature is in shunt across the circuit, hence its
current is proportional to the voltage.
The main current passes through the field F, hence
the strength of the field is proportional to the current.
The speed of the motor is therefore proportional to
both current and voltage, that is to the power or watts.
K AND
TIT
TYPE2 WWLISSS
CAPZE AND
ADA WOLTE
பார
Fig. 158. Thomson Recording Watt-hour Meter.
The armature shaft goes on past the commutator to
a cyclometer with dials like a gas meter. The revolu-
tions are here recorded as watt-hours.
The auxiliary field is just strong enough to nearly
overcome the friction in the bearings and cyclometer, so
that the smallest current through the mains will pro-
duce rotation.
METERS
333
From Dynamo
+
At the bottom of the arinature shaft is an aluminum
disk revolving between the poles of permanent magnets.
This device prevents the meter from running at too
great a speed and gives an adjustment for accuracy.

A
To Lights
Fig. 159. Diagram of Connections. Thomson Recording Watt-
hour Meter.
The further out the magnets are swung the faster is
the motion of the metal passing between their poles and
the greater a retarding effect they produce.

334
ELECTRIC RAILROADING
A meter running too slow from age or dirty bearings
could be brought up to proper speed by swinging the
magnets in a little.
TH
11GMSON RECORDS
WALTMETER
NO CATHE
AM-2000 VOLTS,
GENERAL ELECTHIL CO
SOS HOTARY NYUGA
Fig. 160. Large Capacity Thomson Recording Watt-hour Meter.
For large currents the appearance of the meter is quite
different, as is shown in Fig. 160. The retarding device
is enclosed in a case and the whole instrument enclosed
in a dust-proof glass case.
LESSON 21.
ELECTRICAL WORK, POWER AND EFFICIENCY.
FORCE.-Force is defined as that which produces
motion, or a change of motion; thus force must always.
be applied to any body to cause it to move. To increase,
decrease, or stop this motion, that is to change it, force
must again be applied. For example, to start a loaded
wheel-barrow force must be applied, either by pushing
or pulling it, but when it is set in motion less force will
be required to keep it in motion; to cause a change in
motion, that is to increase or decrease the speed, extra
force must be applied. Force does not always produce
motion, but only tends to produce it, as when a man tries
to push a laden freight car he applies all his muscular
force, but no motion results.
"DIFFERENT KINDS OF FORCE.-There is the
force of gravitation, which causes all bodies free to move
to fall from a higher to a lower level. The force exerted
by a man riding a bicycle or a horse drawing a carriage
are examples of muscular force. An engine draws a
train of cars by reason of the mechanical force applied,
which is due to the expansion of the steam in the steam
cylinder. A mixture of air and illuminating gas in a
room is ignited and the explosion wrecks the room; the
action is due to the chemical force exerted. The force
which produces or tends to produce a flow of electricity
is electromotive force. The rate at which a train moves.
335
336
ELECTRIC RAILROADING
depends upon the force exerted by the engine, so also,
the rate of flow of electricity depends upon the amount
of electromotive force applied.
MASS AND WEIGHT.-The mass of a body is the
quantity of matter in it; the weight of a body is due to
the force of gravity acting upon this matter. Since the
force of gravity diminishes as we ascend from the earth's
surface, the attraction for a mass of matter will diminish,
or it will weigh less on the top of a high mountain than
at the sea level; the mass of matter, however, would be
the same in each case. Weight is not, therefore, the
same thing as mass, but we can conveniently measure a
body by its weight.
WORK.-Work is done when force overcomes a re-
sistance, or, work is force acting through space
(W=FXS).
Work Force XDistance,
or Work Pounds X Feet Foot-pounds.
Work is not always done when a force acts; for in-
stance, a man pushes with all his force against a brick.
wall; he is exerting force, but doing no work because.
no motion results, nor is any resistance overcome.
If a
weight be lifted, work is done directly in proportion to
the weight and to the distance through which it was
moved. Thus, the work done in lifting 4 pounds to the
height of 3 feet is equivalent to 12 foot-pounds of work.
Exactly the same work is performed when two pounds
are lifted 6 feet; or 6 pounds raised 2 feet or 12 pounds
raised I foot. Work does not always consist in raising
weights; the steam engine does work by hauling a train,
due to the expansive force of steam acting upon the pis-
ton; an explosion of powder in a cannon causes an iron
ELECTRICAL WORK-POWER
337
ball to traverse a certain distance. The magnetic action
in a dynamo sets up a force which causes a current to
flow through an electric motor and the motor drives a
car weighing so many pounds a certain number of feet
every minute, hence the total foot-pounds of work are
performed electrically. The work in each case is meas-
ured in foot-pounds. Whether work be done mechani-
cally, chemically, thermally, or electrically, it can be
expressed in foot-pounds. The total amount of work.
done is independent of time, that is, the same work may
be performed in one hour or one year. When different
amounts of work performed in different times are to be
compared, then reference is made to the time, or rate of
working, or the power.
POWER.-Power is the rate at which work is done,
and is independent of the amount of work to be done.
Power (rate of working)=
Work
Time
Foot-pounds
Time
Foot-pounds per unit of time.
For example, it requires four hours for a particular
engine to draw a train from one station to another, while
another engine may draw the same train the same dis-
tance in two hours. One engine is thus twice as power-
ful as the other, because it can do the same work in half
the time. When the train has reached its destination it
would have represented the same amount of work done,
no matter whether it had traveled at one mile per minute
or one mile per hour, leaving, of course, friction and air
resistance out of account.
*By heat.
338
ELECTRIC RAILROADING
Power is estimated according to the amount of work
done in a given period of time. As mechanical work is
measured in foot-pounds, mechanical power would this
be so many foot-pounds per minute, or per second. The
mechanical unit of power is the horse power.
One Mechanical Horse Power=33000 ft. lbs. per Minute
or
33000
60
=550 ft. lbs. per Second.
{
If a body weighing 33000 pounds be raised one foot
every minute then we have a rate of working equal to
one horse power; or if 16500 pounds be raised two feet
per minute, the rate of working is the same, one horse
power. If the work were continued at the same rate for
one hour, we would have a larger unit of work, or the
horse-power-hour. When we say that an engine is de-
veloping 40 horse power we mean that it is performing
550X40 22000 foot-pounds of work every second.
DIFFERENCE BETWEEN ENERGY, FORCE,
WORK AND POWER.—It is important that the stu-
dent should thoroughly understand the meaning of the
above terms. Energy is the capacity to do work. Force
is one of the factors of work and has to be exerted
through a distance to do work, the work being reckoned
as the product of the force and the distance through
which it has been applied. Work is done when energy is
expended or when force overcomes a resistance. Power
is the rate of working.
ELECTRICAL WORK.-Work is
WORK. Work is force acting.
through space, or energy expended, therefore, resistance
is overcome when work is performed. Force may exist
without work being performed, as when you push against
ELECTRICAL WORK-POWER
339
a table and do not move it, no work is done, yet the
force exists. An electrical force exists between the two
terminals of a battery, tending to send a current of elec-
tricity from one to the other through the air. The force
is not sufficient to overcome the resistance of the air,
therefore no current flows and the battery is not doing.
any work; the same is true with a dynamo when run-
ning on open circuit. When a wire is connected across
the battery terminals, the force overcomes the resistance
of the wire and electricity is moved along, around or
through the wire, which becomes heated. The electrical
work, or energy expended, in this case, is represented by
the amount of heat generated. With a small lamp con-
nected to the battery, the work is represented by the
heat and light given by the lamp as well as the heat
given to the remainder of the circuit. The total work
performed is the product of the force, the current, and
the time that the current is maintained or
Electrical Work Volts XAmperes XTime.
But the engineer is not interested much in work-the
element of time is of great importance to him, so he
always figures power used.
ELECTRICAL POWER.-Power is the rate at which
energy is expended, and is independent of the total work
to be accomplished. The rate of working, or the power,
is found by dividing the total work by the time required
to perform it.
Electrical Work
Electrical Power
Time.
The unit of electrical power is a unit of work per-
formed in a unit of time, and is called a Watt.
340
ELECTRIC RAILROADING
NO
Power Volts XAmperes=EC.
Problem 1. A current of 2000 amperes flows at a
pressure of 600 volts. What power is used?
Watts EC-600 X 2000=1200000.
To avoid the use of large numbers the Kilowatt is used.
It is 1000 watts.
The answer to Problem I is therefore 1200 K. W.
(Kilowatts abbreviated K. W.).
Problem 2. How many K. W. will an alternator pro-
ducing 11000 volts and 272 amperes give?
W-EC-11000X272
=2992000 watts
=3000 K. W. (nearly).
A watt is a small unit, for it takes 746 watts of elec-
trical power to exert the same power as one horse power
of steam power.
Hence 746 watts 1 horse power (H. P.)
and 34 K. W.-1 H. P. (approx.)
1 K. W.-1 H. P. (approx.)
A rough rule for figuring is:
To change from K. W. to H. P. add on 3 of the
number, from H. P. to K. W., subtract 14. of itself from
the number.
A very convenient formula for power is obtained in
this way:
E
W EC, but C
R
hence E-CR, so W-CRXC=C2R.
ELECTRICAL WORK-POWER
341
This means the watts power used up in any resistance
is found by the formula W-C2R. The square of the
current multiplied by the resistance.
This is all wasted power and is often referred to as
the "C square R loss."
When a current goes through a motor it produces
some mechanical power, but when flowing through a
wire it produces nothing but magnetism and heat. This
is often referred to by saying a current produces C2R
heat, meaning that the current produces CR watts which
turn to heat.
EFFICIENCY.
When we bring 223.8 K. W. of energy to a motor and
turn out at its pulley 240 H. P., it is because some of
the energy has been lost in the transformation from
electrical to mechanical power.
1
223.8 K. W.=223800 watts.
223800÷746—300 H. P.
Output
Efficiency= Intake
Both being expressed in same units,
300
efficiency= =0.8.
240
Efficiencies are usually multiplied by 100 and then
called per cent. Efficiency of 0.8 would be called 80%
efficiency.

342
ELECTRIC RAILROADING
CIRCUIT BREAKERS.
In its simplest form a circuit breaker is merely a
switch so designed as to be capable of frequently open-
ing the circuit carrying its full current without any
damage to itself.
FORMEN
SENERAL
ELECTRIC COMPANY
AMATIC
Fig. 161. Automatic Circuit Breaker with Low Voltage Release,
Tell-tale Switch and Magnetic Blow-out.
With the large currents handled in railroad work
it has become necessary to define a switch as "a piece
of apparatus to close circuits."
ELECTRICAL WORK-POWER
343
Apparatus to open circuits are
are now called circuit
breakers, trip switches, oil switches or some other spe-
cial name.
In order to have a good contact for carrying current
where breaker is closed, this contact is of copper.
As shown in Fig. 161, the contact is composed of
two large copper blocks against which press the ends
of a curved copper brush. This brush is made of nu-
merous thin sheets of copper, pressed together so as to
form an almost solid block of metal. They are held
together tightly in the middle, and the ends left free.
When the brush is pressed upwards against the
blocks it makes a peculiar scratching or rubbing contact
in which each separate leaf of the brush makes its own
contact, and holds it with a firm pressure owing to the
springiness of the copper.
The scratching or rubbing contact ensures the re-
moval of all dirt or oxidized copper from the block and
the individual action of each leaf makes a good con-
tact, utilizing the total surface of the brush.
While such a contact is an excellent carrier of cur-
rent, it is the worst possible breaker of a current, for
the separate leaves would melt on the edges and fuse
together.
The breaker is arranged so that a second contact of
a carbon plug in a carbon socket always closes before
and opens after the main copper contacts.
In Fig. 161 this secondary carbon contact is on the
*It will be understood that after breaking a current by a cir-
cuit breaker the mere opening of a knife switch cannot be called
opening a circuit, because after the breaker opens there is no
electrical circuit.
1
}
344
ELECTRIC RAILROADING
end of the rod which passes up into the hollow formed
by the nameplate.
In Fig. 162 the carbon plug is K and the sides of the
socket are marked G. The main contact blocks are the
squares and the copper brush is marked H.
The toggle which closes and opens the breaker is
marked F.

·Tat°
4-c
K
ro
I
Base Frame
Fig. 162. Diagram of Fig. 161.
In Figs. 163 and 164 the carbon contacts are seen
at the top in the shape of carbon blocks. In Fig. 163
the main contact is plainly shown below, while in Fig.
164 the main contact is concealed by a metal housing.
The mechanical connection between the main (cop-
per) contacts and the secondary (carbon) contacts has
enough lost motion that the main contact is well opened
before the secondary opens.
What has been described constitutes a circuit breaker,
but a circuit breaker is always an automatic device. An
oil switch may or may not operate automatically, but
when we say circuit breaker we always mean an auto-
matic one.

ELECTRICAL WORK-POWER
345
The circuit breaker is set by hand against a spring
and held shut, closed, or set (the three words meaning
the same thing) by a latch or hooked catch. There is
a rod one end of which is arranged to unfasten or trip
Fig. 163. Large Capacity Breaker.
Carbon Break Type 2000 to
10000 Amperes.
the catch, the other end is fastened to an iron armature
or core.
All the current in the particular circuit which the
breaker is in passes through a solenoid which exerts an
attraction on the core or armature.

346
ELECTRIC RAILROADING
Suppose the normal current on the line to be 700
amperes, then the circuit breaker would have contacts
of sufficient area and a solenoid of such a size that 700
D
Fig. 164. Carbon Break Circuit Breaker, 150 to 800 Ampere Capacity.
amperes could pass through the breaker 24 hours a day
without overheating any part,

ELECTRICAL WORK-POWER
347
The weight of rod and core of armature would be
sufficient so that the lifting power of the solenoid was
not great enough to lift them, but that 1000 amperes
through the solenoid will lift the rod and release the
catch. The spring then opens the breaker. When a
circuit is to be opened the attendants push up the rod
and thus open the breaker.
GENERAL
ELECTRIC COMPANY
MAGNETIC BLOW-OUT
CIRCUIT BREAKER
NO
FORM MLG
AMPERE STO
PATENILO AUD 14-83, APR 9-12 MAY 5-S1
JAR 29-95. AUS 6 MREFUG
SCHENECTADY
USA
Fig. 165. Magnetic Blow-out Breaker. Small Capacity.
When this is done it is called tripping the breaker,
when the breaker is tripped by the action of the current
it is customary to say the breaker has "blown."
Whether a breaker is tripped or blown, it makes a
noise like a pistol shot. The larger the current blown,
the greater the noise..
The tripping solenoid is shown plainly in Fig. 165.
348
ELECTRIC RAILROADING
If large currents are handled by the breaker a sol-
enoid of one-half a turn may create enough power to
trip the breaker.
In Figs. 163 and 164 this is the case, and the tripping
device is not in evidence.
If the rod and its attachments were heavier it might
take 1200 amperes to trip the breaker; if the core or
armature were moved nearer or further from the sol-
enoid, a smaller or larger current would trip the
breaker; if a more or less strong spring were attached
the current required to blow the breaker would vary
with the tension of the spring.
These devices are used to set the current at which
the breaker will operate.
Breakers are made to have a capacity for certain cur-
rents continuously passing through them without over
heating. This is called their Continuous Capacity.
The carbon contacts are then designed to break a
current of from 50% to 100% in excess of this current
for several hundred times without needing renewal of
parts. This is called the maximum capacity.
Sometimes the maximum capacity is two or three.
times the continuous capacity. Such breakers must be
very heavily and strongly built, and are much higher
in price.
The lowest current at which the breaker can be set
to operate is called its minimum calibration.
In Fig. 163 at the left side is a rod screwed in an
arm. The lower end of this rod has a flange which
holds an armature from falling down, but does not
prevent its rising.
The upper end of the rod moves past a scale marked
in amperes, Turning this rod till its head is oppositę
ELECTRICAL WORK-POWER
349
a certain number draws the armature into such a posi-
tion that the indicated number of amperes will pull the
armature up and release the catch or trigger, which can
be plainly seen holding the arm which operates the
toggles in place.
It is evident that the scale reads from the top down,
for then setting screw at smallest number brings the
armature nearest the solenoid. Fig. 165 shows the arma-
ture above the solenoid with a spring to change the
pull required to draw it down and release the trigger.
In this breaker the main contacts are between the
handle and the solenoid, while the secondary contacts.
are up top behind the name plate.
In Fig. 166 is shown a breaker with a core in the
solenoid.
The main current circulates around the solenoidal
coil "B" and tends to draw into the solenoid the mova-
ble plunger "C." The initial position of this plunger
in the solenoid is determined by the adjusting screw
"M." When the current is sufficient to overcome the
weight of the plunger it is drawn into the coil with
constantly increasing velocity, due to intensified mag-
netic action, as the polar distances or air space is de-
creased. When nearing the upward limit of its travel,
having acquired a high momentum, it impinges upon.
the trigger "N" through the medium of the push pin
"E." The immediate result of this is the release of
the switch arm by the displacement of the retaining
catch "F." The upper projection "H" of the trigger
"N" is thrust against the striker plate "K," thereby
utilizing the energy of the current to start the movement
of the switch arm. This movement is intensified and
sustained beyond the point of final rupture between the
350
ELECTRIC RAILROADING
switch contacts by the thrust of the spring "O," which
is released from compression by the initial action of the
trigger. Thus the contact arm is thrown away from
the contact terminal, and the circuit is opened.
As the screw "M" is turned up and locked by "T"
it prevents the core "C" from falling away from the
solenoid. The higher "C" the lower the current at
which breaker blows.
The fact that the
current is broken between the
carbon blocks tends to suppress the arc formed, and in
the breakers shown in Figs. 163, 164, and 166 this is
alone relied on to kill the arc.
It must be remembered that although these breakers.
have two contact blocks at the main copper contact,
yet only one wire of the circuit is attached to the
breaker. The current enters at one block, goes over the
copper brush to the other and out to the line. The
carbon contacts are a shunt. Circuit breakers are
adapted to different voltages by the excellence of the
insulation and by the length of the openings between
contact pieces.
The breakers shown are all suitable for D C and A C
circuits of 100 to 800 volts.
The breakers shown in Figs. 161 and 165 have a
magnetic blowout; that is, a solenoid is situated at the
carbon contact, which actually blows the arc out the
same as in the Thomson lightning arrester.
The breaker in Fig. 161 has two attachments which
are of great service. These are the Low Voltage Re-
lease and the Tell Tale.
The way these act is best explained in connection with
Fig. 167.
The Low Voltage Release is a coil of low resistance
ELECTRICAL WORK-POWER
351

V
"
W
D-
B
OJK G
L
H+
E
N
-M
T
X
-P
SI
U
ITE
A
Fig. 166. Cross Section of Circuit Breaker.
Q
R
352
ELECTRIC RAILROADING
holding by its armature the trigger of the breaker. A
resistance is placed in series with this coil and both
together are placed as a shunt across the line. In the

Low Voltage
Releaso
요
​~Tell Tale Devico
www
Series
Resistance
Speed Limiting
Device
NOON
H
Rheostot
Rotary Converter
Caualizer...
Ground
Fig. 167. Electrical Connections of Fig. 161.
diagram one side of the release coil is connected to
ground, which is negative, and the other side through
the series resistance to the positive brush of rotary
converter.
ELECTRICAL WORK-POWER
353
As long as the voltage is normal this coil is a strong
enough magnet to hold the breaker trigger set, although
at any time the main solenoid can release the trigger
independently of the low voltage coil.
If the voltage falls to half the normal pressure the coil
becomes such a weak magnet that the trigger is re-
leased and breaker opens.
Wires are often run from the terminals of the low
voltage coil to push button in different parts of the
station.
Pushing the button then forms a short circuit across
the low voltage coil and robs it of its current. It ceases
to be a magnet and the trigger is released. The breaker
can thus be opened from several distant points.
To prevent rotary converters from racing at great
speed, when power on A C side is suddenly thrown off,
there is a speed limit device on the rotary which con-
sists of a ring in which a fly-ball governor rotates. The
ring is connected to one side of the low voltage coil and
the fly-balls through the negative wiring, to the other
side. When the rotary goes too fast the fly-balls open
out and touch the ring, completing a short circuit across
the low voltage coil and thereby releasing the trigger.
The Tell Tale is merely a mechanically operated
switch, which the opening of the breaker closes. The
tell tale may close the circuit of an electric bell and call
the attendant's attention.
It usually rings a bell and lights a lamp. It may
even trip a second breaker, if it is desired to always
have the two "go out"* at the same time.
For higher voltages, 6600 volts and upwards, break-
*Another expression for "blowing."
354
ELECTRIC RAILROADING

Disk
Contact
Leat
-101-(8-8)—–—–
1
Restoring
Spring
Valve
Pneumatic
Cylinder
Contact
- Rods
Laminated
Copper
Contact
Brick
[Insulating
-Sleeves -
Wall
-Oil Filled
Cylinders
Porcelain
Insulators
Lifting Table
Contact
-Liffing Cam
Fig. 168. Oil Circuit Breaker.
ELECTRICAL WORK-POWER
355
ers of type shown in Fig. 168 are used. A magnet
when current is too large operates the valve which ad-
mits air to the cylinder. The cylinder piston through a
wooden rod operates the main contact first and then the
secondary contacts which are enclosed in oil filled.
cylinders.
LESSON 22.
DIRECT AND ALTERNATING CURRENT.
We have seen that when direct current, as it is called,
passes through an electro-plating bath, there is a trans-
fer of chemicals in both directions. The metals go from
the anode to the cathode, i. e. from + to- negative
wire. The non-metals such as sulphur, chlorine, etc.,
are transferred from the cathode to the anode.
It seems as if direct current flowed in both directions
around the circuit, but since the metals are of the most
importance to us we speak and often think of direct cur-
rent as flowing only in one direction.
The test for direct current is that it will electro-plate.
Ohms Law in its simple forms as mentioned in Les-
son 19, applies absolutely to direct current.
It is a fact that for the first fraction of a second after
a switch is closed the current is growing to the value
it ought to have as given by Ohms law.
This growth is very rapid when the circuit contains
no coils or magnets. These retard the rise of the cur-
rent.
The current in the field circuit of a dynamo may take
3 seconds to attain its full value, but once there its value
is given by Ohms Law.
Alternating Current.
An alternating current will not electro-plate, for the
metal-plating part of the current reverses direction many
times a second.
356
DIRECT AND ALTERNATING CURRENT
357
An alternating current will not deflect a magnetic
needle because the deflecting impulse reverses its direc-
tion continually.
Alternating current can excite a magnet causing
a core to be sucked into a solenoid or an armature to
be attracted, because induced magnetism in core changes.
with, the polarity of magnet itself.
Alternating current measuring instruments do not
contain magnetic needles, but are supplied with two
coils. The magnetic action between these two coils is
just as strong as if direct current were used, because
the A. C. reversing in each coil at the same time keeps
the relative polarities the same.
Other A. C. instruments like the Thomson Ammeter
Fig. 157, exert a magnetic action on a vane. This vane
is not itself a magnet.
Since A. C. does not electro-plate the original defini-
tion of an ampere is of no use here, but since the heating
done by electricity is the same for equal quantities
whether A. C. or D. C. we define thus:
An ampere of A. C. is that current which produces as
much heat per second as one ampere of D. C.
For example: A car heater raises the temperature of
the car from 60° Fah. to 70° in half an hour. The
ammeter read 20 amperes D. C. If A. C. were supplied
and raised the temperature from 70° to 80° in the next
half hour we would say that 20 amperes A. C. were flow-
ing.
Ohms Law applies to A. C. when written thus:
C=
Impedance
Volts
358
ELECTRIC RAILROADING
The impedance is larger than the resistance of the cir-
cuit, it being the result of the resistance and the react-
ance.
Resistance is the opposition offered by a conductor to
any or all current passing.
Reactance is the extra opposition offered by a con-
ductor to a current which is changing in value. It de-
pends on the rapidity of this change and on the number
of coils of wire in the circuit. It is measured in ohms
and is calculated by the formula:
Reactance 6.28XfXL
where f=frequency
L coefficient of Self-induction.
The frequency, as explained before, is the number of
times the current reverses per second. It runs from
25 in power and railroad work up to 133 in electric
lighting. It is best determined by taking the speed of
the alternator in the power house and counting the num-
ber of pairs of poles that alternator has.
Calculating the number of pairs of poles passed a
second gives the frequency.
Problem: An alternator makes. 75 revolutions per
minute and has 40 poles; what is the frequency of the
current delivered?
40 poles=20 pairs poles
75 r. p. m.—1.25 r. p. second
20X1.25 25 pairs poles per second.
25-frequency,
DIRECT AND ALTERNATING CURRENT
359
Self Induction,
When the current changes strength in a long straight
wire the resistance of the wire does not resist the change,
for the resistance offers the same opposition to any or all
currents; it is the magnetic field around the wire which
causes the reactance of the wire.
Every current has its definite magnetic field in the air
around the wire and when current is increased the mag-
netic field has to increase to its new value. When the
current alternates the rapid dying away and regrowth
of the magnetism consumes some of the power so that
for the same E. M. F. the current is less when it is A. C.
than when D. C.
The greater the frequency the greater is the reactance.
of the circuit because the more frequent the rise and fall
of the magnetic field about the wire.
Perhaps it would be truer to facts to say that the rise
and fall of the magnetism causes it to cut through the
wire and produce an E. M. F. opposite to that produced
by the alternator which reduces the net E. M. F. im-
pressed on line.
When coils of wire are present this action is much
stronger because the magnetism cuts the circuit oftener
on each rise and fall.
The action of the coils is called Self-Induction and the
number representing the action is called henrys, named
after Henry, a noted electrician.
It is well to remember that the reactance of the cir-
cuit is caused by the frequency of the A. C. and the
self-induction of the circuit,
360
ELECTRIC RAILROADING
Problem: Suppose a circuit of 0.12 henrys self-induc-
tion and 184 ohms resistance conducts A. C. at a fre-
quency of 60. What will be the current flowing with
11000 volts
Reactance 6.28XfXL
6.28X60X0.12
=45 ohms
Resistance 84 ohms
Impedance Square root of the sum of squares of re-
sistance and reactance.
Resistance squared=7056 ohms
Reactance squared=2025
Sum of squares=9081
Square root 95.3
Impedance 95.3 ohms.
C=
Volts
Impedance
11000
115.4 amperes.
95.3
Capacity.
The presence of condenser action or capacity in a A.
C. circuit is a help because all circuits have some in-
ductance (self-induction plus the effect of any circuits
near the one in question), and the capacity tends to
neutralize this, bringing the value of the impedance
nearer to the resistance.
It is even possible to artificially make the capacity so
great that the impedance is practically equal to the re-
sistance.
Such a circuit would conduct A, C. or D. C. equally
well,
DIRECT AND ALTERNATING CURRENT
361
}
Lagging, Leading Currents.
If a shunt is put in a circuit and an ammeter con-
nected to it, while a voltmeter is connected to the same
part of the circuit, if* readings could be taken of the
values of current and voltage at any instant of time
we would find that the highest value of voltage and cur-
rent did not appear at the same time.
We would see that the value of the current as given
by C-Volts Impedance, occurs a fraction of a second
after the voltage causing the current has passed. We
say the current lags behind the voltage. If we add
more inductance to the circuit the current will lag
more and more until it seems to the observer at an
oscilligraph that the current can hardly belong to the
voltage he is watching, because the largest current is
flowing when the voltage is almost down to zero and
positive current is flowing when the voltage has re-
versed and is negative.
If capacity is now connected to the circuit the current
will move up to a position nearer where it naturally
should be until with sufficient capacity it will follow
exactly the changes in the voltage. That is the highest
current and voltage will occur at exact instant.
Add more capacity and remove all inductance possible
by taking out of circuit all coils or machinery contain-
ing coils, especially if they have iron cores.
The current will actually lead the voltage. That is,
the highest current will flow a fraction of a second be-
fore the highest voltage occurs.
*An instrument called an oscilligraph can make these instan-
taneous readings.
362
ELECTRIC RAILROADING
Power Factor, Wattless Current.
The power in this circuit while all these changes have
been going on has varied greatly. When the current
and voltage were together the power was the greatest,
when the current either led or lagged the power was
less. This is because the power is determined by mul-
tiplying the current and voltage which occur at the
same time. It makes no difference whether that voltage
belongs to that current or not. It is the product of the
things which are happening at the same time which
gives the power.
If an A. C. ammeter and voltmeter are put in cir-
cuit each instrument reads the average current or volt-
age irrespective of the time at which these currents or
voltages occurred. Multiply these two readings and you
get the power produced by the current and the voltage
which belongs to it. If you should now place a watt---` `
meter in the circuit it will measure the actual power,
i. e. the average of current multiplied by the voltage
which occurs at the same instant.
This wattmeter reading is the actual power. The
ammeter reading multiplied by voltmeter reading gives
the apparent power.
The decimal number by which the apparent power
must be multiplied to get true power is called the Power
Factor.
*
If a current of 250 amperes is flowing at a pressure
of 1000 volts we have an apparent power of 250000
watt or 250 K. W. If the true power as read by the
wattmeter is 200 K. W. the power factor must be 0.8
for 250X0.8=200.
DIRECT AND ALTERNATING CURRENT
363
Power Factor
True power
Apparent power
Wattmeter reading
Volts Xamperes
By saying that the pressure measurement is correct
we throw the blame on the current and say that all the
current which flows, say 250 amperes at 1000 volts,
is measured by the ammeter, while only the current
which works or produces watts is taken into considera-
tion by the wattmeter. According to this idea the
wattmeter would only notice 250X0.8-200 amperes.
The other 50 amperes are called the wattless or idle
current.
It is customary to speak of A. C. waves. This is quite
natural for the rise and fall of voltage and current in an
A. C. circuit reminds one of the waves in a long string
which is shaken to and fro at one end while being held
fast at the other.
LESSON 23.
TRANSFORMING DIRECT OR ALTERNATING CURRENT.
Direct Current.
Perhaps one of the greatest objections to the use of
direct current is the inability to change its voltage with-
out the use of moving machinery.
There is but one way to transform D. C. and that is
by a motor and generator.
This motor-generator set usually consists of a D. C.
motor driven by current at the pressure of the incoming
line. This motor drives a D. C. generator which fur-
nishes current at the desired pressure.
By altering the strength of the field of the generator
we regulate the outgoing pressure to suit the require-
ments.
The motor and generator are built on the same shaft
and set on a long cast iron base, making them mechanic-
ally one machine.
When the incoming and outgoing voltages can have
the same ratio to each other always, a cheaper form of
machine can be used called a Dynamotor.
This is a D. C. motor running on the incoming volt-
ages. On the same armature core is a separate winding
connected to its own commutator at the other end of
armature. The one set of field magnets serves for the
motor winding and the generator or dynamo winding.
364

TRANSFORMING CURRENT
365
This inability to transform cheaply seems to be a
great disadvantage, but as we so seldom want to do it
the inability to do so does not bother us much.
Fig. 169. 500 K. W. 3 Phase Rotary. 460 A. C. Volts to 660 D. C.
Volts. Frequency 25. Commutator End.
In railroad work when we wish to charge storage
batteries from 600 volts circuits we use a motor-genera-
tor.
366
ELECTRIC RAILROADING
Alternating to Direct Current.
Many D. C. traction systems transmit their power by
A. C. Thus we need to transform A. C. to D. C. and
we do so by a certain form of dynamotor called a
Rotary Converter or a Rotary.
The New York Central has a dozen large ones in
its sub-stations; the Interborough Rapid Transit Co. of
New York has 83 of moderate size.
A rotary looks like a dynamotor but has a collector.
or slip rings like an alternator at one end and the regular
commutator at the other.
They often have small motors fitted on the same base
to start them up. After being once started they run
all right.
Fig. 169 shows the D. C. or output end and Fig. 170
shows the A. C. or intake end of a rotary, the starting
motor being clearly shown in each figure.
There is only one winding on the armature core, both
commutator and collector are connected to it.
The reason the A. C: does not pass through machine.
to the D. C. lines is because the commutator rectifies
the A. C., i. e., lets through all the + part unchanged
and reverses all the part as it lets it out to the D. C.
circuit.
The average pressure of an A. C. is of course less
than its highest pressure, and voltmeters read the aver-
age. It is the greatest pressure however which gives.
the pressure to the D. C. end of rotary. It is due to.
this that a 460 volt A. C. will produce by means of a
rotary a 660 volt D. C.
A rotary looks smaller than a generator of equal

TRANSFORMING CURRENT
367
power and this is so. The rotary does very little work,
so it need not be made very heavy and strong.
Rotaries have a tendency to shift in speed running
fast and slow; this is called "hunting." It is prevented
by heavy copper straps around the ends of the field
poles and bars of copper laid in slots of the pole piece.
Fig. 170. Collector End of Rotary Shown in Fig. 169. Motor for
Starting at Right-hand End of Base Plate.
These copper strips have eddy currents in them each
time the speed changes, and the effect of these eddy
currents on the armature is to bring it back to normal
speed.
368
ELECTRIC RAILROADING
Alternating current motors can be built to start them-
selves like D. C. motors, but rotaries are often started
by motors or from their own D. C. ends as direct
current motors. In this latter case the A. C. line is
thrown on when machine is up to speed. The A. C.
then begins to run machine and D. C., power is de-
livered from the commutator A. C.
The transformation of A. C. is the simplest opera-
tion in electrical engineering. No moving machinery is
needed. The same principles which govern the action
of an induction or medical coil operate a transformer.
Electro-Magnetic Induction.
When a dead or idle circuit is approached by a mag-
'net there is a current induced in the idle circuit.
Even should the magnet remain stationary if its
strength changes a current is generated in the idle cir-
cuit.
The complete set of facts is:
If a dead and loaded circuit approach each other:
If the current in loaded circuit increases;
Then a current is induced in the dead circuit in the
opposite direction to the current in loaded circuit.
If a dead and loaded circuit recede from each other;
If the current in the loaded circuit decreases;
Then a current is induced in the direction of the dead
circuit in same direction as current in loaded circuit.
As long as the motion or the change of current lasts,
so long will the induced current last, and no longer.
Furthermore the ratio of the pressures in the loaded
and now alive circuit will be the same as the number of
TRANSFORMING CURRENT
369
turns of wire in the two coils which are acting on each
other.
If in Fig. 171 A represents the alternator, B its
brushes and D and E the mains to the transformer H.
This transformer consists of a core of iron C on which
are two windings. The coil P is called the primary and
is connected to the main from alternator. The other
coil S is called the secondary and to it the load is con-
nected.
Whatever the voltage of alternator A that of the
secondary circuit F. L. G. will be three-eighths of it
A
B
}
D
E
C

F
P
S
G
H
Fig. 171. Diagram of Alternator, Line, Transformer, and Secondary
Circuit.
because there are 8 turns on primary and 3 turns on
secondary. The power in the secondary circuit is prac-
tically the same (minus the losses) as is given out by
alternator, hence the primary current is low and wire
is small. The secondary current is large so wire is
large.
Since one kilowatt can be a combination of a large
current and small pressure or small current and large
pressure, it is evident that the transformer simply trans-
fers the power, and transforms the voltage and indi-
rectly the current.

370
ELECTRIC RAILROADING
Transformer Coils in Wound, Bound and Taped Stages of
Completion.

TRANSFORMING CURRENT
371
Remembering the power formulas in this way W--Ec
or eC helps one to grasp the action of transformer.
This transformer (Fig. 171) lowers the voltage and is
called a step down transformer.
When the secondary is connected to the alternator
the transformer raises the voltage and is called a step
up transformer.
The coils of a transformer must be very well insu-
lated. After winding they are bound to keep them in
Fig. 173. Coils, Air Ducts, and Separators for Transformer.
shape and then wound with linen tape or varnished
cambric cloth. Fig. 172 shows a coil in the three stages
of completion.
In Fig. 173 is shown a set of completed coils, together
with the ventilating ducts and mica barriers sufficient
for one leg of a transformer.
Fig. 174 shows the two legs of a transformer, which
form its iron core, each over half-filled with coils. The
coil is made of sheets of soft iron.

372
ELECTRIC RAILROADING
Fig. 174. Interior Construction of an Air Blast Transformer.
Fig. 175. Set of Coils Made up Ready to Be Placed in Transformer
TRANSFORMING CURRENT
373
Fig. 175 shows the manner in which sets of coils are
sometimes bound up to be placed in transformer as one
coil.
Exciting Current.
The Exciting Current being also called by various
other names, such as leakage current, open circuit cur-
rent, and magnetizing current, is a very important thing.
In order that a transformer may be ready to do its
work it is always connected to the line. This means
that the primary coil is always magnetizing the core if
no current is drawn from the secondary.
This steady flow of current to excite the primary is
the price we have to pay for having the transformer
continually ready for service.
A transformer should therefore never be left on a
line unless it is needed.
Efficiency of Transformers.
The losses in transformers are less than any other
piece of electrical machinery or apparatus; 98% of the
intake being delivered in the larger sizes as used in rail-
road sub-stations or power houses, when fully loaded.
Unfortunately they lose about the same amount of
power at all loads.
A 100 K. W. transformer loses 2 K. W. at full load,
its efficiency is then 98100=0.98. At half load it
loses 2 K. W. but is only carrying 50 K. W. so (its
losses are now equivalent to 4 K. W. on a 100 K. W.)
its efficiency is 48÷÷50=0.96.
374
ELECTRIC RAILROADING
At quarter load it takes in 25 K. W., loses 2 K. W.,
so its efficiency is 23÷25-0.92.

式
​LONGITUDINAL SECTION
OF AIR BLAST
TRANSFORMER SHOWING
AIR DUCTS
Fig. 176. Air Blast Transformer.
By clever designing transformers are built to be most
efficient at three-quarters load. They are a little less
efficient at half and full loads, and still less at quarter
load and quarter overload, but never fall below 95%.
TRANSFORMING CURRENT
375
Cooling Transformers.
Small transformers hung up on poles are cooled by
surface radiation only.
Medium sized ones are filled with oil. This conducts
the heat to the iron case and also acts as an insulator.
The oil will also flow in and fill a break in the cloth or
mica after a puncture.
Air blast avoids the danger of oil in case of fire or
flame due to short circuits. They are cheap as a trans-
former may be much more heavily loaded when cooled
by the air blast, and the blower only consumes 1/10 of .
1% of the full load output of transformer.
Fig. 176 shows the interior construction of an air
blast transformer and Fig. 177 shows how they are in-
stalled.
Water Cooled. These are the smallest and cheapest
transformers to build but not so cheap to run as the air
blast.
The cases are filled with oil which absorbs heat from
coil. Pipes are run through the oil, in which cold water
is circulated.
In a water power plant where the head of water
would render pumps unnecessary the water cooled type
would certainly be the best.
Auto-Transformers.
These are only applicable to certain cases.
2
The idea is shown in Fig. 178. The same coil of wire
A to B is used as primary and secondary, the whole
376
ELECTRIC RAILROADING
376
BLOWER OUTFIT.
INTAKE
DAMPERS
TRANSFORMERS.
AIR CHAMBER
WSOB
INTAXE
BLOWER OUTFIT.
Fig. 177. Installation of Air Blast Transformers.
7
ப
OUTSIDE
INTAKE PIPE.

TRANSFORMING CURRENT
377
being the primary and portions as C to D, D to E, or
C to E being used as a secondary.
They are only used where the primary voltage is fairly

A
B
E
Fig. 178. Diagram of Auto-Transformer or Compensator.
low and the secondary voltage is not less than one-fifth
of the primary voltage.
They are used instead of resistances to start A. C.
motors.
LESSON 24.
THE DYNAMO.
The dynamo is a machine for transforming mechanical
energy into electrical energy, by use of the principles of
electro-magnetic induction. These principles were dis-
covered by Faraday. You may repeat his experiments
for yourself.
Direction of the Induced E. M. F. In front of you
on the table lay a magnet with its N-end projecting over
the edge. Take a copper wire and connect its two ends
to a galvanometer or pressure meter; usually called a
Voltmeter. Stretch a portion of this wire between the
right and left hands, and move the wire rapidly down.
in front of the N-end of the magnet at right angles.
to lines of its action. There will be induced in the wire
a pressure or Electro-motive force which will send cur-
rent through the wire from your right hand to your
left. The galvanometer will give a deflection showing
the flow of current.
This deflection is not a permanent one, the needle
instantly dropping back to zero, proving that only a
momentary current was produced.
If the experiment is tried moving the wire upwards.
the direction of the momentary circuit is reversed.
With a downward motion in front of a S-pole we get
a left to right current.
378
THE DYNAMO
379
1
¡
Hence, starting with a certain polarity and direction.
of motion, changing one changes the direction of the
induced current, while changing both the polarity and,
the direction of the motion does not reverse the cur-
rent.
Now hold the wire a foot away from the magnet and
directly opposite it, moving the wire up to the magnet
and back again, keeping the distance from the wire to
the floor the same, so that the motion shall be parallel
to the flux. No E. M. F. is generated in this case.
An electromagnet would do as well and probably
better as they are usually stronger than permanent mag-
nets.
The value of the Induced E. M. F. depends on the
following:-
1. The greater the strength of the magnet the greater
the E. M. F.
2. The more rapidly the wire is moved, the greater
the induction.
3. The larger the number of turns in a coil of wire
the greater is the E. M. F. induced in it.
The induced E. M. F. therefore depends on the flux,
the speed of cutting this flux, and the number of wires
cutting this flux.
A dynamo reduced to its simplest form is a coil of
wire arranged so as to cut the magnetic flux of an elec-
tro magnet, thus producing an induced electromotive
force.
A dynamo therefore does not generate electricity, but
pumps up a pressure as does a water pump, thus causing
the electricity to flow through the circuit, which is called
a current.
380
ELECTRIC RAILROADING
The current flows through the dynamo and the ex-
ternal circuit in series, hence the greater the current
the larger must be the dynamo and the heavier the wires
of the external circuit.
Since the E. M. F. (electromotive force) can be pro-
duced almost entirely by speed of the machine, the volt-
age at which the current is delivered does not affect the
weight of the machine very much.
It is also evident that the faster a machine is driven
the smaller the magnets can be and yet the same E. M.
F. be produced. This is why high speed generators
weigh less than low speed machines. The usual 600 volt
railway generator weighs II, 13, or 16 pounds per
ampere of current capacity.
The railway generator whose voltage is 600 and
whose resistance is 0.025 of an ohm, would give a cur-
rent which can be calcuiated by Ohms law.
Amperes
E. M. F.
Resistance of generator plus
resistance of the external
circuit.
If we allowed the external resistance to fall too low
by attempting to operate too many locomotives at the
same time, the current drawn would generate a great
amount of heat while passing through the machine. The
amount of this heat can be calculated by the rule.
Heat in Watts is equal to the Square of the current
multiplied by the resistance of the generator.
If we build an II-ton generator and load it too heav-
ily, that is, put 4000 amperes on it; it will have C2R
THE DYNAMO,
381
watts of heat or 16,000,000 x 0.025 equal to 40 K. W.
(kilo watts) to dissipate. Now a machine like this has
such a small surface that it cannot radiate 40 K. W. of
heat to the air, whereas if a heavier machine had been
built, one of 22 tons, it could have gotten rid of the heat.
Moreover the copper wires of the 22-ton machine being
larger than those of the light machine, the resistance.
they offer is less, and there will be less heat generated.
Thus the heavier machine will run cooler than even the
light machine properly loaded.
The danger in overheating of generators is the dam-
age done to the cotton insulation of the wires, due to
scorching, and the melting of the shellac varnish be-
tween the layers of mica. The mica itself stands the
heat very nicely. Any overheating of the armature and
the commutator is at once conducted to the bearings.
To prevent the generation and retention of too much
heat it is customary to allow 700 C. M. (circular mils)
of copper for each ampere of current and to design the
shape of the coils of wire so that they will have one.
square inch of surface for every two watts of heat to
be gotten rid of.
The generator must be protected by fuses (which will
melt) or by circuit breakers (automatic switches open-
ing at a definite current) which will open the circuit and
prevent the further flow of current in case of an acci-
dental low resistance or short circuit, as it is called,
which would otherwise draw a very heavy current and
burn out the dynamo. The armature is the part that
suffers first.
In talking about dynamos or generators (the two
names are used for the same machine) we use the words
382
ELECTRIC RAILROADING
E. M. F. and voltage. By the E. M. F. of a dynamo
is meant the total pressure generated by the armature.
As the current flows through the armature and field cir-
cuits of a railway generator it encounters the internal
resistance of the generator and pressure is lost accord-
ing to the rule: Drop in pressure is equal to the product
of the current and the resistance. Hence the current as
it flows out of the generator is at a reduced pressure;
and this pressure at which current is delivered to the
switch board, is called the terminal voltage or simply the
Voltage of the machine. For the generator like above
Drop Cx R=2000 x 0.025=50 volts.
If we intend to deliver power at 600 volts it will be
necessary to design the speed and the magnetic flux to
produce a pressure of about 650 volts.
If a voltmeter be applied to the brushes of a generator
just ready to go into service, but not yet carrying any
load, the reading obtained is called the E. M. F. When
the switches are closed and the generator furnishes
power to the line the reading of the voltmeter will drop
and its reading is called the Voltage of the machine.
We often speak of current being drawn from the
dynamo. The generator keeps a steady pressure on the
line of 600 volts and the flow of current is regulated by
the load in the following way:
One locomotive hauling a train at speed will have a
resistance of 0.3 ohm and will draw 600 divided by 0.3
or 2000 amperes.
It would be more accurate to, say 2000 amperes are al-
lowed to flow. This locomotive is the only path for cur-
rent to pass from the feeder (third rail) to the return
(rails). When two locomotives are in use there are two
THE DYNAMO
383
paths between the feeder and the return. The conduct-
tivity between conductors has been doubled and the re-
sistance halved. Double the previous current now flows.
In this way we get the current desired by lowering
the resistance, and as the current passes it performs the
work.
"Notation

B
N
S
Fig. 179. Direction of Induced E. M. F. in Dynamo.
Two locomotives draw twice the current of one, hence
their conductivity is double that of one, and their com-
bined resistance is half of one.
The conductivity of three locomotives is treble, so
their combined resistance or Joint Resistance is one-
third that of one.
In the usual type of railroad generator, the revolving
part is the armature and the stationary part the field.
magnets. Fig. 179 shows the elements of a dynamo, and
as the loop is rotated there is an E. M. F. generated
in it.
While the loop is coming into and passing away from
the position ABCD, there is no E. M. F. generated, for
384
ELECTRIC RAILROADING
the motion is parallel to the flux. As the loop moves.
towards the position ABCD by a uniform rotative speed
it cuts the lines of force faster and faster, for first it cuts
in an oblique manner but as the loop comes into the
position of abcd the loop is moving straight across the
flux. Hence the actual number of lines cut per second
is least at ABCD and gradually increasing becomes
greatest at abcd; thus producing an E. M. F. of varying
value.

N
M
D
B
A S
LAMPS
Fig. 180. The Simple Alternating Current Dynamo. Brush M Is
Positive.
During this quarter of a revolution the wire BA has
moved down in front of a S-pole inducing an E. M. F.
tending to send current from B towards A. The other
part of the loop CD has moved upward in front of an
N-pole inducing an E. M. F. tending to send current
from C towards D.
THE DYNAMO
385
These results are in accordance with the experiments
described at the beginning of the lesson. Remember
that in applying the rule you must face the pole.
This action is repeated during the next quarter of a
revolution, and when finally the coil is in the position
ABCD with AB at the bottom the pressure is again at
zero.

N
P
S
Fig. 181. The Simple Alternator, Shows Coil at One-half a Revo-
lution from Fig. 180. Brush M is Now Negative.
The value of the E. M. F. has started at zero, risen to
a maximum, and decreased to zero again. This gives a
fluctuating current or pulsating current in the external
circuit.
*.
When AB rises in front of the N-pole the E. M. F.
will be in the direction of from A to B, while before
386
ELECTRIC RAILROADING
it was from B to A. During each revolution of the loop
the current flows one way half the time and then is re-
versed and flows the other way.
This is what happens in the armatures of all dynamos.
whether alternating (A.C.) or direct (D.C.) current
types.

A
B
Fig. 182. An Armature Coil Connected to a Two-part Commutator,
so as to Deliver Direct Current.
When we wish to utilize the current flowing in the
loop of Fig. 179, we attach two collector rings as shown
in Figs. 180 and 181, which gives us an A. C. generator
or an Alternator. For a D. C. generator or simply
Generator, the ends of the loop are connected to one ring
split as shown in Fig. 182, whose halves are insulated
from each other and from the shaft. Two brushes are
placed as in Fig. 183. In this case the alternating E. M.
F. will be reversed or commuted at the proper instant
and there will be a one direction E. M. F. impressed on
the external circuit. The split ring is called a Commu-
tator.
THE DYNAMO
387
THE ALTERNATOR.
In Figs. 180 and 181 are shown two positions of the
loop on the armature of an alternator. The collector
rings are insulated from the shaft and each other by
mica. The terminals of the loop are soldered or riveted
(sometimes both) to the rings and current is led to the
external circuit containing the lamps by stationary strips
of copper which form a sliding contact with the rings.

Fig. 183. Cross Section of Simple Commutator. Black Represents
Copper; White Space Is Mica Insulation.
Look at Fig. 180 and notice that during the first half
of the revolution of the loop ABCD, the direction of the
E. M. F. in AB is from B to A, and in CD is from C
to D.
The current flows from the brush M to the lamps so
that M is positive.
Looking at Fig. 181 note that the wire in front of
the S-pole is still positive, but that it is now the wire CD
instead of AB, so P is the positive brush for the second
half of the revolution. There are two reversals of the
current per revolution.
The number of alterations per minute is the speed in
revolutions per minute multiplied by the number of
poles.
388
ELECTRIC RAILROADING
The number of cycles, is found by multiplying the
speed in revolutions per second by the number of pairs
of poles. The number of cycles is usually spoken of as
the Frequency of the alternator.

B
N
S
f
LAMPS
Fig. 184, Simple D. C. Generator. At This Instant the Brush M Is
Positive.
The usual frequencies are for power 25, for motor
circuits, and arc lamps 66, and for incandescent lighting
133.
THE DIRECT CURRENT GENERATOR.
In Fig. 184 is shown a loop and a two part commu-
tator of a D.C. generator.
Since the wire AB is moving down past a S-pole, the
current flows from B to A and out of the brush M,
THE DYNAMO
389
which is called the positive brush. In wire CD the cur-
rent flows from C to D, making P the negative brush.
After half a revolution the wire CD is over where AB
was, and is now delivering current towards the external
circuit instead of away from it; but CD is now con-
nected through its commutator bar to brush M instead
of to P so that the brush M is still positive. (See Fig.
185.)

Fig. 185.
N
+
M
B
C
↓
S
D
LAMPS
Simple D. C. Generator. The Armature Has Made Half
a Revolution, but Brush M Is Still Positive.
This arrangement of commutator bars and brushes
performs the duty of connecting the brush M to that
part of the winding, and only that part which is moving
down in front of a S-pole. As long as the wire AB
moves up in front of a N-pole the commutator connects
390
ELECTRIC RAILROADING
it to brush P, but as soon as it begins to move down
in front of a S-pole it is immediately disconnected from
P and a connection made with M.
To increase the E.M.F. The greater the field strength
the greater the E.F.M. and the higher the speed the
greater the E.M.F.
When the speed has been raised until the surface of
the armature is traveling at the rate of 3000 ft. a
minute* no further increase is made, lest the bursting
stresses become too great.
{

Fig. 186. A Single Coil Armature of Many Turns.
In order to further increase the E.M.F. more turns or
loops of wire must be wound on the armature. A coil
of 16 turns as in Fig. 186 will give an E.M.F. 16 times
as great as a coil like Fig. 182. Looking at Fig. 187 will
convince you of this.
Suppose the direction of rotation to be the same as
the hands of a watch (or as we say, clockwise) when
viewed from the commutator end of machine; then the
*This is called the Peripheral Speed of the armature and is
calculated by this rule:
P. S. equals 3.1416 x D x R. P. M. where D is the diameter
of armature in feet and R. P. M. is the revolutions of the arma-
ture per minute,
THE DYNAMO
391
E. M. F.'s induced in the successive portions of the wire
will be as shown by the arrows, and will add to each
other, impressing a high E.M.F. on the brushes. We
say that these turns of wire are all in series.
Any betterment of the magnetic conductivity of the
frame of the machine will increase the E.M.F.; by pro-
ducing a greater flux per pound of copper on the field
magnets. Hence the winding of the armature inductors
(wires) on a core of very softest iron is an economic
necessity, resulting in either a higher E.M.F. or a re-
duction of the expense for copper in the field coils.
JOE

N
Fig. 187.
An Armature Coil of Many Turns Showing How the In-
duced E. M. F. of Each Turn Adds Itself to That of Other Turns.
These cores are called Drum cores when the central
hole is just large enough for the shaft and the insulation
around it (Fig. 188); and are named Ring cores when
the internal diameter of the ring is much larger than the
shaft. (Fig. 190.) The armature in Fig. 191 has a ring
core, but the end plates being in position, the large hole
is concealed,
392
ELECTRIC RAILROADING
These cores are built up of a great many punchings
of soft iron from 15 to 40 mils thick, pickled so as to
rust them a little. Every tenth one is varnished or tissue

Fig. 188. Drum Winding on a Drum Core. Four Coils and Four
Commutator Bars. For Direct Current.
paper pasted on. The rust, varnish and paper are all
insulators and when the punchings are assembled in a

T
N
L
+
B
R
S
Fig. 189. Diagram of Fig. 188.
core prevent currents called Eddy currents from flowing
from one end of the armature to the other and heat-
ing it.

THE DYNAMO
393
These cores are sometimes smooth but more fre-
quently are slotted with the wires laid in the slots.
About 10 to 15% of the length of the core is insula-
tion, and about 50% of the surface is slots containing
the inductors.
Fig. 190. Simple Gramme Ring Winding.
To get a Continuous E.M.F. While a single coil of
many turns produces a high E.M.F., which by a two
part commutator is always applied to the external circuit
Fig. 191. Eight Section Eighty Coil Ring Winding on a Smooth
Ring Core, with Eighty Bar Commutator. For Direct Current.
in the same direction, yet this coil passes through all
the changes in voltage mentioned in connection with
Fig. 179.
394
ELECTRIC RAILROADING
Examine the ring winding (invented by Gramme) of
Fig. 190, which is wound on a ring core made up of soft
iron punchings 25 mils thick.
The wires on the outer surface are active, having
E.M.F. induced in them, and are called armature induc-
tors. The rest of the wire is dead wire and only useful
to complete the circuits between inductors.
Notice the connections between commutator bars and
winding. Number the coils and commutator bars with
a pencil, sketch in the two magnetic poles and the two
brushes. Imagine the armature to rotate clockwise and
figure out the value of the voltage at the brushes during
different parts of a revolution.
In Fig. 192 we have the same windings with eight
coils and eight commutator bars. In Fig. 191 the arma-
ture as diagrammed in Fig. 192 is shown completed
with its four bands. These bands are from 12 to 25
convolutions of phosphor-bronze wire in sizes varying
from No. 20 up to 14 laid on tightly over a mica insula-
tion and sweated with solder all the way round.
In Fig. 192 you will notice that the complete winding
can be divided into two parts, one influenced by the
N-pole, the other by the S-pole standing at the commu-
tator end. The N-pole side moving upwards has its
E.M.F. in direction from back to front of armature
through the inductors; the S-pole side has E.M.F. in
direction from back to front of armature through the
dead wire.
In winding the armature the wire is laid on in a con-
tinuous spiral as shown. This makes the E.M.F. in
each half of the armature in series, and allows the cur-
rent to flow from one coil to another, except at the
points where the N-half and S-half of the armature.
THE DYNAMO
395
meet. Here the E.M.F.'s oppose and if wires were con-
nected for an instant to the winding, as shown in the
picture, the two opposing E.M.F.'s would both force
electricity out into the wire at the top of the armature
and draw it in at the bottom as shown by the arrows on
these wires. This will cause a current to flow in the
external circuit.

S
N
Fig. 192. Eight Coil Gramme Ring Winding, with Eight Part
Commutator.
If the junctions of the coils are connected to eight
commutator bars (one bar per coil) and connect the
ends of the external circuit by brushes to the commuta-
tor bars which are midway between the N- and S-poles,
then each half of the armature separately generates an
'E.M.F. and delivers current to the external circuit.
Suppose the armature to be revolving at the highest
safe speed. Each inductor will move past the magnet
poles at a speed of 3000 ft. a minute. With pole pieces
5 x 8 inches and a flux density of 90,000 lines per square
inch, the total flux will be 5 x 8 x 90,000 or 3.6 million
lines.
396
ELECTRIC RAILROADING
The armature may be 9 inches in diameter, which
gives its rotative speed 1270 (nearly).
For R.P.M.* P.S.†÷(3.1416 X diameter).
3000 X 12
3.1416 X 9
=1270 nearly.
which R.P.S.=21 nearly.
An inductor therefore cuts 3.6 million lines of mag-
netism twenty-one times a second, which is equivalent to
cutting 75.6 millions once per second.
Since the cutting of 100 million lines per second by an
inductor induces I volt pressure, each inductor on this
armature revolving in this field will produce 75.6-100
or 34 of a volt (aprox.).
The 4 coils of 4 inductors each (Fig. 192) on the N-
half of armature being in series produces 3 volts per
coil or a total of 12 volts which is the E.M.F. of the gen-
erator.
The S-half of the armature also generates a pressure
of 12 volts, which is not added to the pressure of the
N-half, being in parallel with.it. An inspection of Fig.
192 shows that they oppose rather than add to each
other; but an outlet being provided they turn aside
through it, and send current separately and independ-
ently towards the outside circuit.
If the armature is wound with No. 10 A. W. G.,§ the
*Revolutions per minute.
†Peripheral speed.
#Revolutions per second.
American Wire Gauge. A table of sizes and properties of
the sizes of wire according to the Brown & Sharp or American
Gauge will be found in Lesson 18.
THE DYNAMO
397
diameter of which is 0.102 inch or 102 mils, its area is
102 squared equal to 10,404 c.m. Allowing 700 c.m. per
ampere, it will carry 15 amperes, without too much
heating.
Since each side of the armature delivers its own cur-
rent to the brushes, the safe current output of this gener-
ator is 30 amperes.
Suppose there are 250 ft. of this No. 10 wire on this.
armature. The resistance of the wire from the wire
table is 1.02 ohms per 1000 ft.
The resistance of all the wire on armature is 0.255
ohm, and the resistance of the wire on each half of the
armature is 0.128 ohm.
But the two halves are in parallel so the resistance of
the armature as measured from brush to brush will be
half of 0.128 or 0.064 ohms.
The drop or loss of pressure in armature will be
CXR or 30X0.064, equal to 1.92 or say 2 volts.
This machine being a shunt generator, the main cur-
rent does not pass through the fields, and there is no
further voltage loss.
The E.M.F. of this dynamo is 12 volts and its voltage
IO volts. Its output in watts will be 10X30-300 watts
or 0.3 kw. This is the rating of the generator.
The generator will carry this load 22 hours a day
without getting more than 90° Fah. hotter than the sur-
rounding air.
A properly proportioned machine will stand a 25%
overload for half an hour rising an extra 30° in tem-
perature, and it will stand a 50% overload for one min-
ute without being damaged by the heat.
4
398
ELECTRIC RAILROADING
Drum Windings.
The extra labor involved in passing the dead wire
through the bore of a ring core is avoided by going back
to first principles again and placing on the core (either
drum or ring) a number of coils shaped as in Fig. 186,
producing a winding as in Fig. 188.
It is to be noted that the inductors lie entirely on the
outer surface of the core and that the percentage of dead
wire is less than in Fig. 190.
For a long, small diameter armature drum winding
uses the least wire; while for a short, large diameter
core the ring winding will require fewer pounds of
copper.
Take Fig. 188 and mark in pencil as directed, using
Fig. 189 as a guide. In order to make the diagram in
Fig. 189 clear, it has its proportions wrong. The dead
part of the wire is drawn very long and the active part
very short. The reverse is true of an actual winding.
Mark the top horizontal coil of Fig. 188 T, the bottom
one B. Mark the right and left hand vertical coils L
and R. Mark the upper brush negative and the lower
one positive.
The left side of the armature is the N-pole side and
the right the S-pole side; then we know that the arma-
ture is revolving anti-clockwise (else the upper brush
would be positive).
The E.M.F.'s on the N-side and S-side of coil T, just
as in Fig. 187, are in series and add producing a current.
flow towards the lower (positive) brush. The current
passes through the inactive (dead) coil R in order to
get to positive brush.
THE DYNAMO
399
At the same time the E.M.F.'s in coil B add up and
passing through the dead coil L drive current out of
lower brush.
The value of the E.M.F. is eight times that which one
inductor can produce. For the active coil T has 4 loops,
i. e., 8 inductors in series, as also has the coil B. Sup-
pose T produces 8 volts, the two coils T and B are in
parallel and do not add their E.M.F.'s.
The coils L and R are dead, L being in series with B
and R in series with T, but they produce no E.M.F. At
the present instant they are but a wasteful resistance,
their value, however, will be soon seen.
When the armature has moved about % of a revolu-
tion, you will find that T is cutting flux slantingly and
that R, which is in series with it, is beginnng to cut flux.
also. T is only 34 active, producing say 6 volts, and R
is not totally dead but 4 active, producing 2 volts.
Hence the voltage of the machine is still 8.
At 4 revolution R is doing full work and B is dead
and in series with it, while T is dead and L in series.
with it is at full activity. Now R and L produce the
E.M.F.
The student must revolve Fig. 189, using slips of
paper as brushes to gain a full understanding of these.
actions.
The current enters the armature through the upper
brush, splits and passes through the armature by two
parallel circuits, one containing T and R in series and
the other containing L and B. During a revolution
these coils interchange places, but two coils are always in
each circuit.
When 6 amperes flow in the external circuit, the No.
16 wire of the armature is not overheated, as it only has
400
ELECTRIC RAILROADING
to carry 3 amperes (half of 6), which it is well able to
do. It has 2583 C.M., and which is more than 3X700
C.M.
Self exciting of a Dynamo. When a dynamo is stand-
ing idle the field magnets are weakly magnetic due to
residual magnetism.
Let the armature revolve and in a shunt or compound
machine open, in a series generator close the external
circuit.
A few volts will be generated and cause a current to
flow through the fields, hence the magnetism will in-
crease and more voltage will be induced. This voltage
will send increased current through the shunt field and
cause more volts to be induced.
The machine is now "building up."
As more and more magnetism is put into the fields,
it becomes harder to get any more in as the iron is ap-
proaching saturation and there is more and more leak-
age.
Hence at a certain point, depending on the design of
the machine, the difficulty of increasing the magnetism
being added to the effect of the leakage just balances the
tendency of the voltage to be increased. If nothing else
is done the voltage of the dynamo will remain constant.
In the series field is passing all the current drawn
from the machine and the field strength and voltage tend
to increase. This increase is opposed by the C. R. loss
in armature and field, and the effect of the increasing
field density. The net result is a building up of the volt-
age and if the load is not changed the voltage of the
inachine will remain constant.
Regulation. If now in the shunt generator you close
the external circuit an extra current (very large in pro-
THE DYNAMO
401
portion to the field current) is drawn from the armature
and causes a CR loss.
A lower voltage is thus impressed on the external cir-
cuit and to make matters worse, also on the field. Hence
the field weakens and the added results of C R loss and
weaker field is a considerable drop in voltage for each
increase in load.
Resistance must be cut out of field as load increases.
When in the series generator the load increases a
shunt should be placed around the field to weaken it, if
a constant potential is desired. :
Position of the Brushes. In order that one set of
brushes may take away from and the other set deliver
current to the generator in a bipolar machine these sets
are on opposite sides of the commutator.
In some dynamos when the inductors come out of the
slots, one goes straight on to a commutator bar and the
other is bent over to its proper bar. This puts the
brushes in line with part of the coil and they will be
found half way between the pole tips.
It is usual to bend both inductors as they leave the
slots and connect to bars half way between the slots.
Then the brushes will be found opposite the middle of
the pole piece.
In dynamos and non-reversing motors the brushes are
a little distance away from the points mentioned, but in
reversing motors are exactly at these points.
If you will consider that a multipolar dynamo or
motor is merely a lot of bipolar fields which for economy
of material are working on one large armature, the
placing of the brushes on such machines will be clear to
you.
402
ELECTRIC RAILROADING
The alternate brushes are of the same polarity and
there is usually a set of brushes for each field magnet.
The placing of the brushes on the commutator with a
certain relation to the winding is necessary as a refer-
ence to Fig. 193 or to the diagram of any winding will
show you that the brush while collecting current is at
the same time short circuiting one of the coils.


N
A
>
S
Two Pole, Two Circuit
B
Four Pole, Four Circuit, Four Brushes
In Multiple.


C
S
N
Four Pole, Four Circuit, Cross Connected
Two Brushes or Four Brushes,
in Multiple.
N
S
Four Pole, Two Circint Ring
Two Brushes or Four Brushes,
u Multiple,
Fig. 193. Showing the Number and Position of Brushes on Different
Armature Windings.
The black brushes are the ones actually used, the dotted ones being
dispensed with on account of the particular winding.
In order that an excessive current may not be gene-
rated in this short circuited coil it must be out in the in-
terpolar space at the time the brush touches the two
bars belonging to it.
THE DYNAMO
403
Sparking. When a current is broken there is always
a spark, which is greater the more turns in the wire and
the more iron within these turns. That is, the more
inductive the current the worse the spark.
The conditions are right for excessive sparking in a
machine, for the circuit is inductive and although the
circuit is not actually broken, the current being merely
shifted, yet the result is equivalent to it.
Positive
Brush

N
N
POLE
B
A
C
mim
N
Fig. 194. Showing Position of Brush for Sparklers. Collection of
Current.
Looking at Fig. 194 and considering the line N N to
be about midway between the pole pieces. The coil B is
short circuited but has no current in it because
Ist. The field is very weak and the coil is moving
parallel to it, so no E.M.F. is generated in the coil.
2d. The currents from the N and S-side of winding
enter the brush without going through the coil B.
Coil B has therefore no current in it, but being con-
nected to A and C whose potential is high B is charged
404
ELECTRIC RAILROADING
ELECTRIC
with electricity, and it is full of coulombs,* which are
at rest.
When the armature revolves as shown and the toe of
a copper brush leaves bar 3 the current from C must
instantly change over going through B to reach the
brush. The coulombs in B which are at rest should in-
stantly move at full speed becoming a part of the arma-
ture current.
It being impossible to set the coulombs in B into mo-
tion instantaneously it is evident that the current from
C encounters more than the ohmic resistance of the coil
B. This extra opposition being called reactance.
The path through B being momentarily practically
nonconducting the circuit is broken by the brush moving
away from the bar, and a spark or arc formed.
The circuit being inductive (having turns containing
iron) the spark is persistent and holds until the react-
ance of coil B decreasing, it begins to conduct and di-
verts enough current into the proper path and the arc
goes out for lack of current to maintain it.
This sparking is avoided in the following way:
Ist. Carbon brushes of high resistance are used which,
as the part of the brush touching a bar gets narrower,
due to the high resistance, throttles the current, gradu-
ally forcing it over to the coil B. Hence B does not
have to instantly carry all the current.
2d. Move the brushes of a dynamo in direction of
rotation until they are nearer the pole shoe, exactly as
is shown in Fig. 194.
*A coulomb is a certain quantity of electricity. When a
coulomb passes a given point every second a current of one
ampere is said to flow.
i
THE DYNAMO
405
The short circuited coil B is now under the fringe
from the pole piece; and is moving obliquely through a
stronger field. A small E.M.F. is generated in it.
From the illustration it will be seen that a current in
the same, as in C (for B and C are under influence of
same pole piece) flows around through B, the bars 2 and
3 and the brush.
By shifting the brushes a little to and fro the correct
strength of field can be selected and the obliquity at
which it is cut adjusted, so that a current will be made
to flow in B not only of the same direction as that in C
but also of exactly the same value.
Hence when the toe of the brush slips from bar 3 the
current in C instead of running against the impedance
(the sum of the resistance and reactance) of coil B, finds
itself merely falling in behind the flow already estab
lished, and there is no tendency to spark.
*
In a motor the brushes are shifted in opposite direc-
tion to the rotation to get to the no sparking position.
Hence the positions for sparkless forward or backward
running are some distance apart.
It is a mere matter of first cost to produce a machine
with absolutely sparkless commutation under any condi-
tions. It is the skill of the designers which has (with-
out prohibitive cost) so reduced the distance between
these two points that it may be spanned by a thick car-
bon brush.
The railroad motor of to-day operates in either direc-
tion, without shift of brushes, under all loads, and some
overloads, without serious sparking. What little occurs.
is of such small volume and such low temperature that
no great harm is done.
406
ELECTRIC RAILROADING
Classes of Dynamos.
Dynamos are divided into classes with reference to the
manner in which their fields and armature are inter-con-
nected.
The series dynamo. Fig. 195. The same current
traverses the field, armature and main or external cir-
cuits. The conductors in these circuits are about the
same size. The circuits are all in series.

S
N
MAIN CIRCUIT
Fig. 195. Circuits in a Series Dynamo or Motor.
This dynamo is used for arc lighting and as boosters
for increasing the pressure on a feeder carrying current
furnished by some other generator.
The characteristic of this type is to furnish power at
an increased voltage as the load increases. If sufficient
current is drawn to overload the machine the voltage
will fall.
The shunt dynamo. Fig. 196. Here the field circuit
is arranged as a shunt circuit. The armature and ex-
THE DYNAMO
407
ternal circuits are in series. The armature current is
the sum of the external and field currents.
The con-
ductors on the field are very much smaller than those on.
armature, as they only carry 2 to 5 per cent as much cur-
rent.
Used for incandescent lamp lighting, mill and factory
power.
Resistance Box
i
Ammeter

Voltmeter
B
B'
Fig. 196. Circuits of a Shunt Dynamo with Instruments and a
Load of Lamps.
The characteristic of the shunt generator is to allow
the voltage to fall as the load is increased.
It is evident that only by a combination of these two
into a compound dynamo, Fig. 197, can a generator be
produced which will deliver any power within its rated
capacity and yet hold a steady voltage.
The armature is the same as a shunt dynamo, but
the fields have two distinct windings, one shunt and the
other series.
408
ELECTRIC RAILROADING
The series dynamo is often called a constant current
generator because its tendency is that way, and with a
regulator it will furnish a constant current.
The shunt dynamo is similarly termed a constant
potential generator. For with a regulator it will keep to
a constant voltage.
The compound generator will of its own accord, with-
out any regulator, furnish at its terminals or at any dis-
tant point on the line steady power, at an absolutely con-
stant voltage.

SHUNT FIELD
SERIES
FILLO
N
S
SHUNT FIELD
RULOSTAT
Fig. 197. Circuits in a Compound Dynamo.
In railway service where the amount of power re-
quired fluctuates violently, the voltage will vary some-
what, for the generator scarcely has time to adjust itself
to the present conditions before the condition, no longer.
exists and a new demand arises.
It is not necessary that the pressure on the third-rail
should be absolutely constant, and for this kind of ser-
vice the compound generator, with the series character-
istic predominating, so as to keep a steady pressure out
on the line is good and plenty.
$
LESSON 25.
MOTORS.
It might be said that another class of dynamos is
motors.
Any of the D. C. dynamos and many of the A. C.
machines in power houses would revolve and produce
mechanical power if they were supplied with the proper
kind of current at proper voltage. In fact, one of the
troubles that may occur in a power house is to have one
out of a set of generators start to act as a motor, thus
placing heavier load on all the other machines.
The same electrical machines can be used as a dynamo
or a motor; but as most dynamos are compound or shunt
and built for power houses, where there is sufficient, if
not plenty of room, and as all railroad motors are
series wound and placed where there is very little room,
it is natural that the dynamos and motors a railroad man
sees should not look alike.
The similarity of their electrical action must be re-
membered so that one may understand that the parts of
a dynamo and motor, though a little different in shape,
act alike electrically and have the same names.
Comparison between Dynamo and Motor. Since it
takes power to force a dynamo armature to revolve
while generating current, and none when not generating
(field and armature circuits open) we conclude that it is
409
410
ELECTRIC RAILROADING
the action between field and armature magnetisms which
causes the dynamo to resist rotation.
To test truth of this remove the armature from the
fields and pass current through its conductors in same
direction as the flow was before. You will find that the
armature is a large, strong electro-magnet.
Testing the polarity of the field magnets and of the
armature poles you will find that where using as a
dynamo, we are forcing a N-armature pole towards a
N-field pole. These poles repel each other and power is
absorbed by the rotation of the dynamo.
The repulsion of these poles would make the armature
rotate if current were supplied to it and the fields, and
the steam engine removed.
The difference between ordinary and railway motors
is the extreme simplicity of the latter.
Many of the refinements of design and construction
which theoretically are necessary, are in railway motors
omitted. It being found that for successful operation
they are not necessary, and by their omission much is
gained, i. e., saving in weight, cost, number of parts,
absence of complication and ease of repair.
It is not needful to say that parts of a railway motor
are put together so as to "stay put."
That motor is best, which with the fewest pounds of
material, will with reliability and low cost of repairs.
propel the greatest number of tons of pay load.
The main differences between all motors and dynamos
are the method of starting and the effect of the E.M.F.
produced.
1
MOTORS
411
Starting Motors.
We can not turn on steam to an engine instantan-
eously, for it takes time to open the throttle. We do,
however, turn it on more slowly than the opening of the
throttle compels us, for we wish to give the engine and
its dynamo time to get up to speed.
In the same way we must give current to a motor
easily, in order to start it. On the closing of a switch
the current jumps up to full value so quickly that the
motor armature would be brought up to such a tempera-
ture as would char the cotton insulation on the winding.
In starting a motor an extra resistance is used, and
it is placed either in the main or armature circuit. It is
only in use for a few seconds at a time and if well ven-
tilated can be made very small and light in proportion
to the current passing.
When applied to small motors where the starting is
at infrequent intervals this starting rheostat and its oper-
ating drum and handle is combined with two automatic
protective devices and contained partly in a latticed iron.
box and partly on its cover. It is called a starting box.
For larger motors doing similar work and for traction
or railway work, each of the parts becomes so large that
the four pieces are mounted separately. The operating
drum, the resistances, the overload release and the no
voltage release.
The operating drum is familiar to us all as the con-
troller of the street cars.
The resistance in the form of cast iron girds held in
skeleton frames are fastened under the sills of the cars.
The overload release or circuit breaker automatically
412
ELECTRIC RAILROADING
opens the circuit when a current large enough to dam-
age the motors is accidentally drawn. In street cars
this device is usually fastened under the hood over the
motorman's head.
No voltage release, a magnetically operated switch or
series of switches kept closed by the magnet, thus giv-
ing the current access to the motors circuits or the cir-
cuits controlling them.

Release Magnet
+
O
'From Supply
Cirquit
Cut-out
Switch
8
Overload
Cirouit Breaker
00000000
Field
Armatars
Fig. 198. Starting Box and Connections for Shunt Motor.
If the power is cut off the line the device operates,
opening all the circuits leading to the motors, thus pro-
tecting the motors from the damage done by applying
full voltage suddenly to a motor while standing still.
Fig. 198 shows a starting box with the proper connec-
tions ready to start a shunt motor. (Off position.)
t
MOTORS
413
As soon as the switch is closed there is full voltage
on the field, but no voltage on the armature, as the cir-
cuit is open at each end of the starting arm.
As the arm is swung clockwise, current flows to arma-
ture through a resistance which gradually grows less,
until when at right angles to its original position the
full voltage is on the armature and the motor operating
at full speed.
The hook on the left end of the arm catches on the
knuckle at the lower left side of the release magnet and
holds the arm in spite of the effort of a coiled spring
(not shown) to return arm to off position.
Tracing the circuits will show that the release magnet
is always energized if the supply circuit is alive and
switch closed. Should the supply be interrupted the re-
lease magnet becomes demagnetized and the upper end
of the knuckle is no longer held. The knuckle turns on
the pin (with screw head) releasing the hook, and the
spring returns the arm to the off position.
The motor would have stopped itself, but now it can
only be restarted in the proper way.
Consider the arm in the "running position," the over-
load circuit breaker magnet in energized, but the arma-
ture* being a considerable distance away the magnet is
too weak to draw it up.
Should the motor be overloaded and too much current
pass the strength of this magnet is increased so that the
armature swings up and jams the jumper in between
the two studs shown on the right of the magnet. This
completes a shunt or by-pass circuit around the release
magnet, diverting enough current from it that it weak-
ens and releases the knuckle. The arm then flies back
*Armature or keeper of a magnet; not of a. dynamo.
414
ELECTRIC RAILROADING
to the off position and the circuit to the armature is
opened.
The motor is stopped, which may be inconvenient, but
it is to be preferred to a burnt out armature.
In a railway motor this heavy current would also pass
through the fields, but they are better adapted to stand.
heat and the armature usually suffers first.
To start a motor with this box, close the switch and
swing the starting arm from off to running position and
let go. The overload circuit breaker may have danced.
up and down while this is being done. If so, next time
swing arm more slowly.
To stop the motor open the switch. The motor will
slow down and stop. Just before stopping, the release
magnet will allow the starting arm to return to the off
position.
The cutout shown consists of a fuse enclosed in a
cardboard tube and designed to melt or blow at a cur-
rent a little higher than that for which the circuit breaker
is adjusted.
COUNTER E. M. F.
Counter E. M. F. When the motor is operating all
the parts and conditions of a dynamo are present, hence
there is a dynamo action which produces an E. M. F. in
opposite direction to the impressed E. M. F. supplied by
the line.*
1
This is a most important and useful action.
*This I know by using the rule: Place the thumb, first and
second fingers of the right hand all at right angles to each other.
1st Thumb in direction of the motion.
2d First finger pointing from a N-pole to a S-pole.
3d Second finger shows direction of induced. E. M. F.
י
MOTORS
415
You will see that when we are starting a motor that
the faster it moves the more C. E. M. F. it generates.
This is why we can not throw full voltage on a motor
until it is nearly up to its full speed.
The actual voltage sending current through a motor
is the difference between the impressed and counter
E. M. F.'s.
The working of this in actual practice is best shown
as follows:
Suppose a set of four motors are on a 600-volt line
making 460 revolutions per minute with 44-inch wheels.
The locomotive they are a part of weighs 100 tons and
pulls 350 tons behind it at 60 miles per hour.
It is on a level track and must exert a pull of 17½
pounds for each ton pulled or 6,125 pounds in all.
It must exert through its drivers at the rail head 6,125
pounds for the train behind and 1,750 pounds for its
own weight. The total tractive effort is therefore 7,900
pounds (7,875 to be exact).*
At 60 miles per hour a train moves 5,280 feet per min-
ute; so the motors move 7,900 pounds 5,280 feet a min-
ute which is 41,700,000 foot pounds per minute. Since
33,000 foot pounds per minute is a Horse Power, we
get the H. P. of the motors as 1,264.
The efficiency of the locomotive is 80%, i. e., the
motors waste 20% of the intake. Hence 1,580 H. P.
is taken from the line.
This is expressed in Kilo Watts by multiplying by 746
and dividing by 1,000 giving us 1,185 K. W.†
*With certain problems a foolish amount of accuracy in
figuring is a waste of time. Since the condition of the rails is a
variable quality in traction work, figuring on the safe side is the
only sensible way to work.
†There are 746 watts in 1 H. P., and 1000 watts in a K. W.
416
ELECTRIC RAILROADING
This being supplied at 600 volts needs 2,000 amperes
(1,975).
An ammeter placed in the main conductor of one of the
New York Central locomotives will read about 2,000
amperes when pulling train No. 51 or No. 41 along the
Hudson River towards Croton, N. Y.
What is it that limits the current in this
amperes, i. e., to 500 amperes per motor?
the ohmic resistance of them.‡
case to 2,000
Certainly not
The resistance of each motor is only o.1 ohm or all
four in parallel or multiple is 0.025. The current is
limited by the dynamo action of the motors, i. e., by the
counter E. M. F.
Each of the motors generates about 1.2 volts per
revolution per minute, hence at 460 revolutions per min-
ute the C.E.M.F. of each motor is 550 volts. This
neutralizes all but 50 of the 600 volts on the line, and
leaves that 50 to send current through the resistance of
the motor. Fifty volts on 0.1 ohm gives 500 amperes or
2,000 amperes for all four motors.
Now let the train strike a grade. It will slow down
in speed and drawing more current develop in its motors
the H. P. required to pull the train.
How can motors whose resistance is fixed draw more
current when the line voltage is constant? By means of
the C.E.M.F.
By ohmic resistance I mean the actual resistance of the ma-
terial the conductors are made of. There is another resistance
which depends on the rate at which a current changes, and has
nothing to do with the material. Counter E. M. F. acts like re-
sistance, as it opposes the flow of current. The apparent`rësist-
ance of a locomotive drawing 2000 amperes is 0.3 ohm for 600
0.3 2000. The actual ohmic resistance is 0.025 ohms.
MOTORS
417
?
!
If the speed drops to 55 M.P.H. then the R.P.M. of
the drivers (and armature) change to 422, and the
C.E.M.F. to 510 volts. Hence 90 volts acting on each
0.1 ohm motor passes 900 amperes, or 3,600 for the
whole locomotive.
+
LESSON 26.
PARTS OF DYNAMOS AND MOTORS.
The following is a short description of the various
parts of a dynamo or motor and an explanation of the
terms used in talking about them.
Base. Made of cast iron and supports the magnet
yoke and bearings. It is made hollow to save unneces-
sary weight, and is braced internally with ribs to give
strength. It is bolted to a masonry foundation.
Railway motors have no base; the yoke being bolted
to the transoms of the truck, either directly or through
a spring supported lug.
Yoke. The ring or shell steel casting to which the
magnet cores are bolted. Sometimes the cores are placed
in the mold and the yoke cast around them.
In railway motors the cores are so short that they
are frequently cast solid with the shell.
Pole pieces or faces. Generally of cast iron bolted or
keyed to the magnet cores. Being greater in area than
cores they serve to hold the field coils in place.
In locomotives they are sometimes made of sheet iron.
Magnet cores. Very seldom made of sheet iron, some-
times of wrought iron forgings, but generally are steel
castings.
Fig. 199 shows a field coil and a magnet core of an
alternator. The winding of copper ribbon wound edge-
wise. The pole piece is almost same size as coil.
418

PARTS OF DYNAMOS AND MOTORS
419
Fig. 200 shows a shunt and series coil (large one is
shunt coil) wound and taped ready to be shipped on the
magnet core.
Fig. 199. Field Coil of Ribbon wound edgewise, with Laminated
Magnet Core (on left).
This core has the pole piece cast with a hole, which
is bored to a driving fit on the core.
Fig. 200. Shunt and Series Coils ready to put on Core.
Fig. 201 shows a ring yoke with the field coils in
place. Fig. 202 shows one of these fields ready to be
bolted in place.

420
ELECTRIC RAILROADING
Bearings. Should be large; four to six times as long
as the diameter of the shaft they contain; on account
of the high speed. They are usually of the self-oiling
type.
If there are collars on the shaft they should be ar-
ranged to allow the shaft to float, i. e., to move to and
fro about 1-16 to 1-8 of an inch so as to distribute the

Fig. 201. Ring Yoke with Field Coils in place.
oil in the bearings and to wear the commutator evenly.
If there were no float, the brushes always touching on
the same line around the commutator would wear
grooves in the bars.


PARTS OF DYNAMOS AND MOTORS
421
Rotary converters will not float of their own accord,
so a magnetic or mechanical device is installed at one
end of the shaft to compel a regular and even float.
At other end of shaft is often installed an "over
speed" device to shut down power in case rotary "races."
Shafts are made thicker under the armature core than
in the bearings; for the stress is greater out between
the bearings, since the load acts with a lever arm.
Fig. 202. Field Coil of Fig. 201 ready to be bolted into place.
They are made larger than in ordinary machinery be-
cause there is frequently a magnetic side pull due to
unequal strength of the field magnets or the polar bore
being eccentric with the shaft.
It is almost impossible to pull an armature out of the
fields while current is passing through the field coils.
Core. The sheet iron body upon which the armature
winding is placed.

422
ELECTRIC RAILROADING
Fig. 203 shows a toothed core into whose slots the
armature winding is laid. The core is held firmly be-
tween two end plates, by bolts passing through tubes of
insulation (usually fibre).
Generally the armature core is held by a spider, whose
hub is turned and keywayed to receive the commutator
hub. The spider hub is also bored, reamed and key-
Fig. 203. Armature Spider and Toothed Core.
wayed so as to form a sleeve or quill, which is slipped
on the main shaft. In this case the complete armature
may be removed for repairs without disturbing the com-
mutator leads or getting core and commutator out of
alignment.
Fig. 203 shows this construction.
PARTS OF DYNAMOS AND MOTORS
423
Hysteresis. When the iron core revolves it passes in
succession under N and S poles and so the magnetism
of the core is reversed.
All iron, no matter how soft, holds some residual
magnetism. This "hanging on" of the magnetism is
called hysteresis.

N
is
Fig. 204. Effect of Solid
and Sheet Iron
Currents.
Construction on Eddy
Before the magnetism in the core can be reversed the
residual magnetism must be wiped out. It takes about
1½ per cent. of the total power of a generator to do
this work. This inevitable loss is made as low as pos-
sible by the use of a small quantity of the softest iron,
worked at a low magnetic density. Increasing the quan-
424
ELECTRIC RAILROADING
tity of magnetism per square inch, the speed of the
machine or the pounds of iron in the core all increase
the loss due to hysteresis.
Eddy currents, sometimes called Foucault currents.
There must be E M F induced in the iron of the core,
just the same as in the copper on the core. Were it
not that the core is in sheets placed parallel to the flux,
there would be a great waste of power sending current

Fig. 205. Ring Winding.
{
through a short thick body of iron. (Hence of low re-
sistance.) The insulation of rust, etc., between the
sheets forms a series of short, very thin conductors which
are of high resistance, and hence the eddy currents are
small. An increase of speed makes a great increase in
the eddy currents. The usual loss due to them is about
1½ per cent. of the total power generated.
Fig. 204 shows how the paths for eddy currents are
made long and narrow by using sheet iron.

ARMATURE WINDINGS
425
ARMATURE WINDINGS.
Ring. These windings are very simple to calculate
but hard to place on the core. The method of winding
is shown in Fig. 205.
Fig. 206. Formed Armature Coil.
Drum. The double cotton covered wires are bent into
shape, insulated with linen tape, baked and shellac var-
nished. A number of these formed coils (Fig. 206) are
placed in the slots (Fig. 203) on the outer surface of
the core (Fig. 207, also Fig. 208) and their ends soldered
to the commutator bar lugs (Fig. 209).
Each slot contains two inductors. One side of a coil
is in the bottom of a slot under a N-pole, and the other
side in the top of a slot under a S-pole. This same slot
has in its bottom a second coil, the outer side of which
is in the top of a slot under a N-pole. The first men-

426
96
ELECTRIC RAILROADING
Fig. 207.
Toothed Core with Formed Coil Winding.

ARMATURE WINDINGS
427
tioned coil has its two ends connected to any two adja-
cent commutator bars, and the second coil is connected
in the same manner to two bars on opposite side of com-
mutator.
Commutators. The peculiar shape of the bar (Fig.
210) makes it possible by the corresponding shape of
the hub and washer to draw bar and insulation (mica)
Fig. 208.
Formed Coil Winding Incomplete and Completed.

428
ELECTRIC RAILROADING
together tightly, both side, endwise and downwards,
locking them absolutely in place by a nut bearing against
the washer.
The hub is sometimes keyed to the shaft. This gives
a chance to remove the commutator for repairs by un-
soldering the leads from armature winding.
Fig. 209. Armature Winding connected to Commutator.
A complete armature, i. e., wound core and commu-
tator, is shown in Fig. 211 on a quill ready to be put
on axle or shaft.
The golden copper color of a new commutator soon
changes to a uniformly rich dark mahogany brown, and
its surface acquires a polish. The degree of the polish
and uniformity of the color are indications of the suc-
cess of operation. Any blackening of the bars or rough-
ness of surface shows defects in machine or manner of
operating.
ARMATURE WINDINGS
429
FT WAYNE,
TAPER RINGS
BAND RINGS
SIEMENS - HALSKE.
TAPER RINGS
SLEEVE FOR SHELL "2
EDISON BIPOLAR
BAND RINGS ·
•
TAPER RINGS
2
SLEEVE FOR SHELL
"3
G E. 800
TAPER BAND RING
TAPER Band Ring
NARROW
WIDE
TARER RINGS
FLANGED FLAT RINO
SLEEVE FOR SHELL
*2


WALKER.
TAPER BAND RINGS
TAPER RINGS
SLEEVE FOR SHELL
"
2
3


WESTINGHOUSE
TAPER BAND RINGS
TAPER RINGS
FLAT RINO
SLEEVE FOR SHELL
1871
འ ་་


Fig. 210. Construction of Commutators Showing Hub, Mica and Bar
1

430
ELECTRIC RAILROADING
Brushes of copper or brass in the form of sheets or
folded gauze were formerly much used. In the modern
machines with the losses reduced by clever designing,
more current is drawn, a higher voltage generated and
larger pole pieces used on the same sized armature.
The tendency of the brushes to spark is thereby in-
creased and to offset this high resistance brushes must
be used. Hence the use of carbon brushes is universal.
Where the tendency to spark is not so great graphite
brushes are used.
Fig. 211. Complete Armature.
For mechanical reasons copper rubbing on copper
wears worse than carbon on copper. The abrasion be-
tween two surfaces of same material is generally worse
than two different ones.
Dynamo brushes sometimes set at a slight angle from
being perpendicular to the commutator as they always
revolve in same direction.
For a motor the brushes are set radially against the
commutator, for otherwise it could not be reversed with-

ARMATURE WINDINGS
431
out danger of breaking the brushes. They are pressed
against the bars at about 14 lb. per square inch.
Sufficient area of carbon must be actually touching the
commutator to collect the current at a density of 30 to
40 amperes per square inch.
This total area is divided up into small blocks about
12x2 or 3 inches, and each has its own spring. This
insures that at all times all of the brush surface is in
contact with the commutator.
Fig. 212. Brush Holder.
Brush holders. The holders must clamp the brushes
securely and press them straight against the commuta-
tor, as in Fig. 212. There must be sufficient area of con-
tact between holder and brush, with good pressure so that
the current may pass from brush to holder without pro-
ducing a great CR loss.
The springs maintaining the pressure of the brush
against the bars should not carry current, as they might
heat and have their elasticity destroyed.
The current carrying capacity of the brush holders is
often supplemented by stranded or braided conductors

432
ELECTRIC RAILROADING
of copper, running from the brushes back to the brush
holder cables. These are called "pigtails."
A set of brush holders is mounted on a brush holder
arm or stud.
Fig. 213. Complete Brush Rigging on a D. C. Generator.
The brush holders on opposite sides of the commuta-
tor are not in the same plane, but by having one stud
a little shorter than the other the brushes are staggered.
There is then no part of the commutator not worn
by the brushes, and this together with the float of the
shaft, keeps the commutator a perfectly smooth cylinder
of slowly decreasing diameter as it wears.

ARMATURE WINDINGS
433
An oval, barrel or spool-shaped commutator due to
improper wear must be swung in a lathe and light cuts
taken until it is again of the correct shape. This is
called turning down.
The brush holder studs project from a ring which
slides in grooved arms supported by the bearing pedestal
or by the field frame. They can thus be moved simul-
taneously and set into the position of no or minimum
sparking for full load, then locked in place. See Fig.
213.
Fig. 214. Brush Holder on R. R. Motor.
On railway motors each holder stud is often clamped
temporarily to the field frame or transoms of truck until
the correct position is obtained, when they are bolted
permanently directly against frame or transom.
The ability to change their position simultaneously is
thus lost, but simplicity and reduction of number of parts
and weight is obtained.

434
ELECTRIC RAILROADING
Figs. 214 and 215 show brush holders of railway
motors.
Fig. 215. Brush Holder on a R. R. Motor.
Fig. 216. Set of Brush Holders and Collecting Cables.
In Fig. 216 is shown an arrangement similar to Fig.
213. It is for a smaller dynamo and has no hand wheel
to set brushes, but merely a set screw clamp shown on
left side.

ARMATURE WINDINGS
435
Field coils. The spools in which these coils are
wound are made of brass or bronze, which being non-
magnetic does not cause any leakage through its flanges.
Copper strip or ribbon is used on railway motors and
fuller board or card board insulation between turns. Fig.
199.
To prevent injury to the windings they are usually
wound with a layer of cord or tape. Fig. 217.
Fig. 217. Field Coils taped ready to place on Magnet Cores.
Fig. 218 is a railway motor field coil wound of strip
copper and protected by a layer of cord. In motors
where the field frame is not a shell completely enclosing
the fields and armature protection is furnished to the
coils by brass shells. These are riveted to the flanges of
the field spool.
In the New York Central locomotive two hand holes.
are left, one containing the two terminals of the coil.
Into these holes are poured a hot bituminous insulating
compound, and when cool the covers are screwed on.

436
ELECTRIC RAILROADING
Fig. 218. Field Coil Wound with Strip Copper Insulated with Asbestos.
Fig. 219.
Field Rheostat for Railway Generator.
ARMATURE WINDINGS
437
From transom to transom under the armature is hung
a curved piece of brass to protect it from flying stones
and pieces of iron. Being perforated with 5-16 holes it
does not interfere with the passage of air to cool the
armature.

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Fig. 220. Diagram of Field Rheostat.
Rheostat. In a dynamo an extra resistance, the value
of which is about 25 per cent. of that of the fields, is
placed in series with them, and by cutting more or less
of this field rheostat in or out of the circuit, the field
current is strengthened and weakened and the voltage of
the generator increased or diminished.
At least part of this resistance is always in circuit and
it is so designed as to size of wire and ventilation as to
do this and not overheat.
Fig 219 shows a rheostat for a railway generator,
438
ELECTRIC RAILROADING
The handle projects through the switchboard, while the
resistances made of cast iron are behind the panel. In
Fig. 220 is shown the operation of such a rheostat. The
current enters at 1 and goes through half of the resist-
ance and out at 2. The amount of resistance in circuit
being thus regulated by position of handle.

LESSON 27.
RAILWAY MOTORS.
The main difference between ordinary and railway
motors is compactness and inclosure.
The space that can be given to a motor on a truck is
limited by the gauge of the rails and the size of the
wheels. The gauge being fixed makes this, dimension of
the motor absolutely fixed; so that more room can only
Fig. 221. D. C. Railway Motor, 40 H. P.
be obtained by using larger wheels. A 36 inch wheel
gives none too much room to instal motors which are to
be called on at times to give 200 H. P. The usual car
wheel is 33 inches in diameter.
A railway motor must be completely inclosed to pro-
tect it from dust and flying stones.
439

440
ELECTRIC RAILROADING
Figs. 221 and 222 show inclosure of the motor and
the gear case. The cast steel box which protects the
motor also serves as the field yoke.
This motor has an armature 14 inches in diameter,
the commutator is 104 inches in diameter and is com-
posed of III bars. Motor with gears and gear case
weighs 2730 pounds.
O
Fig. 222. Gear Case end of D. C. Railway Motor, 40 H. P.
The motor in Figs. 223 and 224 is a 60 H. P. motor
built for A. C. work. The armature is 16 inches in di-
ameter and commutator 12 inches in diameter, having
117 bars.
As shown it weighs 4000 lbs. and the gears and gear
case weigh 500 lbs. more.
When mounted on 33 inch wheels there is 43% inches
clearance between bottom of motor and top of rail.
On account of the almost complete inclosure the arma-
ture must be designed to ventilate itself as much as is
possible.

RAILWAY MOTORS
441
Fig. 223. Commutator end of A. C. Railway Mctcr, 60 H. F.
Fig. 224.
Pinion end of Fig. 223.
442
ELECTRIC RAILROADING
The air is usually drawn in at the rear end (Fig.
225) and forced through windings and core by the shape
of the spider, being discharged between commutator
leads and against the pole pieces.
The case of a railway motor is usually split so that
the lower half swings down or in a few instances the
upper part of case can be swung up.

Fig. 225. Method of Ventilating Armature.
Fig. 226 shows the 40 H. P. motor of Fig. 221 with
lower part of case down. By loosening the bearing
bolts the armature can now be lowered into the pit and
removed.
The pole piece and its field coil surrounding it are
shown in the upper half of case.
The 60 H. P. motor of Fig. 223 is shown with upper
part of case removed in Fig. 227. This is a four pole
motor, two of them showing in the part removed. The
brush holders also show in top part of upper case.

RAILWAY MOTORS
443
The four pole pieces are built up of soft steel punch-
ings, riveted together between end plates of wrought
iron and are held to the motor frame by bolts. The
poles project radially inward at angles of 45° with the
Fig. 226. Lower part of Case let down. Same motor as Fig. 221.
horizontal. Two bolts, secured by lock washers, hold
each pole piece in place. They do not penetrate the pole
face but terminate in heavy rivets inside the pole made
for this purpose. A smooth and unbroken pole face is
thus presented to the armature,

444
ELECTRIC RAILROADING
The poles are made with projecting tips, which prop-
erly distribute the magnetic field, and also serve to retain
the field coils, which are held firmly in place by spring
washers. The coils are wound with asbestos-covered
wire. They are heavily taped and are treated with
specially-prepared insulating compounds which render
them practically moisture proof.
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Fig. 227. Upper part of Case on Motor shown in Fig. 223 taken off.
Fig. 228 shows a 50 H. P. motor for A. C. with upper
part of case raised.
There is in railway use to-day in this country practi-
cally only one motor, the series motor. This is used or
D. C. or A. C. with very little difference in construction.
The armature winding for A. C. use being slightly
different, for a separate winding is connected to the
commutator bars called a preventive winding which pre-
vents sparking.

RAILWAY MOTORS
445
In Europe the induction motor supplied with poly-
phase current is used considerably. The necessity for
two or three line wires and double or triple trolleys,
while not so very objectionable, has prevented its use in
this country.
Fig. 228. Upper part of Case Raised on 50 H. P. A. C. Motor.
Box Frame Type of Motor. The rapid development
of inter-urban railways created a demand for a motor of
large capacity, which could be mounted under a car in
a limited space. To meet this contingency was devel-

446
ELECTRIC RAILROADING
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Fig. 229. Parts of a Box Frame Motor.

RAILWAY MOTORS
447
This type
oped the box frame type of railway motor.
of motor differs from the ordinary split frame motor, in
that the magnet frame consists of a one-piece hollow
casting, open at both ends. The armature is inserted in
position from the side, being retained in place by end
plates, which fasten to the field frame. One of the ad-
vantages of the box frame motor is the continuous mag-
Fig. 230. 125 H. P. Box Frame Motor.
netic circuit, which exists throughout the frame. Addi-
tional advantages consist of a long commutator, ample
room for ventilation, and absence of leakage of oil and
water into the motor body. The armature may be re-
moved from the motor frame at one side, obviating the
necessity of employing a pit. Fig. 229 illustrates the
various parts of the box frame type of motor ready for
assembling. Fig. 230 shows a 125 H. P. motor of the
box type.
448
ELECTRIC RAILROADING
The Series Motor.
The series motor is a motor in which the same current
goes through field and armature. It is usually a four pole
motor only two of which have field coils, the other two
being magnets because they are a part of the magnetic
circuit. The poles are short and the coils broad and flat.
The armatures are drum wound. When used on D. C.
the magnet cores may be solid metal, but for A. C. they
must be of sheet iron, as is also the yoke.
The only difficulty in operating such a series motor on
A. C. circuits is the sparking. This is prevented by a
resistance placed between each commutator bar and the
one next to it, and lowering the voltage applied.
These resistances are wound in the armature slots and
are called the preventive winding.
However, to make the motor operate with good ef-
ficiency on A. C. the field coils are actually imbedded in
the iron of the magnet core, and the armature is made
about 10% greater in diameter, revolving also at a greater
number of revolutions per minute.
Such a motor takes only 250 volts A. C. against 500.
volts D. C. It is larger and heavier than its mate de-
signed to run on D. C.
If you will notice the air gap between pole pieces and
armature it is less on the A. C. motor.
The D. C. series motor can exert a greater H. P. to
start a train than the A. C. series motor; and the D. C.
motor will get the train up to full speed quicker than the
A. C.
It is a peculiar thing that all additions to the D. C.
series motor in order to make it equally good as an A. C.
motor also make it a better D. C. motor.
RAILWAY MOTORS
449
If a 200 H. P. motor giving 80% efficiency at 500 volts
increased in size and weight by, the additions and then
run on 300 volts A. C. it will develop nearly 200 H. P.,
but if put back on D. C. again it will develop 275 H. P.
The fact is that a cheap, light D. C. series motor devel-
ops the same horse power as a more expensive heavier
A. C. series motor.
Further an A. C. and D. C. motor of the same size and
weight operate respectively on 225 and 550 volts and give
125 and 240 horse power.
•
The Induction Motor.
It has been known for a long time that there was a
strong repulsion between the coils of a transformer, so
that it was hardly a novelty when a transformer was made
with the secondary built on the inside of a ring yoke and
the primary on the outside of an armature core.
This transformer acted like a motor-in fact it was a
motor. In order to give the motor good starting power
it was wound for and served with three phase currents,
and a resistance wound in with the primary so arranged
as to be cut out after machine was up to speed.
The names armature and field will hardly apply to such
a motor, so that the names Stator and Rotor have been
adopted.
The Stator is the stationary winding whether connected
to outside power or not.
The Rotor is the rotating part.
As usually built the stator consists of a winding pro-
ducing a large number of poles, six and upwards, for the
more poles the slower the rate of speed. The induction
450
ELECTRIC RAILROADING
motor having an inherent tendency to revolve at tremen-
dous speeds according to formula,
Velocity in rev. per min.-60X frequency-number of
pairs of poles,
it will be seen that many poles and low frequency are.
necessities.
The stator being served with two or three phase cur-
rents each pole is caused by the action of two or three
coils. As the current rises and falls in these coils the
magnetism grows and fades away. Hence the point of
the stator where magnetism is greatest is continually
moving around the stator.
Hence we say that it is a revolving field.
The stator winding is continuous and has no connec-
tion with rotor or outside power. The current in it is.
induced by the transformer actions of the rotor.
The rotor is usually a slotted core of sheet iron in
each of which is part of a single conductor coil. These
coils are all connected together at one end and in groups
of two or three; are connected to slip rings through which
current is carried to the rotor windings.
Sometimes the ends of the windings project out of the
slots and have German silver pieces attached to them, a
ring being arranged to slide along the German silver
pieces. To start motor the ring is slid out so that the
winding has a high resistance. When up to speed the
ring is slid in and cuts out the resistance, leaving only
the regular winding in circuit.
For railway work the coils are usually connected di-
rectly to the slip rings and the resistances inserted in the
lead going to the brush. Care must be taken to have
RAILWAY MOTORS
451
these resistances exactly equal and to have them reduced
simultaneously until cut out altogether.
These motors are doing excellent work in Europe, but
to an American the induction motor equipped locomotive
or car seems a huge joke.
In the first place an induction motor runs at one speed
and only one speed. After train is started it runs at 20,.
30 or 40 miles per hour as steady as a clock, up hills,
down hills.
In order to get different speeds four motors are often
used, all being used at low speeds and only two of them
for high speeds. This is so because if the current from
one stator is fed into next rotor, the result is the same
as if one motor of many poles was being used and the
speed is slow, when each motor is being worked inde-
pendently the result is same as one motor of few poles
and the speed is high.
In certain cases two motors having a different number
of poles are used. For slow speed, the rotor of one feeds
stator of second. For next highest speed the motor with
larger number of poles is used alone; and for highest
speed the motor with fewest poles is used alone.
Induction motors have the peculiar property on down
grades of feeding power back into the trolley and thus
assisting the power house to run other trains up the hills.
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​Relation of Flux in Armature and Field of Motor.
It has caused much surprise to the unthinking that a
series motor should continue to revolve when switched
from D. C. to A. C.
Consider the diagram in Fig. 231. Suppose the current
7
452
ELECTRIC RAILROADING
to flow so that the field polarities are as marked. The
armature polarities will be such that near the upper brush
is a N-pole and near the under brush a S-pole, these poles
being directly opposite each other. The top pole of arma-
ture being N, the N-field magnet will push and the S-field
magnet pull, so that armature will begin to rotate in
clock-wise direction.

N
Fig. 231. Diagram of Circuits in Series Motor.
Suddenly reverse the current. All the polarities will
change, but motor will continue to revolve in same direc-
tion.
The left magnet is now S, the top of armature S, and
the right field magnet is N; hence the push and pull of
fields on armature is same as before. Hence a series
motor will run on A. C. circuits, for while the polarities
keep changing the turning effort or torque is always ex-
erted in some direction.
Reversing a Motor. To reverse the direction of a
motor, you must change the direction of the current
through the fields or through the armature, but not
through both. Interchanging the two main leads to a
motor will not affect its direction of rotation. Remember
that reversing the current reverses the polarity.
RAILWAY MOTORS
453
Direction of Rotation of a Motor. In Figs. 232, 233
and 234, A represents the armature core and S. N. the pole
faces. The windings of armature and fields are indicated
by circles, being marked when current flows toward
observer, and when it flows away from him. The
blank circles carry no current.
In Fig. 232 the flux is due to the field coils alone and
the polarity is indicated by the letters S. and N.

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Fig. 232. Field Flux Alone.
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Fig. 233. Armature Flux Alone.
In Fig. 233 we have the flux due to the armature cur-
rent alone, when the machine is driven as a generator in
direction as shown by arrow, producing poles at N' and
S'.
Instead of letting the machine supply electricity, fur-
nish current to it; flowing through armature and fields at
the same time and in the same direction as before. The
polarities will remain unchanged and the armature will
begin to revolve as a series motor, in the opposite direc-
tion to that in which it was driven as a series dynamo.
A shunt motor will rotate in same direction as a motor
or as a generator because when current is supplied to
terminals of machine it runs through field in same direc-
454
ELECTRIC RAILROADING
tion as before, but through armature in opposite direc-
tion. Refer to Fig. 196.
Sparkless Reversing. The conditions when current
flows through an ordinary series motor ready to operate
in a direction opposite to the indication of the arrow are
shown in Fig. 234.
The brushes are, of course, at N' and S' but since they
should be in a line at a right angle to the general direc-
tion of the flux, it is evident that they are not at the place
for sparkless operation.

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Fig. 234. Combined Field and Armature Fluxes.
The magnetic flux takes the peculiar direction shown in
Fig. 234 due to the interaction of the field and armature
fluxes.
Looking back at Figs. 134 and 135 you will see that it
is natural that when these fluxes occur at the same time,
the N' would attract the S flux, and the S' pull the N
flux so that the resultant or machine flux would be as in
Fig. 234.
The stronger the armature flux and the weaker the
field flux the more the machine flux is twisted.
RAILWAY MOTORS
455
If the armature is weak and the field very strong the
effect of the armature will be very slight, or as we say
"the armature reaction is small," and the machine flux
will look like Fig. 232.
In this case the brushes at N' and S' are in the proper
place for sparkless operation.
If the flux were like Fig. 234 upon reversal of the
armature, current the flux would twist in the other direc-
tion, but if the flux were like Fig. 232 the reversal has no
effect.
The machine flux of all railroad motors is like Fig. 232,
so that they may be reversed without any change of
brushes.
}
LESSON 28.
ALTERNATORS.
The main difference already noticed between the D. C.
generator and the A. C. generator, called for shortness'
sake an alternator, is that one has a commutator and the
other a collector.
There are, however, differences in construction which
must be noticed.
The highest voltage for which D. C. generators are
wound is 1200, this being the lowest voltage for which
alternators are wound, while for railroad work 11000 is
the usual and 22000 not uncommon.
This makes the problem of proper insulation for A. C.
armatures more difficult. To make the work easier, in-
stead of having the field stationary and armature revolve
as in most D. C. generators, in alternators the field re-
volves and the armature is stationary.
The field is fed with D. C. at 250 volts pressure and is
easy to insulate even though subjected to the mechanical
strains of rapid motion and the lack of plenty of space.
The armature being stationary there are no mechanical
strains, also weight being no objection plenty of space
can be given to insulation.
This type of construction is shown in Fig. 235 and 236.
Fig. 235 shows a revolving field of 18 pairs of poles or
36 poles. Current is led in through a collector. This
field revolves inside of the stationary armature (Fig. 236)
whose windings are fully exposed to the cooling effect of
}
456

ALTERNATORS
457
the air. This armature needs no collector, for the termi-
nals of the winding are attached to leads which come out
of the base at one side. (In the Fig. at right side.)
Ventilation of the field and armature is accomplished
by means of air ducts as is well shown in Fig. 237.
Fig. 235. Revolving Field of Alternator.
The magnetism in all armatures fluctuates and reverses
in polarity as it passes or is passed by the poles; but in
alternators these reversals of magnetic polarity are much
more rapid than in D. C. machines.

458
ELECTRIC RAILROADING
Fig. 236. Stationary Armature of Alternator.
Air exit
Note: the course of
circulating air through
iron of field cores and
armature
Air exit
A"Ventilating
A A A
Ducts
Air entrance
Air entrance
Fig. 237. Method of Ventilating Alternator with Revolving Field and
Stationary Armature.

ALTERNATORS
459
To prevent the waste of power necessary to magnetize
and demagnetize solid iron at such a rapid rate, not only
is the armature iron laminated but the magnet cores also.
Fig. 238 shows such a magnet core and Fig. 239 shows
the way these cores are attached to the magnet frame or
yoke.
Fig. 238. Pole Piece and Core of Laminated Construction.
The Exciter.
To furnish the field current for all the alternators of a
station two small D. C. generators are used, one being
run while the other is being cleaned or held in reserve.
When storage batteries are in station it is often the
custom to make each exciter of such a size as to carry
continuously three-quarters of the field load.
When station is fully loaded, i. e. all alternators run-
ning, both exciters are run, and when load on station is
light one exciter is shut down. In cases of exciter trou-
ble the storage battery furnishes the field current.
460
ELECTRIC RAILROADING

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о
Field
Coil
A key
Laminated Pole Piece
о
N
Armature
Magnet
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Field
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Two bolts used on
on larger machines
A
Section at
N-N
Fig. 239. Attaching Cores to Yoke.
Single Phase.
The field coils occupy about 50% of the surface of the
field bore, because when their inner edges are tight to-
gether their outer edges are apart due to the larger cir-
cumference at the pole pieces, and because some inter-
ALTERNATORS
461
polar space must be left to prevent excessive leakage from
pole to pole.
Only 50% of the armature bore is wound, for other-
wise the coils would be so wide that they would extend
over into the field of a wrong pole piece. If one side of
a coil is under a N-pole the other side should be under a
S-pole. Then the two E. M. F.'s induced add together.
Should the coil be so wide as to extend over to the next
N-pole any E. M. F. induced by that pole would be sub-
tracted.
There is then on the ordinary alternator half of the
armature empty. Such a machine is called a Single
Phase Alternator.
It occurred to some inventor that an entirely separate
winding could be put on between the coils of the original
winding and be connected to its own collector. The cur-
rent was to be led to a different circuit, but it soon be-
came evident that it was better to make of the four wires
from the alternator a three-wire circuit by joining two
of them inside the armature and leading out three wires
to the switch board. Such an alternator is a Two Phase
Alternator.
Of course the capacity of the machine is not doubled,
because from a single phase alternator is drawn enough
current to heat it to the safe limit. From a two phase
alternator we do the same thing. The reason we gain in
capacity is because in a single phase machine the heating
is concentrated, while in the two phase machine it is
evenly distributed all over the armature.
Even in a two phase alternator there is a portion of
the armature not used for winding and there was still a
desire to reduce the number of line wires. This led to
the Three Phase Alternator.
462
ELECTRIC RAILROADING
The three årmature windings of the alternator, are con-
nected together at one point and the other ends to the
three collector rings or the three windings are connected
in series and the three points where they are joined are
connected to the three collector rings.

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A
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Fig. 239a. 3 Phase Y Connection.
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The former winding is called a Y winding and is shown.
in Fig. 239a. The latter is a A (Delta) winding and
is shown in Fig. 239b. The European names are re-
spectively Star and Mesh windings.
P
R
S

Fig. 239b. 3 Phase Delta Connection.
The three wires of a three phase system each act as a
main wire and a return wire for one of the others at the
same time. The actual current in the wire is the differ-
ence of the two currents: in and outgoing.
ALTERNATORS
463
If the same three phase armature is connected first as
a Y and then as a A winding these differences will be
noticed.
The Y armature will give the higher voltage and have
less current capacity. The ▲ will give a lower voltage
and have greater current capacity. Power that can be
drawn from each is the same.
Transformers and other apparatus are wound two and
three phase, and also Y and ▲ for use with the cor-
respondingly wound alternator.
By a peculiar connection of coils rotary converters are
wound for six phase currents; it having been discovered
that it is possible to do so with the result of increased
output for a given sized machine.
Two, three and six phase machinery is often grouped
under name of polyphase.
LESSON 29.
*
CATECHISM ON DYNAMOS, MOTORS.†
The very brief answers given here may be added to by
reference to the Lessons just studied.
Question I. How is output of dynamo stated?
Answer. In Kilowatts equal to 1000X volts Xamperes.
Question 2. How is output of motor stated?
Answer. In horse power, equal to Watts intake÷÷746,
Xefficiency expressed decimally. (Not as a percentage.)
Question 3. What is voltage of a dynamo? of motor?
Answer. It is the pressure the generator or alternator
delivers at its own terminals. The voltage of motor is
the voltage which should be applied to its terminals in
order to develop full horse power.
Question 4. What is full load current of dynamo?
of motor?
Answer. Full load current of a dynamo is that cur-
rent which may be drawn steady for 24 hours without.
causing any part of machine to exceed a safe temperature,
i. e. 150° Fah. This applies to factory motors.
Of a railway motor it is the current which passing
through motor for one hour as it runs on the blocks in
testing room, will cause it to rise to a temperature of 212°
Fah. We mean, of course, that the hottest part shall be
no hotter than 212° Fah.
*Includes all machines generating electricity, D. C. or A.C.
†Includes all machines utilizing electricity, D. C. or A.C.
464
CATECHISM ON DYNAMOS, ETC.
465
Question 5. What is meant by the rating of a dyna-
mo? Of a motor?
Answer. The product of full load current multiplied
by the voltage expressed in Kilowatts is rating of a dyna-
mo. The actual mechanical horse power developed at
the pinion of the motor as tested in shop. The gearing
increases the power applied to and reduces the speed
of the car wheels.
Question 6. What is armature core?
Answer. The sheet iron body which carries the arma-
ture winding and conducts the flux from pole piece to
pole piece.
Question 7. What is armature spider?
Answer. The casting consisting of hub and arms
which supports armature core.
Question 8. What are binding wires?
Answer. They are narrow bands of phosphor bronze
wire placed around armature every three or four inches
to help bind winding to core. They rest on strips of mica.
and are sweated with solder all around.
Question 9. What are commutator segments?
Answer. The commutator segments or bars are the
copper pieces of which the commutator is built.
Question 10. What are commutator leads?
Answer. They are the ends of the armature winding
extending from core to the lug of the commutator bar.
Question II. What are pole pieces?
Answer. The end of magnet core nearest the arma-
ture. Usually larger than core.
Question 12. What are magnet cores?
Answer. The iron inside the field coil.
466
ELECTRIC RAILROADING
A
Question 13. What is the yoke?
Answer. The part of magnetic circuit connecting the
magnet cores.
Question 14. What is the pitch of an armature wind-
ing?
Answer. It is the number of teeth between the two
sides of a formed coil plus one tooth.
Example: The two sides of a coil are in slots num
ber 3 and 17, then pitch is 14.
Question 15. Is there insulation between winding
and core?
Answer. Yes. Mica or fuller board; there is also the
tape on coil.
Question 16. What insulation is there between con-
ductors of winding?
Answer. The double cotton covering of each wire
makes four thicknesses between conductors.
Question 17. What is the air gap?
Answer. It is the air space between armature and pole
pieces. In dynamos it is made as small as possible for
efficiency.
In motors it is not made too small because this tends
to make machine spark due to the weak field. In D. C.
series motors it is from 1 to 4 of an inch, in A. C.
series motor it is smaller, say 1/10 to 1% inch.
The larger the air gap of a motor the more the bear-
ings may wear before there is danger of armature rub-
bing against lower pole pieces.
Question 18. What are field spools?
Answer. The brass shells on which the field coils are
wound,
1
.
CATECHISM ON DYNAMOS, ETC.
467
Question 19. What is the commutator?
Answer. It is a series of copper bars placed parallel
to shaft, insulated from each other and from the frame
of machine. Each is connected to the winding and cur-
rent flows from winding through them to brushes. It at
the same time reverses the connections between the
brushes and winding at the proper times so that the brush
always collects current.
Question 20. What is a collector or slip rings?
Ansaver. A collector consists of two or more rings of
copper placed around the shaft and insulated from it and
each other. Each is connected to a part of the winding.
The brushes rest on the rings.
They are used to collect current from a revolving
armature style of alternator, to feed current into arma-
tures of rotary converters or the revolving fields of alter-
nators.
The collector has no corrective influence and passes on
the A. C. or D. C. current exactly as it receives it.
Single phase machines have two rings; two, three and
six phase machines have three rings.
Question 21. Is there a difference between no load
and full load voltage of dynamos?
Answer. Yes. A shunt dynamo gives highest volt-
age at no load and lowest at overloads; the series dynamɔ
gives lowest at no load and highest at full load. The
compound dynamo is a combination of series and shunt
and gives some voltage at all loads. Fig. 240 will make
this clear.
An alternator acts like a shunt dynamo.
Question 22. What is a field rheostat?
Answer. It is a resistance in the field circuit which
468
ELECTRIC RAILROADING
can be varied to change the current, and hence the field.
strength. This alters the voltage of dynamo.
Question 23. What are commutated fields?
Answer. In some motors the field coils are arranged
in sections so that they may be arranged in parallel or
series, or in combinations.
All coils in parallel give the greatest current and hence
slowest speed of motor; all coils in series give the weak-
est field and the fastest speed.



Series
Terminal P.D.
Shunt.
Combined
Series and Shunt
External Resistance
Fig. 240. Voltage Curves of Series, Shunt and Compound Dynamos.
Question 24. What relation has field strength to speed
of motor?
Answer. The weaker the field the faster the speed,
for the motor must revolve fast to generate its proper
counter E. M. F.
Question 25. What relation has armature strength to
speed of motor?
Answer. The greater the armature current the greater
the speed.
CATECHISM ON DYNAMOS, ETC.
469
Question 26. What effect on the power of motor does
field and armature strength have?
Answer. The greater the field and armature current
the greater the power.
Question 27. What is a ring winding?
Answer. One which passes over and under around the
core, a space being left between shaft and core to accom-
modate winding.
Question 28. What is a drum winding?
Answer. One where all winding is on the outer sur-
face of core.
Question 29. Upon what does sparkless commutation
of current depend?
Answer. (1) The more commutator bars the better,
there being less voltage and therefore tendency to spark
between bars. The average railway motor has from 100
to 125 bars on commutator.
(2) The fewer the ampere turns on the armature in
comparison to the ampere turns on the field the less
sparking.
(3) The more turns short circuited by the brush when
touching two or more bars at once the greater the ten-
dency to spark.
Question 30. What is a shunt field?
Answer. One whose coils are placed as a shunt.
across the brushes. It carries a small current.
Question 31. What is a series field?
Answer. One which carries the main or nearly all the
main current and is placed in series with the armature. A
small strip of resistance metal is used sometimes to divert
a portion of the main current from the series field.
1
!
LESSON 30.
POWER HOUSES-SUB-STATIONS.
Power Houses.
The power houses or generating stations of our elec-
tric traction systems are nearly all A. C. installations.
This is because the transmission to the trains is done by
all alternating or partly alternating and partly direct cur-
rent. Thus it happens that though trains may be oper-
ated A. C., D. C., or both, the power house is generally
an A. C. plant.
Perhaps the greatest difference between the plants
serving the electric divisions of our steam roads, and
those of the large city systems is size. The city system
plant is apt to be the larger. This occurs because rail-
roads prefer to have several plants strung along the line
so that no point of line shall be too far from a station.
The city systems operating a network of tracks all fairly
near the station, usually rely on one or two big plants.
Another reason is that steam roads coming into elec-
trical operation at recent dates have taken advantage of
the steam turbine, which will make a smaller plant for
same capacity.
Figure 241 shows the comparatize size of the 5000-
K. W. engine-alternator and 5000-K. W. turbine-alter-
nator, both of which are installed in the Interborough
Railroad plant in New York.
470

POWER HOUSES-SUB-STATIONS
471
The large marine engine type, using the revolving ele-
ment of the dynamo as part or all of its flywheel, seems
the favorite engine unit.
Fig. 241. Comparison of Space Occupied by same Kilowatts of Engine
and Turbine Unit.
Figure 242 shows a 2500-K. W., 600-volt D. C. gen-
erator in the plant of the Providence, R. I., city system.
Its actual size can be judged by height of the hand rail-
ing around the pit.

472
ELECTRIC RAILROADING
The Interborough plants in New York are both large.
Fig. 243 shows the set of 5000 K. W., 11,000 volts, 263
ampere, 25 cycle, 3 phase alternators run by 7500 H. P.
marine type engines at 75 revolutions per minute. These
Fig. 242. Engine Generator of 2,500 K. W.
are in the 59th Street plant. The same type of gener-
ator is installed in the 74th Street plant. A view in the
latter plant (Fig. 244) shows the rear of the same kind
of machine as shown in Fig. 243.

POWER HOUSES-SUB-STATIONS
473
The typical turbine-generator plant is shown in Fig.
245. While machines of this illustration are small ca-
pacity (400 K. W.) the lowness of the ceiling is well
shown.
918
Fig. 243. Set of 5,000 K. W. Engine Alternators, Interborough Plant,
New York.
Figure 246 shows a turbine unit of larger size.
Figure 247 shows another turbine plant and Fig. 248.
is a view of a turbine unit installed along side of an en-
gine unit.

474
ELECTRIC RAILROADING
Turbine Generators.
A 1500 K. W. turbine unit is shown in Fig. 249, and
one with a 7500 H. P. turbine and 5000 K. W. alternator
is shown in Fig. 250.
Fig. 244.
Rear view of same kind of Machines as Fig. 243. Inter-
borough Plant, New York.
The stationary armatures of such units are similar
to the engine type, but are small in diameter and longer.
Fig. 251 shows armature of a 1000 K. W., 2400 volt, 2
phase unit, while Fig. 252 shows an armature of a sim-

POWER HOUSES-SUB-STATIONS
475
ilar machine wound for 5000 volts. Viewed from the
interior the armature cores of Fig. 251 look like Fig. 253.
Owing to the high rate of speed at which a turbine
revolves the revolving field is made bi-polar. The one
in Fig. 254 has the lower coils in place, but the upper
Fig. 245. Plant of 400 K. W. Turbine Alternators.
half is not yet wound. These two coils make the field
core a large magnet with opposite polarities at top and
bottom.
The core of a 6000 K. W. revolving field is shown in
Fig. 255 to give an idea of its size.
Beside the large units just described the small turbine
generators are very much used,

476
ELECTRIC RAILROADING
Fig. 246 Turbine-Generator.

POWER HOUSES-SUB-STATIONS
477
477
T
08
Fig. 247.
A Typical Railway Turbine-Generator Plant.

478
ELECTRIC RAILROADING
Fig. 248. 5,000 K. W. Turbine-Generator in Interborough Plant among 5,000 K. W. Engine-Generators.

POWER HOUSES-SUB-STATIONS
479
The little 15 K. W. units of Fig. 256 are installed in
baggage cars for train lighting, and when protected by
a weather proof casing, as in Fig. 257, are installed on
locomotives as shown in Fig. 258.
Fig. 249. 1,500 K. W. Turbine-Alternator.
Fig. 250. 7,500 H. P. Turbine and 5,000 K. W. Alternator.
The motion of a turbine is given to the rotating parts
by jets of steam blowing against vanes, in much the same
way as a water turbine using a very high head of water.

480
ELECTRIC RAILROADING
Their value lies in the high rate of speed, no recipro-
cating parts, ability to work with as high a vacuum as
the condenser pumps can furnish, and the small space
occupied in comparison with engine units,
Fig. 251. Stationary Armature of 2,400 volt Turbine-Alternator.
SUB-STATIONS.
The sub-station, the link between the transmission line
and the trolley wire or third rail, is a thing we would
like to eliminate.
It is an extra building with costly apparatus, needing
skilled attendance.

POWER HOUSES-SUB-STATIONS
481
11111
Fig. 252. Stationary Armature of 5,000 volt Turbine-Alternator.
Fig. 253. Interior View of Armature Core of Fig. 251.

482
ELECTRIC RAILROADING
With A. C. generation and D. C. utilization of power
the sub-station with its rotary converters is a necessity.
Where A. C is used straight through the sub-station mav
be omitted, by having each station fed directly, with a
very high tension trolley wire.
Fig. 254. Rotating Field of Turbine Generator, half wound.
Fig. 255. Rotating Field of 6,000 K. W. Turbine-Generator.
Usually there will be sub-stations containing only
transformers. The 22,000 volt lines will feed these trans-
formers and they will feed the line with some lower

POWER HOUSES-SUB-STATIONS
483
voltage. The scheme of placing costly gnerators di-
rectly on line, running the danger of static and lightning
discharges, seems rather rash.
Fig. 256. 15 K. W. Turbine-Generator for Baggage Car.
Fig. 257. 15 K. W. set with Weatherproof Casing.
When transformers and sub-stations are used the gen-
erators may deliver a much higher voltage, for the trans-
formers step it down later, and the absence of any elec-
trical connection between primary and secondary pro-

484
ELECTRIC RAILROADING
1606
Fig. 258. Turbine-Generator on Locomotive.


POWER HOUSES-SUB-STATIONS
485
tects the generator by absolutely separating it and the
trolley wire.
Fig. 259. A Frequency Changer.
One must remember that in A. C. work each car or
locomotive carries a small sub-station, i. e. a transformer
to lower the line voltage to a pressure suitable for the
motors.
486
ELECTRIC RAILROADING
The A. C. Sub-Station.
One of the great advantages of A. C. traction is the
simplicity of its sub-stations.
sub-stations. They are small brick
buildings containing the transformers for lowering volt-
age, a simple in-coming and out-going switchboard.
The best frequency for motors is a low one, 25 being
now standard. It has been recently proposed to design
systems at a frequency of 15.

Blommer
Oll Switch
Cells
Motor
BUSGE
AC.Converter
Fonel
Outgoing Line
Pand
A.C.Converter
Panel
Fig. 260.
Three phase
||Transformer
Blower Motor Pancis
Reactive Coll
| mich Storting Panel
A.C.Converter
Ponel
Rotary Converter
D.C.Feeder
1 Pandi's
Aanels
Floor plan of a Typical Sub-Station.
Both of these frequencies are rather low for lighting
and transformers are cheaper to build and operate as
the frequency increases.
Railroads by purchase often acquire electric roads
which as a side issue furnish light to some municipality.
They may continue to do this at the desired frequency
from their low frequency plant by installing a fre-
quency charger, Fig. 259.
POWER HOUSES-SUB-STATIONS
487
This consists of two similar machines, one a simple
A. C. motor (called a synchronous motor) and the other
an A. C. generator built much like an induction motor.
It takes in current of one frequency and delivers cur-
rent at another frequency, higher or lower as desired.
The amount the frequency is changed is determined
by the design of the machine and is fixed once for all.
There can be no regulation of the frequency, nor in
fact is that desired; all that is needed is a change from
25 to say 133 and have it keep at 133.

Outgoing Line
Incoming Line
Fig. 261. View of Rear of Station Shown in Fig. 260.
The A. C to D. C Sub-Station,
When D. C. third rail or trolley is used the sub-sta-
tion contains the step-down transformers which feed the
rotary converters, the converters themselves, and the in-
coming A. C. and out-going D. C. switchboards.
The layout of a typical sub-station is shown in Figs.
260, 261 and 262. The first gives a plan of the station
showing position of each piece of apparatus on the
floor. The second gives view of the transformers with
an A. C. panel for each rotary along side of transformer
488
ELECTRIC RAILROADING
on right. On left of middle transformer is the panel
for outgoing A. C., which goes to next sub-station.
The starting resistances and switch for the rotaries
are between the transformers and between the last trans-
former and blower panels.
High up on the wall are the two lightning arresters
and fuses for the incoming and outgoing A. C. lines.
Figure 262 shows an endwise view of the station
which explains itself.

Vorage Detector
Lightning Arrester arsa incoming
Une Disconnecting Switches
Choke Coll
Lightning Arrester
Platform
Current Transformer
SPOIL
Switch
Direct Current Switchba
MC Converter Panel
Fig. 262. End View of Fig. 260.
The sub-station shown in Fig. 263 has one complete
unit in full view. It consists of a 1000 K. W., 6 phase
rotary fed by a set of 3 single phase transformers con-
nected so as to make one 3 phase transformer. These
are air blast type.
At the extreme left is an induction regulator operated
by a small motor on its top. This motor is controlled
from the switchboard. The rotaries in this station are
started from the D. C. side, for at least one rotary is
always running.

POWER HOUSES-SUB-STATIONS
489
Fig. 263. Sub-Station of 6 Phase Rotaries. Surface Roads, New York.
Fig. 264.
Sub-Station, Rotaries with Starting Motors, Pittsfield, Mass.

490
ELECTRIC RAILROADING
Fig. 265. Sub-Station, Utica, N. Y. Street R. R. Syndicate.
Fig. 266. Interborough Sub-Station No. 8. Four 1,500 K. W. Rotaries.
POWER HOUSES-SUB-STATIONS
491
The station of Fig. 264 is a smaller installation of two
300 K. W., 3 phase rotaries. These are started by auxil-
iary motors, for the plant is shut down from 2 a. m. to
4 a. m. daily.
Figure 265 shows two 300 K. W. rotaries with a re-
serve space for another unit. These rotaries have start-
ing motors. The switchboard runs down center of room
and behind it are the transformers.
Figure 266 shows four 1500 K. W. rotaries in Sub-
station No. 8 of the Interborough Railroad.
Figure 267 shows a rotary converter with switchboard.
At extreme rear are the transformers.
Synchronous Motor.
If two similar single phase machines are connected to
a line the one may be driven as a generator and the other
considered as a motor. This motor will not start when
its switches are closed, because the rapid changes of the
armature polarity give impulses to move first in one
direction and then in another; with the result that motor
stands still.
If the motor machine should be revolved by a smaller
motor till it is moving at the same speed as generator,
or slightly faster, when the switches of the motor are
thrown the motor will continue to revolve at generator
speed.
Such a motor will carry any load up to 50% overload
without the slightest change in speed until suddenly it
stops. To get it started again the load must be thrown.
off and the motor brought up to its proper speed by
the auxiliary motor.

492
ELECTRIC RAILROADING
==
V
k
SENERAL ELECR COMPANY
SEETS
Fig. 267. Sub-Station.
POWER HOUSES SUB-STATIONS
493
The D. C. for the motor field is supplied to the motor
from external source. The strength of the field has no
influence on the speed of motor.
The speed is governed by the frequency of generator.
If the generator passes 25 pairs of poles a second then
the motor will also do so. If the generator and motor
have the same number of poles then they revolve the
same number of revolutions per minute. A 32 pole gen-
erator driving a 16 pole motor goes only half as fast as
the motor, for if frequency of generator is 25 the motor
must go twice as fast so as to pass the same number of
pairs of poles a second.
•
C-
D
J K
M

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F
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Fig. 268. Induction Regulator.
Induction Regulation.
If the current going to a rotary passed through an
auto transformer where part of the coil could be placed
in opposition to the rest of it, then we would have an ar-
rangement capable of slightly lowering or raising the
voltage applied to rotary, according as the part of coil
was in series or in opposition to the rest of the coil.
The induction regulator produces the same effect in a
little different way. It is as shown in Fig. 268. It con-
494
ELECTRIC RAILROADING
sists of a primary P. Q. of a transformer across the line
as a shunt and a secondary S. T. in series with one of
the mains.
An iron core E. F. when in this position causes the
flux to pass through secondary and induce an E. M. F.,
which is added to the line, while if turned by the handle
or by motor into position H. G. the flux through S. T. is
reversed and the E. M. F. induced is subtracted from the
line. This transformer carries full current, but induces
so few volts that the power is small. When only 3 or
4% of its own power is lost, it is a very small fraction
of total power delivered to rotaries.

1
t
LINE
THREE COMPENSATORS
(OR ONE THREE PHASE
COMPENSATOR.)
ARMATURE
CONTINUOUS
CURRENT.
COMMUTATOR
COLLECTOR!
RINGS
Fig. 269. Starting 3 Phase Rotary with Compensator.
Starting Rotary Converters.
To start from the A. C. mains as a polyphase motor
the connections shown in Fig. 269 are used.
The line in this case has a compensator attached and
as shown in Fig. 269 the rotary will now receive only a
fraction of the line voltage, and starts at slow speed.
POWER 495
HOUSESHOUSES-
-SUB-STATIONS
As the taps to rotary are moved up the coils the volt-
age is higher until finally the coils of compensator are
cut out entirely and rotary is revolving at full speed,
taking full line voltage.
When transformers are between line and rotary the
same scheme is applied to the secondaries of the trans-
former.
To start from D. C. mains a regular starting set is
used and operation is like any shunt motor.
Synchronising.
When a rotary is up to speed and ready to be con-
nected to the A. C. line, it must be connected at just the
right instant.
This time can be determined by bridging across the
connecting switch some lamps in series.
Both the rotary and the incoming line will be operat-
ing these lamps. As a result they will flicker. As the
right instant is approached the lamps blink slowly until
the change from darkness to light takes one or two sec-
onds; then at the time of maximum brightness or dark-
ness close the connecting switch. The lamps may then
be disconnected.
Two voltmeters can be combined in one case and
made to indicate through a single pointer. When the
line and rotary agree the pointer stands in center of dial.
These are called synchronism indications or synchron-
izers.
By synchronism for two alternators we mean that the
maximum value of the E. M. F. in each machine occurs
at exactly the same instant. They are then in phase, and
496
ELECTRIC RAILROADING
in step and in synchronism. In this condition they run
as generators in parallel.
If they get out of phase sufficiently they will keep in
step and in synchronism but will be in opposition and one
will continue to generate while the other will begin to
absorb power and act as a motor. This is what is meant
by synchronism for an alternator and a rotary converter.,
}
1
LESSON 31.
SWITCHBOARDS.
A knowledge of switchboards and their wiring is of
great value to a power house attendant and of great in-
terest to all the men in operating department.
Switchboards are made up of panels of slate on a
frame of angle iron. Each panel is designed for certain
work so that a description of the different kinds of pan-
els is sufficient.
The first board to consider is the D. C. outgoing line
board, served from D. C. generators.
D. C. Generator Panels.
Fig. 270 shows three generator panels each of which
is regularly equipped from a capacity of 250 to 6500
amperes with
I Carbon break or magnetic blow-out circuit breaker,
with telltale.
I Illuminated dial ammeter with shunt.
1 Hand wheel and chain for operating rheostat.
I Receptacle for voltmeter plug.
I S. P.-S. T. field switch.*
I S. P.-S. T. main switch.
I Recording Watt-hour meter.
*S. T. means single throw.
D. T. means double throw, i. e. the switch has two sets of.
clips and can be thrown into either of them.
S. P. means single pole.
D. P. means double pole, i. e. opens both sides of circuit.
T. P. means triple pole, i. e. opens every conductor of a 3
phase system.
C
497

498
ELECTRIC RAILROADING
น
Fig. 270. D. C. Generator Panels.

SWITCH BOARDS
499
Fig. 271. Rear View of Fig. 270.
500
ELECTRIC RAILROADING
*
A rear view of these panels is shown in Fig. 271.
The best practice puts a main switch at the machine
so that the cables from machines to board may be cut
off from generator. It is also good practice to run the
equalizer cable along in ducts from machine to machine
without carrying it to the board.
This equalizer connects the junctions of series field.
and brush on all machines as shown in Fig. 272; the
shunt coils being omitted to simplify diagram.

Equalizer Wire
Main
Fig. 272. Equalizer.
Main
It is best to place the main switch and equalizer switch
on a pedestal panel as shown in Fig. 273 for moderate
capacity and in Fig. 274 for 4000 ampere (and larger)
machines. The upper switch being the main switch.
The rear view of these large capacity pedestals is shown
in Fig. 275.
A better view of the 4000 ampere toggle operated main
switch is given in Fig. 276. The quick-break S. P.-S. T.
switch is illustrated in Fig. 277.

SWITCHBOARDS
501
The field switch, Fig. 278, has a carbon break. Just
before the switch opens it makes contact with an extra
clip which puts a resistance on as a shunt around the
field coils.
Fig. 273.
Pedestal Panel for
Fig. 274. Main and Equalizer
Switches for Large Capacity..
Main and Equalizer Switches.
Small Capacity.
If this were not done the fields would act like a kick-
ing or spark coil and their insulation be damaged.

502
ELECTRIC RAILROADING
Fig. 275. Rear View of Fig. 274.

SWITCHBOARDS
503
In Fig. 279 is seen the diagram of the panel shown in
Figs. 270 and 271 when capacity is 800 K. W. or under.
Fig. 280 shows the same panel when capacity is larger.
The panel at left is for 1000 and 1200 K. W., the next
Fig. 276. 4,000 Ampere Toggle Operated
Switch. Laminated Main Contact, Carbon
Secondary Contact with Magnetic Blowout.
Fig. 277.
3,600 Ampere
Quick Break Switch.
for 1500 K. W. and over. The cuts on right side show
the back and side view of the 1500 K. W. panel.
The scheme of electrical connections for panel of Fig.
270 is shown in Fig. 281.

504
ELECTRIC RAILROADING
D. C. Feeder Panels.
A set of feeder panels for one feeder each is shown in
Figs. 282 and 283, a panel for two feeders with sepa-
rate switches and one ammeter reading sum of both
currents is shown in Fig. 284, while Fig. 285 has an
instrument and switch for each circuit.

Fig. 278. Field Discharge Switch.

Fig. 286 gives the diagram of these feeder panels and
Fig. 287 gives the electrical connections.
With panels as described the way to throw a gener-
ator in parallel with other generators already running,
the following procedure should be followed:
SWITCHBOARDS
505
First-Close main and equalizer switches (on pedestal
or panel near machine).
Second-Close field switch (on panel).
Third-Close circuit breaker.



88
62
Momt.
EOD
Porac
Type C Form K
Circuit Breaker
Main Bus Bar
-TID Ammeter
Potential Bus Wire Support →
Rheostat Handwheel
Field Switch (on.
Generator Panel only)
Potential Receptacle
Card Holder
Rheostat Chain
nism}
Operating Mechanism
Lighting Switch
Type QB Form A Switch
28"
Recording Wattmeter
Wattmeter Resistance
16 --.-
Fig. 279. Construction of Fig. 270 for Small Capacity.
Fourth-Insert potential plug in receptacle and regu-
late voltage.
Fifth-When the proper voltage is obtained, close the
other main switch (on panel).
506
ELECTRIC RAILROADING

34
Connection to
Bus Bars included
Type C Form K
Circuit Breaker
46
O
28
'46
Lighting
Switch
Type QB
Form A
Switch
28
TID Ammeter
Fotential Receptacle
Rheostat Handwheel
Field Switch
Card Holder
Rheostat Chain
Operating Mechanism
Toggle Brush Switch
Recording Wattmeter
Wattmeter Resistance-
24
24
Fig. 280.
Construction of Fig. 270 for Large Capacity.
กาก กาก



SWITCH BOARDS
507
All the above applies to the distributing of the out-put
of rotary converters, but as they have some peculiarities.
they will be considered later.
Back View.
Negative Bus
Grounded

Circuit Breaker
Shunt
Ammeler
ece
60 Volt Lamps
Voltm
Volt meter
Fuse
Resistance
Lighting Switchg
To Center Stud
of Lighting SwILET
on adjacent Panel
Fuse
Station Lights
ہیری
w
SPST
Plug.
Receptacle
To Alarm Bell
\Potentio
Buses
Field Switch
w
Discharge
Resistance
Switch
Wallmeler
Rheostol
Positive Bus
Equalizer Bus
Lightning Generator
Arrester
Fig. 281. D. C. Generator Panels
Nearly all railroads are operated by a 3 phase station
although the trains are run by single phase A. C. or by
converted power as D. C.
The consideration of 3 phase A. C. switchboards will
cover all the A. C. power houses.

508
ELECTRIC RAILROADING
Fig. 282. D. C. Railway Feeder Panels.
0 N
08

SWITCHBOARDS
509
J
T
Fig. 283. Rear View of Fig. 282.

510
ELECTRIC RAILROADING
$3
Fig. 284. Two Feeder D. C. Panel.
Fig. 285. 1,200 D. C. Ampere Railway
Feeder Panel for Two Circuits.
SWITCHBOARDS
511
A. C. Generator Panel.
The panel in Fig. 288 contains:
I Horizontal edgewise balanced three-phase indicat-
ing wattmeter, arranged for reading both the kilowatts
output and the wattless component.
1 Horizontal edgewise ammeter.
I Horizontal edgewise voltmeter.
I Balanced three-phase induction recording wattmeter.
1 D. P. D. T. potential reversing switch for the indi-
cating wattmeter.
I Four-point receptacle for synchronizing connections.
1 Hand-wheel and chain operating mechanism for
field rheostat.
I S. P. S. T. carbon break field switch with discharge.
clips.
1 D. P. D. T. engine governor control switch.
1 T. P. S. T. oil switch.
I Current transformer for instruments.
2 Potential transformers for instruments.
The functions of the instruments are to indicate the
current, voltage and kilowatts output of the generator,
and the wattless component of the output. For indicat-
ing the wattless component and potential coil of the in-
dicating wattmeter is wired to the potential reversing
switch, which is normally held by a spring so as to con-
nect the instrument up as a wattmeter. By throwing
the switch against the spring into the other position the
potential coil is reversed and the instrument reads the
wattless component, giving a ready means of detecting
512
ELECTRIC RAILROADING
D
00
28
16
62
0
28
28
16
Fig. 286.
Type M Formk
Circuit Breaker
TË I AMMelers
Kicking Coils
·Card Holder
Type QB Form A
Switches
+ Bus Bar
00
Potential BUS
wire support

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от
16
Construction of Figs. 282 and 285.
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SWITCHBOARDS
513
Back View
Positive
Bus
Back View
Positive
Ous
Back View
Positive
Bus
Circuit
Breaker
Shunt
0000
Ammeter
To Alarm Bell
Potential
Bises
Kicking Corl
S.PS.T. Switch
Lightning
Arrester
To Feeder
Ground
Circuit
Breaker
Ammeter
Shunt
eeee
Circuit
Breaker
Ammeter
Shunts
To Alarm Be//
Potential
Kicking Coil
Buses
SPST Switches
0000
oooo.
To Alarm Bell
Potential
Buses
Kicking Coils
& SPST Switches
Ground
To Feeders
Lightning
Arresters
Fig. 287. Three Styles of D. C. Feeder Panels.
Ground
bund
To Feeders
Lightning
Arra sters




514
ELECTRIC RAILROADING
Fig. 288.
A. C. Generator
Panel.
any currents flowing between the alter-
nators which are operating in parallel.
The engine governor switch is to op-
erate the motor which temporarily con-
trols the governor on engine or tur-
bine when their speeds are being altered
to bring two alternators into synchro-
nism or adjusting the division of load
when operating in parallel.
The generator oil switch has no auto-
matic overload release, as it is important
to keep the generator in service during
heavy short circuits caused by trouble
on the transmission lines. When such
short circuits occur, the generators are
immediately relieved by the opening of
the automatic line switches.
The diagrams for connecting up gen-
erator panels according as transformers
are or are not used will be found in
Figs. 289 and 290.
A. C. Outgoing Panel.
The panel on left of Fig. 291 contains:
3 Horizontal edgewise ammeters.
I T. P. S. T. oil switch, with overload
release.
3 Current transformers.
Three ammeters-one for each phase-are furnished.
for each line, to facilitate the detection of unbalancing
due to open circuits or leakage. With balanced loads,
SWITCHBOARDS
515
Case''A*
ATG Panel with Type F Form H, Switch
Case 'B'otherwise os Case A*
ATG Panel with TypeFForm K Switch

Main.
Buses
Couplings
Switches/25 Volt DC Buses
on Oil Switch
Godo
4321
+
Resistance
Terminal Block
on Oil Switch
Resistance
Voltmeter.
Balance 3 Phase
Recording Wattmeter
Synchronizing Buses
Switch
Normally in
Lower Clips
Receptacle
Red Lamp
(Closed)
Switch
To Emergency
Governor on Turbine
Oil Switch Operating
'Buses on Panel
+
Ground Bus.
Green Lamp
(Open)
Ground Bus
Potential
Transformer
Fuses
To Positive Bus
Switch
Rheostat
To Positive
Exciter Bus
Discharge
Resistance
Switch
Starting
Running
Synchronizing Plugs
Alternating
Current
Generator
Connections for
the Engine Governor Control Motor
and Switch when Supplied
Fig. 289.
Indicating
Wattmeter
-ToPositive Exciter Bus
Trip Coil
To Emergency
Governor on Turbine
-Ammeter
Current
Transformer
Bus
A. C. Generator Panel without Step-up Transformers.
516
ELECTRIC RAILROADING
1233-
Case A
ATG Panel with Type F Form H, Switch
Case B'otherwise as Case1"
ATG Panel with Type FForm KSwitch

Main
Buses
Coupling
=
Switches
Resistance
Switch
Normally in
Lower Clips
Ammeter
Voltmeter
Switch-
Green Lamp
(Open)
Receptacle
Red Lamp
(Closed)'
125 Volt D.C.Buses
on Oil Switch
+ Indicating Wattmeter
Terminal Block
on Oil Switch
Wattmeter.
Synchronizing Plugs
Starting
P
Running
Synchronizing Buses
To Emergency
Covernor on Turbine
Oil Switch Operating
Buses on Panel,
Ground Bus
+
Switch
To Positive
Exciter Bus
Trip Coll
To Emergency
Governor onTurbine
ad
Potential
Transformers
Fuse
Main
Transformer
To Positive
Exciter Bus
LO
Rheostat
Current Transformer
To Positive
Exciter Bus
Switch
Connections for the Engine
Governor Control Motor
and Switch when Supplied
Alternating Current Generator
-Bus
ALTERNATING CURRENT GENERATOR PANEL FOR GENERATOR WITH STEP-UP
TRANSFORMER
Fig. 290. A. C. Generator Panel for Generator with Step-up Trans-
former.
↑
1

SWITCHBOARDS
517
0
..
Fig. 291. A. C. Outgoing Line Panels.
the ammeter pointers should show equal deflections
under normal conditions. As the ammeters are ar-
ranged in a perpendicular row any variation in the
deflections of the pointers is readily detected.
518
ELECTRIC RAILROADING
Case A'ATF Panel
with Type F Form H₂ Switch
Case B otherwise as Case ÄATF Panel
with Type F Form K Switch


Switches
Switch.
Ammeters
Terminal Block
on Oil Switch
Current
Transformer
Overload
Relay
Red Lamp
(Open)
Fuses
Switch
Green Lamp
(Closed)
Coupling
Oil Switch operating
Buses on Panel
Outgoing Line
Choke
Coils
Lilig Voltage Detectors
Lightning
Arresters
Fig. 292. A. C. Outgoing Line Panel.
Trip Coils

SWITCH BOARDS
519
The current transformers serve to operate the am-
meters and the automatic release on oil switches.
The panel on right of Fig. 291 has but one ammeter
and merely has the handle for operating the oil switch.
The actual switch being in a brick compartment at rear
of panel. The overload relay (3 pole) which trips the
oil switch is at base of panel.
Fig. 292 gives the electrical connections of panels in
Fig. 291.
Fig. 293. Synchronism Indicator and Exciter Voltmeter on Swinging
Bracket.
The swinging bracket of Fig. 293 contains a syn-
chronism indicator, two lamps for synchronizing (prac-
tically a duplicate set of synchronizers) and a voltmeter
for the station exciter *generator.
To use the synchronism indicator put one plug in on
panel of a generator which is running and the other
plug in the panel of the generator which is starting.
*D. C. Generator furnishing current for fields of alternators.

520
ELECTRIC RAILROADING
0
Fig. 294. Main Station Switchboard for One A. C. Generator and
One Outgoing Line.
Fig. 294 shows a complete switch board of one gen-
erator panel in center, a panel for one outgoing line on
the right, an excited panel on left, with the swinging
bracket on extreme left.

SWITCHBOARDS
521
Such a switch-board would be extend-
ed towards the right indefinitely, as
more lines were put on the station, by
the addition of more outgoing line
panels.
Exciter Panel.
Each exciter panel is equipped with:
I Thomson feeder type ammeter.
1 Hand-wheel for operating rheostat.
1 Two-point potential receptacle con-
nected to voltmeter.
1 S. P. S. T. positive lever switch,
with fuse mounted back of panel.
One Exciter Panel in every switch
board is furnished with the following
additional switches: (as in Fig. 295.)
2 S. P. S. T. lever switches, with
fuses back of panel, for the control of
station lighting and auxiliary circuits.
On the frame of each exciter there
are required the following switches,
mounted on a common slate base:
I S. P. S. T. negative lever switch.
I S. P. S. T. lever switch for equaliz-
ing.
0
Fig. 295, Exciter
Panel Auxiliary
Lighting Switches
on Sub-Base.
The exciter panels are designed single
pole, i. e., only the positive leads of the
generators are connected to the switch-
board panels and only the positive
mounted back of them. The negative and equalizer
leads are connected through their switches to the nega-
bus-bar
is
522
ELECTRIC RAILROADING

Voltmeter
125 Volt DC.Buses
on Oil Switch
Instrument
Exciting Bus
Shunt
Fuse
Dotted Leads to be Furnished
for only one Panel in
each Station
Fuse -
To Station
Lights
I
This Fuse and Switch
to be Furnished ·
by Customer'
plugi
Switch
Fuse
+
Bus
Oil Switch
Operating Buses
on Panel
+
"Potential
Buses
Receptacle
+1
Rheostat
To Generator
Field Rheostat
Exciter
Fig. 296. Exciter Panel.
Buses

SWITCHBOARDS
523
tive and equalizer bus-bar, which are placed under the
floor near the exciters. With the bus-bars of opposite
polarity so widely separated there is practically no
chance of short circuit of the exciter connections. The
positive field leads of the alternators are carried to the
panels, while the negative field leads are permanently
connected to the negative exciter bus-bar.
Fig. 296 will give the electrical connections of an ex-
citer panel.
Fig. 297. Starting Panel
for D. C. Blower Set.
Fig. 298. Main Switch Panel
for A. C. Blower Set.
The blower motors running the blowers which cool
transformers are of the 3 phase induction type or D. C.
shunt motors.
The D. C. motors are started by the regular starting
box, Fig. 297.
524
ELECTRIC RAILROADING
The current to an induction motor is controlled by a
switch like Fig. 298, if from auxiliary low voltage buses
or from an oil switch on a panel like Fig. 299, if full
station voltage is used.
The actual starting is done by a switch as in Fig. 300,
which is between secondaries of transformers or react-
ance coils and the induction motor.
Fig. 301 shows connections of an induction motor
to main buses, using an oil switch and a starting switch.
The operation of several sub-stations on a single line
is generally recognized as good practice, especially for
interurban systems on which the traffic is not very
dense.
To insure continuity of service in the event of line
trouble, it is expedient to sectionalize the line at every
sub-station that is located at an intermediate point of
the line. This sectionalizing is accomplished at each
intermediate station by carrying the incoming line to
the bus-bars through the air break disconnecting
switches which are installed in connection with the ar-
resters, and by carrying the outgoing line through an
oil switch. In case of line trouble, this arrangement
allows all sections of the line between the generating
station and any section on which the trouble occurs to
be operated continuously. The power is automatically
cut off from the section in trouble by an oil switch in
the outgoing line panel equipment of the sub-station at
the generating station end of the section, so that the air
break disconnecting switches in the sub-station at the
other end of the section need never be opened under
load.
When duplicate transmission lines are used, two in-
SWITCHBOARDS
525
coming line panels and two outgoing line panels are.
recommended for each intermediate sub-station. The
installation of these individual panels facilitates the dis-
connection of either line of any section and the continu-
ance of the service over the other line of the section'
without any interruption.
L
The arrangement of switchboard panels in sub-sta-
tions differs from the generating station arrangement,
in that the alternating current panels are, preferably,
installed individually near their several line or trans-
former oil switches, thus greatly simplifying the high
tension wiring and the oil switch operating mechanisms;
while the continuous current panels are grouped into
a single switchboard conveniently located. The loca-
tion of the alternating current panels, transformers, oil
switch cells, continuous current switchboard, and ma-
chines, as shown in Figs. 260, 261 and 262, is suitable.
for a 13,200 volt 3 phase sub-station.
Standard sub-station line panels are equipped as
follows:
A. C. Incoming Line Panel.
These are only used when lines are in duplicate, and
are shown in Fig. 299.
A. C. Outgoing Line Panel.
These are necessary in every sub-station except the
terminal one. This panel is shown on left of Fig. 291.
The ammeter on incoming panel must be able to show
all the current ever drawn by its own sub-station and
those beyond. The capacity of the three ammeters on
any outgoing line panel, however, need only be large

526
ELECTRIC RAILROADING
Fig. 299. Oil Switch A. C.
Panel for Incoming Line
Motor Driving Exciter or A. C.
Side of Rotary.
Fig. 300. Induction Motor
or Rotary Starting Panel.
SWITCHBOARDS
527
Case A*
Case B otherwise as Case 'A'
ATI
ATI Panel with Type F Form H, Switch ATI Panel with Type F Form K Switch


23
Main
Buses
=
Switches
125 Volt DC Buses
on Oil Switch
+
Trip
Coil
Switch-
Ammeter
Overload
Relay
Fuses
Switch
~327
Terminal Block on
Oil Switch
Current Transformer
Red Lamp
(Closed)
Green Lamp
(Open)
Oil Switch
±Operating Buses
on Panel
Main Transformer
Switch
Induction Motor
Fig. 301. Induction Motor Panel.
}
528
ELECTRIC RAILROADING
enough to read the maximum load on the line beyond
the sub-station in which the panel is installed. As al-
ready stated for the outgoing panels of the generating
station, three ammeters are furnished in order to indi-
cate, by their unbalanced readings, any open circuit
leakage on the outgoing line.
A. C. Rotary Converter Panel.
The panel controlling the intake of the rotary is shown
in Fig. 291 (on right). It contains:
I horizontal edgewise ammeter.
1 T. P. S. T. overload relay for oil switch.
I current transformer.
Three-Phase Rotary Starting Panels.
In Fig. 300 is shown this panel. The switch is used
for starting the converter by connecting two of the three.
converter leads, first to half-voltage taps and then to the
full voltage terminals of the transformer. The third con-
verter lead is permanently connected to the third termi-
nal of the transformer.
Six-Phase Rotary Starting Panels.
As shown in Fig. 302 contains 2 T. P. D. T. lever
switches.
These switches are used for starting the converter by
connecting three of the six converter leads, first to one-
third voltage taps, next to two-thirds voltage taps, and

SWITCHBOARDS
529
finally to the full voltage terminals of the transformer.
The other three converter leads are permanently con-
nected to the remaining three transformer terminals.
Position of Panels.
The A. C. incoming line panels are connected between
the high tension bus-bars and the three-phase primaries
of the step-down transformers, and are, therefore, suit-
able either for three or six-phase converters. Convert-
Fig. 302. Six-Phase Rotary Starting Panel,
ers of capacities up to 400 kilowatts are usually three-
phase, and above that capacity, six-phase. The sec-
ondaries of the transformers are not carried to the main
switchboard but are connected through separately mount-
ed starting panels to the converters. The dimensions of
rotary converter starting panels vary with the capacity

530
ELECTRIC RAILROADING.
Fig. 303. Rotary
Output Panel.
Fig. 304. D. C. Feeder Panels.
SWITCHBOARDS
531
of the converters, but they are of suitable size for mount-
ing near the latter. In most cases where compound
wound converters with reactive coils are used, the coils
are connected between the transformer secondaries and
the converters, and the starting panels are mounted on
top of the reactive coil casings.
Rotary Output Panels.
These panels are the same as D. C. generator output
panels and are shown in Fig. 303.
The circuit breaker is furnished with a low voltage
release coil, which trips when the voltage drops to ap-
proximately half of its normal value, and with a tell-
tale switch, for connection to an alarm bell which will
ring when the breaker opens automatically. To prevent
racing of the converter caused by accidental disconnec-
tion on the alternating current side, an adjustable speed
limiting switch is mounted on the converter shaft. This
speed limiting switch operates to short circuit the low
voltage release coil when the speed of the converter in-
creases a certain degree above normal, thereby tripping
the breaker and disconnecting the converter from the
continuous current bus.
The continuous current rotary converter panel is con-
nected in the positive side of the circuit, and the nega-
tive side is permanently connected to the grounded nega-
tive bus, which is run along below the machine. The
equalizing switch, and the switch for opening the shunt
to the series field, required for a compound wound ro-
tary converter, are mounted directly on frame of
machine.

532
ELECTRIC RAILROADING
The advantages of equalizing on negative side and of
using single pole switches has been discussed under gen-
erators.
D. C. Outgoing Line Panels.
The panels for one and two circuits are shown in
Fig. 304.
Fig. 305. Voltmeter Bracket.
Placing Rotaries in Service.
After a rotary converter has been started from the
alternating current ends and builds up with the proper
polarity, the following procedure should be followed to
throw the direct current end in parallel with other ma-
chines running:
First-Close equalizer switch (on machine).
Second-Close circuit breaker (on panel).
Third-Insert potential plug in receptacle and regulate
voltage.
Fourth-When the proper voltage is obtained close
positive switch (on panel).

SWITCHBOARDS
533
Swinging Bracket for Voltmeter.
As shown in Fig. 205 a swinging bracket is provided
to be mounted at end of board, carrying:
I Thomson illuminated dial station type D. C. volt-
meter.
ON
Fig. 306. Storage Battery Panel.
I plug for insertion in receptacles on the rotary out-
put panels, thus connecting the voltmeter to the particu-
lar machine.
534
ELECTRIC RAILROADING
If the rotary when started from the A. C. side comes
up with polarity reversed, the voltmeter will swing back
of zero.
The polarity of the converter can be corrected by oper-
ating the four pole double throw field break-up revers-
ing switch, which is mounted on the frame of the con-
verter and included in its equipment. This field revers-
ing switch stands normally in its "up" position, and the
operation of throwing it into the "down" position re-
verses the field magnetization. When the voltmeter
needle indicates that the throwing of the switch into the
"down" position has established correct polarity, the
switch should immediately be thrown back into the "up"
position, thereby connecting the field correctly for
service.
1
The operation just described should be performed
while the alternating current side of the converter is
connected to the low voltage taps of the transformer.
When the voltmeter indicates the correct polarity, the
converter may be connected to the full voltage terminals
of the transformer. The continuous current voltage may
then be adjusted by means of the field rheostat, and the
machine thrown on the continuous current bus.
When motor operated oil switches are installed in the
sub-station, a storage battery is used as a source of
power for the small 110 volt series motors which operate
the switches.
The storage battery consists of:
55 cells, giving 110 volts, the type and capacity of the
cells depending upon the number of switches to be op-
erated.
1
SWITCHBOARDS
535
Case AATF Panel with
CaseB ATF Panel with
Type FForm K Switch
Type FForm H, Switch
Coupling
=
Case C
Incoming Line Without Panel

Main
Buses
Switches
125 Volt DC Buses
Grounded Bus
Switch
Trip Coil
Ammeter
Current
Transformer
Overload
Relay
Red Lamp
(Closed)
Fuses
GreenLamp
(Open)
Switch
Oil Switch operating
Buses on Panel
togget
on Oil Switch
+
Grounded
Terminal Block on
Oil Switch
+1
Incorning Line
ไฟฟ
888
Voltage
Detectors
Switches
Choke
Coils
Lilili
66
66
"CRRIDO OPLO (
afood
Lightning Arresters
Fig. 307. Outgoing A. C. Line Panel.
Libili
-Hip o oko o
အစော
536
ELECTRIC RAILROADING
Case 'A' ATP Panel for ▲▲ Connected
Transformer withTypef Form K Switch
33
Potential
Transformer
=
Case B
Otherwise as Case A, ATR Ponel
For YA Connected Transformer
with Type Fform K Switch
Main Buses
Coupling
Case'c"
Otherwise as CaseA ATR Panel
For AA Connected Transformer
with Type F Form H, Switch

Switches
Ground Bus
Potential
Transformer Bus
た
​125 Volt DC Buses on
Oil Switch
Grounded
Trip Coil Switch-
Voltmeter Ammeter
Current Transformer
Resistance
Synchronizing Buses
Synchronizing
Receptacle-bob
Splug
Main Transformer
Switch
Red Lamp
(Closed)
Fuses
GreenLamp
(Open)
سد
Overload
Reloy
-Fuses
ToNext Transformer
+1
Terminal Block
on Oil Switch
Oil Switch
Operating
Buses on Panel
Reactive Cails 888
To Blower Motor
Synchronizing Connections (Shown Dotted) for Rotaries.
Started from 0.C. End or by Induction Motor
Rotary Converter
Fig. 308. A. C. End of Three-Phase Rotary.
SWITCHBOARDS
537
2
Storage Battery Panel.
As shown in Fig. 306 contains:
I Thomson feeder type ammeter, with zero at center
of scale.
I Rheostat.
2 S. P. S. T. quick-break switches.
2 enclosed fuses.
The battery is charged by connecting it in series with
the rheostat across the 600 volt bus-bars. The rheostat
is provided with a dial switch for regulating the charg-
ing current.
Blower Motor Panels
Are required for controlling the induction motor
blower sets, which are used with air blast transformers.
Each panel, as shown in Fig. 298, contains:
I T. P. D. T. lever switch.
3 enclosed fuses.
The motors are usually wound for 350 volts, and are
operated from the secondary side of the power trans-
formers. The panels are located near the blowers.
As the transformers are not connected in parallel on
the low tension side, the double-throw switch is fur-
nished for connecting either of the duplicate blower
motors, which are usually furnished, to whichever bank
of transformers happens to be in use, as already de-
scribed for the generating station,
538
ELECTRIC RAILROADING
CaseA
AHR Panel with Type Fform K Switch
2
3
Fuses
WPotential
Coupling
Case B otherwise as CaseA
AHR Panel with Type F Form HSwitch

Main
Buses
Transformer
Potential Transformer Bus
125 Volt DC Buses
on Oil Switch
Grounded
Voltmeter!
Ammeter
-Switch
Resistance
Receptacle
Potential
Transformer
Fuses
Current Transformer
Synchronizing Buses
89
Synchronizing
plug
Red Lamp(Closed
Overload
Relay
Switch
Fuses
Fuse
Switches
{གམ་
Terminal Block on
Oil Switch
Green Lamp (open)-
+
Oil Switch Operating Buses on Panel
Main Transformer
Reactive Coil
-Two TP.DT Switches
·Synchronizing Connections (Shown Dotted)
for Rotaries Starting from D.C. End
Switch
To Next Transformer
Fuses
To Blower Motor
Rotary Converter
Fig. 309. A. C. End of Six-Phase Rotary.
1
SWITCHBOARDS
539

Low Voltage
Release
Bus
Battery. Bell and
Connections to be
Furnished by Customer
Tell Tale
Circuit Breaker
Resistance
Voltmeter
Ammeter
Shunt
Low Voltage
Release Bus
ToLower Studs
of Main Switches
21, 22,
*Switch
Potential Buses
Plug
Receptacio
Station
Lights
Resistance
Lightning
Arrester
Recording
Wattmeter
t
Dotted Leads to be furnished
for only one Panel in each Station
Rheostat
Speed Limit
Device
Bus (Grounded)
Fig. 310, Rotary Output Panel,
=Bus
1
540
ELECTRIC RAILROADING

Switche's
fuse
Rheostat
•10
Ammeter
}
Battery
Bus 600 Volts
To 125 Volt Oil Switch
Operating Buses
7
Bus (Grounded)
Fig. 311. Storage Battery Panel,
SWITCHBOARDS
541
Electrical Connections of Panels.
A. C. incoming lines are shown in Fig. 307.
Connections for a three-phase rotary high voltage
panel, low voltage starting panel and blower motor panel
are shown in Fig. 308, while similar panels for six-phase
rotaries are shown in Fig. 309.
Feederwith One Ammeter TwoFeeders with Two Ammeters Two feeders with One Ammeter


Battery, Bell and Connections
to be furnished by
Customer
Bus
Circuit
Creaker
Tell Tale
Ammeter
Shunt
&
Kicking Coil
Switch
Lightning Arrester
}
eeee
Potential Bus
To Feeder
Fig. 312. D. C. Feeders.
The connections of a rotary panel are given in Fig.
310.
The storage battery panel is shown in Fig. 311.
D. C. feeder panels are connected as shown in Fig. 312.
;

LESSON 32.
DETAILS OF SWITCHBOARD EQUIPMENT AND STATION
ACCESSORIES.
Lever Switches of type shown in Fig. 313, are used
only to close circuits. When used to open circuits the
Quick Break type is used, shown in Fig. 277. Half
Fig. 313. Knife-blade Lever Switch.
the blade comes out of the clips when the handle is drawn
back. This stretches the spring and the tension finally
pulls the other half of blade out of clips at great speed,
thus preventing much arc.
542
SWITCHBOARD EQUIPMENT
543
Field Discharge Switches, Fig. 278, are furnished only
on the alternating current generator panels, and as they
must be relied upon to shut down the generators under
emergency conditions they embody several features of
importance. As stated in the description of the generator
panel equipment, the field switches are single pole and
are furnished with clips for connecting a discharge re-
sistance across the field when the latter is disconnected
from its source of excitation, thereby preventing the
generation of an excessively high potential, which might
puncture the field insulation, when the field circuit is
opened. The construction is such that in opening the
switch the resistance circuit is closed before the field is
disconnected from the exciter, while in closing the switch
the resistance circuit is opened before the field is con-
nected to the exciter. By this means all destructive
arcing is avoided, for the field can never be broken with-
out shunting it through the discharge resistance, yet the
latter is not even momentarily connected across the ex-
citer bus-bars while the switch is being closed.
Oil Switches. The severe conditions which must be
anticipated on railway systems demand the use of
switching apparatus which will protect the machines and
lines from excessive overloads and short circuits with-
out injury to the switches, as the latter must be in con-
dition to put the machines back into service as soon as
any temporary trouble has been remedied.
These re-
quirements are best met by reliable oil switches, properly
installed in brick cells situated apart from the switch-
board to prevent any local trouble from spreading.
In case of a dead short circuit on a feeder near the
generating station, the current in the circuit which must
33

544
ELECTRIC RAILROADING
be opened reaches a maximum the value of which may be
many times the normal capacity of the generators. The
automatic feeder switches must be capable of breaking
this maximum current instantaneously. The non-auto-
matic switches, on the other hand, are not required to
HOU
Fig. 314. Front View of Oil Switch.
open the maximum current, but must be capable of open-
ing the load after the current has dropped to a value
which the generator will maintain on short circuit.
Figs. 314 and 315 show the operating handle and the
switch mechanism of a three pole oil switch.
A triple pole double throw oil switch for panel use is
shown in Fig. 316.

SWITCHBOARD EQUIPMENT
545
It is often desired to have the switch at some distance
from the panel on which it is controlled.
Fig. 315. Rear View of Oil Switch.
In Fig. 317 is shown a triple pole single throw 15,000
volt 300 ampere oil switch. It would be very unsafe to
have this on the switchboard,

546
ELECTRIC RAILROADING
It is built into a three compartment brick cell at
some distance behind board and controlled by a long rod
running from lever on panel. This switch is of the
non-automatic type, being used for a main generator
switch.
SH
Fig. 316. Three Pole, Double Throw, Oil Switch.
Such switches, when used on transformers, are so far
from the panel that some arrangement as in Fig. 318
is used.
Switches at a distance from the board may be con-
trolled electrically if fitted with a tripping magnet and

SWITCH BOARD EQUIPMENT
547
closed by sending an attendant to the switch. This is
very bad practice, as the time wasted and even possi-
bility of closing wrong switch must be considered. The
switch in Fig. 319 is operated by two magnets, the left
hand one (not clearly shown) opening, the right hand
one closing, switch. A small S. P. D. T. switch on panel
Fig. 317. Oil Switch 15,000 Volt, 300 Ampere Triple Pole, Single
Throw. Brick Partitions Not Shown.
controls the two magnets. Large switches, as Fig. 320,
are opened and closed by motors. For such a motor
switch there will be on the panel:
1 S P. D. T. operating switch for the control of the
oil switch motor.
548
ELECTRIC RAILROADING

-36′4″.
420-
2078"
!
Fig. 318.
Arrangement of Remote Control Lever Oil Switches.
304:
776*.

SWITCHBOARD EQUIPMENT
549
2 miniature lamps, one with red and other with
green bull's eye.
If the switches must open automatically there is pro-
vided in addition to the above:
I overload relay.
Fig. 319. Magnetically Operated Oil Switch.
The lamps with bull's eyes are controlled by an auxil-
iary switch attached to the operating mechanism of the
oil switch. The opening of the oil switch lights up

550
ELECTRIC RAILROADING
Fig. 320. Motor Driven, T. P. S. T. 13,000 Volts 300 Ampere Oil
Switch in Brick Cell.
SWITCHBOARD EQUIPMENT
551

Door
Operating Mechanism
Soapstone or Slate
ToGenerator or Feeder
-Copper Tubing
Disconnecting Switch
Concrete Slab
Bus Bar
Bus Bar Support
Fig. 321. An Arrangement of 13,000 Volt Buses and Oil Switches.
Very Little Floor Space Required,
552
ELECTRIC RAILROADING
the green bull's eye, and its closing lights up the red
bull's eye, assuring the attendant that the throwing of
the controlling switch has been followed by the proper
operation of the oil switch.


1
Fig. 322. A More Compact Arrangement Than Fig. 321. Needs More
Floor Space.
When the current in the main circuit exceeds a pre-
determined value the overload relay closes a continuous.
current circuit, thereby tripping the oil switch.
Under some conditions, however, it is desirable to de-
lay, for a certain length of time, the opening of the
switch under its predetermined overload. To accom-
SWITCHBOARD EQUIPMENT
553
plish this result the overload relay is equipped with a
time limit device.
As already stated, all high tension oil switches should
be mounted in brick cells situated apart from the
panels.

Fig. 323. Arrangement Similar to Fig. 322 When More Space is
Available.
The bus-bars, disconnecting switches and oil switches,
need not only good insulation but separation. Fig. 321
shows one way of handling a 13,000 volt set. Fig. 322
shows side and rear view of another scheme and Fig. 323
still another way of placing them.
Field Rheostats being of such large size the arrange-
ments shown in Fig. 324 are often necessary. In Fig.
318 the rheostat is on floor below.
554
ELECTRIC RAILROADING
Cable Connections. In order to connect large cables.
to the bus-bars, instrument, and machine terminals, the
cables are split and the parts soldered into lugs. Fig.

Wood
Slate
Braces so located as
to support the slate Slabs
Fig. 324. Mounting and Control of Field Rheostat.
325 shows how five of these lugs can be placed on a stud
so as to occupy as little end room as possible.
The Voltage Detector, Fig. 326, is a static device hav-
ing a movable element which is set in rotation when it is

SWITCHBOARD EQUIPMENT
555
subjected to the line potential. A detector is attached to
each conductor of every line, on the line side of the dis-
connecting switch. A complete set, therefore, consists
of three detectors for each line. This device also serves
as a ground detector, as its moving element will come to
rest when a ground occurs on the conductor to which it
is connected.
Fig. 325. Clamping a Five
Terminal Cable to Panel Stud.
Fig. 326. Voltage Detector, for
Circuits up to 15,000 Volts.
Three Single-Pole Double-Blade Disconnecting
Switches (Fig. 327) are placed in each incoming and
outgoing line, one switch in each conductor. One blade
is used for disconnecting the lightning arrester from
the line, while the other blade is used for disconnecting
the station from the line. Choke coils also are recom-

556
ELECTRIC RAILROADING
mended for connection in series with the line between
the arrester taps and the switchboard in order to protect
the station apparatus. The arresters, switches and choke
coils are designed for mounting on the wall at the point
Fig. 327. 13,000 Volt, Three-Phase Lightning Arrester.
where the lines enter the station. The switches may be
furnished either front or back connected, and are mount-
ed on slate bases and provided with heavy corrugated
glass insulators for the switch studs. The blades are not
SWITCHBOARD EQUIPMENT
557
provided with handles, but have holes in the ends to en-
able them to be operated by a hook mounted on a long
wooden handle.
med'urn Resistance
Low Resistance
Fuse
Spark Gop
wwwwww E

High Resistance
тераграглаграпрамал
Mg Gmg
Fig. 328. Diagram of Multigap Graded Shunt Resistance, Three-Phase
33,000 Volt Arrester.
Arresters. In Fig. 327 is shown a 13,000 volt 3-phase
arrester with disconnecting switches. This is the older
type, but is the kind in most stations.
558
ELECTRIC RAILROADING
In Figs. 328 and 329 are given diagrams of the con-
nections of the newer graded shunt resistance type of
arrester.

Spark Gap
High Resistance
LowResistance
Medium Resistance
мамамамали
M
GL
GM
GH
Gs
терилилили
Fig. 329. Arrester Similar to Fig. 328 Arranged for Y System with
Grounded Neutral.
In all these note the connections between line and
line, besides the line and ground connections.
"
LESSON 33.
TRANSMISSION LINES, FEEDERS, TROLLEY AND THIRD
RAIL.
The transmission line from power house to sub-station
or point of feeding into trolley or third rail is usually a
pole line.
With high voltages the use of iron poles along the
right of way is becoming standard practice. Such a pole
is shown in Fig. 330.
From the thickly settled parts of cities and at terminal
stations the transmission line should be excluded; but
the feeders must be carried underground.
This is done by running insulated cables in ducts. Fig.
331 shows cables supported on side wall of tunnel; Fig.
332 shows ducts for cables in side wall of tunnel or a
station; Fig. 333 showing these same ducts arranged
under platform of station.
The pole line is of bare wire, copper or aluminum,
supported on porcelain or earthen ware insulators.
Fig. 334 shows a 50,000 volt insulator of three separate
pieces of porcelain cemented together. It is II inches
high and weighs 27 pounds. The distance the voltage.
would have to jump to get to pin or cross arm is 8½
inches.
A 60,000 volt porcelain insulator of four pieces is
shown in Fig. 335, while Fig. 336 shows a 75,000 volt
three piece porcelain insulator, 15 inches high, weight
40 pounds, with a sparking distance of 11 inches,
559
560
ELECTRIC RAILROADING
7'0"
----
■9,12
Parabolic Curve
Section A-A
i 12:4 Concrete
with 1' Finish
of 1:2
5′0″ ---
"Bolt.
Malleable Iron

6"x5" Yellow Pin e
(6x5&Yellow Pine.
6'x5' Timbers, Dressed
to 5¾ x4¾¾
4-3"x3 L
*1/0
6x5"Yellow Pine,
Sa
"Hole
In each
Concrete
1:4.7
Top
of Foundation 6'aborè
Base of Rail in Cut
Top of Foundation 6"
below Base of Rail on Fill.
звон
No.3 Annealed Solid Copper
Wire Connection to Ground
Elevation

5'0"
Plan
ר
Fig. 330.
Transmission Line Pole. New York Central R. R.
TRANSMISSION LINES
561
When cables are used the voltage is usually lower and
glass may be used. Fig. 337 is a glass insulator for
cables carrying a pressure of not over 10,000 volts.
Iron pins are used now, as shown in Fig. 338, because
the distance the arc must jump is increased by use of
a porcelain covered iron pin. Fig. 339 shows the spark-
ing distance with wood pin, and Fig. 340 the increase
with porcelain covered iron pin.
Bolted to Flange
Tunnel Segment
Section of
Cable Support & Shield
Iron
Shield
Fig. 331. Cables Supported on Side of Tunnel.
:

1
Fig. 341 shows a pin ready to be put straddle of a
pole top and Fig. 342 shows an iron pin adapted to bolt
on the side of the pole. The porcelain cover has not yet
been attached to this pin.
The sparking or arcing distance on an insulator is
estimated by imagining a rain storm coming at an angle
of 45° and thus conducting the electricity from top um-
brella or petticoat to the pin sleeve as in A, Fig. 343-
562
ELECTRIC RAILROADING

Center Line
*
ONCO
}
INSIDE WALL OF TUNNEL
SHOWING 64 DUCTS
Fig. 332. Ducts Inside of Wall of Tunnel,
}

TRANSMISSION LINES
563
Q
Fig. 333. Ducts Under Passenger Station Platform.
Fig. 334. 50,000 Volt Insulator.

564
ELECTRIC RAILROADING
This distance plus the distance B across which the spark
would have to jump gives total sparking distance.
When the high tension wires enter a sub-station the
arrangement of Fig. 344 is a good one. A large square
of slate holds a tube of porcelain, while the shed keeps
Fig. 335. 60,000 Volt Insulator.
whole dry. A sectional view of the porcelain tube is
given in Fig. 345.
When the line drops from pole to sub-station a set of
strain insulators must be put in to hold the end of line
taut. Fig. 346 shows a complete one for moderate pres-

TRANSMISSION LINES
565
Fig. 336. 75,000 Volt Insulator.
Fig. 337. Glass Cable Insulator, 10,000 Volts.

566
ELECTRIC RAILROADING
sures and one end of a triple one when the line is very
heavy.
The testing of insulators is shown in Fig. 347, but in
addition to this insulators are also tested when complete
in their natural position, with regular voltage, while a
stream of water, at a downward angle of 45°, is being
played on them from a hose.
Fig. 338. Iron Pin
for Cross Arm.
FIRE
Fig. 339. Arcing When
Wood Pin is Used.
Fig. 340. Sparking Distance
When Porcelain Covered Iron
Pin is Used.
Overhead Trolley Line.
Its
The old-fashioned single trolley wire with trolley wheel
collecting current is unsuitable for high speeds.
place is taken by the catenary line and bow trolley.

TRANSMISSION LINES
567
Fig. 341. Pin for Top of Pole.
Fig. 342. Pin for Side
of Top of Pole.
=
A+B=4" Arcing
Distance Wet
Fig. 343. Measurement of Arcing or Sparking Distance.
568
ELECTRIC RAILROADING
Figs 348 and 349 will best explain the catenary trolley.
Two steel cables are slung between the cross bridges and
hang in a natural curve. They are six feet apart at the

Fig. 344.
1
Bringing In or Taking Out High Tension Line.
36-
-10°

42
WAYNE,
J
Fig. 345.
Sleeve of Fig. 344, also used for Transformer Leads.
ends of the span and six feet lower in center than at ends.
A number of triangles of light rods are made up of dif-
ferent sizes. The largest being 6 feet on each side and
smallest I foot on each side.
TRANSMISSION LINES
569
These triangles are fastened to the two steel cables
at their corners. This brings the cables in near each
other at centers of spans. They therefore, starting from
the cross bridges or gantries curve in and down.


Fig. 346.
Single Pin Strain Insulator and one end of a Triple Pin
Strain Insulator.
The other corners of the triangles all fall in a straight
line 22 feet above the level of track. The copper trolley
wire is soldered into the ears which the lower corners of
triangles carry.
Fig. 349 shows the curve of the supporting catenary
construction and the straight line of the trolley wire.
Fig. 350 shows a gantry with section switches and
transformers for operating switches and lights. These
gantries occur every two miles. Fig. 351 gives a diagram
of such a gantry, also carrying signals. Fig. 352 gives
a diagram of a whole span showing curving of cables,
Method A
Method C
Fig. 347.
کام
Testing Strain
Insulators
Testing Wall
insulators
Testing Tubos
Method of Testing Insulators.
570


TRANSMISSION LINES
571
Fig. 348. Four Track Catenary Line, N. Y. N. H. & H. R. R.

572
ELECTRIC RAILROADING
Fig. 349. Catenary Line,

TRANSMISSION LINES
573
Fig. 350. Gantry with Section Switches, N. Y. N. H. & H. R. R.
574
ELECTRIC RAILROADING
Third Rail.
The third rail is usually a 70 pound ordinary steel rail,
but lately rails with a certain percentage of copper in
them are being used. The rail of the New York Central
is copper alloyed.

LIGHTNING ARRESTER BOX
AUXILIARY LINE
FEEDER
CONDUIT
FOR CONTROL WIRES
FOOT WALK
CIRCUIT BREAKER,
HAND RAIL
„TRANSFORMER
TRANSFORMER
LAMP
„BUS DAR
LADDEN'
SCMAPHORE
Fig. 351. Gantry with Full Equipment Showing Clearance of Two
Locomotives with Trolleys Raised.
Some of the methods of installing the third rail are
shown in Fig. 353, while Fig. 354 shows the New York
Central under contact type. Heavy snow and sleet storms
have shown the under contact to be the most reliable
under such conditions.
TRANSMISSION LINES
575
་


300-0°
Fig. 352.
Side View and Plan of Catenary Span.
576
ELECTRIC RAILROADING

-2-2
Milan Gallarȧle Railwayi
4-84

Wilkesbarre 8 Hazleton-Railway
Manhattan Elevated Railway.
4-8½″-
-4-85-

Paris-Orleans Railway.
-4-82-
Fig. 353. Third Rail Constructions.
1-01


TRANSMISSION LINES
577
4-84
Fig. 354. New York Central Third Rail Construction.
DOULTONS PATENT
Fig. 355. Third Rail Insulators.

578
ELECTRIC RAILROADING
CONDUOTOR RAIL
G.W.RI. SECTION
WHITE POREL
W. I.
TRIPOD
EPCR
A. FELT CUSHION
B.SPRIMO
C.INON TUBE
D.CEMENT
E.STEM
Fig. 356. Two English Third Rails and Insulators.

TRANSMISSION LINES
579
Insulators for third rail are made of earthen ware and
stones such as soap stone. Figs. 355 and 356 show such
insulators.
Fig. 357.
Third Rail, Insulator, Connector and Riveted Bond..
Bonding.
The resistance of the joints in the third rail or track
rails (which return current to power house) is so great
that they are shunted by copper conductors called bonds.

580
ELECTRIC RAILROADING
LORD ELEC CO.
BOSTON, MASS
Fig. 358. Bond Protected by Fish-Plate. Soldered to Rail.
Fig. 359. Riveted Bond and Screw Compressor.

TRANSMISSION LINES
581
Fig. 357 shows a bond whose conductivity is as good
as that of the rail itself.
To prevent theft of bonds, for the value of the copper,
they are generally installed under the fish plates as in
Fig. 358. They may be soldered on rail as in this case
or may be inserted in drilled holes and riveted in by
screw press. Fig. 359 shows the riveted end and the
screw press.
Fig. 360. Insulated Joint.
Insulated Joints.
If for signalling reasons it is desired to cut the track
rails into sections, raw hide is placed between ends of
rails and wood insulators under fish plates. See Fig. 360.
STEAM OR ELECTRIC TRACTION.
No one disputes the ability of our manufacturers to
build electric locomotives light enough to operate upon
the present roadbed and bridges and yet possess twenty-
five per cent more horse-power than its steam-powered
rival.
It is admitted that these electric locomotives will haul
heavier trains faster and more economically.
Owing to the huge sums of money necessary to elec-
trify a division it is a question whether there will be
sufficient saving to pay interest on and retire the debt
incurred by the electrification.
As far as passenger business is concerned, probably
the income from its new business (which invariably fol-
lows electrification) will be the factor, inducing com-
panies to change over to electricity.
The more frequent service. at higher schedule speed
has always built up the country feeding the line and in-
duced more traffic.
The number of people who must travel is increased
by the higher speed (less time spent on road); the
number who want to travel and don't will be reduced. ·
This is because those sections whose distance in time
was too great will become populated by city workers,
and the number of pleasure travelers is increased as soon
as the expression, "You can catch a train at any time,"
becomes prevalent and truthful.
582
STEAM OR ELECTRIC TRACTION
583
+
At the present time the obvious solution of the question
is to equip those portions of divisions where the local
traffic is heavy with third rail and run shorter trains (not
less than three cars) with motor trucks, at more frequent
intervals. The through service will be carried over the
same rails by steam.
At large terminal stations the through trains should be
hauled to the end of the electric division by the electric
locomotives and then forwarded by steam.
It will be the freight business, the expense of which
goes by the train mile and its income by the ton mile,
which will force trunk lines to electrify whole divisions.
As a consequence of this they will be able to furnish
a high speed passenger service at less cost per car-mile
than at present. The income being regulated by the
passenger-mile, increased earnings will result.
There are two ways of moving a load by electricity, the
car motor and the locomotivc system.
For all traffic whose origin and destination is within
the limits of the Electrical Division of a railroad, the car
motor plan is the cheapest; and the saving in money in-
creases with the frequency of the car's movement.
You pay interest on the cost of a coach, and it brings
in no revenue, every moment it stands idle at a terminal,
so that when you are paying interest on a motor equip-
ment at the same time it becomes a matter of vital im-
portance that these cars be kept moving.
When the electrical division exchanges through traffic
with a steam division and the coaches will be away for
long periods, the interest charges on idle motors becomes
so great, and the amount of extra equipment, so that
plenty of motor cars shall still be at home, grows so
584
ELECTRIC RAILROADING
large, that it is cheaper to concentrate a small fraction of
these motors on large trucks and use them to haul the
trains.
}
Then when the train is forwarded over the steam di-
vision the electric locomotive can lay over 15 or 20 min-
utes and pull the next incoming train back.
One of the economies of transportation is to make the
car miles per motor as large as possible.
For freight, where traffic is interchanged with foreign
roads, motor equipment on the cars is out of the question.
The large portion of its life spent on sidings and in ter-
miņals makes it very doubtful whether car motors would
ever pay.
For hauling freight over electric divisions some people
figure that steam will do it better. I believe every one
sees that long freight trains with as high a speed as is
consistent with coal economy is the thing to be desired.
With steam this means 12 to 15 M. P. H.
The weight of the locomotive is limited by the strength
of bridges and wear and tear upon the road bed. An
electric locomotive can be built weighing the same as a
steam freight locomotive with 25 per cent more hauling
power.
It seems then that the proper way to handle freight
in an electric zone is by electric locomotives at a higher
speed and less cost per ton mile.
All heavy pusher work on long steep grades would be
done more economically by electric locomotives.
A road will handle its suburban business with coaches
having motors in the trucks and all through traffic with.
electric locomotives.
The result of the electrical equipment will be several
great economies:
STEAM OR ELECTRIC TRACTION
585
1. In order to haul a train a steam locomotive must
be made ready at an expense for labor and coal.
The new locomotive is made ready by closing one
switch.
2. Burning coal in many small inefficient fireboxes.
means a large coal bill per ton mile of traffic moved.
Using cheaper coal in a power-house with more effi-
cient furnaces, a gentler draft and mechanical stokers.
results in a great saving in coal bills.
3. A steam locomotive standing in a station or in the
yard at a terminal after a run, is burning coal with no
return.
The instant an electric locomotive stops, the flow of
current ceases, and the moment a run is over the ex-
pense for coal drops to almost nothing. There is coal
burning at the power station, but this coal is for the
average load and very little of it is chargeable against
an electric locomotive.
4. When a delayed locomotive attempts to make up
time, coal is burned at a more rapid rate and steam is
used with a longer cut-off; both of which are expensive.
operations.
The normal operation of an electric locomotive does
not utilize the full power of the motors, and when behind
schedule the full power is used without any appreciable
change in the efficiency.
5. The total expense for two power houses, eight sub-
stations, thirty locomotives and the third rail is greater
than for thirty steam locomotives, but the saving in op-
erating expenses and maintenance of way goes each
month to pay the fixed charges of the plant and there is
something left over to pay off the debt incurred when
installing the electrification.
586
ELECTRIC RAILROADING
It is a mistake to think that the horse power of these
two power houses must be the sum of the horse power of
the thirty steam locomotives they are designed to replace,
for all these locomotives are not running at once. The
power house only has to take care of the power required
for the maximum number of trains running at the same
time. This information taken from a train diagram
usually results in about 25 per cent of the horse power
being installed for service, with some extra for reserve.
6. For the same traffic fewer electric locomotives will
be needed.
The average month of a locomotive's life is made up
of pulling trains 30 per cent of the time, loafing around
under steam waiting for transportation department 50
per cent, under care of motive power department 20 per
cent, and a little "soldiering" out on the road.
An electric locomotive is built with an idea of giving ·
almost continuous service. They will tax the ingenuity
of the transportation department to find enough work
for them to do.
7. A moderate percentage of the expansive force of
the steam cannot be used, for the connecting rod would
tear the crank pins out. The exhaust is closed ahead of
time to avoid this, and the power of engine reduced. A
very annoying feature of the steam locomotive is its
persistent effort to drive the rails down to China and
the seat of the engineer's overalls upwards, due to the
flinging effect of any unbalance in the parallel rods and
crank pins.
The electric locomotive with its purely rotative motion
is very easy on the track, and saves many dollars of
expense.
STEAM OR ELECTRIC TRACTION
587
Selection of Equipment.
The type of motors being fixed upon, the actual horse
power to be installed on locomotives or cars is deter-
mined by consideration of:
I.
2.
Schedule speed.
Number of miles between stops.
3. Rate of acceleration.
4.
Maximum speed.
5. Weight of trains.
6. Grades and curves of track.
The New York Central demanded for its through traf-
fic a locomotive which must be capable of running from
Grand Central Station to Croton (34) miles hauling a
total train weight of 435 tons in 44 minutes without a
stop. To attain on a tangent track with this train a
speed of not less than 60 M. P. H. Speed in excess of
65 M. P. H. under these conditions not desired.
To be able to pull a train of 875 tons, making same
schedule speed as is at present made with steam locomo-
tives.
Let us ourselves roughly design a locomotive and see
how things turn out.
I
Required the weight and horse-power of an electric
locomotive capable of hauling itself and 8 cars of 65 tons
each up a 12% grade at 50 M. P. H., at the same time
rounding a curve of 2 degrees; also capable of starting
this train from a station on a tangent and level track, in
a less time than the present steam locomotives.
To haul a train we must overcome the friction in jour-
nal boxes and between wheels and rails; the air resist-
ance and the side thrust of curves. We must apply
588
ELECTRIC RAILROADING
enough power to actually lift the train against the force
cf gravity up any grades.
For every 1% of grade it takes 20 lbs. to pull i ton
up it. Every 1° of curvature requires 0.7 lbs. per ton
to draw train around. These figures are in addition to
the pull required for the train friction and air resistance
at the particular speed in question.
1% grade needs 20 pounds per ton.
1° curve needs 0.7 pounds per ton.
50 M. P. H. needs 13 pounds per ton.
Hence for our conditions we need
For grade 12X20=30.0 lbs. per ton.
For curve 2X0.7= 1.5 lbs. per ton.
For speed
=13 lbs. per ton.
Total ..
44.5 lbs. per ton.
8 cars at 65 tons=520 tons.
The pull required at the draw bar of the locomotive
will be 44.5X520-24,000 lbs. draw bar pull.
The locomotive must brace its feet (drivers) against
the road bed (rails), and, having no hoofs to dig in, must
develop its grip by pure friction. Usually steel tires.
against steel rails grip with only 14 the weight upon them.
Figuring on the safe side, call this 1/5, and we have the
weight of the locomotive resting on the drivers, which
must be 5 times the draw bar pull.
This calls for 60 tons on the drivers, but since prob-
ably 14 the total weight of the locomotive will rest on
the trucks, the total weight will be about 80 tons, in order
to get sufficient adhesion to pull the load.
This 80 tons will need 80X45 or 3,600 lbs. to propel
}
STEAM OR ELECTRIC TRACTION
589
•
itself. The tractive force to be exerted at the rail head
will be 24,000+3,600 or 28,000 lbs. in order to haul the
total train weight of 520+80-600 tons. There will be
24,000 lbs. draw bar pull exerted to haul the coaches.
The horse power to be installed in this locomotive un-
der the given conditions will be the same as if it were
steam driven, i. e., 5 H. P. per ton of train or 5X600-
3,000 H. P.
If this locomotive can accelerate a train from a stop on
a level, straight track faster than a steam locomotive, it
⚫ will be satisfactory.
ค
It takes 90 lbs. per ton to increase speed at rate of 1
M. P. H. P. S. on this kind of track. The tractive effort
of the locomotive is 28,000 lbs., and dividing by train
weight 600 tons gives 46 lbs. per ton to start train on
level. 46 is half of 92, so we can accelerate at ½ M. P.
H. P. S., which beats a steam locomotive.
The 35 locomotives which the General Electric Com-
pany, aided by the American Locomotive Company, built
to fit these requirements were found to weigh 100 tons
and the power installed was four 550 H. P. motors or
2,200 H. P. in all. These motors are capable of deliver-
ing 3,000 H. P. continuously for long periods of time.
Since the conditions of speed, grade, and curve in this
problem do not occur very often at the same time, nor
even then for long periods, this motor equipment is suf-
ficient.
A view of this locomotive is given in Fig. 361.
The principal dimensions of the locomotive and other
data regarding it are given below, and for sake of com-
parison, the corresponding dimensions of a standard high
speed steam locomotive of the Atlantic type are printed
in a parallel column.

590
ELECTRIC RAILROADING
6000
6000
N.Y.C. & H.R.
6000
6000
A
Fig. 361. New York Central Electric Locomotive.
STEAM OR ELECTRIC TRACTION
591
COMPARATIVE DATA OF ELECTRIC AND
STEAM LOCOMOTIVE.
ELECTRIC.
No. of driving wheels
No. of truck wheels
Weight.
Weight on drivers
Wheel base, driving
total
Max. tractive power (draw-bar pull)
Tractive power per ton engine weight
Wheels, driving.
engine truck
STEAM.
8
4
95 tons.
68
13 ft.
27 "
•
34,000 lbs.
330
44 in.
36 "
No. of driving wheels
No. of truck and tender wheels.
Weight
Engine, 100 tons
Tender, 61
<<
on drivers
Wheel base, driving
4
14
161 tons.
55
7 ft.
CC
engine
27 ft. 9 in.
engine and tender
53 ft. 8 in.
Maximum tractive power.
Tractive power per ton engine weight
Wheels, driving.
engine truck
trailing
"
tender
27,500 lbs.
171 lbs.
79 in.
36 "
50 **
36 "
592
ELECTRIC RAILROADING
The following additional data apply to the electric loco-
motive of the New York Central R. R.:
Length over buffer platforms
Extreme width.
Height to top of cab
Diameter of driving axles
Normal rated power
Maximum power
Speed with 500-ton train
Voltage of current supply
Normal full load current
•
Maximum full load current
No. of motors
Type of motor.
·
Rating of each motor
37 ft.
10 "
14 ft. 4 in.
8.5 in.
2200 H. P.
3000 H. P.
60 m.p.h.
600
3050 amperes.
4300 amperes.
4
GE-84-A
550 H. P.
It is most interesting to note the differences as tabu- ·
lated below:
Steam.
Electric.
Difference in
favor of elec-
tric.
Length over all.........67 ft. 734ins. 36 ft. 11 ins. 30 ft. 8½ ins.
Total weight (including
tender for steam loco-
motive ...
342,000 lbs.
200,500 lbs.
141,500 lbs.
Concentrated weight on
each driving axle.
Revenue bearing load
back of locomotive...
Acceleration M.P.H.P.S.
averaging up to 50
M.P.H...
Time required to reach
speed of 50 M.P.H.
47,000 lbs.
35,500 lbs.
11,500 lbs.
256 tons
307.25 tons
51,25 tons
.246
.394
.148
203 sec.
127 sec.
76 sec.
!
STEAM OR ELECTRIC TRACTION
593
31750
31750
Total Weight Tender
-loaded 127,000 Iba.
31750
21750
38000
-67-73-
47000
Fig. 362 shows the comparative distribution of weight
for electric and steam locomotives.
The New York Central demanded motor cars which
would be able to improve the general suburban traffic con-
ditions, and practically asked for the best equipment
which could bé furnished them.

+36
kinx+
-7-01
29230
35500
35500
13-0='
-36-111-
Weight on Drivers
-142,000 Iba-
-Total Weight 200,500 lbs.-
35500
O O O O For
-130-
d
47000
Wt. on Drivers
141,000 Iba
Total Weight,Locomotive Only, 215,000 lbs
Grand Total,Locomotive Complete 342,000 lbs-
Strest Ry, Journal
DIAGRAM OF COMPARATIVE WEIGHT DISTRIBUTION
ELECTRIC AND STEAM LOCOMOTIVES
Fig. 362.
This resulted in the building of 125 steel cars (Fig.
363) shown in end view by Fig. 364, which are fitted
with the Sprague-General Electric multiple unit system.
of control, known also as Type M control.
47000
18000
18000
35500
-7-0 1-1-236-1
29350

594
ELECTRIC RAILROADING

·384
#376
k-----
الصامنا الحجامة
49
LONGITUDInal elevation of nEW YORK CENTRAL STEEL MOTOR CAR
Fig. 363. New York Central Steel Motor Car.

-210/2
---- 1042/" -
-76-----
K
98%
-102 1
-9101/

CROSS-SECTION AND END VIEW OF NEW YORK
CENTRAL STEEL MOTOR CAR
Fig. 364.
They weigh 51 tons each. Under one end is a M. C.
B. trailer truck (with no motors), under other end is a
motor truck, both built by American Locomotive Com-
pany. The motor truck has two 200 H. P. motors weigh-
ing six tons each, geared to wheels by a 2:1 gearing. The
trailer wheels are 33 inch, the motor truck wheels 36
STEAM OR ELECTRIC TRACTION
595
inch. There are five tons of electrical equipment on each
car besides the motors. They can accelerate at rate of
1.25 miles per hour per second and attain a maximum
speed of 52 miles per hour.
A. C. or D. C. TRACTION.
The question as to which is the best A. C. or D. C.
systems of traction should not be one of heated argument,
as it often is; but rather one of plain presentation of
facts, and the drawing of a logical conclusion from them.
For some circumstances an A. C. system is the proper
solution of the problem; for others a D. C. system is best;
while in still other situations nothing but a combined
A. C.-D. C. system will do the work.
The general advantages and disadvantages of each sys-
tem will be given and a few general conclusions drawn.
Advantages:
A. C. System.
(1) A high voltage may be used allowing use of small
feeders and trolley wires.
(2) Distance between power houses may be great,
hence only a few are needed. Several large power houses
are cheaper to build and operate than a greater number
of smaller ones.
(3) The control of speed of train is by "potential con-
trol;" this is cheapest method.
Disadvantages:
(1) The trolley must be an over-head system. The
conductivity of a third rail for A, C. is low.
7
596
ELECTRIC RAILROADING
(2) A breakage of trolley which might occur (not
very likely to happen) would be very dangerous to life.
(3) A stiff, non-swaying overhead trolley is as ex-
pensive as a third rail.
(4) A. C. motors do not get a train up to speed as
quickly as D. C. motors.
(5) To develop same power on A. C. from the same
weight of motor, as could be done on D. C. with same
weight of material, motors must be cooled by air blast.
(This helps to keep dust out.)
(6) Not adapted to freight pusher work as A. C. mo-
tors cannot stand still and push.
D. C. Systems.
Straight D. C. or A. C. Transmission.
Advantages: All D. C. systems:
(1) Train gets up to speed very rapidly.
Disadvantages:
(1) Power is delivered to train at 600 volts so feeders
and trolley (if used) are large.
Straight D. C. System.
Advantage:
(1) Simple; well understood.
Disadvantages:
(1) Transmission at low voltages makes distance be-
tween power houses small.
STEAM OR ELECTRIC TRACTION
597
A. C. Transmission, D. C. Utilization.
Advantages:
(1) Transmission by A. C. high voltage is cheap.
(2) Few power houses required.
(3) D. C. motors' used have good acceleration, i. e.,
get up to speed quickly.
Disadvantages:
(1) Rotary converters must be used.
Conclusions.
It seems from this summary that when getting up to
full speed quickly is desired, the D. C. motor should be
used. For any economy A. C. transmission should be
used.
Let us see if the quick "get away" from stations is of
much importance to the operation of a railroad.
The technical name for rate of speed increase is accel-
eration. By this I mean the increase in speed in miles
per hour which occurs every second from the start from
rest until the train reaches its maximum speed.
If a train pulls out of a station and steadily increases
its speed, finding itself going at 50 M. P. H.* 203 sec-
onds later, it is evident that each second it went 0.246
M. P. H. faster than the previous one, for 0.246X203=50.
If some other train accelerates at the rate of 0.394 M.
P. H. per second, it will take 127 seconds to attain a
speed of 50 M. P. H.
*M. P. H.-Miles per hour.
598
ROADIN
ELECTRIC RAILROADING
Acceleration must be high, else the schedule speed for
a given maximum speed will be too low, and the time oc-
cupied running between stations too long. It cannot be
too high, as it would be uncomfortable for passengers,
and would require much larger motors, which would not
be needed as soon as train was at full speed.
The great virtue of an electrically driven or hauled
train is its ability to accelerate rapidly.
For example, let an electric train be capable of acceler-
ating at rate of 0.4 and a steam train at 0.25 M. P. H. P.
S.* Suppose both can run at a maximum of 50 M. P. H.,
but no higher. They start together at a station and run
to the next station three miles away.
The steam train takes 200 seconds to arrive at 50 M. P.
H. and therefore moves 200 seconds at an average speed
of 25 M. P. H. or 36.6 F. P. S., and in getting up to speed
it passes over 200X36.6 or 7,320 feet. Allowing 2,500
feet for stopping train, there arc 6,020 feet to traverse at
50 M. P. H. or 73.2 F. P. S.
73.2÷6,020 gives 82 seconds.
The stop will take 67 seconds.
Total Time-Steam Train.
200 seconds accelerating over.
82 seconds free running over.
67 seconds braking over..
349 seconds over.
·
•
5 min. 49 secs. for 3 miles.
*M.P.H.P.S.-Miles per hour per second.
7,320 feet
6,020 feet
•
2,500 feet
•
15,840 feet
ཝཱ
STEAM OR ELECTRIC TRACTION
599
Total Time-Electric Train.
125 seconds accelerating over.
120 seconds free running over..
67 seconds braking over..
312 seconds
5 min. 12 secs. for 3 miles.
4,575 feet
8,765 feet
2,500 feet
.15,840 feet
The difference in time is 37 seconds in favor of the
electric train.
In a suburban run of 33 miles with stations every 3
miles, this saving of time is repeated 11 times and the
gain in schedule time for the run is 634 minutes.
This is assuming what is quite true; that curves,
grades, slow downs for signals, stops at stations, will
equally affect each train.
When the stations are closer together the saving is
even greater. For a two mile interval the log of runs
works out as follows:
Total Time-Steam Train.
200 seconds accelerating over.
10 seconds free running over..
67 seconds braking over
277 seconds.
4 min. 37 secs. for 2 miles.
7,320 feet
740 feet
2,500 feet
.10,560 feet
600
ELECTRIC RAILROADING
*
Total Time-Electric Train.
125 seconds accelerating over.
48 seconds free running over..
67 seconds braking over.
240 seconds..
4 minutes for 2 miles.
Gain for electric train, 37 seconds.
4,575 feet
3,485 feet
2,500 feet
.10,560 feet
In a run of 34 miles with two mile station intervals
there would be a clear gain of 10½ minutes by electric
operation.
To show that this is not a mere paper result, I am
showing Fig. 365. This run took place last April on the
Mohawk Division of the New York Central, out at
Wyatts, just west of Schenectady. The two trains were
each of six cars of equal weight. The electric locomotive.
was No. 6000 and the steam locomotive No. 2797. From
the standing start No. 6000 accelerated the more rapidly,
and at 1,500 feet from the starting point this photograph
was taken. Three and a half minutes after the start No.
6000 was 2,500 feet ahead.
It will thus be seen that for suburban service, where
the stations are close together, the acceleration is the most
important feature and considerable expense and perhaps
even complication may be incurred in order to get good
acceleration.
This same argument that an electric motor is better
than a steam engine for suburban service holds good to
a lesser degree, that a motor driven by D. C. is better for

STEAM OR ELECTRIC TRACTION
601
suburban service than one driven by A. C., because the
D. C. motor accelerates the faster.
The advantage of the D. C. motor in this respect begins
to be of less consequence as the distance between stations
increases. For express train service there is practically
no difference in the schedule speeds that they can main-
tain.
Fig. 365. Acceleration Test between No. 6000 and Pacific No. 2797.
Notice that the longer the runs between stations, the
nearer the schedule speed approaches the maximum speed
which is attained during free running.
However, the whole story between D. C. and A. C.
motors in suburban service is not yet told..
Locomotives making an acceleration of 0.4 or with
short trains of 0.5 M. P. H. P. S. are worthless in a
602
ELECTRIC RAILROADING
A
suburban service compared with trains of motor cars
making an acceleration of 1.25 M. P. H. P. S., for this
three times as great acceleration makes an enormous dif-
ference in schedule speed.
With D. C. motors these motor cars can be run in trains
and controlled as easily as a single car.
A certain timidity is felt about bringing an 11000 volt
A. C. circuit down through a car full of people. About
3,000 volts is all the engineers have screwed up their
courage to. But at 3,000 volts the A. C. system has lost
all its advantages as regards low cost. It is no cheaper
than D. C. It being understood that in A. C. case 11000
volts are reduced in sub-stations to 3000 for trolley, and
in D. C. case 11000 volts A. C. are reduced in sub-sta-
tions to 600 D. C. for third rail.
Hence we must compare D. C. motor car trains at high
acceleration to A. C. locomotive drawn trains at low ac-
celeration.
I think it will be seen that systems using A. C. motors
in the present state of the art are not suitable for subur-
ban service on steam roads.
It will be equally obvious that for express service or
trunk line operation, the simplicity of the straight A. C.
system with 11000 volt trolley and locomotive drawn
trains is the better system.
I
Locomotives or Motor Cars.
The choice between these two depends on whether
through or local traffic is to be handled.
The motor car can accelerate at 1.25 M. P. H. P. S.
No locomotive could do this, for it could not be made
STEAM OR ELECTRIC TRACTION
603
heavy enough to get the requisite adhesion, without
breaking down all the bridges.
Such a locomotive would need 200 tons on its drivers.
No existing bridges could stand the strain.
But if we take a 600 ton train of cars, the weight being
distributed can be borne. By putting the motors on
trucks at one end of each car we get half the weight or
300 tons for adhesion, which is more than is needed.
Motor car trains are then a necessity for suburban
traffic.
LESSON 34.
SYSTEMS OF CONTROL.
The control of speed of train is by means of a con-
troller, which throws grids of resistance in or out of
motor circuits for D. C. motors; connects motor to dif-
ferent taps of the transformer for A. C. motors; and
interchanges the relations of armature and field terminals.
for either A. C. or D. C. motors.
A control with resistances alone must be used when
there is but one motor, as in some mine and factory
locomotives. This is called rheostatic control.
When there are two motors we may place both in
series, giving each motor 250 volts, for half speed, and
both in parallel, giving each motor full voltage for full
speed.
Acceleration is controlled by use of grid resistances,
made of cast iron, shown in Fig. 366. These are cut
in the circuit at start by controller and cut out one by
one while accelerating to full series; they are then cut
into the circuit with the two motors in parallel and again
cut out one by one until motors are in full parallel. Thus
at the two free running speeds there are no resistances
in circuit.
This is called the series-parallel control.
When A. C. is used the voltage applied to the motors
is varied by connecting more or less of the secondary
turns of the step down transformer to the motor. This
is called potential control.
1
{
604

SYSTEMS OF CONTROL
605
The series-parallel control is the most familiar to us,
for the two K controllers shown in Figs. 367 and 368
are regular equipment on many interurban lines.
Fig. 366. Cast Iron Grid Resistances.
The letter K designates a controller which never opens
the circuit from time motors are started till they are in
full parallel or multiple (two names for same thing).
For very heavy equipments the K controller takes the
form of Fig. 369, where the cylinder is gear driven.
The letter L used in connection with controllers means

606
ELECTRIC RAILROADING
Fig. 367.
K Controller.

SYSTEMS OF CONTROL
607
DOUZE ELECTRIC
Fig. 368.
K Controller.
608
ELECTRIC RAILROADING
that when changing motors from full series to parallel
with resistance the circuit is momentarily opened. Fig.
370 shows such a controller.
When fitted for electrical braking the letter B is used
to designate the type of controller. See Fig. 371.
Fig. 372 shows the electrical connections made by a K
controller with two motors.
The notches of a controller are the positions of handle
where a spring pawl drops into notches on a plate so
as to hold the handle against vibration or slight pressure.
The notches are named resistance, running and transition
notches.
A resistance notch is one where some resistance is in
circuit. These should only be used for very short periods
of running. It not only wastes power to use them, but
by getting the resistance grid red hot may warp it or
might even start a fire.
The running notches are those where there is no re-
sistance in circuit and the motors are in an arrangement
suitable for continued use.
A transition notch is where the motors are in some
combination so unsuitable for delivering power, that the
notch should be passed over quickly.
All notches except transition ones are indicated on top
of controller.
Fig. 373 shows connections made by a K controller
with four motors.
Fig. 374 shows connections made by an L controller
with two motors. The points to be noticed are: The
gradual decrease of the resistance in circuit, it taking
*The decrease of resistance is shown in a novel way by plac-
ing more of them in parallel. In diagram the wider the resist-
ance, the lower it is.

SYSTEMS OF CONTROL
609
WESTINGHOUSE ELEUTA C
MANUFACTUR COMPANY
Fig. 369. K-B Controller.

610
ELECTRIC RAILROADING
12 notches to get a full series. There are a lot of re-
sistance notches called transition notches simply because
there are no marks on top on controller to indicate them
Note the opening of circuit at notch 122.
C
Fig. 370. L Controller.
The student should number the multiple notches up tc
24 himself.
Fig. 375 shows the connections made for electrical
braking when two and four motors are used.

SYSTEMS OF CONTROL
611
B
Fig. 371. B Controller.
612
ELECTRIC RAILROADING

10
11
12
4
تن
ct
Ct
NOTCH
RESISTANCE
RUNNING
TRANSITION
CONTROLLERS
K₁U AND K₁,
1
RES.
MOTOR 1
MOTOR 2.
что-то-
61
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Fig. 372. Scheme of K Control with Two Motors.
SYSTEMS OF CONTROL
613

NOTCH
RESISTANCE
RUNNING
TRANSITION
1
CONTROLLER
K
RES. MOTORS 1 & 3
1.
MOTORS 2 & 4
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Fig. 373. Scheme of K Control with Four Motors.
614
ELECTRIC RAILROADING
Electrical braking uses the motors more than simply
running the car, and so they heat more. This means a
larger motor for the same schedule speed.
NOTCH
RESISTANCE
RUNNING
TRANSITION
3
-
2
h
4
LO
5
7
9
10
11
12
121
I

SERIES
L₂ CONTROLLER
MULTIPLE
RES.
MOTOR 1.
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MOTOR 2,
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A
Fig. 374. Scheme of L Control.
In some controllers the movement of the hand is
mechanically connected to the cylinder. Such a control
is a manual control,
SYSTEMS OF CONTROL
615
In other cases the controller merely arranges contacts
which energize circuits to electro-magnetically operated
switches called contactors; or electro-magnetic valves

GROUND
GROUND
ARMA
ARMATURES
BRAKE
SHOES
FIELDS
RESISTANCE
CONNECTIONS FOR ELECTRIC BRAKE
B13 AND B CONTROLLERS
23
ARMATURES
BRAKES
OO
FIELDS
о
RESISTANCE
.CONNECTIONS FOR ELECTRIC BRAKES
BB AND B19 CONTROLLERS
GROUND

GROUND
Fig. 375.
Scheme of Electrical Braking Connections.
are operated which in turn operate pneumatic cylinders.
The push rods from these cylinders open and close the
switches. Controllers of this class are called master
controllers,
LESSON 35.
THE SPRAGUE GENERAL ELECTRIC TYPE M CONTROL.
The Sprague-General Electric Type M Control is de-
signed primarily for the operation of a train of motor
and trail cars, coupled in any combination and the whole
operated as a single unit from any controller on the train.
The system may also be used to advantage on individual
equipments and locomotives.
The control apparatus for each motor car may be con-
sidered as consisting essentially of a motor controller and
a master controller.
The motor controller comprises a set of apparatus
(Fig. 376) usually located underneath the car (Fig. 377),
which handles directly the power circuits for the motors,
connecting them in series and parallel and commutating
the starting resistance in series with them. This motor
controller is operated electrically, and its operation in
establishing the desired motor connections is controlled
by the motorman by means of the master controller, Fig.
378, which is similar in construction to the ordinary
cylinder controller and is handled in the same manner.
Instead of effecting the motor combinations directly, how-
ever, this controller merely governs the operation of the
motor controller.
The master controller operates a number of electri-
cally operated switches, or "contactors," which close and
open the various motor and resistance circuits, and an
electrically operated "reverser" that connects the field
616

SPRAGUE CONTROL
617
AUTOSTATS
Fig. 376. General View of Apparatus Type M Control.

618
ELECTRIC RAILROADING
3212
Fig. 377. Arrangement of Control Apparatus Under Car.

SPRAGUE CONTROL
619
and armature leads of the motors to give the desired
direction of movement to the car. Both the contactors
and reverser are operated by solenoids, the operating
current for which is admitted to them by the master
controller.
Fig. 378. Master Controller for Sprague-General Electric Control.
Each motor and trail car is equipped with train cable,
consisting of nine or ten individually insulated conduc-
tors connected to corresponding contacts in coupler sock-
ets located at each end of the car. This train cable is
620
ELECTRIC RAILROADING
connected identically on each motor car to the master
controller fingers and the contactor and reverser oper-
ating coils, and is made continuous throughout the train
by couplers between cars, connecting corresponding ter-
minals in the coupler sockets.
All wires carrying current supplied directly from the
master controller form the "control circuit"; those car-
rying current for the motors form the "motor" or "power
circuit."
Inasmuch as the motor controller operating coils are
connected to this control train line, it will be appre-
ciated that energizing the proper wires by means of any
master controller on the train will simultaneously oper-
ate corresponding contactors on all the motor cars, and
simultaneously establish similar motor connections on all
cars.
Advantages.
The Sprague-General Electric Type M Control per-
mits a train of motor cars and trailers to be operated
as a single unit from any master controller on the train.
If desired, a master controller can be placed on each
platform of trail cars, thereby providing for the operation
of the train from any platform. With this arrangement,
the motorman can be always at the head of the train,
regardless of the combination of the cars.
The entire train, equipped with Type M Control, may
thus be regarded as a unit; the motorman has the same
control over a train that he would have over a single
car with the ordinary cylinder controller.
Should the motorman remove his hand from the oper-
ating handle of the master controller, the current will
SPRAGUE CONTROL
621
be immediately cut off from the entire train, thus dimin-
ishing the danger of accident in case the motorman should
suddenly become incapacitated.
The system will operate at any line potential between
300 volts and 600 volts, and the action of all contactors
is absolutely reliable and instantaneous.
On heavy equipments the effort of the motorman in
operating the master controller is so much less than that
required to handle a large cylindrical controller that he
can give more attention to the air brakes and other parts
of the equipment, especially in cases of emergency.
The approximate total weight per motor car of control
equipments, exclusive of supports, is 2,500 pounds for
300 H. P. of motors.
The approximate weight of the apparatus for each trail
car, which comprises train cable, coupler sockets and
connection boxes, is 100 lbs.
In many cases it will be found advantageous to antici-
pate the future growth of an interurban road by equip-
ping each motor car with Type M Control. In these
cases it will be easy to change from single car to train
service whenever warranted by traffic conditions."
The position of the handle on that master controller
which the motorman is operating always indicates the
position of motor control apparatus on all cars.
Contactors.
The contactors are the means of cutting in and out
the various resistances, of making and breaking the
main circuit between trolley and motors, and of chang-
ing from series to parallel connection.

622
ELECTRIC RAILROADING
Each contactor consists of a movable arm carrying a
renewable copper tip which makes contact with a similar
fixed tip, and a coil for actuating this arm when sup-
plied with current from the master controller. The con-
tactor is so designed that the motor circuit is closed
Fig. 379. Contactors with Interlocks.
only when current is flowing through its operating coil;
and gravity, assisted by the spring action of the finger,
causes the arm to drop and open the circuit immediately,
when the control circuit is interrupted. Each contactor
has an effective and powerful magnetic blow-out, which
SPRAGUE CONTROL
623
will disrupt the motor circuit under conditions far ex-
ceeding normal operation. In closing, the copper tips
come together with a wiping action, which cleans and
smooths their surfaces.
All contactors in an equipment are practically identi-
cal, and the few parts which are subject to burning and
wear are so constructed as to be readily replaceable.
In order to save space and eliminate interconnections
as much as possible, several contactors are mounted on
the same base (Fig. 379). The contactors should prefer-
ably be located under the car, and boxes are therefore
supplied which facilitate installation, protect the con-
tactors from brake-shoe dust and other foreign material,
and provide the necessary insulation. These boxes are
built with perforated openings for ventilation, but shields
are supplied for closing these perforations whenever
desirable.
J
Reverser.
The general design of the reverser (Fig. 380) is
somewhat similar to the ordinary cylindrical motor re-
versing switch with the addition of electro-magnets for
throwing it to either forward or reverse position. In
general construction, the operating coils are similar to
those used on the contactors, but in order to secure abso-
lute reliability of action in throwing, the coil is given
full line potential. The reverser is provided with small
fingers for handling control circuit connections, and when
it throws, the operating coil is disconnected from ground
and is placed in series with a set of contactor coils, thus
cutting the operating current down to a safe running
value. These coils are protected by a fuse, which will

624
ELECTRIC RAILROADING
immediately open the circuit if the reverser fails to
throw. If the position of the reverser does not corre-
spond to the direction of movement indicated by the
reverse handle on the master controller, the motors on
that car cannot take current. While the motors are tak-
ing current the operating coil is energized, and the elec-
trical circuits are interlocked to prevent possibility of
throwing.
MAAA
Fig. 380. Reverser on Motor Cars.
Master Controller.
The master controller (Fig. 378) is considerably small-
er than the ordinary street car controller, but is similar
in appearance and method of operation. Separate power
and reverse handles are provided, as experience has led
to the adoption of this arrangement in preference to pro-
viding for the movement of a single handle in opposite
directions.
SPRAGUE CONTRÓL
625
An automatic, safety, open-circuiting device is provided
whereby, in case the motorman removes his hand from
the master controller handle, the control circuit will be
automatically opened by means of auxiliary contacts in
the controller, which are operated by a spring when the
button in the handle is released. This device is entirely
separate and distinct in its action from that of the main
cylinder. Moving the reverse handle either forward or
backward makes connections for throwing the reverser
to either forward or backward position. The handle
can be removed only in the intermediate or off position.
As the power handle is mechanically locked against move-
ment when the reverse handle is removed, it is necessary
for the motorman to carry only this handle when leaving
the car.
When the master controller is thrown off, both line
and ground connections are severed from the operating
coils of important contactors, and none of the wires in
the train cables are alive.
The current carried by the master controller is about
2.5 amperes for each equipment of 400 H. P. or less.
This small current carrying capacity permits a compact
construction, and the controller weighs only 130 lbs.
Master Controller Switch.
A small enclosed switch with magnetic blow-out is used
to cut off current from each master controller, and is
supplied with a small cartridge fuse enclosed in the
same box. When this switch is open all current is cut
off from that particular master controller which it pro-
tects.
626
ELECTRIC RAILROADING
Control Cable.
A special flexible cable, made up of different colored
individually insulated conductors, is used for the train
cable and, whenever possible, to make connections be-
tween the various pieces of control apparatus.
Connection Box.
Connection boxes are provided for connecting the con-
trol circuit cables at junction points without splicing, and
small copper terminals are supplied for attaching to the
ends of the individual conductors.
Control Couplers.
The master control cables of each car terminate in
sockets and are interconnected by means of a short sec-
tion of similar flexible cable fitted with plugs. Each
socket contains a number of insulated, metallic contacts
connected to the train wires, and the terminal plugs of
the coupler contain corresponding contacts. The parts
subject to wear are readily replaceable.
All coupler sockets are provided with spring catches
which hold the plugs in contact under normal condi-
tions, and permit them to automatically release in case
two cars separate.
1
Control Cut-Out Switch.
1
This is a switch, usually nine-point, installed on each
motor car and is used to disconnect the operating coils.
of the contactors and reverser from the train cable, and
hence render them inoperative.

SPRAGUE CONTROL
627
Control Fuses.
On each car several small enclosed fuses are placed
in the control circuit at such points as to effectively pro-
tect the apparatus.
Fig. 381. Control Rheostat.
Control Rheostat.
While starting car, tubes of a high resistance rheostat
are connected in series with the contactor coils to cut
down the operating current to a value approximating
that for the running positions of the controller. This
rheostat is enclosed in a sheet iron case for protection.
Fig. 381.
628
ELECTRIC RAILROADING

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SPRAGUE CONTROL
629
Circuits.
The motor circuit is local to each car, and on the first
point the current on entering from the trolley or third
rail shoe passes through the following pieces of appara-
tus in the order named: main switch and fuse, con-
tactors, resistances, reverser, motors; thence to ground.
In the control circuit, the course of the current from
trolley to ground is through the master controller switch
and fuse, the master controller, connection box, to the
cut-out switch. From the cut-out switch the current
passes through the control cable to the operating coils
of the reverser and contactors, and thence through fuses
to ground.
Automatic Features.
The apparatus described is used with the standard
equipment for hand control. If automatic features are
desired they can be installed. See Lesson 36.
Wiring Diagram.
A diagram of the wiring of apparatus shown in Fig.
376 will be found in Fig. 382.
LESSON 36.
AUTOMATIC ACCELERATION.
In some systems of control the closing and opening
of switches is in unison with the movement of the con-
troller handle.
This has two disadvantages. In the first place the
motorman by a too rapid movement of the handle gives
the motor current too fast, which results in the car
starting too fast, causing a waste of current and dis-
comfort to passengers. Secondly, the motorman may
through caution start train too slowly and thus spoil the
schedule speed.
To remedy the first and most important, starting too
fast, controlled acceleration was adopted. Devices called
"motoneers," "auto motors," etc., were placed on con-
trollers. All these are friction or rachet and pawl af-
fairs which bind when handle is moved too fast, or
which compel a stop at each controller point.
Some controllers, as the New York Central locomo-
tives, have a friction clutch operated by the main cur-
rent. When engineer moves controller handle too fast,
too much current flows to motors. This excessive cur-
rent sets the friction clutch so that handle can be moved
no further till current falls to its proper value.
The New York Subway controllers (Fig. 383) have-
handle geared to the main cylinder but the motion is
transmitted from handle to gears through a heavy spiral
spring. The handle may be thrown all the way round,
1
630

AUTOMATIC ACCELERATION
631
3
Fig. 383. Controller Used with New York Subway Equipments.
ELECTRIC RAILROADING
632
which winding the spring, causes it to turn the main
cylinder. The speed of this main drum is regulated by
a friction clutch operated by the current passing through
motors.
At I in Fig. 383 is the button which must be held
down at all times when motors are receiving power.
Should it be allowed to rise it will allow the auxiliary
contacts at 2 to make upper contact, thus cutting power
off the motors while at same time through the medium
of a pilot valve at 3 (hardly visible in figure) and a
brake valve at 4, giving the emergency application of
air brakes.
When handle is at "Off" the button may be let up
without applying brakes.
The New York Central automatic acceleration is not
an attachment to the controller, nor is it a controlled
acceleration as in the Subway type. It is a true auto-
matic acceleration and the whole system of control is
built with that end in view.
The controller is shown in Fig. 493.
The controller when on second and fourth notch ahead
or on second notch reverse, has two wires in circuit
called the pick up and hold up wires. The duty of the
pick up wire is to close contactors, the contactor is then
held up by the hold up wire.
Fig. 384 shows how the automatic acceleration takes
place.
The power circuit comes from the trolley connection
through the resistances and through the coil of the relay
R and thence to the motors. E is the contact which the
relay opens and closes. The coil which operates the
The rod which pulls up the
contactor is marked M.
jaw of the contactors passes up through the contactor
}
AUTOMATIC ACCELERATION
633
coil M and carries four plates A, B, C and D. A series
of contacts as shown by the little black circles are ar-
ranged as in the diagram.
The two control wires I and 2, are connected to trol-
ley and energized through the controller.
pick up and W2 is the hold up wire.
WI is the
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Fig. 384. Diagram of Wiring and Interlocks for Automatic Accelera-
tion.
The contactor marked S is shut and the one marked
O is open.
By reference to O you will understand how S was
closed, in the following manner.
Current comes through WI and passes through the
B contacts down through the coil M and along W2 to
the next contactor,
634
ELECTRIC RAILROADING
The contactor now closes and a reference to S will
show how it remains closed.
The closing pushed the plates up and out of contact.
at B and D; and into contact with A and C. The
current from WI now passes through the A contacts
and on to the next contactor, where it "picks it up."
The coil M is now in the W2 circuit by means of the
C contacts and is "held up."
The circuit of WI is always closed either through the
A or the B contacts of some contactor. When passing
through the A contacts of a shut contactor it simply
passes on to the next. When passing through the B
contacts it is "picking up" the contactor for it goes
through the coil M in passing on to the next contactor.
The circuit of W2 is always closed either through the
Cor D contacts. When passing through the D contacts
of an open contactor the current passes on to the next
contactor. When passing through the C contacts of a
closed contactor it is "holding up" the contactor for it
passes through the magnet coil M.
If there were no relay R all the contactors would
close practically at once. When a contactor shuts like
S there is a sudden increase of the current to the motors
and the contact E is pulled open by the relay R. The
circuit of W1 is interrupted and hence contactor O does
not close.
When the motor speeds up the current is reduced and
E closes when O closes at once, for the current flows
again in WI and the magnet is energized.
So Wi picks up the contactors in succession as al-
lowed to do so by the contacts E; and W2 holds up
the contactors when closed by WI and passes through
the contactors, which are open, without affecting them,
AUTOMATIC ACCELERATION
635
The contactors are operated from a controller´ with
four notches forward and two backward.
reverse lever.
There is no
The controller handle will stay at the off position,
but at no other unless held there, as a spring acts against
the engineer whether handle is moved forward or back-
ward.
This is a safety device which cuts off the power if
the engineer becomes disabled or careless. There is a
button on the handle which when the handle is in the
off position is idle, but to start the train in order to
get power to the motors it must be pushed down and
kept down as the handle is moved around.
When the handle is returned to the off position in
making an ordinary stop this button is released but does
nothing except cut off power from the controller, which
has already cut power off from the motors.
Should this button be allowed to rise when handle is
in any on notch the emergency brake will be set.
The notches of the controller are named:
1. Switching.
2. Series.
1. Switching.
FORWARD.
3. Lap.
4. Parallel.
REVERSE.
2. Series.
When the controller is moved to N. 1 Forward the
I
reverser is thrown to the forward running position, and
contactors are closed placing the motors in series with
all resistance in.
636
ELECTRIC RAILROADING
This gives a slow speed for moving about the yards,
switching and the like. It is also your first speed in
starting a train. This speed must not be used very long
at one time as the resistances will heat. The proper
management of the train is to put on the switching speed
and then coast; or if that won't take you then throw
to the second notch, shut off and coast.
Notch 2: Five contactors are now automatically
energized in succession, separated by a sufficient time to
allow the train to accelerate at 114 M. P. H. P. S. This
time interval between the contactor closings is regulated
by the throttle relay.
When these operations are finished the motors are in
full series without resistance.
In moving from N 2 to N 3 there is a bridge con-
nection thrown across and the contactors put all the
resistance in with the two motors in parallel.
Notch 3 is a temporary notch and the handle is at
once moved to N 4 when the resistances are automat-
ically cut out at such intervals as will accelerate the train
at 14 M. P. H. P. S.
This finally places the motors in parallel without re-
sistance.
If the engineer wishes the handle can be thrown at
once to N 4 and the train will move forward at 14
miles acceleration. The contactors make all the above
mentioned changes automatically, so that 40 seconds.
after the start the train is moving at the rate of 50.
M. P. H.
In fact to get the quickest and smoothest start this
is the best way to handle the controller,
LESSON 37.
SINGLE-PHASE COMPENSATED MOTOR EQUIPMENT.
WITH SERIES PARALLEL CONTROL.
Electric railway motors in general use throughout the
world are operated, as is well known, by direct current
with a trolley voltage of about 600 volts. For heavy
service and extended systems the cost of copper re-
quired at 600 volts becomes a serious item, and for some
time there has been felt the need of a higher trolley
voltage. The use of alternating current for the trolley
would admit of a higher voltage than is possible with
direct current, as the voltage could be reduced by a
transformer on the car to the potential required by the
motors. The development of large power stations and
transmission systems has been principally with alternat-
ing current, requiring rotary converters, or other com-
mutating devices for changing the alternating current
into direct current suitable for the operation of electric
railways. Obviously there would be a great advantage
in a railway motor equipment that could be operated
from an alternating current high voltage trolley and
without the necessity of intermediate commutating de-
vices. Such an alternating current equipment would
offer a further advantage if it could be operated both
on alternating extensions of existing systems and also
on the direct current trolley where the latter is already
installed.
637
638
ELECTRIC RAILROADING
}
For several years engineers have been working on
this problem, and have developed a type of alternating
current equipment suitable for general traction work.
The activity displayed in Europe in adapting the three-
phase alternating current motor to the conditions of
railway service has never been fully shared by American
engineers, due to the limitations of the multiphase* in-
duction motor. The development of the single-phase
compensated motor (with a commutator) with its in-
herent fitness for traction work has attracted very wide
attention among railway interests, and work of a prac-
tical nature has been actively pushed on both sides of
the Atlantic. Considerable importance is therefore at-
tached to the operation in regular service of single-phase
alternating current motors. Its commercial possibilities
are largely due to the fact that the motors operate with
alternating current power outside the city limits and
with direct current power inside the city limits.
Alternating Current Motor.
The alternating current motor, Fig. 385 and Fig. 386,
is of the "compensated" type, so named on account of
the character of the field winding, which fully neutralizes
or compensates for the armature reaction. Both the com-
pensated motors and control are adapted for operation on
the 2,000 volt alternating current trolley between cities
and the standard 600 volt direct current trolley in cities.
This ability of the compensated motor equipments to run
over tracks equipped with either alternating current or
*Another word for polyphase.

SINGLE-PHASE EQUIPMENT
639
Fig. 385. 75 H. P. Series Compensated Motor. Pinion End.
Fig. 386. Car Axle Side of Motor in Fig. 385.
640
ELECTRIC RAILROADING
i
direct current trolley makes their field of application very
broad, as the cars can secure all the benefit of running
over existing city tracks without in any way sacrificing
their running qualities upon suburban sections equipped
with alternating current trolley.
The alternating current motor, with its inherent ad-
vantages of high voltage distribution, is eminently
adapted to replace the steam locomotive on either high
speed passenger or heavy freight haulage work; and as
the compensated type of motor is perfectly adapted to
operate on both alternating current and direct current
trolley, the alternating current motors must be consid-
ered a large factor in future suburban railway systems.
The compensated motor is essentially a variable speed
motor, differing in this respect from the multiphase in-
duction motor, whose constant speed characteristics
proved so serious a handicap to its successful adoption
in railway work. The characteristics of the compensated
motor are very similar to that of the direct current series
motor, while its commutating qualities and method of
control prove equally satisfactory.
The truck with two 75 H. P. motors is shown in
Fig. 387.
The A. C. compensated motor consists of an annular
laminated iron field with a winding similar to that of an
induction motor, and an armature provided with a com-
mutator similar in general mechanical construction to a
direct current railway motor armature. These motors
are wound, for 200 volts, are permanently connected two
in series, and are fed from the 400 volt secondary of
an 80 k. w. air-blast step-down transformer carried on
the car. The distributed character of the field winding

SINGLE-PHASE EQUIPMENT
641
fully compensates for the armature reaction, so that
power factors are relatively high throughout the range
of operation. This type of motor is so designed that
Fig. 387. Truck with 150 H. P. of Compensated Motors.
at the free running speed of the car, which is the condi-
tion most frequently met with in suburban work, the
power factor and efficiency are nearly at their maximum
642
ELECTRIC RAILROADING
values. A high power factor is desirable, as it reduces
the capacity and cost of the generating and distributing
systems, and more especially effects a material improve-
ment in the regulation of the alternating current gen-
erators. Unlike a direct current system which has a
practically constant potential at the sub-station bus-bars,
irrespective of the load, the drop in an alternating cur-
rent railway system increases with the load. It is de-
sirable therefore to maintain as good a power factor
as is consistent with good motor design, in order to
limit the total drop of the system to a reasonable amount.
The characteristics for alternating current running are
equal to direct current running in meeting the require-
ments of railway work. Unlike the multi-phase induc-
tion motor with its practically constant speed character-
istic, the compensated alternating current motor varies.
its speed with the load, and is thus better adapted to
operate trains over an irregular profile. The commuta-
tion of the compensated motor is equally satisfactory
when running on alternating current or direct current,
and this good commutation is secured by careful elec-
trical and mechanical design without resorting to high
resistance leads or other expédients liable to give trouble
in case of sustained heavy overloads.
Alternating Current Equipment Adapted for Direct
Current.
Our city railway systems have so expanded and cover
such a large territory as to make it very objectionable,
both on the score of first cost and complication, to in-
stall a separate alternating current trolley at reduced po-

SINGLE-PHASE EQUIPMENT
643
tential in order that cars equipped with alternating cur-
rent motors may benefit from running over city streets
at terminals and en route. There is a comparatively
small additional expense required to adapt alternating
current equipments to run on either alternating current
Fig. 388. Commutating Switch.
or direct current. This is accomplished with the use of
a standard K direct current series parallel controller
used in connection with a commutating switch, Fig. 388,
to change field connections, cut out step-down trans-
former, change line fuses, etc. The time required to
operate the commutating switch is but a few seconds.
The scheme of connections for the complete car wiring
is shown in Fig. 389.
4
644
ELECTRIC RAILROADING

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SINGLE-PHASE EQUIPMENT
645
The commutating switch is interlocked with two main
oil switches, Fig. 390, one being in the high tension
alternating current and the other being in the direct
current circuit; this interlocking being so arranged that
only one switch can be closed at a time, and the com-
mutating switch can only be thrown when the oil
switches are in the off position. Owing to the fact that
the alternating current trolley construction is off center,
while the standard city and suburban trolleys are di-
rectly overhead, it has been necessary to provide double
Fig. 390. Oil Switch. Interlocked with Commutating Switch.
sets of trolleys, one for alternating current and the other
for direct current, hence the necessity for interlocking
the oil switches and commutating switch to prevent trou-
ble should both trolley poles accidentally be up at the
same time. Where center wire construction is used on
both the city and suburban sections, the alternating cur-
rent and direct current trolley wires may be overlapped
for a short distance to facilitate changing from one trol-
ley to the other.
646
ELECTRIC RAILROADING
Sub-Station.
Owing to the fact that 25 cycle, three-phase gen-
erators are almost universally used to supply rotary con-
verters in existing interurban railway systems, both the
design of the compensated motor and the alternating
current distributing system is adapted to operate from
existing 25 cycle generating stations. As the alternating
current motor is single-phase, a single-phase generating
and distributing system commends itself on account of
its simplicity. The step-down transformers may be tied
together on the low tension side through the trolley with
consequent reduction in amount of copper required. Each
sub-station acts as a reserve to the adjacent one, and
a transformer may be cut out without shutting down.
a trolley section.
Trolley.
The form of alternating current trolley used is well
adapted to the requirements of steam roads where the
local service is taken care of electrically and through
passenger traffic and freight handled by steam locomo-
tives, pending a complete change to electrical operation.
The trolley wire and insulators being off center of track
are not exposed to the gases of the locomotive exhaust
with consequent deterioration, and furthermore a caten-
ary* construction placed off center can be hung much
lower than a standard center wire without interfering
with brakemen on freight cars. A low running trolley
at the side of the car is also preferable in main line
*See Lesson 33,
SINGLE-PHASE EQUIPMENT
647
operation, as it conforms better to the clearance diagram
of such roads without calling for too great a change in
height of the trolley wheel or bow.
Control.
With equipments operating with both alternating cur-
rent and direct current power, it is preferable to utilize
the standard series-parallel controller in order to mini-
mize the weight of controlling apparatus. Such a meth-
od of operation will not give quite so high efficiency
when accelerating with alternating current as could be
obtained with potential control. This difference in ef-
ficiency, however, is very small, partly due to the in-
frequency of stops occurring upon those sections of the
road equipped with alternating current trolley, but prin-
cipally due to the flexible character of the alternating
current motor which gives a high efficiency of accelera-
tion with series-parallel control.
With modern suburban cars, especially those equipped
with train control, air brakes, air compressors, etc., there
is some difficulty in suitably locating the power appara-
tus, even when equipped for direct current running only.
With cars equipped for both alternating current and di-
rect current running, using series-parallel controller,
there will be required but slightly more space and weight.
than for direct current running only. Should, however,
advantage be taken of the slightly better efficiency of
alternating current potential control, such cars must be
operated by alternating current upon suburban and city
sections with the resulting disadvantages, or the installa-
tion of two separate controlling systems must be consid-

648
ELECTRIC RAILROADING
ered, necessitating a considerable increase in weight and
difficulty in providing room for the necessary apparatus.
The efficiency of the potential control is not over 2
or 3 per cent higher than that of the series-parallel con-
trol, but the use of the latter, permitting operation with
both alternating current and direct current, secured the
advantage of the higher efficiency of the motors when
running with direct current over city streets.
Fig. 391. Air Cooled Step-Down Transformed.
For locomotive or other service where no necessity
exists for operation over city direct current systems, the
potential method of control does offer advantages suf-
ficiently great to warrant its adoption.
The 80 k. w. step-down transformer, Fig. 391, is air
cooled, forced draught being obtained by the motion of
the car itself. The transformer is suspended below the

SINGLE-PHASE EQUIPMENT
649
car floor, and all primary leading-in wires are carried in
brass tubing which is grounded. Car lighting and heat-
ing are effected from the direct current trolley in the
standard manner, and from the alternating current trol-
ley from the secondary of the transformer. Trolley
poles and wheels are of standard design, the alternating
Fig. 392. Air Compressor with Compensated Motor.
current trolley pole being somewhat shorter, as this wire
is lower than the direct current trolley. The base of the
alternating current trolley is treated with vacuum com-
pound, and further insulated from the car body by com-
position insulators. The air compressor for the brakes
and whistle is operated by a compensated motor which
operates from both alternating current and direct cur-
rent circuits. Fig. 392.
650
ELECTRIC RAILROADING
Comparative Operation on Alternating and Direct
Current.
It is instructive to compare the performance of the
compensated motor equipment when operated with al-
ternating current and direct current.
Comparative Alternating Current and Direct Current
Runs.
Length of run.
Weight of car
Time
• •
Average current on.
•
Average voltage.
*Kilo-volt-amperes full speed on
level.....
Volt-ampere-hours per ton-mile
of given run
Schedule speed including 15-
Average speed..
second stops
D. C.
A. C.
1.6 miles
1.6 miles
31.55 tons
180 seconds
31.55 tons
180 seconds
229 amperes
346 amperes
606
425
98
110.
86.3
125.5
32 m. p. h.
32 m. p. 1.
29.5
29.5
The lower volt-ampere-hours per ton-mile of the di-
rect current run are partly due to the better efficiency
and power factor of the compensated motor when run
with direct current, and partly due to the somewhat
higher rate of acceleration, permitting some coasting and
resulting in a more efficient speed-time curve. The dif-
ference in kilo-volt-amperes alternating current and di-
rect current depends upon the length of the run, and
*Another name for kilowatts.
SINGLE-PHASE EQUIPMENT
651
Full Series AC
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Motor Connections for 4-AC Motors used on both AC and DC Service
irviv
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Switch
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16 Aug. 1904
Fig. 393.
Engineering Dept.
General Electric Company
DS 4823
Arrangement of Fields and Armatures when Running D. C. and A. C.



ww
652
{
ELECTRIC RAILROADING
the values approach each other more nearly the longer
the run.
It will be noted that the compensated motors
run the car at practically the same speed with 200 volts
per motor alternating current and 300 volts direct cur-
rent. This uniform speed is obtained by series parallel-
ing the fields as shown in diagram of connections. Fig.
393.
Commercial Possibilities.
The compensated motor, having demonstrated its fit-
ness for traction work, opens up possibilities in convert-
ing main line steam roads which were closed to the direct
current motor and the rotary converter combination on
the score of first cost of operation. The form of trolley
suspension used is capable of being operated at more
than 2,000 volts, which together with its mechanical
construction, helps to solve the question of current col-
lection of heavy units at high speeds. The commercial
development of the alternating current motor is oppor-
tune, as steam railway managements throughout the
country are displaying great activity in acquiring com-
peting electric roads and in electrically equipping por-
tions of their systems now operating at a loss with steam
locomotives. The compensated motor is well qualified
to meet the conditions of local passenger service, and,
holds out the promise of much larger possibilities in
the way of direct competition with the steam locomo-
tive in main line work.
Fig. 394 shows car equipped with above described ap-
paratus.

SINGLE-PHASE EQUIPMENT
653
BALLS TOW SAN
Fig. 394. Car Equipped with Compensated Motors for Operation on A. C. or D. C.
654
ELECTRIC RAILROADING

Transmission Line o Incoming Line
·Disconnecting Switches
Incoming Line
Outgoing Line
O
5
Potential
Indicators
HI
Ground
Current
Transformers
22000 Volt Buses
Ammeter
Form K.DPOil Switch HHI
Trip Coil
S.P.S.T.Switches
Oil Cooled
Transformer
22000 Volt Auxiliary Buses
Reserve or
Future Transformer
Switc
Form K,S.POil Switch
Curr
Current Transformer
Lightning Arrester
2200 Volt Bus
Section Insulator
Trolley
HH
7
Intermediate Sub-station
Terminal Sub-station
DISTRIBUTION SYSTEM FOR SINGLE-PHASE RAILWAY, SINGLE-PHASE TRANSMISSION
Fig. 395.
SINGLE-PHASE EQUIPMENT
655

Incoming
Line
Potential
Indicators
Ground÷
Outgoing Line
HHH
Current
Transformers
Transmission
Line
Incoming Line
·Disconnecting
Switches
FormK, T.P
HHH
Ammeter
Oil Switch Trip Coil
Current
Transformer
22000 Volt Buses
S.P.S.T.Switches
Transformers
1
Form K, S.P.
Oll Switch
Lightning
Arrester
A
22000 Volt
Auxiliary Buses
Reserve or
Future Transformers
A
B
2200 Volt
Two-phase Buses
Trolley
HHH
L
Section Insulator
Intermediate Sub-station
Terminal Sub-station
DISTRIBUTION SYSTEM FOR SINGLE-PHASE RAILWAY. THREE-PHASE TRANSMISSION, SINGLE TRACK
Fig. 396.
656
ELECTRIC RAILROADING
The connections between the transmission line and
the trolley wire are shown in Fig. 395, where single-
phase current is used throughout. With a three-phase
transmission line, Fig. 396 shows the connections.
LESSON 38.
SPRAGUE-GENERAL ELECTRIC MULTIPLE UNIT CONTROL
FOR ALTERNATING AND DIRECT CUR-
RENT OPERATION.
Since the first single-phase equipment was placed in
commercial operation, the advantages gained by the
adoption of such a system for certain phases of railway
work have become more generally recognized. In con-
sequence its field has enlarged, and now there is a de-
mand for such cars equipped with multiple-unit control.
The General Electric Company has designed and devel-
oped suitable apparatus capable of controlling both single.
cars and trains equipped with single-phase motors when
operating on lines supplied wholly with alternating cur-
rent, or with alternating current on one portion of the
line and direct current on another.
In general the alternating direct current multiple-unit
system of control is similar to the well-known Sprague-
General Electric type M control for direct current op-
eration. The changes necessary in the type M control
to adapt this apparatus for alternating current operation,
are of a simple nature, and in this later development all
the essential features and advantages of the older type
of construction are maintained.
The multiple-unit system may conveniently be divided
into two parts, the first consisting of a motor controller,
composed of a number of electrically operated switches
657
2
658
ELECTRIC RAILROADING
called "contactors," which take the place of the ordinary
cylinder controller, and may be considered as a more
refined development of such, designed to handle currents
of too large a magnitude to be dealt with by the ordi-
nary controller. This apparatus is usually installed un-
derneath the car.
The second part comprises a "master controller," the
function of which is to operate the contactors; and a
multiple cable, which extends the length of the train,
and is provided with couplers between cars.
The train line apparatus, such as connection boxes,
couplers, cut-out switches and cables, are identical with .
those used on standard type M equipments for direct
current operation.
To adapt such a system for both alternating and di-
rect current operation changes are made in the circuits
of the contactor coils when the car passes from an alter-
nating to a direct current section, and vice versa; the
motor fields are also connected in series for direct cur-
rent operation, and in parallel for alternating current.
These changes are made as the car passes the short.
dead section separating the alternating and direct cur-
rent portion of the trolley line, and at the same time
either the resistance or compensator leads are put in cir-
cuit, as required.
1
For alternating current operation "Potential Control":
is used; that is, acceleration is obtained by increasing
the potential at the motor terminals by connecting com-
pensator taps of successively increasing voltage to the
motors in proper sequence, corresponding to the resist-
ance steps of the direct-current equipment.
When the cars are to run on both alternating and
{

MULTIPLE UNIT CONTROL
659
6
GOVERNOR
MOTOR CUTENES
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BELIGHTNING ARRESTER
COMMUTAKING
HELME
MOTORS
Fig. 397. Arrangement of Sprague-General Electric A. C. and D. C. Control on Car.

660
ELECTRIC RAILROADING
direct current lines, a special switch is supplied to make
all the necessary changes in the circuits, and suitable
cast grid rheostats are provided for giving the desired
direct current acceleration which is obtained by cutting
out resistance from the motor circuit step by step, in
an exactly similar manner to that employed on ordinary
direct current equipments.
Fig. 398. Direct Current Contactor.
List of Apparatus.
The apparatus for each alternating-direct current car
equipment consists essentially of:
Master controllers, Fig. 378.
Train cable and couplers, Fig. 397.
Contactors, Figs. 398 and 399.

MULTIPLE UNIT CONTROL
661
Compensator, Fig. 400.
Set of rheostats.
Commutating switch, Fig. 388.
Trolleys, Fig. 397.
Motor cut-out switches, and
The necessary protecting devices.
The master controller and contactors are same as type
M equipment.
Fig. 399. Alternating Current Contactor.
Compensator.
The compensator, Fig. 400, which reduces the trolley
potential to the proper voltage required for the motor,
is of the oil-cooled type, suitably designed for suspend-

662
ELECTRIC RAILROADING
ing underneath the car body. It consists of a specially
designed transformer structure entirely enclosed in a
corrugated iron casing. The end castings are provided
with stuffing boxes to prevent any leakage of oil where
the taps enter. The coils of the compensators are
specially well insulated to withstand the vibration to
which such equipments are subjected. Taps giving vari-
ous voltages are provided for controlling the speed of
the motors.
Fig. 400. Compensator.
Rheostats.
The rheostats are of the standard cast grid type, and
are exactly similar in all respects to those used on the
ordinary street car equipment.

MULTIPLE UNIT CONTROL
663
Commutating Switch.
The commutating switch, Fig. 388, is used to make
all the necessary changes in the circuits when the car
passes from an alternating to a direct current section of
the line, or vice versa. All such changes are accom-
plished by one operation.
Fig. 401. Oil Switch for A. C. with Low Voltage Release.
Current Collectors.
The current may be collected by means of standard
trolley wheels, poles and bases applicable for high speeds,
or, when desired a sliding or rolling contact collector
of the pantograph or bow type, such as has been used
in Germany for a number of years, may be employed.
Insulation from the roof of the car is obtained by
specially treated hard wood planking mounted on high
tension insulators.

664
ELECTRIC RAILROADING
Protective Devices.
The oil switch, Fig. 401, in the high tension circuit
is electrically operated and held closed by a coil energized
from a small auxiliary transformer. This switch is pro-
tected by an expulsion fuse, Fig. 402. The main direct
current switch, Fig. 403, has the same characteristics
Fig. 402. Expulsion Fuse Rated at 30 Amperes with 6,600 Volts A. C.
as the oil switch but is energized directly from trolley.
It is insulated for the alternating current line voltage
and is protected by a copper ribbon fuse with magnetic
blow-out. Fig. 404.
A single fuse of the magnetic blow-out copper ribbon
type is used for protecting the motor circuit when oper-
ating either A. C. or D. C.
Both the alternating and direct current circuits are
protected by suitable lightning arresters.

MULTIPLE UNIT CONTROL
665
Fig. 403. Direct Current Switch.
Fig. 404. Fuse Box for D. C. Circuits.
666
ELECTRIC RAILROADING
Cut-Out Switches.
A cut-out switch is used in connection with each pair
of motors to disconnect a disabled motor when any car
is operating individually as a single unit. As all the leads
from each pair of motors run through their own cut-out
switch, this is accomplished by simply turning the handle
of the switch to the proper position.
Train Line.
The train line consists of a cable composed of ten
conductors and runs through the entire train; the con-
nections being made between the individual cars by
means of suitable couplers. The master controller is
connected to the train line at the connection boxes on
each car, from which a multiple cable is run through
the control cut-out switch to the operating coils of the
contactors.
Auxiliary Circuits.
The circuits for the air compressor motor and those
governing the lighting and heating of the car, are all
protected by enclosed switches and fuses.
Air Compressor Motor.
The air compressor motor of the alternating-direct
current compensated type; its exciting fields are con-
nected in parallel for alternating current and in series
for direct current operation, Fig. 392. The necessary
!
MULTIPLE UNIT CONTROL
667
changes in connection are made through the medium of
the commutating switch already described. The air pres-
sure is regulated by a standard General Electric air com-
pressor governor. Fig. 476.
Motor Connections.
The arrangement of the motor connections are de-
pendent upon the service conditions required. The usual
arrangement for both alternating and direct current op-
eration is with all the motors on the car connected in
series which permits of the use of fewer pieces of con-
trolling apparatus and of less current carrying capacity
than would be necessary if the motors were connected in
parallel.
Method of Control.
During alternating current operation the car is con-
trolled as follows:
On the first point of the master controller the motors
are connected to a compensator tap giving approximately
half voltage. After this point acceleration is obtained
by cutting in more sections of the compensator winding,
until on the last tap the motors are connected to the full
working voltage tap. A small section of cast grid rheo-
stat is cut into circuit during the instant of changing
the motor connection from each compensator tap to the
succeeding tap. This permits of an uninterrupted cur-
rent supply to the motors without short-circuiting the
various sections of the compensator winding. There are
five steps on the master controller for alternating current
operation, each constituting a running point, and seven
668
ELECTRIC RAILROADING
steps for direct current operation, the last step being
the running one.
Changing from Alternating to Direct Current Operation.
The change from alternating to direct current opera-
tion is accomplished at a dead section in the trolley wire.
At the instant the car enters this dead section whichever
main switch is closed will open owing to the fact that
the circuit energizing its retaining coil is broken. The
car can run over this dead section at full speed and all
that the motorman has to do to obtain the proper con-
nections is to throw the commutating switch and close
the main alternating or direct current switch, as the
case may be.

LESSON 39.
WESTINGHOUSE UNIT SWITCH SYSTEM.
This system is operated by a small controller (Fig.
405) which has a center or off position and three posi-
tions on each side of the center for forward and reverse
movements.
Fig. 405. Controller. Cover on and off.
The circuits which this controller opens and closes are
supplied with current by a 14 volt storage battery, there
being a duplicate set on each car.
The arrangement of motor circuits is done by a set
of 13 switches or contactors which are opened and closed
by small pneumatic cylinders drawing their supply
through electro-magnetically operated valves, from a res-
ervoir containing 70 lbs. pressure.
669

670
ELECTRIC RAILROADING
These electro-magnetic valves are operated by the cir-
cuits which are open and closed by the controller.
These 13 switches, with their air cylinders, magnetic
valves and air reservoir, together with a blow out mag-
net to suppress arcing at switches, are all arranged into a
Switch Group.
This switch group is shown as it appears when bolted
to the under frames of car in Fig. 406. With covers
Fig. 406. Switch Group. Cover on.
removed it looks as in Fig. 407. The cast iron flange
which is bolted to car frame shows plainly. Below are
the magnetic valves, and at bottom are the arc chutes
of the switches.
The sectional view in Fig. 408 shows the different
parts of the switch group.
Air is supplied from the reservoir N by action of the
electro-magnet L through a valve not shown by means

WESTINGHOUSE SYSTEM
671
of a passage as on right side of figure (where the sec-
tion comes between two cylinders) to the cylinder above
the piston C.
The piston is forced down against the spring P, which
will return piston to original position when air is ex-
hausted.
Fig. 407. Switch Group Opened.
This swings the outer end of arm E up against ter-
minal H. The two studs M are the terminals of a motor
circuit. They are insulated from the plate J which they
are in. T also serves as the pole piece of the large mag-
net A which is the blow out for all switches.
The end of E has a rocker motion controlled by spring
F, so that a rubbing contact is made with H. The ex-
treme end of the contact piece D is a removable piece G.
The upper end of the piston rod engages some con-
tacts at K. These interlocks control the passage of cur-
rent to next valve magnet and thus produce an auto-
matic acceleration.
672
ELECTRIC RAILROADING

Total length 20%-
Fig. 408.
Sectional View Switch Group.
L
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WESTINGHOUSE SYSTEM
673
Since the normal position of all switches is open, any
failure of air supply will allow all switches to open and
no harm will result.
Controller.
In the off position of the controller all unit switches
are open and the reverser in position last used. The
first position of controller throws the reverser (by op-
erating its air valve) to forward or reverse position,
according to whether handle is moved to right or left
of center position. If reverser is already in correct posi-
tion it simply stays there. In addition the motors are
placed in series with all resistance in.
The second position puts the "lift up" and "retaining"
wires in commission and by means of interlocks and the
limit switch* (explained in Lesson 36) in four steps it
cuts out resistance and places motors in full series.
The third position changes motors to parallel with
resistance and then cuts out resistance until full parallel
is reached.
}
1
Limit Switch.
This switch (Fig. 409) consists of a copper disk rest-
ing on two terminals which are in the pick up wire. The
magnet which by means of an iron core raises the disk
is in series with one of the motors. At any time the
current input exceeds the proper amount the limit
switch is operated and pick up wire opened, thus arrest-
ing further closing of unit switches. (See Lesson 36.)
*This device is practically a relay, but is called a limit switch
by Westinghouse Co. and a current limit or throttle relay by
General Electric Co. In Lesson 36, it is simply called a relay.

674
ELECTRIC RAILROADING
Reverse Switch.
This switch (Fig. 410) with its magnetic valves and
air cylinders arranges the motor field and armature cir-
A13321500
Fig. 409. Limit Switch.
cuits for forward or reverse running. It is provided
with an interlock so that switch group is inoperative

WESTINGHOUSE SYSTEM
675
unless the reverse switch is fully thrown, and making
good contact, in the direction indicated by controller
handle.
Storage Battery.
The current for magnet valves is furnished by two
storage batteries of 7 cells each, with 40 ampere hours
capacity. One battery is on operating circuits, while
the other is being charged by the lighting circuit.
Fig. 410. Reverse Switch.
The positive side of the battery is connected to train
cable through controller and the negative side to the
valve magnets. In this way when a train cable circuit
is completed at the controller current flows through valve
magnet.
676
ELECTRIC RAILROADING
Circuit Breakers.
Each car has a circuit breaker which is reset after
blowing by a magnet. All the breakers of a train can
be reset at once by using the reset switch on the car the
motorman is on. In a similar way in case of electrical
troubles all the circuit breakers may be opened or tripped
by a switch in motorman's compartment. Current may
be cut off from any one car by opening line switch cut
out without affecting operation of other cars.
Line Relay.
A device similar to limit switch, which is connected
as a shunt, across supply mains. It has a series resist-
ance to protect it from the high voltage. Its copper disk
is held against the terminals by the magnet against the
tension of a spring. Should the voltage fail on trolley
or third rail, this spring will open the circuit from the
storage battery, the unit switches will open and no harm
will result when voltage is suddenly re-established.
Operation of System.
Fig. 411 gives a wiring diagram of the unit switch
control, the operation of which will be better understood
after a study of Fig. 412.*
*In studying this and other diagrams, if a few pieces of paper
be cut of such a size as to just cover the numbers of the switches
or contactors, and as the text says the switches close, cover the
numbers, the circuits formed will be closely indicated.
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WESTINGHOUSE SYSTEM
677
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Fig. 412. Diagram of Motor Control.
Unit Switch System.
6
678
ELECTRIC RAILROADING
With controller on second point the following things.
happen: Switch 8 is closed, cutting out resistances Ri
and R5;* the interlock† on 8 closes switches 9 and 10.
Looking at Fig. 411, where the interlocks are shown
directly above the air cylinders of the switches, you will
see that when 9 closes its interlock closes and when 10
closes its interlock opens.
It is the closing of interlock on 9 which closes switches
II and 3, cutting out more resistance. Switch 3 has no
interlock, but the interlock on switch II closes switches
I and 2, thus placing motors in full series.
With controller on third point all these switches re-
main closed and 5 also closes. This does not produce
any electrical change, but through its four contact inter-
lock it opens switches 7, 8, 9-10, 11-3, 1-2. It does this.
to prepare circuits for next change, and it keeps the
motors in series itself by cutting out all resistance.
Now that switch 10 is open its interlock is closed
again (Fig. 411) and current flows from the low con-
tact on interlock 5 to the magnet coil 4-1, which closes
switches 4-12-13.§
The state of affairs is now such that if switch 5 were
*Because current will flow around the low resistance shunt
instead of through resistance grid.
tInterlocks move down when switches close.
These switches are mentioned together in this way, because
they always open or close together, being controlled by the same
magnet valve. See Fig. 411.
Because when switch 4 closes its interlock energizes lower
coil which is marked 4-12-13. This coil closes switches 12 and 13,
and keeps switch 4 closed, even though later switch 10 will close
and open its interlock,
WESTINGHOUSE SYSTEM
679
1
to open, the motors would be in parallel with all resist-
ance in.
When controller is on first point switch 6 is closed, its
interlock closes switch 7. The motors are then in series
with resistance.
The interlock on 4 has right hand finger short enough
so that when switch is closed coil 5 is cut off of circuit
and switch 5 opens thus, placing motors in parallel with
resistance. Although 12-13 close a fraction of a second
before 5 opens no harm could result, for the state of af-
fairs is as follows:
2
There is a circuit from T₁ to G₁ containing two mo-
tors in series; perfectly safe. A circuit from T₂ to G₂
containing resistance R, R., R, Re, R, and Rg
amounting to 1.36 ohms; sufficient to prevent a short
circuit. A circuit between T, and T, containing a
motor and the resistance R., R, and R. also perfectly
safe.
1
The interlock on 4 when closed energizes the short
left hand contact which closes switches 9-10. Then in
succession as described before switches 3-11 and 1-2
close, thus placing motors in full parallel.
Automatic Acceleration.
In the system of automatic acceleration described in
Lesson 36 the contactor coil was shifted from pick up
to hold up circuit.,
In the unit switch system most of the valve magnets
of the air cylinders have two operating coils called the
pick up and retaining coils. The pick up coils are in
circuits affected by the action of limit switch and the
retaining coils are in other circuits.
680
ELECTRIC RAILROADING
Thus the controller and interlocks may arrange cir-
cuits so that a certain switch would close were it not
that the circuit is open at the limit switch. As soon as
that switch closes the valve magnet operates and switch
closes.
If a certain switch is being held by the retaining coil
the action of limit switch has no effect on it.
In Fig. 411 the wire L or lifting circuit comes from
the limit switch, while wire R or retaining circuit comes
directly from battery.
}
LESSON 40.
LOCOMOTIVE FOR THE NEW YORK, NEW HAVEN AND
HARTFORD RAILROAD USING EITHER ALTER-
NATING OR DIRECT CURRENT:*
General System-The New York, New Haven & Hart-
ford Railroad Company has started the electrical opera-
tion of their main line between New York City and Stam-
ford, Conn., a distance of over 33 miles. That portion of
the road which lies between the Grand Central Depot and
Woodlawn, New York, utilizes the tracks of the New
York Central Railroad and constitutes a portion of the
electrical zone of that company within which the direct-
current third-rail system is installed. Between Woodlawn
and Stamford the road is equipped with the Westing-
house single-phase alternating-current system and the
trains will be operated by electric locomotives which take
alternating current from the overhead trolley line. The
power station of the New Haven Company is located at
Riverside, Conn., three miles from Stamford. The power
equipment includes three Westinghouse-Parsons horizon-
tal steam turbines driving 25 cycle, alternating-current
generators of the revolving field type, which have a rated
continuous capacity of 3.750 kw. each when running
single-phase and of 5,500 kw. when supplying a three-
phase service. The generator armatures are designed for
*To Railroad Men (a monthly magazine) we are indebted for
cuts.
681
682
ELECTRIC RAILROADING
both single-phase and three-phase connection. They are
wound for 11,000 volts and are connected direct to the
trolley system. Absolutely no transforming stations or
reducing transformers along the line will be required, but
the entire system will be operated direct from a single
central station without the interposition of substations or
auxiliary apparatus of any kind between the switchboard
and the cars. This desirable simplicity is made possible
by the alternating-current system and the high trolley
e.m.f. which will be employed. It is probable that, with
a service equivalent to that now given by steam locomo-
tives, electrical operation can be extended a distance of
20 miles beyond Stamford without the use of a higher
transmission potential or the introduction of transforming
stations.
High Potential Trolley Line-The overhead construc-
tion is supported from steel bridges which will be located
every 300 feet and which will normally span from four
to six tracks, though on certain portions of the road
longer bridges will be employed. Every two miles the
bridge is made of a specially heavy construction-forming
an anchor-bridge to make the overhead structure even
mote secure. The trolley wires are hung from steel mes-
senger cables which, in turn, are supported by heavy in-
sulators mounted upon the steel bridges. Each trolley
wire is suspended from a pair of steel messenger cables
by triangular supports, forming a double catenary sus-
pension of great strength and stiffness. The triangular
supports are placed about ten feet apart. The messenger
cables will have a total sag of about six feet, while the
trolley wire itself will be held in a practically horizontal
position.
ELECTRIC LOCOMOTIVES
683
The trolley system is divided into sections approxi-
mately two miles in length, each section being separated
from its neighbors by heavy line insulators. Adjoining
sections will be connected through automatic oil-type cir-
cuit breakers. If a short circuit or other trouble occurs
in any section, therefore, it can be cut out without dis-
turbing the operation of other portions of the line. Two
feeder wires will be carried the whole length of the alter-
nating-current line and will be so connected to the various
sections of the trolley system by automatic switches that
any section of four or more trolleys can be cut out of
service and those beyond kept in operation.
The trolley wires will be held normally at a height of
22 feet above the track. The overhead system is designed
with a safe margin to meet the stresses imposed by the
most severe conditions—such as high winds or heavy
coatings of ice.
Locomotives-Thirty-five locomotives are to be fur-
nished by the Westinghouse Company, suitable for opera-
tion on the direct-current division between the Grand
Central Depot and Woodlawn, and on the alternating-
current portion of the line between Woodlawn and Stam-
ford. Ten locomotives have already been constructed.
The frame, trucks and cab of the locomotive were built
by the Baldwin Locomotive Company, according to de-
signs developed with the co-operation of the New Haven
Railroad and the Westinghouse Electric and Manufactur-
ing Companies.
The Frame-As the entire space between the wheels is
occupied by the motors, it was impossible to transmit the
draw-bar pull through the center line of the locomotive;
so the entire strain is carried by the strong plate girders
684
ELECTRIC RAILROADING
which make up the locomotive frame. A Westinghouse
friction draft gear is mounted directly underneath the
box girder at each end and is applied to two steel bump-
ers laid horizontally between vertical gusset plates on the
ends of the side channels.
The Trucks-The running gear consists of two trucks,
each mounted on four 62-inch driving wheels. The trucks
have side frames of forged steel to which are bolted and
riveted pressed steel bolsters which carry the center
plates. The weight on the journal boxes is carried by
small semi-elliptic springs with auxiliary coiled springs
under the ends of the equalizer bars, to assist in restor-
ing equilibrium. A very strong construction is secured
without excessive weight by the use of bolsters 30 inches
wide at the center plate and extended to nearly double
that width at the ends which are bolted to the side frames.
Center pins 18 inches in diameter transmit the tractive
effort to the frame. They are well lubricated to permit
free motion on curves. The truck pedestals are provided
with wedge and gib adjustments to take up wear, and the
bearing brasses are easily removable by hand. The dis-
tance between truck centers is 14 feet, 6 inches.
Cab-The cab is formed of sheet steel mounted on a
framework of Z bars which supports the walls and roof.
Windows are provided at each end, giving an outlook on
both sides and in front of the locomotive; and the driver
is so close to the front that he can see the track a very
few feet ahead. This advantage is not possessed by any
type of steam locomotive now in service. The master-con-
trollers, auto-transformers, instruments, grid resistances,
air operating valves, compressors and other auxiliary
apparatus are mounted inside the cab upon an angle-iron
ELECTRIC LOCOMOTIVES
685
framework which is built into the cab and securely an-
chored to floor and roof. A clear passage-way is left
through the center. Trap doors in the floor furnish easy
access to the motors for inspection or repair.
Equipment-The equipment of the locomotive includes
four gearless motors, controlling apparatus and auxili-
aries.
Motors-The motors are of the gearless type, designed
for operation on both single-phase alternating and direct.
current. They are wound for approximately 235 volts
on alternating current and 275-300 volts when operated
by direct current. They have normal rated outputs of
250 H. P. on the basis of ordinary railway practice, and
a continuous capacity of 200 H. P. each. The locomotive
therefore, has a continuous operating capacity of
800 H. P.
The motor frames are made of cast steel and are of a
circular, skeleton form. They are divided horizontally
into two parts in order to give access to the inside of the
field or to the armature. A laminated core with slotted
projecting poles is built up within this frame and wound
with field coils of flat copper strap insulated between turns
with asbestos and filled with an insulating compound
which is heat-conducting and water-proof, so that a
sealed coil is produced which can withstand moisture.
and internal heat. Copper bars are placed in slots in the
pole faces and connected to form a continuous neutral-
izing winding which forms part of the circuit including
the main field coils, the armature coils and the auxiliary
winding, all in series. This auxiliary winding produces a
magnetic field which opposes and neutralizes the reaction
of the armature. It is so formed that it need not be dis-
turbed in order to remove the main field coils.
686
ELECTRIC RAILROADING
The armature core is built up of soft steel punchings
which are assembled on a cast iron spider and held in
place and keyed to prevent their turning. The surface is
slotted and the armature winding is arranged in three
layers. The two upper layers are composed of copper
strap connected to form the usual direct-current type of
winding. The third layer constitutes the preventive wind-
ing. It is connected between the commutator and the
main winding. This preventive winding is so propor-
tioned as to prevent sparking, due to the normal working
current and that which is produced in the coil under com-
mutation, when short-circuited by the brush in an alter-
nating field. The individual coils are insulated along
their entire length by overlapping layers of mica tape,
and each group is further insulated from the core by a
molded mica cell. The completed winding is held firmly
in position by insulating wedges. The ends are banded
down against the coil supports.
Suspension-The weight of each motor is carried on a
frame which passes over the wheels and side frames and
rests on the journal boxes. Each frame carries four bolts
which receive the weight of the motor and each bolt is.
fitted with a heavy coil spring at its lower end through
which all weight is transmitted to it, so that the motor is
carried on very flexible springs and is independent of the
truck frame. The torque of the motor and the jar caused
by sudden starts and stops are transmitted from the
motor to the truck through heavy tie-rods which affect
the motion of the motor only lengthwise of the locomo-
tive. The armature is not placed directly on a shaft but
is built up on a quill through which the car axle passes
with about five-eighths inch clearance all around. The
ELECTRIC LOCOMOTIVES
687
bearings which carry the field frame are mounted on
this quill and from a flange at each end of the quill seven
round pins project parallel to the shaft into corresponding
pockets formed in the hub of the driving wheel. The
torque of the motor is transmitted from these pins to the
wheel through helical steel springs which are wound with
their turns progressively eccentric, and which are con-
tained between two steel bushings, the smaller of which
slips over the pin and the larger fits in the pocket in the
wheel. These springs are under compression both longi-
tudinally and horizontally so that, at all times, they fill
the pockets in the wheel but permit a vertical and a lateral
motion. Their longitudinal compression between the
quill and the segmental cover over the outer ends of the
pockets in the wheel keeps the motor at all times midway
between the hubs. The end play of the motor does not
come directly on the wheels but is taken by strong coiled
springs inside of the driving pins, which press against the
covers in the outer ends of the spring pockets in the
wheels. Though normally required to transmit only the
torque of the motor and to keep the motor axis parallel
to the axle, these springs are amply strong to carry the
entire weight of the motor. They allow a total vertical
movement of about 3/4 inch. The torque of the motor is
taken by heavy parallel rods which anchor the frame to
the truck above and below the axle and permit vertical
or side motion of the motor but prevent excessive bump-
ing strains from coming on the driving springs. If these
springs are compressed more than 1/4 inch by the heavy
centrifugal force exerted by the motor when rounding
curves, the force is taken up by noses on the motor which
fit into corresponding recesses in the cross ties between
the side frames of the locomotive.
688
ELECTRIC RAILROADING
This suspension has the advantage of removing all
dead weight from the axle, of driving through springs,
and at the same time of having the motor thoroughly
anchored to prevent undue strain on the driving spring.
The only parts of the locomotive not spring supported
are the driving wheels, axles and journal boxes.
Forced Ventilation-The motors are arranged for ven-
tilation by a forced circulation of air which enters under
pressure, is distributed throughout the motor and escapes
through the perforated covers. In the floor of the cab
there is a natural conduit formed by the side channels of
the frame, the floor and side walls of the cab, and a lower
plate, through which air is carried to the motors, trans-
formers and resistances. This method of cooling im-
proves the continuous capacity of the apparatus and is, in
a large measure, accountable for the high continuous
rating of the motors which almost equals that on the
one-hour railway basis. The air furnished to the motor
may be taken from the inside of the cab and can there-
fore be kept relatively clean and dry.
Current Collection-On the direct-current part of the
line current is taken from the third-rail system by eight
collecting shoes, four on each side of the locomotive,
arranged in pairs of two each. There are two pairs on
. each side, one at each end, for the purpose of bridging
such gaps as may occur in the third-rail system. The
direct-current contact shoes are designed to work on two
forms of third rail-one in which the shoe runs under the
rail, and the other on top of the rail. To collect alter-
nating current from the high-potential overhead trolley
line, the locomotive is equipped with two pantagraph type,
bow trolleys, each of which has a capacity sufficient to
•
ELECTRIC LOCOMOTIVES
689
carry the total current required by the locomotive under
average conditions-two being provided to insure reserve
capacity.
The Control System-On direct current the motors are
controlled in series parallel as in ordinary railway prac-
tice. In alternating current operation no resistance is
used in the regular run, but a small resistance, which
constitutes a preventive device to diminish the short-cir-
cuiting effect when changing from one transformer tap
to another, is employed in passing from one working step
to the next. There are six alternating-current voltages
or running points, corresponding to six taps from the
auto-transformers, and there are a small number of mid-
way steps which are used only in passing between work-
ing notches. Experience has shown that the number of
steps required in alternating-current operation to give a
smooth acceleration is considerably lower than in direct-
current practice. In consequence, the controller is so ar-
ranged that on alternating current about half as many
steps are used as on direct current. Tests so far con-
ducted show that the acceleration on both alternating and
direct current is very smooth.
There is one feature of the direct-current control which
is not generally found at the present time in direct-cur-
rent equipments, viz., the shunting of the field for higher
speeds. In the series position in direct-current operation
the motors have an efficient running point. It is usual
railway practice to pass from the series to the multiple
position without an efficient intermediate running speed.
With the New Haven equipments, however, the type of
motor used permits shunting of the field without impair-
ment of commutation or operation and higher speeds are

069
ELECTRIC RAILROADING
427
027
3469
Fig. 413. New Haven Locomotive in D. C. Zone. A. C. Trolleys Down. Third Rail Shoes Down.
ELECTRIC LOCOMOTIVES
691
provided by shunting the fields before passing into mul-
tiple. In this way several efficient running points are
obtained between the series and multiple positions; and
tests have shown that these motors operate properly on.
direct current with their fields shunted down to half their
normal strength. When operated on direct current, the
current is fed directly to the motors. On alternating cur-
rent, however, auto-transformers are required, as the
alternating-current trolley voltage is 11,000. Two such
transformers form part of each equipment—one mounted
on each side of the cab floor to balance the weight. They
are connected in parallel across the high voltage, but on
the low-voltage side each transformer feeds one pair of
motors through a separate control unit. This means that
the control system when operated on alternating current,
consists of two normally independent units.
The main controllers are the Westinghouse electro-
pneumatic unit switch type. The design differs somewhat
from that used in direct-current service, because of the
fact that the switches, blow-outs, etc., must operate on
both alternating and direct current, as many parts of the
controller are common to both systems. The reversing
switches are also parts of the unit switch groups. The
main controllers are operated from master controllers at
each end of the cab. The control system is arranged for
multiple unit service, so that two or more locomotives can
be coupled to the same train and handled by a single
driver.
There are six switch groups, each containing unit
switches. The two line switches are so connected in the
switch groups that each carries the current supply to each
pair of motors when they are operating in parallel com-

692
ELECTRIC RAILROADING
827
027
2
Fig. 414. New Haven Locomotive in A. C. Zone. A. C. Trolleys Up. Third Rail Shoes Up.

ELECTRIC LOCOMOTIVES
693
Fig. 415. New Haven Train.

694
ELECTRIC RAILROADING
bination. When the motors are in series, one of the line
switches carries the current supply to all. Each line switch
is provided with an overhead trip so connected that all
of the switches of both switch groups as well as both the
line switches open in case of an overload or short circuit
on either pair of motors or in the circuit of either pair.
The overload trip is automatically locked out when
brought into action and cannot be reset until the master
controller is returned to the off position.
Fig. 416. One Truck of New Haven Locomotive.
The external resistances used in regulating the flow of
current to the motors are arranged in two groups which
are connected in series when the motors are in series, and
in series with each motor when the motors are in parallel.
The change over between the direct current third rail and
the alternating current overhead system can be made
easily and quickly even when the locomotive is running
at full speed.

ELECTRIC LOCOMOTIVES
695
An ammeter is mounted in each end of the locomotive
in plain view of the operator when at the master con-
troller.
The master controller is of the drum type and is oper-
ated by a lever which moves through an arc of about 60
degrees, with notches and latch wheel to define the dif-
Fig. 417. One Complete Motor for New Haven Locomotive.
rerent positions. Reversing is accomplished by a separate
handle which interlocks with the main lever. When the
master controller is in the off position, connections are so
established that all circuit breaker trips which may be
open are closed by the simple closing of a small switch

696
ELECTRIC RAILROADING
conveniently located in the locomotive cab. Current is
supplied to the control circuits by two sets of 7-cell
storage batteries, each of which has a capacity of 40
ampere-hours and weighs 150 pounds.
In connection with the switch groups, cut-out switches
are provided so that either pair of motors may be cut out
by simply rendering certain switches inoperative. It is
thus possible to cut out the motors without manipulating
the main circuit.
Fig. 418. Complete Armature Mounted on Locomotive Axle.
Auxiliaries-The auxiliary equipment includes two air
compressors driven by motors which can be operated on
either alternating or direct current; two blowers driven.
by similar motors and which furnish air to the trans-
formers, motors and direct-current rheostats; oil circuit-
breakers for the high-tension circuits; switches to change
the equipment from alternating to direct current; a steam

ELECTRIC LOCOMOTIVES
697
generator to supply heat to the railway coaches in cold
weather; a complete Westinghouse air brake equipment,
signal apparatus, automatic bell ringers, whistles, sanding
apparatus, etc.
Dimensions and Performance-The New Haven loco-
motive measures 36 feet, 4 inches over the bumpers and
weighs approximately 85 tons. It is capable of handling
a 200-ton train in local service on a schedule speed of 26
Fig. 419. Armature Mounted on Quills.
miles an hour, with stops averaging about two miles apart
-making in such service, a maximum speed of about 45
miles per hour. It can also handle a 250-ton train on
through service with a maximum speed of about 60 miles
an hour. With heavier trains it is planned to couple two
or more locomotives together and operate them in mul-
tiple.
Tests-The tests which have been made on the first
locomotive equipped show that it will, without difficulty,
meet all the requirements for which it has been designed,

698
ELECTRIC RAILROADING
Fig. 420. Driving Quill.
Fig. 421. Pockets in Driver for Fingers of the Quill,
ELECTRIC LOCOMOTIVES
699
This locomotive has, on actual test, repeatedly accel-
erated a 200-ton train at a rate of .5 of a mile per hour
per second, which is in excess of the rate required by the
service conditions of the New Haven road. The locomo-
tive has been operated at speeds above 60 miles per hour.
without difficulty.

Fig. 422.
N
Method of Placing Springs Between Quill Fingers and Driving
Pockets.
In Fig. 413 is shown a locomotive standing in D. C.
zone with both trolleys and shoes down; when standing
in A. C. zone, as in Fig. 414, both trolleys and shoes are
up. In Fig. 415 is shown a regular New Haven train,

700
ELECTRIC RAILROADING
One of the two trucks under the locomotive is shown
in Fig. 416. One complete motor mounted on its pair of
drivers is shown in Fig. 417. The eyes for the tie rods,
three on each side show plainly. On a level with axle are
two lugs on each side, through which the four suspension
bolts pass.
Fig. 423. Master Controller.
The complete armature with the end plates which sup-
port field, are shown in Fig. 418, mounted on the axle.
Fig. 419 shows armature with its driving quills. Fig. 420
மா
Fig. 424. Unit Switch Group.
shows one driving quill in greater detail. Note the cen-
tral hole through which locomotive axle passes. The key
way to connect armature spider to quill is shown. The

ELECTRIC LOCOMOTIVES
701
driving pegs of quill are hollow to contain the end thrust
springs.
Fig. 421 shows the outside of driver with the driving
pegs in the pockets of driver. Two of these pockets have
the cover plates in position. Fig. 422 gives the details
of the springs.
Fig. 425. Speed Recorder.
Fig. 423 shows the master controller, and Fig. 424 a
group of unit switches.
Each locomotive has a speed indicator whose mechan-
ism is shown in Fig. 425. It being a magneto frictionally
driven from a locomotive driver.
LESSON 41.
NEW YORK CENTRAL MOTOR CARS.
1
The one hundred and twenty-five steel motor cars of
the New York Central are of pressed steel even to doors
and window casings and ornamental mouldings. They
áre 60 feet in length over all with a wheel base of 45 feet.
They are designed to pass around a curve of 135 feet.
radius.
The light weight of motor cars and trailers is 102,600
and 78,600 lbs. respectively, giving weight per passenger
of 1,603 and 1,228 lbs. respectively. The weight of the
usual 60 foot wood coach is 61,800 lbs., or 965 lbs. per
passenger. In spite of this extra weight the total train of
six cars is lighter than a steam train, the gain being due
to absence of locomotive weight.
An electric fan is located in each end of car for cooling
and ventilating.
The two 200 H. P. motors on the motor truck are con-
trolled by the Sprague-General Electric Type M Control
with automatic acceleration at rate of 14 miles per hour
per second up to a maximum speed of 52 miles an hour.
The arrangement of motor control apparatus is shown
in Fig. 426.
When controller is thrown to first notch forward wire
number 4 (which will be referred to as W4) and wire
number 2 (W2) are energized.
W4 goes through the reverser coils and through coils
of contactors II, 12, 1, 10 and thence to ground. This
702
NEW YORK CENTRAL MOTOR CARS
703
пи
R7
3
୪
7
4
6
am
1-12-11 - Qomm
•11+Q
F
ww
R4
R 5
R6
5
9
G2
R1
R2
Gj
10.
ми
и
R 3
ww
F2 A 2
13
14
15
Fig. 426. Diagram of Motor Control, N. Y. C. & H. R. R. R. Motor Car.
2.
T2

704
ELECTRIC RAILROADING
swings the reverser into the forward position and closes
the four series contactors II, 12, I and 10.
W2 has its circuit closed at controller but completed
through the interlock on contactor 12, so coil of con-
tactor 3 is now energized; 3 closes and motors are in
series with full resistance.
Turning controller to notch 2 places WI in service.
This is the pick-up wire. It goes to the throttle relay
across its disk and up through a magnet which lifts the
disk and then on through contactors 13, 6, 8. It does not
close all these at once because as it is closing 13 it is also
lifting the core of the throttle relay in order to break its
own circuit. There is a slip joint between core of magnet
and disk on throttle relay so that contactor 13 has time
to close and throw its own coil (by means of interlock)
over to W2, but contactor 6 does not have time to do
this before throttle relay breaks circuit of W1.
3
The closing of contactor 13 cuts out R,, R, and R, so
that motors take more current.
1
It is this increased current passing through the series
coil of the throttle relay that holds the disk up, continu-
ing to keep pick-up wire (W1) open circuited until the
current through motors dies down to its normal value.
Then throttle relay closes, WI instantly picks up con-
tactor 6, which itself gets on to W2 before the throttle
relay can open WI. The rush of current holds relay up
till the current falls again. Contactor 8 is then closed
in same way and motors are in full series.
While this has been going on W2 has been trying to
close contactors 4 and 7 but could not on account of inter-
locks until 13 and 6 were closed, then 4 and 7 close in suc-
cession and then 8 closes.
1
NEW YORK CENTRAL MOTOR CARS
705
While moving from notch 2 to notch 3 the bridge con-
tactor 9 is closed and 3 is opened. This makes no elec-
trical changes, nor does the opening of 8, 7, 4, 6, 13.
1
2
When notch 3 is reached W3 is energized and con-
tactors 2 and 5 close. This arrangement is safe because.
even in the lowest resistance circuit from T, to G, there
is sufficient to prevent a short circuit. However, the
closing of 2 and 5 by means of interlocks throws 9 open,
placing the motors in parallel with resistance.
At notch 3 wire I is not connected, so motors stay in
parallel with resistance till controller is moved to notch
4 which cuts in WI; thus starts the automatic closing
of contactors. Due to the action of interlocks, when
contactors 2 and 5 are closed the order of closing con-
tactors by WI is to close them by groups, each group
awaiting the action of the throttle relay. 6-15-4 close,
then 14-7, then 13-8, when the motors are in full parallel
with no resistance.
Contactors 11-12-1-10 close when the reverser is
thrown and are always closed unless controller is in off
position.
The action of contactors for reverse motion is the same,
except that W5 closes the contactors II-12-1-10 and pass-
ing through other coil on reverser throws it into the
position for backward motion of car.
On the reverse the full series position is as far as the
acceleration will
progress.
ì
LESSON 42.
NEW YORK CENTRAL LOCOMOTIVES. *
The locomotive, 35 of which are in use on the N. Y.
C. & H. R. R. R., weighs about 100 tons and has 71 tons
on its drivers. These are four in number, 44 inches in
diameter. The driving wheel base is 13 feet.
A Pacific type steam locomotive has three driving
axles, with 75 inch drivers, and the same 13 foot wheel
base.
The electric and steam locomotives can take same
curves, but the electric has the better grip on the rails
due to the four driving axles and it has as much weight
on drivers as steam locomotive has altogether.
From last
At each end of the locomotive is a swiveling truck with
one axle; these axles carry 36 inch wheels.
driver axle to truck axle is 7 feet and from truck axle
to end of locomotive is 5 feet more. This with the 13.
foot driving wheel base gives a total length of 37 feet
or 30 feet shorter than a steam locomotive.
Each driving axle is 8½ inches in diameter and has
keyed to it a sleeve upon which is carried the armature
core sleeve and the commutator hub, each separately
keyed. The drivers are forced on the axles as usual,
forming a rigid and solid unit.
$
*To Mr. J. C. Irwin and Mr. S. A. Bickford, both of New York
Central, are due thanks for completeness of following information.
706
NEW YORK CENTRAL LOCOMOTIVES
707
Fig. 427 shows one of these units standing inside its.
field coils with one driver removed to afford a better view.
The top bar is not a mechanical part of the frame, but
is one of the two pieces of soft steel, running the length
of the motors to improve the conductivity of the mag-
netic circuit.
Since the commutator ends of the motors are the light-
er, these bars lie on that side of the frame, preserving
a mechanical balance.

Fig. 427, Locomotive Motor.
This bar shown in Fig. 428 runs the length of the four
motors.
In Fig. 427 the broad piece below the bar is the loco-
motive frame which together with the transoms acts as
the main magnetic circuit. The transoms are bolted to
the frame as shown.
::
The five transoms in the middle of the frame carry
708
ELECTRIC RAILROADING
bosses which serve as magnet cores and the field coils are
'placed on them.
The pole face not shown in Fig. 427, but in Fig. 428,
is of soft iron sheets held between two heavier end pieces,
dove-tailed to the magnet core and keyed. These pre-
vent the field coils from slipping off.
The ordinary motor has a cylindrical pole face, but
these are almost flat, so that the armature can stay still
on the track and the frame with the poles swing up and

6000
N.Y.C.
& H.R.
6000
Fig. 428. The First New York Central Locomotive.
down without striking the armature. This shape also
makes it possible to drop an armature down into a pit.
without disturbing the pole faces or field coils.
The brush holders being on the transoms, move up
and down with the frame, being kept in contact with the
commutator by springs.
The collector shoes are also fastened to the frame,
being kept on the third rail by springs.
The field coils are 80 turns of copper ribbon 3 inches
NEW YORK CENTRAL LOCOMOTIVES
709
wide insulated by card board. They are wound on a
brass spool which is slipped into a shell and the protection
completed by riveting the joints and pouring shell full of
a bituminous compound.
The journal bearings each have a pedestal resting on
them which carries on its upper end a half elliptic spring.
The bearings slide in jaws of the frame.
The weight of each pair of drivers, the axle, the com-
plete armature, journal bearing, pedestal and spring rest
solidly on the track. The two trucks do the same.
Everything else rests on the frame, and the frame is
hung from the springs.
The two trucks and the drivers furnish six axles to
support the weight of frame and its load.
Equalizing levers distribute the load properly, and
cross equalizers give a three-point support.
The superstructure consists of the cab in the center
and two end compartments.
In the center of the cab stands the steam heating
apparatus. A kerosene automobile burner heats a coil
tube boiler, producing superheated steam. This when
passed through a reducing valve furnishes to the train
absolutely dry low pressure steam. In this way the size
of plant capable of heating a train is reduced to a mini-
mum. The fuel and water pumps are motor driven.
At one end of this heater is the motor driven air com-
pressor.
There are two motors on its shaft connected
in series. This gives 300 volts per motor and enables
them to run at the low speed of 175 R. P. M. The com-
pressor supplies 130 lbs. of air for braking, whistling,
bell ringing and sanding. It is regulated by a starting

710
ELECTRIC RAILROADING
and stopping switch which is opened and closed by an
electro magnet. This magnet is operated by switch opened
and closed by the action of the air on a diaphragm. 125
lbs. pressure starts and 135 lbs. stops the motors.
At both corners diagonally opposite are duplicate sets
of controlling apparatus. They consist of the controller
bar and reverse lever under left hand. In front are the
automatic and straight air brakes, the hand sander, the
Fig. 429. Motor Armature.
ammeter and air gauge, and the control circuit switch.
At the right hand is the air blast sander, bell and whistle
valves.
The end compartments contain a central aisle and on
either side in asbestos lined sheet steel cabinets are con-
tained the other apparatus of the control.
Each of these four (two at each end) cabinets contains
the resistances and the contactors for one motor. Evenly
NEW YORK CENTRAL LOCOMOTIVES
711
distributed among the four are the two reversers, the
main power switch, the circuit breaker, the throttle relay,
air pressure governor, air sanders, and the contactors for
motor combinations.
The lighting and head light switches are in the aisles
for ready access.
A view of a complete armature mounted on driving
axle is given in Fig. 429.
The locomotive is fitted with the Sprague-General
Electric Type M Control with a controlled acceleration.
There is a friction clutch attached to the main shaft of
the controller, operated by a magnet. This magnet is in
the circuit of wire 18 which also contains a magnetically
operated switch.
The operating coil of the switch is a part of the main
power circuit leading to motor No. 2.
When the motor is taking less than 900 amperes from
the line the magnet is too weak to close the switch, and
so the locking coil is not energized, and the controller
handle is free to be moved.
Should the motor current rise above 900 amperes the
magnet closes the switch, the lock coil throws the clutch
and the engineer can not advance the handle until the
current falls to its normal value.
Fig. 430 shows the wiring of the four motors, their
resistances and contactors as arranged in the New York
Central locomotive No. 6000, the first one built.
The terminals marked T are connected to the third
rail or "trolley," those marked R to the rails or return
circuit, often called "ground."
The armatures are represented by circles and the fields
by squares. The resistances are shown by the crooked.
712
ELECTRIC RAILROADING
T
L
ד
72
R
26
25
24
о
6
2
8
9 10
R
14
15 16
27
16 17 18 19 20
73-
22-T
35
28-
29 30
T
23
43
R
O
44.
37 38 39 40 41
36
hhhhhhh
hhhhh!
31 32 33 34
27R
46
42
45
42-T

Fig. 430.
Diagram of Motor Control New York Central Locomotive.
NEW YORK CENTRAL LOCOMOTIVES
713
lines, being a rough imitation of the shape of the cast
iron grids used as resistances.
On No. I motor at the top has been indicated how
the leads go to a reverser, but this has been omitted from
the rest of the diagram for the sake of clearness.
Each number represents a contactor and when the con-
tactor is closed the gap in the circuit as shown in the
diagram is closed and current is permitted to pass.
The wiring which actuates these contactors is called
the control system and will be the subject of another il-
lustration. This diagram (Fig. 430) only shows the
main or power circuits. Each wire in the control is num-
bered and this number is used to refer to it.
The controller which actuates these 47 contactors has
24 positions or notches numbered consecutively. Nos. 10,
17 and 24 are running positions, placing the motors at
N 10 all in series; at N17 in series-multiple i. e., two in
series and two in parallel or multiple; at 24 all in mul-
tiple. This gives quarter, half, and full speeds. At
all the other notches there is more or less resistance in
the circuits, and the controller must not be left perma-
nently at any notch but these three.
The motors are numbered from the top of Fig. 430
down, Nos. 1, 2, 3 and 4. The numbers 1, 2, 3 and 4
after a symbol denote the motor to which the part belongs.
FI denotes the field of motor No. 1. R 12 denotes the
second resistance (counting from left to right) of the
first motor. R 36 denotes last resistance of third motor.
Each motor has a set of six resistance grids whose
total for each motor is 0.4 ohm and whose parts have
resistances as given in Table A. In Table B is given the
resistance left in each motor circuit when the previous
grids are cut out.
714
ELECTRIC RAILROADING
7
TABLE A.
Resistance I=0.120 ohm.
Resistance 2=0.085 ohm.
Resistance 3=0.055 ohm.
Resistance 4-0.050 ohm.
Resistance 5 0.046 ohm.
Resistance 6-0.044 ohm.
TABLE B.
Resistance I to end 0.40 ohm.
Resistance 2 to end 0.28 ohm.
Resistance 3 to end 0.195 ohm.
Resistance 4 to end=0.14 ohm.
Resistance 5 to end=0.09 ohm.
Resistance 6 to end 0.044 ohm.
There are four other resistances, one per motor, located
as follows:
BI between contactor 4 and R.
B 2 between F 2 and 12.
B 3 between A 3 and 35.
B 4 between 45 and R.
These resistances are 0.48 ohm. each. B 2. and B 3
are used as bridge resistances to prevent short circuits.
when changing from slow to middle speed. B 1 and B 4
are used as resistances during electrical braking.
Fig. 431 shows the electrical connections of a locomo-
tive reverser.
The right and left sides are exact duplicates, so only
one side will be described.
NEW YORK CENTRAL LOCOMOTIVES
715
As shown the S portion of the reverser is shut and
the O part is open. The magnets and link bars operating
the two pairs of toggles S and O are left out, in order
to make diagram simpler.
T represents a tap from the main power cable and may
be considered as "trolley."

S
B
T
f
a
C
HE
M
Fig. 431. Diagram of Locomotive Reverser.
The current comes from T goes through B to the
armature a (circle), thence to C and passes through the
field F (square). The same thing happens on the other
side of S.
If, however, the magnet connected to O is energized,
the toggles O will straighten and close the contacts L
and N on both sides. The magnet S being interlocked
with O is now de-energized and the S toggles loosen
and contacts C and B open.
Then the current goes from T to L and through the
armature in opposite direction than before, thence to N
716
ELECTRIC RAILROADING
and through the field in the same direction as before. The
motor now reverses; for to reverse a motor, reverse the
armature or field but not both.
Operation of Control.
Imagine the engineer standing in the cab with the re-
versing and air wrenches in his hand. The controller
levers are not removable and are both in place in the off
position. In fact they had to be there before the revers-
ing wrench could be removed, and the air brake wrench
had to be at lap before it could be taken off. There is
but one reverse and one air wrench per locomotive.
He seats himself, puts on the two wrenches and throws
the reverse wrench to forward. This puts wire 8 to
trolley and ground (T. and R.), and the control current
passes through the reverser magnets and pulls both to
the forward position.
Wires 51 and 52 now close contactors 1-5-21 and
28-44-36. These are always closed while the locomotive
is running.
Notch I now energizes W 1, closing C 2-24-46, com-
pleting a series circuit of the four motors and 1.6 ohms
resistance.
For the next nine notches these contactors remain
closed and in addition contactors close and open as fol-
lows:
Notch 2 energizes W 6, closing C 20, cutting out all
of the resistance belonging to M 2 thus reducing the
total resistance to 1.2 ohms.*
*By this I mean the extra resistance in grids is 1.2 ohms. The
resistance of the motors is always present and need not be men-
tioned each time.
NEW YORK CENTRAL LOCOMOTIVES
717
Notch 3 energized W 7, which picks up C 20 (which
W 6 no longer holds) and also C 42, which cuts out
0.4 ohms more, reducing resistance to 0.8 ohms.
Notch 4 energizes W 10 which holds up C 20 and 42
and also closes C 34 cutting out 0.4 ohms more.
Notches 5-6-7-8-9: While W10 continues to be ener-
gized holding C 20-34-42, wires 11-12-13-14-15 are suc-
cessively energized closing C 6-7-8-9-10 one after the
other. Thus gradually reducing the resistance from 0.4
to 0.044 ohms as shown by Table B. Each contactor
stays down until the following one closes.
Notch 10: Wire 16 is energized and W 10 de-ener-
gized but C 20-34-42 are held up by W 16 and it picks
up C II in addition, thus putting the motors in full series
between Trolley I and Return 4, without resistance. N
10 is a running position at a slow speed.
In moving from N 10 to N II many changes occur.
W 51 and 52 are of course still working. W 5 cuts in
and transfers C 2 and 46 from W 1 to itself, it also closes
C 12 and 35. The two bridging resistances B 2 and B 3
being together equal to 0.96 ohms prevent a short circuit
from T 3 to R 2.
The circuit containing B 2 is called a bridge because
it bridges over what would otherwise be an opening in
the circuit as the changes occur.
W I now drops out of circuit allowing C 24 to open,
thus placing two motors in series between T and R.
W 2 now is energized and closes C 25 and 23 cutting
out B 2 and B 3 considerably reducing the resistance of
each motor combination.
W 10 now closes C 20 and 42 but not C 34 as it did
before. W 10 can only shut C 34 if C 24 is already closed.
718
ELECTRIC RAILROADING
This is due to a system of interlocks. C 24 is now open,
for it dropped when we shifted from W I to W 5.
The motors are now in series-multiple with half of the
resistance in series.
Notches 12 to 17 (both inclusive) energize in succes-
sion W 11-12-13-14-15-16 closing C 6 and 29, then C 7
and 30, etc., thus stepping out the remaining resistance
until at N 17 we are at a free running position with no
resistance in.
Between N 17 and 18 we shift from W 2 to W 3 which
performs same duties as W 2 and in addition closes the
bridges C 14 and 43. These two contactors produce no
electrical changes for the resistances were already cut out
entirely by W 16 through the contactors under its control.
W 16 can now be and is dropped without any electrical
change. W 4 is now energized closing C 3-22-27-47.
There are no short circuits caused because between trolley
and return on one side of bridges are the motors and on
the other side are the double resistances, each 0.8 ohms.
W 2 is again taken up which takes care of C 24-25
holding them up and W 2 is dropped, letting go of C 14
and 43.
We are now in multiple with resistance in series.
Notches 19 to 24 keep W 2 and 4 energized and suc-
cessively energize W 11-12-13-14-15-16, closing contact-
ors four at a time, i. e., C 6-15-29-37 then C 7-16-30-38,
etc., until finally W 2-4-51-52 and 16 keep the contactors
closed for free full multiple running.
The spaces between N 10 and 11; N 17 and 18 are
wider than the others to give room for enough motion to
make the desired wire changes. These spaces must be
passed over by a continuous motion of the controller arm.
NEW YORK CENTRAL LOCOMOTIVES
719
Wires 11 to 16 always close contactors four at a time
but the first and second times they are used part of the
contactors closed produced no electrical changes and for
simplicity mention of the fact was omitted.
Contactors 4-26-13-45 are used when braking electric-
ally in this way.
A switch called a commutating switch is thrown and
the controller pulled to first notch.
The commutating switch brings in wires 17-4 and 5,
W 17 closes contactors 4-13-26-45.
W 4 and W 5 due to interlocks do not close as many
contactors as they would if energized through main con-
troller so W 4 only closes 3-27 and W 5 only closes 12.
Notch I of controller energizes W 51 and W 52. W
52 as usual closes 28-36-44 while W 51 on account of in-
terlocks only closes 5 and 21. The four motors are now
in parallel across the track rails all connection with third
rail being cut off. They now act as generators and act as
brakes.
This can only be done when one locomotive is on a
train else the other locomotive being so near (40 feet)
acts as a short circuit.
The one wire not mentioned W 18 is the one called con-
troller lock. It energizes the magnet of the friction clutch.
through a relay whenever current input exceeds 900
amperes per motor.
Table C gives the number of the control wire, the con-
tactors operated by it, and the notches of the controller
making use of the wire.
In this table and elsewhere I to 10 means both inclusive
and 1-2-10 means separate numbers.
1
720
ELECTRIC RAILROADING
}
TABLE C.
Wires
Contactors
Notches.
in circuit.
closed.
All
All
I to IO
2
3
4 to 9
II to 16.
5-12-19
51
52
1-5-21
28-36-44
I
6
2-24-46
20
7
20-42
IO
20-42-34
IO (interlock)
20-42
ΙΙ
6-15-29-37
6-13-20
12. i
7-16-30-38
7-14-21
13
8-17-31-39
8-15-22
14
9-18-32-40
ነ
9-16-23
15
10-17-24
16
II to 17
· 2
18 to 24
II to 17
ir
5
10-19-33-41
II-20-34-42
25-23
I2-35-2-46
Between
17 & 18
18 to 24
Reverse lever.
3-
14-43-25-23
4.
3-22-27-47
Forward..
...8 Reverser forward.
Backward.
O
Reverser backward.
•
Braking
17
Braking
51-(Interlock)
Braking
52
Braking
4-(Interlock)
4-13-26-45
5-21
44-36-28
3-27
Braking
5-(Interlock)
12
Trolley wire
18
Controller lock coil.
NEW YORK CENTRAL LOCOMOTIVES
721
This table will enable you to find what groups of con-
tactors go into operation at same time.
It being found that electrical braking when two loco-
motives were being operated was useless it was cut out
of the equipments delivered to the Central.
Changes in the numbering of the contactors were also
made, but the method of control is the same. This les-
son will enable the student to get information from the
wiring diagram given in connection with the catechism on
the locomotives.

LESSON 43.
ROLLING STOCK.
The electric locomotive as a slow speed, heavy load
tractor is quite old and there are many of them doing
good service to-day that were built ten years ago.
Fig. 432 is in use by the American Bridge Co. Fig. 433
is used in the works of the Westinghouse Electric Co.
Fig. 434 is in use in a lumber mill. Fig. 435 is used to
haul scrap and pig iron. Fig. 436 is used by the Mary-
land Steel Co. to haul ingots and moulds. Fig. 437 is in
use in Hawaiian Islands.
Fig. 432. 10,000-Pound Locomotive.
Fig. 438 shows how standard motors can be adopted to
narrow gauge locomotive.
Figs. 439, 440 and 441 show conventional types of
higher speed locomotives the latter showing the use of
two trolleys allowing the collection of larger currents
722

ROLLING STOCK
723
SE ELECTRIC & MFG.CO.
Fig. 433. 95,000-Pound Locomotive.
Fig. 434. 2,600-Pound Locomotive.

724
ELECTRIC RAILROADING
without too great a resistance and sparking at trolley
wheel.
Fig. 442 shows a 560 H. P. locomotive operating along
the Hudson River steamship wharfs. Gear reduction is
3:1. It makes 8 miles an hour.
No
Fig. 435. 8,000-Pound Locomotive.
Fig 443 shows an American locomotive operating in
the Austerlitz Station of the Paris-Orlean R. R. The
same locomtives also haul 160 ton trains under Paris in a
tunnel to the Quai d'Orsay terminal.

ROLLING STOCK
725
M.S.CO.
Fig. 436.
10,000-Pound Locomotive.
241
Fig. 437. 19,000-Pound Locomotive.

726
ELECTRIC RAILROADING
Fig. 438.
Special Design for Using Very Large Motors on Narrow
Gauge Track.
NAVAL PROVING GROUNDS
4
Fig. 439. 45,000-Pound Locomotive.

ROLLING STOCK
727
Fig. 444 shows the locomotive of the Buffalo & Lock-
port R. R., designed to handle freight and passenger serv-
ice between these stations. They are equipped with
motors capable of developing 600 H. P. Owing to slow
speeds required (15 miles per hour) the motors are con-
nected two in series permanently. They start with all
CAPS NACIELE WALANG SEWELLSTMENT RAILMAN
READING No. 1
Fig. 440. 47,000-Pound Locomotive.
four in series and then place them in series parallel. They
draw 500 amperes while accelerating a 450 ton train up to
14 miles an hour.
Fig. 445 shows a locomotive used in factory yard to
drill freight cars.
The Baltimore & Ohio R. R. has been using 87 ton
electric locomotives to haul its steam trains (locomotive
and all) through the tunnel under the city of Baltimore.

728
ELECTRIC RAILROADING
METROPOLITAN
RAILWAY
Fig. 441. 55,000-Pound Locomotive.
Fig. 442. Steamship Connecting R. R. Draw-Bar Pull at 8 M. P. H.
10,000 Pounds.

ROLLING STOCK
729
Fig. 443. Electric Locomotive at Austerlitz Station. Paris and Orleans
R. R.
Fig. 444. Buffalo and Lockport Locomotive,

730
ELECTRIC RAILROADING
G.E.CO.
NO. 4
Fig. 445. Factory Yard Locomotive.
B.BO
正
​Fig. 446, B. & O. Gearless Locomotive.

ROLLING STOCK
731
One of these locomotives is shown in Fig. 446. Three
we put in service in 1896 and for ten years have given
good service: They will each haul a 2300 ton freight at
10 miles an hour, or a 500 ton passenger train at 35 miles
an hour. They draw 2200 amperes at 625 volts during
acceleration, dropping to 1800 at full speed.
Fig. 447a. B. & O. Locomotive Truck.
One of the two trucks is shown in Fig. 447. The
motors are six pole and connected directly to axle. There
are two motors in each truck making four in all.
In 1903 the B. & O. put in service two more locomo-
tives. Each one is composed of two units. Each unit
contains four motors, each geared to one of the axles by
a 4:1 gear. The motors are 4 pole. Each unit weighs 73

732
ELECTRIC RAILROADING
tons. Thus the whole locomotive of 146 tons has 1600
horse power.
The geared type is perhaps best for such slow speed
work.
Fig. 447b. B. & O. Locomotive Frame and Cab.
The freight locomotive of to-day will be a 16 wheel lo-
comotive of the 0-16-0 type with a joint in the center of
its frame like a Mallet Compound. This is called an ar-
ticulated frame.
Each axle will have its motor. Its general dimensions
are shown in Fig. 448.
A New York Central locomotive drawing a train is
shown in Fig. 449.
ROLLING
STOCK
733

12 IM. A.
-3 ft. 0 in. -
-9 ft. 0 in. x 6 ft. 0 in--
ft. b lar
15 ft. 6 in. x 10 ft. 0 in.
-9 ft. 0.in. x 6 ft. 0 in.
RETRACTED POSITION OF D. C. OVERHEAD CONTACT SHOE
7,10.
-J IN. AL.
·6 IM. A.
~~4 ft. 4 in.~~-~-
14 FT. 914 IN. TO TOP OF RAIL"
12 FT. 1 IN, I
TO TOP OF RAIL
}
Fig. 448.
3 14. RIGID WHEELBASE
16 ft. 1 in.
ARTICULATION AND 2 BIDE, SLARINOJ
~36 FT. 6 IN. INSIDE TO INSIDE KHUCKLE~
12 FT. 3 IN. TO TOP OF RAIL
→2 ft. 10 in-
-3 ft. 0 in.-
-3 ft. 0 i
-20 FT. 414 IN. TOTAL WHI „BASE
Typical Freight Locomotive of 0-8-8-0 Type.

734
ELECTRIC RAILROADING
Fire proof cars are a very valuable asset to a road, as
a means of gaining public favor and their actual calming
influence in case of not only slight fires due to electrical
troubles but also in slight collisions. Figs. 450 and 451
show a fire proof car designed by Mr. Gibbs. The Erie
railroad is using similar ones for Postal Service. The In-
terborough Co. is using the Gibbs car for motor cars.
000
6000
Fig. 449. New York Central Locomotive with Train..
These are finished inside with dark green enamel and
aluminum paint which although a little hard looking
makes a good appearance.
Fig. 452 shows a train on the West Shore R. R. oper-
ating between Utica and Syracuse.
Fig. 453 shows a locomotive and Fig. 454 a motor car
of the Valtellina Rail Road of Italy. This is a 3 phase
equipment.

ROLLING STOCK
735
3354
Fig. 450. Gibbs' Fire-Proof Car..
Lorg Island R. R. and New York Subway.

736
ELECTRIC RAILROADING
3354
T
30
Fig. 451, End View of Fire-Proof Car.

ROLLING STOCK
737
504
Fig. 452.
West Shore Motor Car Train..

738
ELECTRIC RAILROADING
Fig. 453.
Valtellina Three-Phase Locomotive.

ROLLING STOCK
739
Fig. 454.
Valtellina Three-Phase Motor Car.
740
ELECTRIC RAILROADING
Trucks.
While the size of motors has been limited by the gauge
of the rails, yet the demand for larger horse powers
has influenced truck builders to put 36 inch wheels on the
motor trucks. Such trucks will soon be standard for steam
road work. The trailer truck at other end of car will
have 33 inch wheels as standard.
Fig. 455 shows the general dimensions of a motor made
for a 33 inch wheel truck. It will be noticed that the car
axle goes through a set of bearings on the side of the
motor frame. The large gear is fastened to the car. The
motor shaft runs in bearings at either end of the frame.
The pinion on motor shaft engages with gear on 'car axle.
Some of the weight of motor is given to car axle by
the bearings in motor frame through which this axle
passes. The rest is transferred through the truck frame.
Any motion of the motor must be in a circular arc
around the car axle as a center, for the distance between
center of car axle and motor shaft must always be same,
else gear teeth will bind.
The Master Car Builders Association has given its
sanction to certain constructions which are familiarly
known by the initials, M. C. B.
A truck called the "M. C. B. equalizing truck" is shown
in Fig. 456. The center pin is shown on center transom
with bearing plates on either side. Outside of these are
the side bearings to catch the weight when car rolls. Any
up and down motion due to compressing the springs
should not bring side bearing plates into contact. They
generally come into contact when rounding curves, and
to prevent interference with swiveling of trucks under
ROLLING STOCK
741


-2318"
Ground Terminal
Cen. Line of Armature,
Mux.Axle
-2′07″-
Line
of Motor]
00
Cen. Line of Xxle)
-3′1131
133
OD
93
I´día. M B.
Mach. B.
14.83
1
J
'
24. „208-
-15
1.835
fit
107
117"
Keyway in Axle
+
Finish for Bearing
17.
-13
16 4′0″ Between, Finished Hubs
Finisli for Bearing and Gear Hub
Fig. 455.
General Dimensions of Railway Motor.


742
ELECTRIC RAILROADING
these circumstances, these bearings are frequently made
with rollers.
In the plan view of Fig. 456 only one motor is shown
to give a clearer view of the motor suspension. A rec-


Fig. 456.
M. C. B. Electric Truck. Cradle Suspension.
tangular frame of iron bars is hung by the centers of its
shorter sides at each end of the truck. The connecting.
bolt at the same time compressing a spiral spring. On

ROLLING STOCK
743
Fig. 457. Cradle Suspension.

744
ELECTRIC RAILROADING
TA
Fig. 458.
Gibbs' Cradle Suspension, End View.
Fig. 459.
Gibbs' Cradle Suspension with Truck Frame Lifted.

ROLLING STOCK
745
B
Fig. 460.
Nose Suspension.

746
ELECTRIC RAILROADING
each side of the motor is a lug which is bolted to the long
or side bars of this frame.
This suspension is the cradle suspension. It has many
modifications. In Fig. 457 the center of end bar of
cradle is slung without springs from a cross bar which is
spring borne at the outside of the frame.
Fig. 461. Nose Suspension.
One of the best cradle suspensions is the Gibbs (Fig.
458) as shown in Fig. 459 the whole truck frame of a M
CB truck may be hoisted clear of the wheels and motors.
The nose suspension is simpler than the cradle. The
end of motor not resting on car axle is hung from a
spring borne cross bar. See Fig. 460.
Another very simple nose suspension is shown in Fig.
461 where the truck transom has a frame bolted to it con-

ROLLING STOCK
747
Fig. 462. Parallel Bar Suspension.
748
ELECTRIC RAILROADING
taining a spring supported U or loop. A lug or nose on
the motor sticks into this U. This illustration shows the
king pin, bearing plate, and side bearings all mounted on
transom.
Fig. 462 shows a suspension made of two bars running
length-wise of truck which hold the motors. These bars
are each spring borne at ends of truck, directly from
frame. In the illustration two long bars are supporting
the parallel bars because there is no truck there to do it.
Such a suspension needs four spring supports and is no
more flexible than the cradle suspension using only two.
It is called the parallel bar suspension.

LESSON 44.
CAR EQUIPMENT.
The electrical equipment of a car consists of the motor
truck, the controller, resistances, iron pipe conduits con-
taining the motor circuits, and the motor control circuits,
WESTINGHOUSE
ELECTRIC & MFG.CO.
PITTSBURG PA USA
RAILWAY
LIGHTNING
ARRESTER
MP-TYPE-500-750 VOLTS
PATS APPLIED FOR.
STYLE 371470
WURTS NON-ARCING
RAILWAY
LIGHTNING ARRESTER
WESTINGHOUSE
ELECTRIC & NG CO.
PITTSBURG PA
PAT NOV 28 93-JAN.8 95
STYLE NO.6799
WE
M.P.
VOOTSING ARRESTIS
Fig. 463. Lightning Arresters.
a trolley or set of third rail shoes and a few auxiliary
pieces of apparatus. Some arresters are shown in Fig.
463. An arrester installed with a kicking coil is shown
749

750
ELECTRIC RAILROADING
in Fig. 464. A switch called a canopy switch is shown in
Fig. 465. It is mostly used in interurban cars where the
motorman's cab is built on front platform and this
switch is installed over his head: It is a snap break switch
and is used to cut off current from car at base of trolley.
Fig. 464. Choke Coil and Lightning Arrester.
WESTINGHOUSE
ELECTRICEMFG CO.
TBURGH
Fig. 465. Canopy Switch to Cut Off Current at Base of Trolley.
When a canopy switch has a magnet trip operated by
current to motors it is called a current breaker. The one
in Fig. 466 has a magnetic blow-out, which expels the arc
through the chute shown on right side. The button on

CAR EQUIPMENT
751
front is to trip the breaker. The handle on top is for
closing it.
Main fuses (Fig. 467) should be protected by iron
cases but wood boxes are still used.
Cleco Breaker
Fig. 466. Automatic Circuit Breaker.
JAMP
600 VOLTS
S 29302
PATD
APR 989
APP1889
JAN 1793
JAN3193
WESTINGHOUSE
ELECAMEG CO
Fig. 467. Fuse Block.
Fig. 468. Snap Switch
for Lighting Circuits.
The car and vestibule lights are controlled by snap
switches on porcelain bases, enclosed by porcelain or iron
covers (Fig. 468). Head lights have same style switches
of heavier construction.

752
ELECTRIC RAILROADING
Contact Devices.
The type of trolley with a wheel to collect current from
wire is not satisfactory for high speeds. The wheel is apt
Fig. 469. Pantagraph Bow Trolley. Raised and Lowered.
to jump the trolley wire and smash the guy wires of ordi-
nary, or the braces of catenary construction.
A bow trolley where the wheel is replaced by a broad
plate of copper or iron some two or three feet wide and

CAR EQUIPMENT
753
three inches across, must be used for high speeds. Then
no matter how the train sways the trolley and wire always
keep in contact.
The latest form of bow trolley is called The Panta-
graph Trolley, as shown in Fig. 469. It is raised and
lowered by an air cylinder shown in center.
Fig. 470. Third Rail Shoes.
When a third rail is used shoes as in Fig. 470 are the
current collectors. These are of cast iron pressed by
springs against the top or bottom of the third rail.
Heaters.
In trains of motor cars the only way to heat cars is by
resistances made hot by electric current. This is the most
expensive way to heat and in interurban cars where
motorman is always on front platform (the cars passing
around a loop at each end of route) it is better to install
a hot air or hot water heater and let motorman attend to
it. This can be done at terminals and at turnouts or even
at stops where eight or ten passengers are being let off or
taken on.
754
ELECTRIC RAILROADING
When electric locomotives are drawing the standard
railway coach, steam must be furnished. To do this steam
heating plants with kerosene blue flame burners are
placed in locomotives and attendance given by the second
man in the cab.

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1
2
3
wwwwwww
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6
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A
B
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2
To Ground

Fig. 471. Diagram of Car Heater Connections.
To furnish two degrees of temperature with electric.
heaters the heaters although all placed in series, are each
individually connected as in Fig. 471,

CAR EQUIPMENT
755
SAUSE
PRAKE
36344 2741M
SWITCH
EXHAURT
MUFFLER
GOVERNOR DE
ACSERVOIR
F
FAXSIBLE HOSE
CONNERTION
Fig. 472.
THOULEY
DIRONAR
PIPE
CUT OUT COEL
AIR STRALYER
INSULATING
UZINT
COMPRESOR
WRATE PIPE
AOVERNOR
GROUND
GAUGE
ORDINARY PIPE PITTINGE, HIRE, WIBING
AND WHISTLE SETS DO NO FORM PART
OF THIN EQUIPMENT UNLER ADDITION
ALLY SPECIFIED AS EXTRAS
EXHAUST
MUFFLER
Car Equipment Straight Air Brake.
756
ELECTRIC RAILROADING
Terminals A, B, are connected to the same lettered
terminal of heater behind; C and D are connected to C
and D of heater ahead.
2
The first heater has A and B connected to switches S₁
and S₂ which are connected to trolley. The last heater
has C and D connected to a ground wire which is con-
nected to some part of frame of truck.
If with switch S₁ closed a certain amount of heat is
generated, with S, closed twice the heat is obtained, while
with both closed the maximum heat is obtained, being
three times that given by the switch S, alone.
1
Air Brake.
For complete description of all air brake equipment
read Vol. III.
Suburban lines feeding steam roads usually run single
cars which are fitted with a straight air equipment like
Fig. 472.
The electric locomotives of the New York Central R.
R. have the Westinghouse E-T equipment.
Practically all the motor car of railway coach type
running in trains have the regular automatic air brake
with an air compressor on each motor car.
The parts of such a compressor are shown in Fig. 473.
the complete compressor in Fig. 474, and a side view of
compressor in its suspension is given in Fig. 475.
The New York Central motor cars have a governor of
type shown in Fig. 472.
The New York Central locomotives and the Pennsyl-
vania motor cars have a governor as in Figs. 476 and 477-
Showing it closed and open.

CAR EQUIPMENT
757
JO BUREAU
1-
Fig. 473. Parts of Motor Driven (Geared) Air Compressor.

758
ELECTRIC RAILROADING
The construction is shown in Figs. 478 and 520. The
cylinder head is provided with a tapped hole for the in-
sulated pipe which makes connection between the govern-
or and the compressor reservoir. The head is so con-
Fig. 474. Motor Driven (Geared) Air Compressor.
Fig. 475. Air Compressor (Fig. 474) in Suspension.
structed that this connection may be placed at the back
or at either side of the governor, as desired. It is bolted.
to the frame and holds the rubber diaphragm A against
the retaining ring. This ring serves as an abutment for

CAR EQUIPMENT
759
the piston B against the upper surface of which the dia-
phragm A is pressed. The lower side of the piston is
acted upon by the operating spring C, the pressure of
which is adjusted by means of the screws R bearing
against the washer S. Attached rigidly to the piston B
is the rod D, the lower end of which is connected to one
of the operating levers. The largest of these levers is
AIR COMPRESSOR
THE CO
Fig. 476. Air Compressor Governor, Case Closed.
provided with a recess into which a mica insulated stud
has been forced by hydraulic pressure. Attached to the
stud are the cable terminal and the spring carrying the
contact finger. The finger tip through which the circuit
is completed and broken is so made as to be readily re-
newable when worn. This finger completes the circuit

760
ELECTRIC RAILROADING
through the stationary contact, the tip of which is also
renewable. Enclosing these contact members is the arc
chute, which is composed of a special molded insulating
compound and is provided with renewable plates of a
highly refractory material. This material has the prop-
Fig. 477. Air Compressor Governor, Case Opened.
erty of resisting the action of the electric arc to a great
degree. In series with this circuit is the blow-out coil O,
for producing the magnetic field which extinguishes the
arc when the circuit is broken. This coil is made of
CAR EQUIPMENT
761
enameled copper ribbon wound edgewise, and connected
with it is the line terminal, which is provided with two
set screws for clamping the wire. The protecting cover
is hinged at the back of the frame and is held in the

N
M
HJG
F KP
C
A
B
-L
Fig. 478. Construction of Air Compressor Governor.
closed position by a spring catch. On the inside of this
cover adjacent to the arc chute is a plate of insulating
material which prevents the possibility of the arc striking
the metal.
762
ELECTRIC RAILROADING
Operation.
The action of this governor in opening and closing the
motor circuit of the compressor is as follows:
As the compressor continues to operate, thereby in-
creasing the pressure of air in the reservoir, the pressure
in the chamber above the diaphragm A rises and forces
the piston rod downward against the action of the oper-
ating spring C, turning the lever E around its fulcrum F.
This brings the pivot H above the centre line of the ten-
sion springs J, which connect the intermediate lever G
with contact carrying lever K. The action of these
springs then pulls the end of the intermediate lever down-
ward; this movement quickly carries the centre line of
the springs past the pivot P, thus reversing the action of
these springs on the contact carrying K, and causing the
free end of this lever to be drawn downward, separating
the contacts M and N with a quick snap.
The object of this double system of levers is to main-
tain a constant pressure between the contacts until the
tripping point is reached, thus preventing burning of the
contacts.
As the pressure in the reservoir is reduced the piston
rod O raises the rear end of the lever E, a projection of
which engages with the intermediate lever G. This car-
ries the center line of the tension springs J above the
pivot of the contact carrying lever K and thereby pulls the
contact finger upward, quickly closing the circuit.
The information given here is the same as that which
the Pennsylvania R. R. demands that the motor-men
should know before operating its trains.
CAR EQUIPMENT
763
The following pages contain a description of the elec-
trical apparatus used on the motor cars of the West Jer-
sey and Seashore R. R., one of the Pennsylvania lines
running from Philadelphia to Atlantic City. This road is
practically a straight line between the two cities with no
grades worth mentioning. It is 60 miles long and can be
done by express trains in very little over an hour.
These conditions while ideal for steam locomotives are
even yet more suitable for electric traction. When it
comes to local trains the electric cars are vastly superior
and can make much better time with increased economy.
L
'
INSTRUCTIONS FOR THE OPERATION OF
I.
MULTIPLE UNIT CONTROL.
GENERAL DESCRIPTION OF APPARATUS.
THE MOTOR CARS ON THE WEST JER-
SEY AND SEASHORE RAILROAD are equipped
with two General Electric (No. 69-C) 200 horse
power railway motors, both of which are mounted on
one truck, known as the MOTOR TRUCK. The
Sprague-General Electric (type M) multiple unit system.
of control is used.
2. BY MULTIPLE UNIT CONTROL is meant the
operation of a train of two or more motor cars from a
single master controller on any car in the train; that is,
a train of several cars, each propelled independently by
its own motors, is controlled as one car.
3.
THERE ARE TWO CONTROL CIRCUITS on
each car: First, the MASTER CONTROL, which is
operated by the motorman; second, the MOTOR CON-
TROL, which depends for its operation on the master
control. Both master control and motor control cables
are enclosed in iron pipe conduit.
4. EACH MOTOR CAR is provided with two mas-
ter controllers, one at each end of the car in the motor-
man's compartment. All master controllers are con-
nected to a seven-wire TRAIN CABLE running the
entire length of each car and connected together between
cars by the TRAIN CABLE JUMPER. Current re-
ceived through the master controller and train cable
764
MOTOR CONTROL
765
operates electrically controlled switches known as CON-
TACTORS on each car, and establishes the motor con-
trol on their respective cars. The motor control is local
with each car and can be governed by any master con-
troller on the train.
5. EACH MOTOR CAR TAKES CURRENT from
the third rail, through the third rail shoes, or from the
trolley wire, through the trolley. All third rail shoes
and trolleys are connected through switches to a BUS
LINE, which runs the entire length of each car and is
connected together between the cars by the BUS LINE
JUMPER; therefore, if any third rail shoe or trolley is
in contact with the third rail or trolley wire, all motors of
the train can be supplied with current through the bus
line.
MOTOR CONTROL.
6. THE MOTOR CONTROL CIRCUIT (Fig. 479)
is the circuit forming 'the path of the current from the
third rail shoes or trolley through the motor control ap-
paratus and motors to the track rails, and is THE MAIN
CIRCUIT.
7. THE ESSENTIAL PARTS of the motor control
of each car comprise the following apparatus:
One set of fifteen CONTACTORS, which
close and open the circuit to the motors.
One REVERSER, which determines the di-
rection of train movement.
སྐ
One set of eight RESISTANCES, which
limit the flow of current to the motors when
starting.
*
766
ELECTRIC RAILROADING

Trolley Fuse
PLATE No. 1.
Trolley
Trolley
Lightning Arrester
Trolley
Switch
Kicking
Coil
Third Rail Switch
Bus Fuse
Main Switch
Main Fuse
To Circuit Breaker
Bus Line Coupler
Sockets
Shoe Fuses
GENERAL ARRANGEMENT OF MOTOR CONTROL WIRING.
Fig. 479.
MOTOR CONTROL
767
ONE CIRCUIT BREAKER, which protects
the motors and motor control apparatus
against excessive current.
ONE MAIN FUSE, which-like the circuit.
breaker, and in addition to it-protects the
motors and motor control apparatus against
overload in case circuit breaker fails to
operate.
ONE MAIN SWITCH, by which the current
can be cut off from motor control circuit
for inspection or in case of defective ap-
paratus.
ONE THIRD, RAIL SWITCH, by which
current can be cut off from third rail shoes
when operating from trolley.
ONE TROLLEY SWITCH, by which the
trolley can be cut off from the bus line.
FOUR THIRD RAIL SHOES, which col-
lect current from the third rail.
FOUR SHOE FUSES, which protect the
apparatus and car wiring against excessive
current.
TWO TROLLEYS, either of which take
current from the trolley wire.
One TROLLEY FUSE, which protects the
apparatus and car wiring from excessive
current.
One BUS LINE, which, together with the
bus line jumper, connects all shoes and trol-
leys of a train together.
TWO BUS LINE FUSES, which protect
the bus line against excessive current.
768
ELECTRIC RAILROADING
}
ONE KICKING COIL and one LIGHT-
NING ARRESTER, which protect the cir-
cuits and apparatus against lightning dis-
charges.
8. THE FOUR THIRD RAIL SHOES are con-
nected together through the shoe fuses by a cable, from
which a connection is made through the third rail switch
on switchboard, through the main switch, main fuse, cir-
cuit breaker, contactors, resistances, reverser and motors
to the track rails.
9. THE TWO TROLLEYS are connected together
by a cable, from which a connection is made through the
trolley fuse, then through the kicking coil and trolley
switch,, located in a box on the roof of the car, to the
bus line, from which a connection is made between
switch. From the main switch the circuit is the same as
from the third rail shoes. A connection is made between
the trolley fuse and kicking coil through a lightning ar-
rester, located in the box with the kicking coil on the
roof of the car, to ground.
IO. THE CONTACTORS, fifteen in number, are
enclosed in an iron box, known as the contactor box,
located under the car.
The Contactor (Fig. 480) is a switch, the movable
portion of which is operated by an electro-magnet re-
ceiving line current through the master controller and
the train cable. The main contact is made between two
heavy copper tips, which are enclosed in an arc chute.
A magnetic blowout is provided, having poles extended.
along two sides of the arc chute, for extinguishing the
arc formed in breaking the circuit.
}

MOTOR CONTROL
769
By means of the contactors the motor control is es-
tablished on individual cars.
II. THE CONTACTOR BOX (Fig. 481) is lo-
cated beneath the car, about midway between the trucks.
GO
Fig. 480. Contactor.
This box is of iron, lined with asbestos and other in-
sulating materials to prevent short circuits, and is pro-
vided with two hinged sheet iron covers. When it is
desired to inspect the contactors the sheet iron covers

770
ELECTRIC RAILROADING
Fig. 481. Contactor Box. Contain 15 Contactors and Potential Relay, Train Cable Connection Box is
Mounted on Left End.
MOTOR CONTROL
771
can be dropped by releasing the catches which hold them
in place.
12. THE REVERSER (Fig. 482) is enclosed in a
metal box, and located near the end of the contactor box
toward the trailer truck.
The movable part of the reverser is a rocker arm, con-
trolled by two electro-magnets, one for each direction.
These magnets are operated by current from the master
controller through the main cable, the connections being
made so that only one magnet can receive current at a
time. Cables from the motor armatures and fields are
connected to the fingers of the reverser, and by means
of contact pieces mounted on, but insulated from, the
rocker arm, proper connections of armatures and fields
are established for producing forward and backward
movement of the car.
The control connections for the reverser are so ar-
ranged that, unless the reverser is at the proper position,
current is cut off from the contactors, and consequently
the motors on that car receive no current. When the
reverser is in the correct position it is electrically locked
and cannot be operated while the motors are taking
current.
The reverser is always closed, either in the forward or
backward position, depending on whether the master con-
troller handle has been moved to the left or to the right.
13. THE RESISTANCE (Fig. 483) is located be-
neath the car, near the contactors, and is made up of
cast iron grids mounted in, and insulated from, an iron
frame.
These resistances are used to regulate the flow of cur-
rent to the motors while the car is accelerating. Cables

772
ELECTRIC RAILROADING
Fig. 482. Reverser.

MOTOR CONTROL
773
connect the various resistances to different contactors, so
that sections of the resistance may be cut out to in-
crease the speed. Resistances are used only in starting,
switching, or moving at low speeds, and are entirely cut
out either in the one-half or full speed positions of the
master controller handle.
ERAL ELECIFIC.CO
VENECTOMERY USA
Fig. 483. Motor Control Rheostat.
14. THE CIRCUIT BREAKER (Fig. 484) is en-
closed in an iron box, located beneath the car at the end
of the contactor box toward the trailer truck.
The circuit breaker is similar in construction to the
contactor, but designed to carry and break the full cur-
rent taken by the car. It is closed and opened by means

774
ELECTRIC RAILROADING
D
99
Fig. 484. Circuit Breaker.

MOTOR CONTROL
775
of two electro-magnets, acting independently, and oper-
ated by current through the train cable and the circuit
breaker switch (Fig. 485) which is located in the motor-
man's cab, above the master controller. The circuit
breaker on any car is opened automatically when exces-
GENERACIELECTRIC CO.
SCHENECTADY S
OFF
ON
Fig. 485. Circuit Breaker Setting and Tripping Switch.
sive current flows through the motor circuits on that car.
As the setting and tripping circuits of all circuit breakers
of a train are connected through the train cable, all cir-
cuit breakers are closed and opened simultaneously by
operating the circuit breaker switch.
The circuit breakers are normally closed when the train
is ready for operation.

776
ELECTRIC RAILROADING
15. THE MAIN FUSE (Fig. 486) is located be-
neath the car, at the trailer end, near the main switch.
It is made from a thin copper ribbon and is contained
in a box composed of insulating material. Sheet iron
poles partially surround the insulation and provide a
magnetic blowout for extinguishing the arc formed when
the fuse blows.
FUSE BOX
MA
FORM
KRATENTED APR 529
GENERAL ELECTRIC CO
CHENECTADY NY BAS
Fig. 486. Main Fuse.
The fuse is held in place by copper clamps, fastened
with thumb screws having insulated handles. It may
be replaced after opening the main switch, loosening the
clamps and removing the ends of the old fuse. Ordi-
narily the current breaker will open automatically from
excess current before the fuse has time to blow.

MOTOR CONTROL
777
16. THE MAIN SWITCH (Fig. 487) is located in
a box beneath the car. It is a quick-break, knife-blade
switch, and is used to cut off the supply of current to
00
6
Fig. 487. Main Switch.
the motor circuit from both trolley wire and third rail.
This switch is normally closed, BUT SHOULD AL-
WAYS BE OPEN when examining or working on the
motor control apparatus.

778
ELECTRIC RAILROADING
10 Aimp
20 Amp
Car Lights-1 Amp.
imp Fuses GE U
στο
Control
Cut out
Switch.
Current
Limit
Relay
Fig. 489. Switchboard on West Jersey & Seashore Cars.
Headlight
Transfer
Switch.
MOTOR CONTROL
779
17.
THE THIRD RAIL SWITCH is located on the
switchboard (Fig. 489). It is a quick-break, knife-blade
switch, and is used to cut off current from the third rail
to the motor control circuit and to cut out the third rail
shoes when operating from the trolley wire.
This switch is normally closed when the car is taking
current from the third rail and open when taking cur-
rent from the trolley wire. THE SWITCH SHOULD
NOT BE OPENED WHILE THE MOTORS ARE
TAKING CURRENT, EXCEPT IN AN EMER-
GENCY.
18. THE TROLLEY SWITCH is located in a box
on the car roof. It is a quick-break, knife-blade switch,
and is used to cut off the trolley and its fuse from the
bus line circuit. This switch is normally closed, BUT
SHOULD ALWAYS BE OPEN WHEN WORKING
ON THE TROLLEY OR RENEWING A TROLLEY
FUSE.
19. THE BUS LINE COUPLER SOCKETS, four
in number, are located under the platforms, two at each
end of the car.
The coupler socket (Fig. 490) is composed of a body
of moulded insulating material, containing a large split
plug contact. Supporting feet of malleable iron are se-
cured to this insulating body for attaching to the under
side of the car platform. The socket is provided with
a hinged lid, having a projection on the inside to hold
the jumper plug in place. The cover also excludes dirt.
and water when the jumper is not inserted. Only one of
the two bus line coupler sockets at each platform is in
use at a time.

780
ELECTRIC RAILROADING
20.
THE BUS LINE JUMPER (Fig. 491) is used
to connect the bus line coupler sockets on adjacent cars.
It consists of a short section of flexible cable, with a
plug attached to each end, and completes the bus line
between the cars. Only one bus line jumper is required
Fig. 490. Bus Line Coupler Socket.
for connecting between adjacent cars, the additional
sockets being provided so that cars may be turned end
for end or coupled in any desired relation.
21. THE BUS LINE FUSES, two in number, are
located beneath the car, one at each end. They are sim-
ilar to the main fuse. These fuses are placed in the bus
line circuit to protect it against excessive currents.

MOTOR CONTROL
781
Fig. 491,
Bus Line Jumper,
.782,
ELECTRIC RAILROADING
22. THE BUS LINE JUNCTION BOXES, two in
number, are located beneath the car, one at each end.
The box is made of cast iron and contains an insulated
board, to which is secured a single stud bolt for holding
the cable terminals. This box is provided for connecting
the bus line coupler sockets to the bus line cable.
23. THE BUS LINE CONNECTION BOX is lo-
cated beneath the car, midway between the trucks.
This box is similar to the bus line junction box, and is
provided for connecting the third rail and trolley circuits
to the bus line cable.
24. THE SHOE FUSE BOXES, four in number,
are located on the wooden shoe béams, one on each side
of each truck.. The box is similar to the main and bus
line fuse boxes and contains the shoe fuse.
25. THE TROLLEY FUSE BOX is located on the
roof of the car. It is similar to the main and bus line
fuse boxes and contains the trolley fuse.
1
MASTER CONTROL.
26. THE MASTER CONTROL CIRCUIT (Fig.
492) is the circuit forming the path for the current from
the bus line, through the master controller and the train
cable, to the operating coils of the motor control ap-
paratus.
27. THE ESSENTIAL PARTS of the master con-
trol of each car comprise the following apparatus:
TWO MASTER CONTROLLERS, which
operate the motor control.
TWO MASTER CONTROLLER
SWITCHES, used to cut off current from
their respective master controllers when
not in use.
ONE MASTER CONTROL SWITCH, to
cut off current to master controller and cir-
cuit breaker switches.
ONE TRAIN CABLE, which connects the
master controllers to the motor control ap-
paratus.
-FOUR TRAIN CABLE COUPLER SOCK-
ETS, to which the train cable jumpers are
connected.
ONE TRAIN CABLE JUMPER, which
connects the train cable between cars.
TWO TRAIN CABLE CONNECTION
BOXES, where connection is made to mas-
ter controllers, coupler sockets and seven-
point cut-out switch,
1
783
784
ELECTRIC RAILROADING

Master
Controller
Switch
To Third Rail Switch
cut-out
Switch
To Contactor Bok
Master
Controller
Current Limit
Relay
Connection Box
Train Cable
GENERAL ARRANGEMENT of MasteR CONTROL WIRING.
Fig. 492.
C.B. Setting
Switch
Set.....Triq
No.2
Couples
Sockets
MASTER CONTROL
785
ONE SET OF RESISTANCE TUBES,
which limit the current in the master con-
trol circuits.
ONE CURRENT LIMIT RELAY, which
limits the rate of acceleration.
ONE POTENTIAL RELAY; which opens
the master control circuit when power is
cut off from the train.
ONE
SEVEN-POINT
CUT-OUT
SWITCH, to disconnect motor control ap-
paratus from train cable.
TWO CIRCUIT BREAKER SWITCHES,
for setting and tripping circuit breakers.
CONTROL FUSES, which protect master
control wiring against excessive current..
DESCRIPTION OF MASTER CON-
TROL APPARATUS.
28. THE MASTER CONTROLLERS, two in num-
ber, are located in the motorman's compartments, one
at each end of the car.
The master controller (Fig. 493) contains a single
movable contact cylinder and stationary fingers, mounted
on an insulated support. The controller has a single
handle for both forward and reverse direction of train
movement. Four points are indicated on the cap`plate
for forward direction and two for reverse. The first
point in either direction is called the "Switching" or
"Lap" position; the second, "Full Series." The third
point is called the "Parallel Lap" position, and the fourth,
"Full Parallel."
The master controller governs the admission of cur-
rent to the train cable for operating the reverser and
contactors,

786
ELECTRIC RAILROADING
Fig. 493. Master Controller.

MASTER CONTROL
787
29.
THE MASTER CONTROLLER SWITCHES,
two in number, are located above each master controller,
one at each end of the car.
GENERAL ELECTRICA
COMPATTY
SCHENECTADY LY
WE
SWITCH
20 SE
FORM
RATLANK GES
OFF
an
Fig. 494. Master Controller Switch Without Fuse. Also Negative Con-
trol Switch on Locomotive.
The master controller switch (Fig. 494) is a pivoted
switch mounted in an iron box and having a projecting
handle. It is provided with a magnetic blowout. This
switch is used to cut off current from its master con-
troller when the latter is not in use. It also serves as
an emergency switch in case of any failure of the master
controller.
788
ELECTRIC RAILROADING
30. THE MASTER CONTROL SWITCH is lo-
cated on the switchboard and is of the quick-break,
knife-blade type.
The switch is used to cut off current from the master
controller and the circuit breaker switches..
The normal position of the switch is open except when
the train is being operated from a master controller on
that car.
31. THE TRAIN CABLE is located in an iron pipe
placed beneath the car.
The train cable is composed of seven conductors, each
being covered with a different colored outer braid for
identification. These conductors are attached to num-
bered plugs in the coupler sockets at the ends of the car.
Branch cables run from connection boxes in the train
cable to the master controllers, seven-point cut-out switch.
and coupler sockets.
The train cable is used to connect the operating mas-
ter controller of the motor control apparatus of the car
or train. The seven wires are used as follows:
No. 1. (Red) for accelerating or notching
up.
No. 2. (White) for series connection of mo-
tars.
No. 3. (Green) for parallel connection of
motors.
No. 4. (Green and White) for operating re-
verser one direction.
No. 5. (Yellow) for operating reverser other
direction.
No. 6 (Red and Black) for tripping circuit
breakers.
No. 7 (Black) for setting circuit breakers.

MASTER CONTROL
789
32. THE TRAIN CABLE COUPLER SOCKETS
(Fig. 495), four per car, are attached to the under side
of the car platform. These sockets are of malleable iron
and contain a body of moulded insulation, into which are
set seven bronze split plugs, one being attached to each
conductor of the train cable.
Fig. 495. Train Cable Coupler Socket.
Each socket is provided with a hinged cover adapted
to hold the jumper plug in place and to prevent the en-
trance of dirt and moisture when no jumper is inserted.

790
ELECTRIC RAILROADING
Fig. 496.
Train Cable Jumper.
MASTER CONTROL
791
33. THE TRAIN CABLE JUMPER (Fig. 496) is
used for connecting the train cables on adjacent cars.
It consists of a short length of seven-conductor cable,
with iron heads or plugs attached to the ends, each con-
taining seven insulated contacts, one being secured to
each conductor. The jumper heads fit into the coupler
sockets on adjoining cars, and connect together their
train cables.
34. THE TRAIN CABLE CONNECTION
BOXES, two in number, are located beneath the car.
The train cable connection box (Fig. 497) is of iron
and is used for making the connections from the mas-
ter controller, circuit breaker, coupler sockets and cut-
out switch to the train cable. Seven screw studs, which
are held in an insulating board, are used for securing
the terminals attached to the ends of the entering cables.
Conductors provided with the same colored covering
are connected together, except at one connection box
on each car, where Nos. 4 and 5, which operate the re-
verser, are crossed in order to obtain a direction of car
movement to agree with the position of controller handle
in either controller.
35. THE RESISTANCE TUBES are located in the
contactor box, and consist of twelve tubes wound with
resistance wire. They are used to regulate the current
in the operating coils of the contactors.
36. THE CURRENT LIMIT RELAY (Fig. 498)
is located on the switchboard. It consists of an electro-
magnet provided with two coils. The master control cir-
cuit passes through the upper coil and the main circuit
for motor No. I through the lower coil. The master
control circuit coil lifts the plunger for each step during
acceleration and interrupts the contactor pick-up circuit.

792
ELECTRIC RAILROADING
192
OF LOB
CONNECTION BOX
BUCE FORMS
CENERAL ELECTRIC CO.
SCHENECTADY NYU.S.A
Fig. 497. Train Cable Connection Box.

MASTER CONTROL
793
130428
498. Current Limit Relay.
794
ELECTRIC RAILROADING
If the current flowing through the main circuit coil is
more than a certain amount the plunger is held in its
upper position and cannot drop until the motor current
has fallen to the desired amount.
The relay is provided for the purpose of producing an
automatic control during acceleration.
37. THE POTENTIAL RELAY (Fig. 499) is
mounted in the contactor box. It is similar to the cur-
rent relay in construction, but is used for a different pur-
pose. The relay has a coil which is connected between.
a point in the motor circuit, ahead of the first motor, and
ground. If for any reason the motor current is inter-
rupted on a car, this relay will open the master control
circuit to the contactors on that car, causing them, in
turn, to open. When current is restored to the car, the
relay will again pick up and complete the master control
circuit. The contactors will then pick up in regular suc-
cession, the same as if the motorman had shut off power
and immediately turned the master controller handle on
again.
38. THE CONTROL CUT-OUT SWITCH is
mounted upon the switchboard. It consists of copper
contacts, mounted on an insulated drum, and two sets
of fingers fastened to the switchboard. It is provided
for the purpose of disconnecting the master control cir-
cuit, to the contactors reverser and circuit breaker on
the car, from the train cable.
39. THE CIRCUIT BREAKER SWITCHES, two
in number, are located one above each master controller.
The circuit breaker switch (Fig. 485) is mounted in
a cast iron box and consists of a pivoted blade, with a
handle extending below the box.

MASTER CONTROL
795
Fig. 499. Potential Relay.
796
ELECTRIC RAILROADING
1
A
The handle, when turned to the right, makes connec-
tion through a contact with the setting coils of the cir-
cuit breakers; when turned to the left, with the tripping
coils of the circuit breakers. These positions are indi-
cated by the words "On" and "Off" on the face of the
box.
The normal position of the handle is vertical, and is
held in this position by two springs.
40. CONTROL FUSES are mounted on the switch-
board beside the control cut-out switch. A fuse is placed
in each of the seven control circuits between the train
cable and the cut-out switch.
41. THE SWITCHBOARD (Fig. 489) is located in
the vestibule at the trailer end of the car, and has
mounted upon it the following apparatus:
The THIRD RAIL SWITCH. (Paragraph
No. 17.)
The SEVEN-POINT CUT-OUT SWITCH
and FUSES.
(Paragraph Nos. 38 and
40.)
The CURRENT LIMIT RELAY. (Pará-
graph No. 36.)
The MASTER CONTROL SWITCH AND
FUSE. (Paragraph No. 30.)
SWITCHES AND FUSES FOR AIR I
COMPRESSOR, LIGHTS AND HEAT-
ERS.

EMERGENCY AIR BRAKE ATTACHMENT.
42. THE EMERGENCY AIR BRAKE ATTACH-
MENT for master controller (Fig. 493) consists of a
main valve outside of the controller (Fig. 500), and a
small pilot valve (Fig. 501) within it. The main valve
A
Fig. 500. Main Valve. Emergency Air Brake Attachment.
contains a chamber "A," divided into two parts by a pis-
ton "B" connected to a valve "C," exhausting to at-
mosphere. The lower part of the chamber "A" con-
nects directly to the brake pipe. The upper part of "A"
connects to the pilot valve through "F" and pressure in
both parts is equalized by a small hole in the piston "B."
When the pilot valve is opened, pressure in the upper
part of the main valve is reduced, and the piston lifts,
allowing the brake pipe to exhaust through a hole in the
797

798
ELECTRIC RAILROADING
bottom of the main valve to atmosphere. The pilot valve
is opened by a loose collar on the cylinder shaft in the
controller, which presses against the stem of the valve
when the controller handle is at the "Off" position and
the button released.
www
Fig. 501. Pilot Valve Emergency Air Brake Attachment.
TRAIN OPERATION.
43. GENERAL-The apparatus will be inspected
and the train put in condition for operation by the in-
spectors; but the motorman will be held responsible for
the operation of the apparatus while in his charge, and
he should, therefore, familiarize himself with the location,
use and operation of all apparatus on the cars, and should
carefully follow the instructions below:
PREPARATIONS FOR STARTING-When
the train is turned over to motorman, he should:
FIRST-Pass along the outside of train,
carefully examining bus line and train
cable jumpers between cars, to assure him-
self that all connections are properly made
and that main switches are closed.
SECOND-Pass through the train, closing
air compressor and third rail switches in
each car, and opening master control
switches in all cars except head car or car
from which train is to be operated.
THIRD-Pass along outside of train again
and satisfy himself that the air compressors.
are working properly.
FOURTH-Take position in the motorman's
compartment at forward end of train and
note the brake pipe pressure, which should
be seventy pounds, close master controller
switch. The circuit breakers should then
799
800
ELECTRIC RAILROADING
be set by moving the circuit breaker switch,
over the master controller, to the "On" po-
sition-holding it there about one second to
allow time for all circuit breakers to set.
FIFTH-Test the brakes as required by "Air
Brake Instructions," making, upon request
of the trainmen or inspectors, a full service
application (twenty-pound reduction of
pressure), holding them on until the train-
men or inspectors have examined the
brakes on each car.
If the brakes are found in proper condition,
trainmen or inspectors shall signal the mo-
torman, from the rear of the train, who
will then release the brakes.
The test is not complete until the trainmen
or inspectors have re-examined the brakes,
which should be done as quickly as pos-
sible, to see that they have released proper-
ly, after which the inspectors must report
their condition to the motorman.
The train is now ready to be started.
45.
TO START-Press down the button in the con-
troller handle, insert the handle key and give it a quarter.
turn. The button must now be held down to prevent
the pilot valve in the controller from operating and ap-
plying the brakes. Move the controller handle to the
left as far as it will go, holding it there against the spring,
which tends to return it to the "Off" position. The mo-
tor control will then notch up to full speed position by
the automatic progression of the contactors, in successive
steps, under the control of the current limit relay. In this
TRAIN OPERATION
801
position it is not necessary to hold the button down to
prevent application of the brakes.
46. COASTING-Hold the button down and move
controller handle to "Off" position. In this position
power will be shut off and the train may coast free.
47. SERVICE STOP-The service stop will be made
by the air brake valve in accordance with the "Air Brake
Instructions."
48. EMERGENCY STOP-The emergency stop
may be made by releasing the controller handle, which
will then return to the "Off" position, shutting off the
power and applying the brakes.
49. TO START SLOWLY-Move the controller
handle to the left to first point. In this position both
motors on each car are connected in series with all re-
sistance in circuit and the motor control will not "notch
up" to higher speed.
50. TO INCREASE SPEED SLIGHTLY-Move
the controller handle to the second point and quickly re-
turn it to first point. This operation results in the cut-
ting out of one step of resistance, and may be repeated
until all the resistance is cut out, thus slowly notching up
under the control of the motorman and not automatically.
If the controller handle is left on the second point for
a sufficient length of time, all resistance will be auto-
matically cut out in successive steps, under the control of
the current limit relay, until full series or half speed is.
reached.
51. RUNNING POSITIONS-The second and
fourth notches are running positions, and the train should
not be operated for more than a few minutes at a time
with the controller handle on intermediate notches.
{
802
ELECTRIC RAILROADING
52. TO REVERSE-Move the controller handle to
the right to the first point. The reverser will change the
direction of train movement, and the motors will be con-
nected in series with all resistance in circuit.
}
It is not possible to run above half speed in the re-
verse direction, and if higher speed is required, it can
only be obtained by operating the master controller at
the other end of the car or train.
TRAIN FAILURE.
53. A TRAIN FAILURE, that is, a failure of a train.
of one or more cars to move or to attain full speed, when
the directions for train operation have been followed,
may be due to one or more of the following causes:
FIRST-FAILURE OF POWER.
SECOND-DEFECT
CIRCUIT.
IN MASTER CONTROL
(a) Master control fuse blown or imperfect.
(b) Grounded train cable.
(c) Poor contact in master controller.
(d) Loose train cable jumper.
THIRD-DEFECT IN MOTOR CONTROL CIR-
CUIT.
(a) Circuit breakers open.
(b) Bus fuses blown.
(c) Loose or disconnected bus jumper.
(d) Main fuse blown.
(e) Shoe or trolley fuses blown,
FOURTH—FAILURE OF AIR BRAKES TO RE-
LEASE.
TRAIN OPERATION
803
FAILURE OF POWER.
54. A FAILURE OF POWER can be detected by
closing the lighting switches; if lights burn, power is on.
DEFECT IN MASTER CONTROL CIRCUIT.
55. TO DETERMINE IF MASTER CONTROL
CIRCUIT IS OPEN turn master controller handle to
the first notch and open the master controller switch.
The noise of slight arcing indicates that the master con-
trol circuit is closed and that the trouble is elsewhere.
No arcing shows that the master control circuit is open
and indicates that fuse is blown or imperfect. A black
or charred spot in the center of the label, called a "Tell-
tale," indicates that the fuse is blown and should be re-
placed. A fuse which shows no indication of being
blown should be tested to detect faulty construction by
removing a fuse from a lighting circuit and inserting the
fuse to be tested. The lights burning indicate that the
fuse is good, and it can then be replaced.
56. TO DETERMINE IF TRAIN CABLE IS
GROUNDED, operate the master controller. If the
master controller fuse blows, it indicates that one or more
wires of the train cable are in contact with the ground,
and the cable is said to be "grounded."
To locate a ground in the train cable, disconnect train
cable on operating car from rest of train by removing
train cable jumper from its socket on second car. If
the fuse now blows, when the controller handle is oper-
ated, it indicates that the ground is either in the operat-
ing car or its train cable jumper.
To determine whether ground is in train cable or jum-
per, remove the jumper. If the fuse blows when the con-
804
ELECTRIC RAILROADING
I
troller is operated, the ground is in the car. If it does
not blow, the ground is in the jumper, and a new one
should be inserted. If the fuse does not blow when the
jumper is disconnected from the second car, the jumper
should be replaced, and the one between the second and
third cars disconnected from its socket on the third car,
and so on until the fault is located.
If the fault is found to be caused by a defective jump-
er, and if the train is not provided with an extra jumper,
the jumper between the two last cars of the train should
be taken to replace the defective one.
If the fault is found to be on the car and not in the
jumpers, the seven-point control cut-out switch on that
car should be turned to the "Off" position, and the test
repeated. If the fuse still blows when the handle is oper-
ated, the fault is in the train cable. If the fuse does not
blow, the ground is between the cut-out switch and the
contactors, reverser and circuit breaker. If this is the
case, the cut-out switch on the defective car should re-
main in the "Off" position, thus cutting out the fault as
well as rendering the car inoperative, but in no way in-
terfering with the train cable, and permitting the oper-
ation of other cars in the train, through the train cable
in the usual manner.
If opening the cut-out switch does not remove the
fault, that is, if the fault is in the train cable and the de-
fective car is near the rear end, the train should be oper-
ated from the front car as usual, the defective car and
those following being cut out by removing both train
cable jumpers on that car; if at or near the head of the
train, the train should be run from the following car,
all cars ahead being cut out.
TRAIN OPERATION
805
57. TO DETECT POOR CONTACT IN MASTER
CONTROLLER, open the master controller switch, re-
move the cover from the controller and turn the handle
slowly, noting if each finger makes good contact with the
drum. If any contact is poor and cannot readily be re-
adjusted by the motorman, he should run the train from
the next car.
58. TO DETECT LOOSE TRAIN CABLE JUM-
PER, the trainmen should note if the contactors on each
car are working while the train is accelerating. If there
is a loose train cable jumper, all cars ahead of the jumper
will operate; others will not. The motorman should be
'immediately informed if any car is not operating.
DEFECT IN MOTOR CONTROL CIRCUIT.
59. IF ONE OR MORE CIRCUIT BREAKERS
OF A TRAIN BLOW when starting or running, return
the controller handle to the "off" position and move the
handle of the circuit breaker switch to the "on" position.
If the circuit breakers again blow when the controller
handle is operated, the brakes should be examined to see
if they have released.
If the circuit breaker on any car repeatedly blows, the
motorman should make an examination to see that it is
properly adjusted. If the trouble is not with the circuit.
breaker, the car should be cut out by opening the seven-
point cut-out switch on the switchboard and the main
switch beneath the car.
Blowing of the circuit breaker is accompanied by a
loud report.
806
ELECTRIC RAILROADING
60. AN OPEN CIRCUIT IN BUS LINE may be
detected when the train is at a crossover and current can-
not be obtained on operating car, although other cars of
the train have current. This indicates that the bus line
fuse or fuses are blown, or that a bus line jumper is loose
or disconnected between the operating and adjacent cars.
The motorman should inspect the bus line jumpers,
and if the trouble cannot be quickly remedied, he should
go back to the first car having current and move the
train through the crossover. The motorman should then
return to the first car and proceed in the usual manner.
61. WHEN THE MAIN FUSE IS BLOWN, the
motors will not operate, although the contactors may be
in working order and the circuit breaker closed. This
should occur very seldom, as it can only be caused by
short circuit or grounding in the motors or motor cir-
cuits, which are usually protected by the quicker acting
circuit breaker. This fuse should not be replaced on the
road except to avoid serious delay to the service, as in
the case of single cars. BEFORE RENEWING MAIN
FUSE, OPEN THE MAIN SWITCH.
62. A SHOE FUSE MAY BLOW from short cir-
cuit, grounding of the car wiring on some part of the
car or truck, or may be caused by a contact shoe on the
car or train grounding, due either to being broken or
from fouling or picking up something along the line. If
it is necessary to replace a shoe fuse on the road so as
to prevent delay to service, the motorman should open
the third rail switch on the switchboard and insert the
wooden paddles, provided for that purpose, between all
shoes on that car that are in contact with the third rail.
63. A TROLLEY FUSE MAY BLOW from short
circuit or grounding of the car wiring on the car or
TRAIN OPERATION
807
truck, or because it has been overloaded by running in
a train with other trolleys down and taking current for
the whole train through the one fuse. If this latter has
been the cause, the fuse should be replaced on the road if
it is required to prevent delay to service. Before replac-
ing the fuse, pull down both trolleys and open the trolley
switch.
{
GENERAL DIRECTIONS.
64. IN CASE OF FIRE beneath any car in the train,
the motorman should open all circuit breakers by mov-
ing the circuit breaker switch to "OFF" position. If
this fails, he should open the main switch beneath the
car and the seven-point cut-out switch on the switch-
board.
65. IF SMOKE OR FIRE IS OBSERVED by the
trainmen in any of the lighting or heater circuits within
the car, they should IMMEDIATELY open the switch
controlling the circuit, and extinguish the fire with
SAND. NEVER USE WATER to extinguish a fire.
when power is "ON," as water is liable to increase the
danger by causing further short circuits.
66. UNUSUAL NOISES in train movement should
at once be located. To avoid delay the conductor or
brakeman should stand beside the train while it is moved
slowly. If noise is caused by brake rigging, the same
should be tied up; if the noise is located within the mo-
tors, and the schedule permits it, the motors should be
cut out by opening the seven-point cut-out switch on that
car.
· 808
ELECTRIC RAILROADING
1
67. A BROKEN THIRD RAIL SHOE or shoe sup-
port should be broken completely off or tied up, which-
ever, in the judgment of the motorman, will cause the
least delay. In either case, open the third rail switch on
switchboard and insert wooden paddles between third
rail and all contact shoes on the car. To break off re-
mainder of shoe, use some tool with a wooden handle, as
a hammer or ax. NEVER USE A CROWBAR OR
COUPLER PIN FOR THIS PURPOSE.
68. TO STOP TRAIN WHEN AIR BRAKES
FAIL, turn controller to first notch in reverse position.
THIS SHOULD ONLY BE DONE IN CASE OF
EMERGENCY AND TO AVOID ACCIDENTS.
69. CAUTION-Employes should exercise extreme
care while working about or on car wiring. The switch
controlling the circuit on which work is being done
should always be open.
70. MOTORMEN MUST REPORT at the end of
each trip, on the regular form provided for the purpose,
all detentions and reasons for such detentions and any
defects in electrical, air and signal apparatus.
1
The New York Central is now operating a portion of
the 289 miles of track which will soon be entirely operated
by electricity.
Their equipment which is now all in use consists of 125
motor cars each containing 400 H. P. of electric motors
and 35 locomotives each of 220 H. P. with large over-
load capacity. Each locomotive will develop 2500 H. P.
before blowing fuses, and can sustain that power for sev-
eral minutes.
Recently a train of 9 Pullmans went dead on a 0.5%
grade in the tunnel, on account of engine trouble. One of
the electric locomotives coming up behind with 7 coaches,
at once coupled on and started the whole combination of
itself, a dead locomotive and 16 cars, the whole weighing
about 1000 tons. It drew the whole up a 1% grade about
half a mile long at good speed and landed them at the
Mott Haven yard.
The motor car trains. make a maximum speed of 52
miles per hour.
The locomotive trains make a maximum of about 66
miles an hour with regular trains.
+
•
809
SUBURBAN MOTOR CARS.
A.-GENERAL.
1. Sprague-General Electric Type "M" control sys-
tem, as supplied to the Suburban Motor Cars of the New
York Central & Hudson River Railroad Company, com-
prises two distinct sets of controlling apparatus, namely,
the main or motor control and the master control.
2. Each motor car is equipped with a set of motor
control apparatus which serves to carry current from the
third rail through the motors to ground, forming dif-
ferent combinations of motors and cutting out resistances.
in starting that particular car. Each motor circuit is
local, being confined to its respective car.
3. Every motor car in the train is equipped with
master control apparatus, the office of which is to operate
the motor control. An important feature of the master
control is the train cable, comprising seven conductors.
running the entire length of the train with suitable coup-
lers between cars. On every motor car a connection is
made from this cable to the motor control apparatus on
that car. At every cab connection is made from the train
cable to a master controller. Consequently, any master'
controller on a train can energize the entire train cable
and operate all the motor control apparatus connected
to it,
810
SUBURBAN MOTOR CARS
811
B.-MOTOR CONTROL.
4. The motor control on each car consists of the fol-
lowing apparatus:
A set of Contactors mounted in a box.
A Reverser.
A set of Rheostats.
A Circuit Breaker
A Main Fuse.
A Main Switch.
5. In addition to these pieces of apparatus there are
four third rail shoes with the necessary main cables con-
necting them to the control apparatus on the same car.
There is also a main cable extending the whole of the
train and provided with couplers between cars which
connects the third rail shoes throughout the train to-
gether. This cable is termed the bus line.
6. From the third rail shoes the main circuit is car-
ried to the main switch on the panel board and from
there through the main fuse and circuit breaker to the
contactors.
7. THE CONTACTOR (Fig. 480) is a switch, the
movable portion of which is operated by an electro-mag-
net which receives line current from the master controller
through the train cable. Where the main contact is
made two heavy copper tips are provided. These two
contact tips are inclosed in an arc chute, and a powerful
magnetic blowout is provided having poles extending
along two sides of the arc chute for promptly extin-
guishing the arc formed in breaking the circuit.
812
ELECTRIC RAILROADING
}
8. A CONTACTOR BOX (Fig. 481) is provided
for holding the set of fifteen contactors. This box is of
iron, heavily lined with asbestos and other insulating
materials for preventing short circuiting. This box is
provided with two sheet-iron covers, which can be readily
dropped down by releasing suitable catches when it is
desired to inspect the contactors. These contactors are
supported in the box by means of insulated bolts.
THE REVERSER (Fig. 482) is a multiple
switch, the movable part of which is a rocker arm opera-
ted by two electro-magnets, one being used for each
direction. These coils are energized by current from the
master controller circuit, and the connections are such
that only one coil can receive current at one time. Wires
from the motor armatures and fields are connected to the
fingers of the reverser, and, by means of contact pieces
on the rocker arm insulation, the proper connections of
armatures and fields are established for producing for-
ward and backward movement of the car. The reverser
is installed in a metal box provided with a hinged cover,
held in place by a swing latch.
10. THE MOTOR CONTROL RHEOSTAT (Fig.
483) is made up with a number of cast-iron grids
mounted in, and insulated from, an iron frame. These
rheostats are used to regulate the supply of current to
the motors while the car is accelerating. Cables connect
the various rheostats to different contactors, so that the
latter may cut out sections of resistance as required.
II. THE CIRCUIT BREAKER (Fig. 484) is simi-
lar in construction to a contactor, but designed to carry
and break the full current taken by a car. It is closed by
means of an electro-magnet which is energized by a set-
ting switch located in the motorman's cab. The circuit
SUBURBAN MOTOR CARS
813
breaker is tripped automatically when excessive motor
current flows through its series tripping coil. The mo-
torman may also trip the circuit breaker by moving the
combined setting and tripping switch handle to "off" or
trip position.
I2.
THE MAIN FUSE (Fig. 486) is a thin copper
ribbon contained in a box composed of insulating ma-
terial. Sheet-iron pole pieces partially surround the in-
sulation and provide a magnetic blowout for expelling
the arc formed when the fuse melts. The fuse will or-
dinarily not melt and open the circuit, as the time re-
quired for this is greater than that taken by the circuit
breaker to trip. A continued excessive current will,
however, melt the fuse.
13. THE MAIN SWITCH is a knife blade quick
break switch, located on the panel, and is used to cut off
the supply of current through the main fuse, circuit
breaker, contactors and motors. This switch should not
be opened while the motors are taking current, except in
an emergency. It should, however, always be opened
before the main fuse, circuit breaker or contactors are
examined. Fig. 502.
14. THE BUS LINE COUPLER SOCKET (Fig.
490) composed of a body of molded insulating material
containing a large split plug contact. Supporting feet of
malleable iron are secured to this insulating body for
attaching to the under side of the car platform. A hinged
lid at the front of the socket is also provided, having the
two functions of holding the coupler plug in place and
excluding dirt and water when the jumper is not
inserted.
15. THE BUS LINE COUPLER OR JUMPER
(Fig. 491) consists of a short section of flexible insulated

814
ELECTRIC RAILROADING
Vestibule & Headlight Fuse. Car Lighting Fuses.
Fan Motor
Fuse.
Vestibule &
Head Light
Switch.
Car Lighting
Switch.
Fan Motor
Switch.
Heater
Switches,
Heater
Fuses.
Main
Switch.
Control
Cut out
Switch &
Fuses.
Air
Compressor
Switch.
Air
Compressor
Fuse.
Current
Limit
Relay.
Fig. 502. Switchboard-New York Central Equipment.
SUBURBAN MOTOR CARS
815
cable with a plug attached to each end. But one jumper
is required for connection between two adjacent cars,
the additional sockets being provided so that cars may be
turned end for end, or couple, in any desired relation.
16. THE BUS LINE FUSE is identical with the
main fuse. Two of these are provided, as shown on
diagram, for protecting the bus line.
17. THE BUS LINE JUNCTION BOX is provided
for connecting the ends of the bus line cable. The box
is composed of cast iron and contains an insulating board,
to which is secured a single stud bolt for holding the
cable terminals.
18. THE SHOE FUSE BOX is very similar to the
main and bus line fuse boxes, but is adapted for attach-
ment to the wooden third rail shoe beam.
C.-MASTER CONTROL.
19. THE MASTER CONTROL APPARATUS
comprises the following for each car:
Two Master Controllers.
Two Master Controller Switches.
Train Cable.
Four Train Cable Coupler Sockets.
One Train Cable Coupler or Jumper.
Two Train Cable Connection Boxes.
Current Limit Relay.
One Potential Relay.
One Cutout Switch.
Two Circuit Breaker Setting and Tripping
Switches.
Control Fuses..
816
ELECTRIC RAILROADING
20. THE MASTER CONTROLLER (Fig. 493)
contains a single movable contact cylinder and stationary
fingers mounted on an insulated support. The function.
of the master controller is to supply current at the will
of the motorman to the train cable for operating the re-
verser and contactors. The controller has a single handle
for both forward and reverse direction of train move-
ment. Four points are indicated on the cap plate for
forward direction and two for reverse. The first point
in either direction is called the "switching" or "lap" posi-
tion, the second "full series." The third point forward is
called the "parallel lap" position and the fourth the "full
parallel."
21. THE MASTER CONTROLLER SWITCH
(Fig. 503) is located over the master controller and is
used for admitting current to the master controller at the
operating end of the train. A suitable enclosed fuse is
located within the switch box to protect the master con-
trol circuit.
22. THE TRAIN CABLE is composed of seven con-
ductors, each being covered with different colored braid-
ing for identification. These conductors are attached to
numbered plugs in the coupler sockets at the ends of the
car and branch wires extend to the master controllers.
These seven wires are used as follows:
No. I.
No. 2.
For accelerating or notching up.
For series connection of motors.
No. 3. For parallel connection of motors.
No. 4. For operating reverser one direction.
No. 5. For operating reverser other direction,
No. 6. Tripping circuit breakers.
No. 7. Setting circuit breakers.

SUBURBAN MOTOR CARS
317
817
Fig. 503. Master Controller Switch: Pump Switch; also Main Sander Switch on Locomotive.
818
ELECTRIC RAILROADING
In order to secure the proper protection from injury
the train cable is carried in iron conduit.
23. THE TRAIN CABLE COUPLER SOCKET
(Fig. 495) is attached to the under side of the car plat-
form. This socket is of malleable iron and contains a
molded insulation body into which are set seven bronze
split plugs, one being attached to each conductor of the
train cable. The socket is provided with a hinged cover,
adapted to hold the jumper plug in place and to prevent
the entrance of dirt and moisture when no jumper is
inserted.
24. THE TRAIN CABLE COUPLER, OR JUMP-
ER (Fig. 496) is used for connecting the train cables
on adjacent cars together. It consists of a short length
of seven-conductor cable, with heads or plugs attached
to the two ends, each containing seven insulated con-
tacts, one being secured to each conductor. The jumper
heads fit into the coupler sockets on two adjoining cars,
and connect their train cables together.
25. THE TRAIN CABLE CONNECTION BOX
(Fig. 497) is used for making the connections from
master controller, circuit breaker setting and tripping
switches and coupler sockets to the train cable. Seven
screw studs, which are held in an insulating board, are
used for securing the terminals attached to the ends of
the entering cables. Conductors provided with the same
colored covering are connected together, except at one
connection box on each car, where the two wires Nos.
4 and 5, which operate the reversers, are crossed in order
to obtain the direction of car movement to agree with
position of controller handle in either controller.
26. THE CURRENT LIMIT RELAY (Fig. 498) is
provided for the purpose of producing an automatic
{
SUBURBAN MOTOR CARS
819
operation of the control. The control circuit passes.
through the upper coil and the main circuit for one motor
through the lower coil. The control circuit coil lifts the
plunger for each step during acceleration and interrupts
the contactor pick-up circuit. If the current flowing
through the main circuit coil is more than a certain
amount the plunger is held in its upper position and can-
not drop until the motor current has fallen to the de-
sired amount. This relay is mounted on the panel board.
27. THE POTENTIAL RELAY (Fig. 499) is
somewhat similar to the current limit relay in construc-
tion, although it is used for a different purpose. This
relay has a coil which is connected between the motor
circuit, before reaching the first motor, and ground. If
for any reason the motor current is interrupted on a car,
this relay will open the control circuit to the contactors
on that car and the contactors will drop open. When
current is restored to the car the relay will again pick
up and complete the control circuit. The contactors will
then pick up in regular succession the same as if the
motorman had shut off power and immediately turned
the master controller handle on again. This relay is
mounted in the contactor box.
28. THE CONTROL CUT-OUT SWITCH (Fig.
502) is provided for the purpose of disconnecting the
control circuits of the contactors, reverser and circuit
breakers on a particular car from the train cable. This
switch is located on the panel board at one end of the
car where it can be easily reached.
29. CIRCUIT BREAKER SETTING AND TRIP-
PING SWITCH (Fig. 485). This switch is provided
with a single handle having springs to return it to a
820
ELECTRIC RAILROADING
F-
mid-position. Moving the handle in one direction makes
connection from the master controller switch through
the train cable to the various setting coils of the circuit
breakers. Moving the handle in an opposite direction.
completes a circuit from the master controller switch.
through train cable to the tripping coils on the various.
circuit breaker's throughout the train. This switch is
conveniently located above the master controller, and
the two operating positions for the handle are indicated
by "on" for setting and "off" for tripping.
30.
CONTROL FUSES (Fig. 502) are placed in
the circuits between cut-out switches and operating coils
of contactors, reverser and circuit breaker on each car
for providing suitable protection. These fuses are located
on the panel switchboard in an accessible place.
31. EMERGENCY AIR BRAKE ATTACH-
MENT.—The emergency air-brake attachment for mas-
ter controller (Fig. 500) consists of a main valve out-
side of the controller and a small pilot valve (Fig. 501)
within it. The main valve contains a chamber "A,”
divided into two parts by piston "B," connected to a
valve "C" exhausting to atmosphere. The lower part of
the chamber "A" connects to the pilot valve through
"F," and pressure in both parts is equalized by a small
hole in the piston "B." When the pilot valve is opened
pressure in upper part of main valve is reduced and the
piston lifts, allowing the train line to exhaust through a
hole in the bottom of the valve to atmosphere. The pilot
valve is opened by a loose collar on the cylinder shaft
in the controller, which presses against the stem of the
valve when controller handle is at the "off" position and
the button released.
}
SUBURBAN MOTOR IOTOR
821
CARS
D.-TRAIN OPERATION.
32. Before attempting to start a train the motorman
should close the air-compressor switches located on the
panel boards of the various cars and wait until the train
line and reservoir are properly charged, following the
air-brake instructions in regard to testing brakes.
33. He should then see that all main switches are
closed and all master controller switches open, with the
exception of the one near the controller, which he is to
operate. He should also move the circuit-breaker switch
to its "on" position, allowing about a second for the
circuit breakers throughout the train to close.
34. To start the train press down the button in the
controller handle, insert the handle key and give it a
quarter turn. The knob in the top of the handle must
now be held down to prevent the pilot valve in the con-
troller from operating and applying the brakes.
35. If it is desired to have the control notch up to
the maximum speed position, the operating handle should
be moved at once to the left as far as it will go and held
there against the spring pressure tending to return it to
the "off" position. While in any running position the
knob in the handle need not be held down, as the air
brakes will not be applied automatically unless the con-
troller handle is at its "off" position and the knob re-
leased.
36. When the controller is at the full "on" position
control current passes from the master controller switch
through the master controller to the train cable and thence
to the various cars of the train. If the reversers are
not thrown to the position corresponding with the move-
t
822
ELECTRIC RAILROADING
ment of the controller handle current will first pass
through the proper operating coil of the reversers to
ground. After the reversers have reached the correct
position interlocking contacts on them cut off circuit to
ground and establish one through four contactor coils.
Simultaneously current passes from the master controller.
through another train wire (called the series retaining
or No. 2 wire) to a fifth contactor coil, and this con-
tactor, in conjunction with the other four, produce the
first or switching point. At the same time a third wire
(the notching or No. I wire) is energized and the circuit
is established through the current limit relays pick-up
coil and the resistance contactors, so that the progressive
steps are started. Each of these resistance contactors in
picking up prepares the control circuit, by means of in-
terlocking switches located on the bottom of contactors,
for the next step; it also cuts out the contactor from
the "notching" circuit and connects it in the "retaining"
circuit. The current limit relay, in lifting, opens the
notching circuit and thereby prevents the contactor for
the succeeding step from lifting at once. When the cur-
rent in the motor circuit coil has reached a sufficient
amount to prevent the current limit relay from dropping,
this notching circuit is not immediately completed and
the progression is temporarily arrested. When the relay
again drops another contactor is closed, and the same
action is repeated until the last or full parallel is reached.
37. The main or motor current flows from the third
rail shoes to the main switch, through the circuit breaker
and main fuse to the contactors, then through the re-
verser and No. I motor to a set of rheostats, then through
another set of rheostats and No. 2 motor to ground.
The motors are now in "series" with all resistance in
SUBURBAN MOTOR CARS
823
circuit and the car starts slowly. On succeeding steps
until the full series position is reached, the rheostats are
cut out in five more steps by the automatic operation of
the contactors. After the full series position has becn
reached a "Bridge" connection is established by the con-
tactors, and the motors are then connected in parallel
with rheostats connected in series with each. The same
automatic "notching up" of the contactors continues, the
controller handle being in the fourth forward position,
until all the resistance is cut out of circuit by means of
the contactors, and the motors are in full parallel.
38. If it is desired to operate the train at low speed,
as in switching, the master controller handle should be
moved to the left for forward direction, to the first point
only. On this point the full resistance will be in circuit,
while the two motors in series and the control will not
"notch up." If it is necessary to slightly increase the
speed the controller handle should be moved to the sec-
ond point to start the automatic progression of the con-
tactors through the resistance steps and quickly returned
to the first or lap position. The notching up will be
arrested, but the contactors which have picked up and
cut out more resistances will remain closed. This manip-
ulation of the controller handle may be repeated and a
slow acceleration obtained when it is necessary. If the
handle is left on the second point for a sufficient time
all of the resistance will be automatically cut out of the
motor circuit in successive steps under the control of the
current limit relay until full series, or half speed, is
reached.
39. When it is necessary to reverse the direction of
the train movement the master controller handle should
824
ELECTRIC RAILROADING
be turned to the right. The first point in this direction.
is a switching point, similar to first point forward, and
the train will move slowly without materially increasing
its speed. If a higher speed is desired the handle should
be moved to the second point and the automatic notch-
ing started for cutting out the resistance. It is possible
to obtain only half speed in the reverse direction, as the
second point leaves the motors in series relation.
40. Returning the master controller handle to the
"off" position cuts off the supply of current to the train
cable and contactors, and the latter therefore drop out
and open the main circuit through the motors. Should
the motorman from any cause remove his hand from the
controller handle while it is at an "on" position a spring.
will return it to the "off" position and thereby automati-
cally cut off power from the train and apply the air
brakes. When the motorman turns to the "off" position
it is necessary to hold down the knob in the controller
handle to prevent the application of air brakes.
41. The controlling cut-out switch disconnects the
operating parts of contactors, reverser and circuit breaker
on the car from the train cable, but does not affect the
operation of the rest of the train, although the car may
be the one from which the train is being operated.
42. The arrangement of apparatus is such that the
train may be operated in either direction from any mas-
ter controller in the train. It is necessary, however, in
order to operate in a reverse direction at full speed, to
operate from a master controller at the end of a car to-
ward the direction in which the train is to be moved.
43. Should the train break apart the control couplers
will pull out, cutting off current from the train cable on
the section of train behind the break. This drops out all
SUBURBAN MOTOR CARS
825
the contactors on the rear section, while the front sec-
tion continues under the control of the motorman.
44. The control connections for the reverser are so
arranged that unless the reverser is at the proper position
current is cut off from the contactors, and, consequently,.
the motors on that car receive no current. When the
reverser is in the correct position it is electrically locked
and cannot be operated while the motors are taking
current.
45. The wires of the master control circuit are all
protected from damage due to excess current by means
of small fuses. In case of electrical trouble within the
master controller, train cable, couplers or connection
boxes, the single fuse in the master controller switch
will protect them. In case of trouble in the control cir-
cuit at contactors, reverser or circuit breaker, the fuses
on the panel board will protect the circuit.
ELECTRIC LOCOMOTIVES.
A. GENERAL.
46. The general remarks pertaining to the Sprague
General Electric type "M" control, as applied to the
Suburban Motor Cars (see paragraphs 1, 2 and 3), will
also apply to the electric locomotive control, except that
the train cable in the locomotive control has twenty wires,
seventeen of which are connected to the master controller
and to the motor control apparatus. Of the remaining
three wires two are used for the sander device and one
is an extra. This control, in the same way as on the
Suburban Motor Cars comprises two distinct sets of cir-
cuits, namely, the main or motor control circuits and the
master control motor circuits, the former being governed
by the latter. Each locomotive has four motors, the con-
trol being arranged for operating the motors first, all in
series, then in series parallel, and then in parallel rela-
tion. The two ends of locomotive are designed the "A"
end and the "B" end, the main switch being located on
the "B" end.
•
B.-MOTOR CONTROL.
47. THE MOTOR CONTROL on each locomotive
consists of the following apparatus:
Contactors.
Reversers.
Rheostats.
Main switch.
Main motor cut-out switches. ·
Individual motor fuses.
826
ELECTRIC LOCOMOTIVES
827
In addition to these pieces of apparatus there are four
sets of third-rail contact shoes (two shoes in each set)
and two overhead contact shoes, with the necessary main
cables connecting them to the control apparatus on the
locomotive. There is also a main cable extending through
the locomotive terminating with couplers at the ends, so
that the third-rail shoes and the overhead shoes of any
two or more locomotives may be connected together. This
cable is termed the Bus Line. The circuits from the
contact shoes (both third rail and overhead) are pro-
tected by fuses, a set of two fuses in multiple being
located near each shoe to protect the circuit of that shoe.
From the third-rail shoes or from the overhead shoes the
main circuit is carried through the respective fuses of
each to the main switch and through the motor fuses to
the contactors and thence to motors.
48. THE CONTACTOR (Fig. 504) is an electro-
magnet switch (see general description under paragraph
7, Suburban Motor Cars), with two contact arms and
sets of contacts in multiple operated by one plunger.
There are 43 of these contactors which are located in
the end compartments of the cab, one group on each side
of each end compartment. The contactors are suspended
by insulating bolts from channel iron supports. The con-
tactors are numbered progressively around the cab, No. I
being the nearest the No. I reverser. Each contactor
has a plate with its number, which is attached in front
above the arc chute.
49. REVERSER (Fig. 505) (see general descrip-
tion, paragraph 9, Suburban Cars). There are two re-
versers; one in each end compartment. The No. I
reverser, which is on the main switch end of the locomo-
tive, has the armature and field leads of the two motors

828
ELECTRIC RAILROADING
on that end connected to the studs of its contact brushes.
The connections of armatures and field leads for pro-
ducing forward and backward movement of locomotive
are established by means of copper bars pressed against
spring contact brushes, through a toggle mechanism.
GENERAL ELECTR
Fig. 504. Contactor for Large Current
50. THE
THE MOTOR CONTROL RHEOSTATS
(Fig. 506) are similar to those described under para-
graph 10, Suburban Cars. These rheostats are located
in four groups on the floor in end compartment of cab,
under the contactors.

ELECTRIC LOCOMOTIVES
829
51. THE MAIN SWITCH (Fig. 507) is a knife-
blade quick-break switch, with a lower mechanism for
operating. The switch itself is enclosed in a box, lined
WW
with fireproof insulation, the handle for operating being
located outside the box, where it is readily accessible.
This switch is located in "B" end compartment of cab.
Fig. 505.
Reverser for Locomotive.

830
ELECTRIC RAILROADING
Fig. 506.
Grid Resistance

ELECTRIC LOCOMOTIVES
831
J
Fig. 507. Main Switch.

832
ELECTRIC RAILROADING
It should not be opened while current is on motors ex-
cept in an emergency. It should, however, be opened.
before the individual motor fuses or contactors and re-
versers are examined.
Fig. 508. Main Motor Cut-out Switches.
52. MAIN MOTOR CUT-OUT SWITCHES (Fig.
508) are for the purpose of cutting out the individual
motors in case of any ground or defect in a motor which

ELECTRIC LOCOMOTIVES
833
renders it inoperative. There are four of these cut-out
switches, one for each motor, and they are located on the
sides of the cab, the switches for No. I and No. 2 motors
being just over the No. 1 reverser and for No. 3 and
No. 4 motors over the No. 2 reverser. The number of
the motor to which it is connected is marked on each
switch. Each switch also has a small auxiliary control
cut-out switch which opens and closes with the larger
switch for operating the circuit of the series contactor
620
FUSE BOX
MA
GENERAL ELECTRIC DE
Fig. 509. Motor Fuse Box.
coils.
These switches are normally kept closed, except
in case of individual motor trouble. It should be seen
that they are well closed, so that the small auxiliary
switches make good contact. When one of these switches
is opened on account of motor trouble, the locomotive
will not move until controller handle reaches the eleventh
notch.
53. MOTOR FUSE BOX (Fig. 509) (see para-
graph 12, Suburban Cars, for general description of this
type of fuse box). There are four of these fuse boxes,

834
ELECTRIC RAILROADING
each motor having its individual fuse. These boxes are
located one over each third-rail shoe, just above the shoe
fuse boxes. A copper ribbon fuse of 800 ampere rating
is used in these boxes. Each box has marked on it the
number of the motor whose circuit it protects.
Fuse Box
MAD
RENTAL ELECTRIC CL
Fig. 510.
Third Rail Shoe Fuse Box.
54. THIRD-RAIL SHOE FUSE BOXES (Fig.
510) are similar to the motor fuse boxes, but somewhat
larger. There are two of these arranged in multiple for
each pair of third-rail shoes and are mounted on brackets
just above their shoes. Copper ribbon fuse of 1,600 am-
pere rating is used in each of these boxes.
55. OVERHEAD SHOE FUSE BOXES are practi-
cally the same as those for third rail shoe, but are
mounted on the roof, two in multiple near each other.
ribbon fuse of 1,600 ampere rating is used here
A copper
also.
ELECTRIC LOCOMOTIVES
835

Poppet
Kalve
Highest Position-
Operating Range for Valve i.
Running Position-
Retracted Position.
MH<
· 14 Ft9ŝin.
-UIEVALGI-
*2/1736/-
-15Ft.6in.
D
Engineers Valve
Double Check Valve
To Reservoir
Exhaust
Exhaust
THRA!!!
Po Reservoir
Fig. 511. Overhead Contact Device.
三
​
836
ELECTRIC RAILROADING
56. THIRD-RAIL CONTACT SHOES.-These
shoes are of the "Slipper" spring actuated under-running
type. The shoe bracket is mounted on a wooden insu-
lating beam. There are two shoes in multiple on each
bracket. Fig. 470.
57. OVERHEAD CONTACT DEVICE (Fig. 511)
is a pneumatically operated shoe. There is a valve near
each master controller in the cab, by means of which the
Fig. 512. Bus Line Coupler Socket.
shoe may be raised or lowered. When air is applied the
shoe is lifted so as to make contact with the overhead
rail. When air is released, the shoe drops; also if the
shoe runs off the rail it is tripped automatically and drops.
Moving handle forward operates a pilot valve, by means
of which a slide valve is thrown to admit air from reser-
voir to cylinder of contact shoe device. Pulling handle.
back operates another pilot valve and the slide valve is

ELECTRIC LOCOMOTIVES
837
Fig. 513,
Bus Line Coupler or Jumper.
838
ELECTRIC RAILROADING
thrown over to connect air chamber of contact device to
exhaust. The handle will spring back to the middle posi-
tion from either direction. There are two of these over-
head contact shoes, which are controlled in common by
either valve in the cab. They are mounted on wooden
insulating blocks. It is very important that these shoes.
should not be raised when they will come in contact with
overhead obstructions.
58. THE BUS LINE COUPLER SOCKET (Fig.
512) has three split plug contacts, which are connected
together for obtaining sufficient carrying capacity. (See
paragraph 14, Suburban Cars, for general description.)
59. THE BUS LINE COUPLER OR JUMPER
(Fig. 513). (See paragraph 15, Suburban Cars, for gen-
eral description.)
C.-MASTER CONTROL.
60. THE MASTER CONTROL APPARATUS
comprises the following for each locomotive:
Two master controllers.
One main master controller switch.
Two overhead master controller switches.
One negative control switch.
Train cable.
Four train cable coupler sockets.
One train cable coupler or jumper.
One train cable connection box.
One train cable cut-out switch, combining also a sec-
ond train cable connection box.
One current limit relay.
Control fuses,
ELECTRIC LOCOMOTIVES
839
61. THE MASTER CONTROLLER (Fig. 514)
contains two movable cylinders, which are geared to-
gether, and stationary contacts for each mounted on insu-
lation supports. The function of the controller in gen-
eral is to supply current at the will of the engineer to the
train cable for operating the reversers and contactors.
The primary or slow-speed cylinder operates the con-
tactors which produce motor combinations. The second-
ary of high speed cylinder operates those contactors.
which cut out the main motor resistance. The second-
ary cylinder is geared to primary at the ratio of about
three to one. Geared to cylinders is a governor device,
by means of which the movement of the controller handle
and the cylinders is checked when current through the
motors exceeds a certain amount. The controller has a
separate reverse cylinder, and there is a separate handle
for this. The reverse handle can be thrown only when
the controller handle is in the "off" position. The "off"
position of the controller handle is indicated and is the
extreme forward position.of handle. There are twenty-
four operating notches and an "off" point on the con-
troller dial ring. A latch on the handle engages the
notches on the dial ring and has to be released in moving
from notch to notch. The first ten operating notches
are for series, the next seven for series parallel and the
next seven for parallel operation of motors. The tenth
notch is full series, the seventeenth full series parallel and
the twenty-fourth full parallel position of motors, and at
all other points motors will have resistance in circuit.
62. MAIN MASTER CONTROLLER SWITCH
(Fig. 503) is located on side of passage way in "B" end
compartment of cab and is used for admitting current to
master controllers and should be closed to operate from

840
ELECTRIC RAILROADING
either master controller. The main purpose of this
switch is to cut off line from the master controller fuse,
which is located in this switch, in case the fuse has to be
inspected or renewed. The fuse for this switch is 25
ampere capacity.
63. THE OVERHEAD MASTER CONTROLLER
SWITCHES (Fig. 494) are located one over each master
controller and are used for admitting or cutting off cur-
Fig. 514. Master Controller.

ELECTRIC LOCOMOTIVES
841
THE
rent from the controller over which it is located.
NEGATIVE CONTROL SWITCH (Fig. 494) is
located on the side of the passage way of the "A" end.
Opening this switch cuts off ground from the reverser
and contactor coils. It must be kept closed for opera-
tion. Ordinarily it need not be touched.
Fig. 515, Train Cable Coupler Socket.

842
ELECTRIC RAILROADING
Fig. 516. Train Cable Coupler Plug.
ELECTRIC LOCOMOTIVES
843
a
64. The TRAIN CABLE is composed of twenty con-
ductors, which are attached to numbered plugs in the
coupler sockets, and there are branches from seventeen
of these wires extending to the master controller.
These seventeen wires are used as follows:
No. 1.-For operating series contactors.
Nos. 2 and 5.-For operating series-parallel con-
tactors.
No. 3.-For operating bridge contactors.
Nos. 2 and 4.--For operating parallel contactors.
Nos. 6, 7, 10, 11, 12, 13, 14, 15 and 16.-For operating
resistance contactors.
No. 18.—For operating controller governor.
No. o. For operating reverser one direction.
No. 8. For operating reverser other direction.
Nos. 19 and 20 are used for operating the sander de-
'vice.
No. 17 is an extra wire.
65. THE TRAIN CABLE COUPLER SOCKET
(Fig. 515) has twenty contact studs otherwise the gen-
eral description, paragraph 23, Suburban Cars, will apply
to this coupler socket.
66. THE TRAIN CABLE COUPLER PLUG (Fig.
516) has twenty contacts to agree with coupler socket.
(See general description, paragraph 24, Suburban Cars.)
67. TRAIN CABLE CONNECTION BOXES are
used for making connections from master controller and
coupler sockets to the train cable. One of these connection
boxes (Fig. 517) is combined with the twenty-point cut-
out switch. This is mounted on the back of the master
controller on the "A" end of the cab. This is the No. 2
connection box. The plain connection box (Fig. 518) is

844
ELECTRIC RAILROADING
Fig. 517.
Train Cable Connection Box.

ELECTRIC LOCOMOTIVES
845
mounted on the back of the controller at "B" end of the
cab. No. o wire from No. 1 box connects to No. 8 wire.
in No. 2 box, and No. 8 from No. 1 box connects with
No. o in No. 2 box. All other wires connect number to
number. One of the wires in the outside layer is covered
ભેં
000000
Fig. 518. Plain Connection Box.
with green braid. This is No. I wire, the other wires of
this layer being numbered in the counterclock-wise direc-
tion from this. The red covered wire in the inner layer
is No. 14, the others being numbered counterclock-wise
direction.
F

846
ELECTRIC RAILROADING
D
Fig. 519. Current Limit Relay for Locomotive.
ELECTRIC LOCOMOTIVES
847
68. THE CURRENT LIMIT RELAY (Fig. 519)
is located just above the No. 1 reverser and is provided
for the purpose of checking a too rapid movement of the
controller handle in getting the train up to speed. The
relay coil is connected in series with No. 2 motor circuit.
If the current through the motor exceeds a certain
amount, the plunger of relay picks up and closes a set
of contacts which supplies current to the controller gov-
ernor. The controller handle is thus held from being
moved on and cannot be moved another notch until the
current through the motor falls to a certain amount.
69. THE CONTROL CUT-OUT SWITCH (Fig.
517) has already been referred to under the subject of
CONNECTION BOXES. The connection studs of this
box also serve the purpose of the No. 2 connection box.
This cut-out switch serves the purpose of disconnecting
the control circuits of contactors and reversers on a loco-
motive from the train line. The cut-out switch has twenty
sets of contacts which are connected or disconnected ac-
cordingly as the handle is full around to the left or to
the right.
70. CONTROL FUSES (Fig. 517) are mounted on
the same insulation back as the cut-out switch and are
contained in the same box. The fuses numbered from
the top protect the following circuits:
No. 1-Series contactor coils.
Nos. 2 and 5-Series parallel contactor coils.
Nos. 2 and 4-Parallel contactor coils.
No. 3-Bridge contactor coils.
Nos. 8 and 9-The reverser operating coils.
Nos. 6, 7, 10, 11, 12, 13, 14, 15 and 16—The resistance
contactor coils, respectively, one fuse protecting the con-
tactor coils for each resistance step of controller,
1

848
ELECTRIC RAILROADING
No. 17 is not required but is extra.
No. 18-Controller governor circuit.
Nos. 19 and 20-Sander circuits.
D.-AIR-COMPRESSOR CONTROL
71. The air-compressor control comprises the follow-
ing pieces of apparatus:
A pump motor switch..
A pump governor.
A
pump motor circuit contactor.
72.
Fig. 520. Sectional View Air Pump Governor.
PUMP MOTOR SWITCH (Fig. 503) is located
on side of passage "A" end compartment. This switch is
for the purpose of opening the pump motor circuit when
locomotive is not in service. This switch contains a 40-
ampere fuse, which protects the pump motor circuit.
73. PUMP GOVERNOR (Fig. 520) is located in
"A" compartment on side opposite No. 2 reverser. The
ELECTRIC LOCOMOTIVES
849
governor is of the diaphragm type of construction, the
movement of the.diaphragm, as air pressure falls or rises,
operating a lever mechanism which serves to give a quick
make and break to a small switch of the contactor type.
This switch does not close the pump motor circuit itself,
but closes the circuit through the PUMP MOTOR CIR-
CUIT CONTACTOR, which has higher current capacity
on its contacts than the governor. This contactor is lo-
cated to the left of the governor. When the air pres-
sure in the reservoir falls to 130 pounds, the governor
closes its contacts, thereby energizing the contactor coil,
which in turn closes its contacts; the pump motor circuit
being thus completed the pump starts. When the air
pressure reaches 140 pounds the governor opens the cir-
cuit of the contactor coil, which in turn opens and breaks
the pump motor circuit and the pump stops.
But the governor and the contactor have strong mag-
netic blow-outs at their contacts, sufficient to handle any
current which they may take in this service.
E. TRACK SANDER CONTROL.
74. The track sander control comprises the following
pieces of apparatus:
One main sander switch.
Two sander operating switches.
Two electro-pneumatic valves.
- 75. MAIN SANDER SWITCH (Fig. 503) located
in the "A" end compartment of cab, is for the purpose of
admitting or cutting off current from the sander operat-
ing switches. This switch contains a 10-ampere fuse.
The switch should be opened on inspecting fuse. This
switch has plate marked "Sander."

850
ELECTRIC RAILROADING
76. SANDER OPERATING SWITCHES (Fig.
521) are located one on side of cab near each master con-
troller. These are double-throw switches and are
marked "Sand Forward," "Sand Reverse."
Moving
ANSAL SWITCH
NO 182231FORM B
DATAPP SIGS
GENERALELECTRIC CO.
SCHENECTADYNY.U.S.A.
Fig. 521. Sander Operating Switch.
handle to the "Forward" position energizes the valve
which will apply sand to rail for forward direction. "Re-
verse" position of handle will apply sand for the reverse
direction.
77. ELECTRO-PNEUMATIC VALVES (Fig. 522)
are located one in each end compartment. One valve
operates a sander for one direction of movement, the
ELECTRIC LOCOMOTIVES
851
other valve operates a sander for the other direction,
only one valve being operated at a time. The valve is
operated by a magnet which is energized by current ap-
plied in the sander operating switch.
F.-TRAIN OPERATION-GENERAL.
78. Before attempting to start the locomotive of train
the motorman should first close the pump switch, then
close the main switch and see that the main control switch
and all the cut-out switches are closed. After the reser-
voir and train line are charged the overhead control
switch over the controller from which locomotive is to be
operated should be closed and the reverser handle thrown
in the direction of desired movement of locomotive. The
motorman may then proceed on the signal.
After releasing the latch on controller handle pull con-
troller handle to the first notch, then to the second notch,
and so on, until the desired speed is attained. For coup-
ling, with the locomotive, light, the first or second notches
will ordinarily be sufficient. If it is desired to get up to
speed as soon as possible the handle may be moved around
notch by notch, allowing the latch to take each notch
until the last notch is reached.
If the motorman feels at any point, the further move-
ment of the controller checked, he should not exert un-
due pressure on handle-no more than is ordinarily re-
quired to move the handle from one notch to the next.
Whenever the current through the motors is higher than
a certain amount the automatic governor acts and stops
the further movement of handle. When the current falls
to a certain amount the governor releases controller cylin-

852
ELECTRIC RAILROADING
ders and another notch may be taken, and so on. Every
notch on the controller should invariably be taken by
latch in moving controller on, whether in accelerating or
in throwing controller on with motors already up to
Fig. 522. Electro-Pneumatic Sanding Valve.
speed. In throwing off, the notches need not be ob-
served.
The "off" notch of the controller may be called the zero
notch. The first closed position of the controller is the
first notch and so on, the tenth notch being the full series
ELECTRIC LOCOMOTIVES
853
position, the seventeenth notch the full series parallel
position and the twenty-fourth notch the full parallel
position. The tenth, seventeenth and twenty-fourth
notches may then be called running points. The inter-
mediate points are resistance points and should ordinarily
be used only for accelerating or switching. The tenth
notch gives one-quarter speed, the seventeenth notch one-
half speed and the twenty-fourth notch full speed. The
transition from the tenth to the eleventh notches and
from the seventeenth to the eighteenth should be made
promptly, without pause between.
When the controller is on any notch the current passes
from the master controller switch through the master
controller of the train cable of one or two locomotives
and thence to the reverser operating coils and the con-
tactor coils, which correspond to the given notch, as
shown in the following table. This table give the num-
bers of the contactors which are closed on each step of
the master controller. The numbers that are underscored
indicate the contactors which are closed on that step in
addition to previous ones.
Controller Steps.
Contactors Closed.
I 1-2-4-19-22-25-33-41-42
2
1-2-4-18-19-22-25-33-41-42
3 1-2-4-18-19-22-25-33-39-41-42
4
Series.......5
1-2-4-18-19-22-25-31-33-39-41-42
1-2-4-5-13-18-19-22-25-26-31-33-34-
39-41-42
6 1-2-4-5-6-13-14-18-19-22-25-26-27-
31-33-34-35-39-41-42
854
ELECTRIC RAILROADING
}
First Bridge.
Series
7
1-2-4-6-7-14-15-18-19-22-25-27-28-
31-33-35-36-39-41-42
8 1-2-4-7-8-15-16-18-19-22-25-28-29-
31-33-36-37-39-41-42
9 1-2-4-8-9-16-17-18-19-22-25-29-30-
31-33-37-38-39-41-42
IO 1-2-4-9-10-17-18-19-22-25-30-31-33-
II
38-39-41-42
I-2-4-11-19-25-32-33-41-42
1-2-4-11-18-19-21-23-25-32-33-39-
41-42
Parallel..12
Series
Parallel..13
14
15
16
1-2-4-5-11-13-18-19-21-23-25-26-32-
33-34-39-41-42
1-2-4-5-6-11-13-14-18-19-21-23-25-
26-27-32-33-34-35-39-41-42
1-2-4-6-7-11-14-15-18-19-21-23-25-
27-28-32-33-35-36-39-41-42
1-2-4-7-8-11-15-16-18-19-21-23-25-
28-29-32-33-36-37-39-41-42
1-2-4-8-9-11-16-17-18-19-21-23-25-
17
29-30-32-33-37-38-39-41-42
1-2-4-9-10-11-12-17-18-19-21-23-25-
30-31-32-33-38-39-40-41-42
I-2-4-12-19-21-23-25-33-40-41-42
18 1-3-4-19-20-21-23-24-25-33-41-43
Second Bridge
!
ELECTRIC LOCOMOTIVES
855
}
Parallel....19
20
1-3-4-5-13-19-20-21-23-24-25-26-33-
34-41-43
1-3-4-5-6-13-14-19-20-21-23-24-25-
26-27-33-34-35-41-43
21 1-3-4-6-7-14-15-19-20-21-23-24-25-
27-28-33-35-36-41-43
22 1-3-4-7-8-15-16-19-20-21-23-24-25-
23
Parallel....24
28-29-33-36-37-41-43
1-3-4-8-9-16-17-19-20-21-23-24-25-
29-30-33-37-38-41-43
1-3-4-9-10-17-18-19-20-21-23-24-25-
30-31-33-38-39-41-43
If the reversers are not already thrown to the posi-
tion corresponding with the position of the reverser
handle, when the controller is thrown to the first notch,
current will first pass through the proper operating coil
to ground. After the reversers have reached the correct
position interlocking contacts on each reverser cut off
current to ground and establish a circuit through three
contactor coils. Moving the reverse handle does not
operate the reversers, but simply arranges the contacts,
so that when the controller is turned to the first position
reversers will be thrown in the proper direction. The
operating coil for one direction on one reverser is in
multiple with the corresponding coil on the other re-
verser, these two coils being controlled by one wire from
the master controller and protected by one fuse.
On the first notch the main or motor current flows
from the third-rail shoes or from the overhead shoes
through the shoe fuses to the main switch, then through
856
ELECTRIC RAILROADING
the No. I motor fuse, through the reverser and No. I
motor, through a set of rheostats to reverser and No. 2
motor, then through the other reverser and No. 3 motor
through a set of rheostats, then through another set of
rheostats to reverser and No. 4 motor and then to ground.
The four motors are here all in series, with all the re-
sistance in circuit; and the locomotive, if light, may
start, or if coupled to a train may simply take up draw-
bar slack. Each of the next three steps cuts out one com-
plete set of motor resistance, and on succeeding steps,
until full series is reached, the remaining set is cut out in
six more steps. After full series, between the tenth and.
eleventh notches, bridge connections are established, and
then on the eleventh notch motors are thrown in series
parallel relation. Resistance is cut out in six steps to full
series parallel, the seventeenth notch. Bridge connec-
tions are then established and motors are then thrown
all in parallel, the resistance being cut out again in six
steps. When motors are in parallel each is protected by
its own fuse.
When it is necessary to reverse the direction of train
movement, leaving controller handle in the off position,
throw the reverser handle in the opposite direction and
then move controller handle on in the same way. The
reverser handle is to be thrown in the direction corre-
sponding to direction of movement required. The motors
should not be reversed while the locomotive is moving,
except in case of emergency and then if speed is more
than a few miles per hour the wheels would probably slip.
If it is necessary to reverse while moving, do not throw
controller handle beyond the first notch, if all the motors
are cut in, or beyond the eleventh notch if one motor is
cut out.
ELECTRIC LOCOMOTIVES
857
When operating on an overhead rail section the over-
head contact shoe will be tripped and will drop on leav-
ing this section. The motorman should, however, as an
extra precaution, throw the valve handle back. Either
for raising or lowering the overhead shoe it is necessary
to hold handle in position only long enough for the shoe
to start movement.
To sand the rails the SANDER OPERATING
SWITCH should be moved over in the direction of
movement of the locomotive. To stop the sand the handle
of this switch must be brought back to the middle posi-
tion.
The control cut-out switch, if open, disconnects the
operating parts of contactors and reversers on the loco-
motives from the train cable, but does not affect the
operation of the other locomotive if two are connected
together, although it is cut out on the locomotive whose
master controller is being operated. The control connec-
tions for the reverser are so arranged that unless it is at
the proper position current is cut off from contactors, so
that motors on that locomotive will receive no current.
In case of electrical trouble within the master controller
train cable, couplers, or connections boxes, the single
fuse in the master control switch will protect them. In
case of local trouble on contactors or reversers the fuses
in the cut-out switch will protect the circuit.
1
AIR-BRAKE EQUIPMENT ON MOTOR CARS.
A.-GENERAL.
The air brakes on the cars and locomotives in electric
service are essentially the same as those on the other pas-
senger equipment, except that the steam driven air pumps
on the locomotives are replaced by electrically driven air
compressors, one on each electric locomotive and each
motor car, and the design of the air brakes is such that
their release, as well as application, can be graduated.
The use of an air compressor and main reservoir on
each motor car necessitates the use of an additional train
pipe to connect all the main reservoirs together and to
the motorman's brake valve. This extra train pipe is
called the control pipe.
A safety valve is placed in the end of the main reser-
voir on each motor car to prevent overcharging the brake
system in case the electric pump governor fails.
B.-HINTS TO MOTORMEN.
In suburban service it is highly important not to block
the road. Therefore, remember in case anything gets
out of order that the first important thing is to get out
of the way; learn carefully just what to do in order to
make the proper move quickly; for example:
I. In case of a burst hose, if it be the control pipe.
hose, the cut-out cock on both sides of it should be closed;
but if it should be the brake pipe hose, then it is neces-
858
AIR-BRAKE EQUIPMENT
859
sary to close the cut-out cock ahead of the brake and the
double cut-out cocks on each of the cars back of it; then
open, and leave open, the auxiliary reservoir bleed cocks.
on all of the cars that are cut out. In a case of this kind
some one would be designated and prepared to operate
the hand brakes on the cars that are cut out in case a car
coupling should break and cause the train to separate.
2. In case of inability to release a brake, caused, for
instance, by the emergency valve remaining unseated
after an emergency application, close double cut-out cock
and open and leave open, bleed cock of auxiliary reser-
voir on this car and proceed.
3. In case of brake sticking after service application,
make about a ten-pound reduction and place the handle
of the brake valve in release position. This will usually
release the brake. If not, or further trouble is had with
this brake, do as recommended in preceding case 2.
It will be seen by these examples that by a knowledge
of the operation of the air-brake the motormen and train-
men can formulate rules for themselves that, in case of
trouble, will enable them to get out of the way with little
or no delay.
To gain time adapt the brake-pipe reduction, or appli-
cation of brakes, to speed. For example, for high speed
made a full application and graduate off when a short
distance from the stop. To handle train smoothly make
the application heavy and soon enough, so that if held on
the train would stop a car length or so short of the mark.
Then as the stop or mark is approached graduate the
pressure out of the brake cylinder so that little remains.
when stop is made. If on a level, complete the release;
if on a grade, hold until the signal to start is given, then
release. As the pressure has been graduated down so
{
860
ELECTRIC RAILROADING
that little remains in the cylinder, it will be seen that the
start can be made promptly.
As the automatic brake is applied by the reduction of
the brake-pipe pressure, no matter how produced, it is
plain that leaks will produce results not intended or de-
sired by the motorman, and sometimes interfere with the
accuracy and smoothness of the stop. Therefore, they
should be kept down and reported as surely and promptly
as any other defect. Motormen should observe as care-
fully as possible the action of the governor, feed valve
and gauges; that is, their adjustment, etc., as much better.
operation can be obtained if all are approximately uni-
form.
One of the things that the motorman should learn
carefully regarding the automatic brake is, that after a
certain reduction of pressure in the brake pipe, say
eighteen to twenty pounds, the auxiliary reservoir and
brake cylinder have equalized. Therefore, no greater
braking power can be obtained, and to further reduce the
brake pipe pressure wastes a great amount of air which
must be restored to the brake pipe before a release can
be made, and interfere with that release to such an extent
that a rough stop is usually the result.
Properly handled this brake possesses all the flexibil-
ity of the straight-air brake, while the safety and relia-
bility of the automatic brake has been greatly increased.
Therefore the motorman should endeavor to understand
its principles, so that he can handle the brake so as to
obtain its maximum efficiency with credit to himself and
comfort to the passengers.
#1
1
AIR COMPRESSOR ON ELECTRIC LOCO-
MOTIVES.
A.-GENERAL.
3
The CP-19-B air compressor consists of a duplex,
single-acting, vertical air pump, located between and di-
rectly connected to two 8-pole series, direct-current mo-
tors. It has a piston displacement of 75 cubic feet per
minute, when operating on 600 volts, and against a tank
pressure of 130 pounds per square inch. Fig. 523.
The compressor frame is so shaped as to form a large
oil chamber for the cranks and connecting rods. It is
provided with a pedestal-like base, arranged to support.
the machine, and bolted to the floor of the locomotive
cab. To this frame the motor frames are bolted, one
to each end. The vertical cylinders are bolted to the top,
and large oil-tight doors are provided, one on each side,
for admission to the cranks and bearings.
The pistons are provided with single rings of the three-
section type. Each cylinder is provided with independent
intake and exhaust valves. These valves are of the
tubular type, operating in a vertical position on the tops
of the cylinders.
The intake for the air is provided with a copper screen,
located in a box, which can be easily removed and cleaned
when necessary.
The crank chamber is provided with baffle plates,
above and below, for the purpose of preventing too much
splashing of oil into the cylinders.
861
862
ELECTRIC RAILROADING
The armatures are fastened directly to the crank shaft.
Each end of the shaft is tapered and supplied with key
and clamping nut, for the purpose of securing the arma-
tures and providing means for their removal.
The pole pieces are made of soft iron sheets, securely
riveted together and bolted to finished surfaces on the in-
side of the motor frame.

Fig. 523.
The brush holders are supported on insulated radial
studs held by clamps bolted to the ends of the motor
frames in such a manner as to permit adjustment to ac-
commodate the wear of the commutator. The outside
end of each motor is provided with a large ventilated
AIR COMPRESSOR
863
t
1
shield, semi-closing the machine, and affording protec-
*tion for the armatures and brush holders.
The machine has a total of six bearings, consisting of
one crank bearing, and one wrist bearing for each of the
two connecting rods, and two main bearings. The main
bearings are located in the motor frames, one on each
side of the crank portion of the driving shaft. All bear-
ings are provided with removable bronze linings. The
connecting rods are split on the diameter of the crank
pin, and the crank bearings are held in place by caps
bolted to the lower ends of the connecting rods. The
main bearings are oiled from waste packed pockets
formed in the motor frame castings. The crank bearings
are lubricated by oil splashed by the connecting rods.
The wrist bearings are lubricated by oil supplied to them
through pipes connected to pumping devices located on
the lower ends of the connecting rods so as to dip into
oil in the bottom of the crank chamber.
B.-OPERATION.
The CP-19-B air compressor is intended to operate on
600 volts, and for such operation the motors should al-
ways be connected in series.
The direction of rotation of the armatures should be
such that the top side of the commutator travels toward
the observer, when standing on the side of the compres-
sor where the air intake is located, and the intake open-
ings in the oiling devices should recede while sweeping
through the oil.
Should it be necessary to remove an armature, take off
the end shield and remove brush holders; then take off
the armature nut. Before removing the nut, it will be
864
ELECTRIC RAILROADING
necessary to straighten out lock washer underneath the
same. When the nut has been removed two bolts of
proper length, with hooked ends, should be hooked be-
hind two spokes of the armature spider diametrically op-
posite each other. The outside ends of these bolts should
be threaded, and should pass through holes in a piece of
iron, held against the armature shaft in such a manner
that when tightened the armature will be loosened and
pulled off.
When it becomes necessary to replace a lining for a
main bearing it will be necessary to remove the armature
and armature key. The lining can be then drawn out of
the motor frame over the shaft by bolts screwed into
tapped holes in the end of the lining.
As the commutator wears down it may become neces-
The brush holders
sary to adjust the brush holders.
should be located about one-eighth of an inch from the
commutator, and can be adjusted by loosening clamping
bolt so the supporting stud can slide in the clamp.
In replacing brush holders which have been removed,
care should be taken to move them over as far as possible
in the direction opposite to the rotation of the commu-
tator, so as to produce sparkless commutation.
If it should be observed that a compressor appreciably
increases its speed, from causes other than increase in
voltage, and seems not to be delivering the proper amount
of air, attention should be given to the intake valves, as
such a condition might be caused by valves sticking, or
not properly seating due to accumulation of dirt. The
valve in question should be taken out and thoroughly
cleaned, care being taken not to leave particles of thread
or lint sticking to it.
AIR COMPRESSOR
865
Should the intake valves fail to open with every stroke
on the compressor, attention should be given to the ex-
haust valves. If the exhaust valves leak, or remain open
for any reason, the cylinder will receive air from the
reservoir, and will not give the intake valves an oppor-
tunity to open. When these valves are out care should
be taken not to drop dirt into the cylinders, as the clear-
ance between tops of cylinders and pistons is very small.
Valve trouble of any kind rarely happens with this type
of valve, and can be caused only by accumulation of dirt.
The operator will soon learn to know from the peculiar
click of the valves whether or not they are working prop-
erly.
Should it become necessary to remove a piston or con-
necting rod, the cylinders must be taken off, then the
crank caps removed from the connecting rods, upper
baffle plate removed, and connecting rod and piston
drawn upwards out of the compressor frame.
Oil should be maintained in the crank chamber to
within about one-half inch of the centre portion of the
lower baffle plate, and should never be allowed to become
so low as not to permit the oiling device to properly dip
into the same.
The frame of the machine is designed to catch oil
splashed in the crank chamber and deliver it to the main
bearings. However, the waste pockets around these
main bearings should be examined from time to time to
see that the waste is tight against the shaft, and is re-
ceiving the proper amount of oil. If splashing fails to
supply oil to these bearings, the pockets should be filled
by hand once a week.
Oil in the crank chamber should not be too thick, but
should be of medium or light weight so that the oiling
866
ELECTRIC RAILROADING
device can work to the best advantage. A light gas en-
gine cylinder oil is recommended. When the oil in crank
chamber becomes muddy it should be removed and re-
placed by a fresh supply.
Should pounding develop in the compressor, the crank
bearings should be inspected, and if found in good condi-
tion, it is probable that the cylinder clearance has filled
with dirt, or wrist bearings have become defective, and
the cylinders should be removed and cleaned and bear-
ings inspected.
In replacing pistons in cylinders care should be taken
not to omit any of the little springs in the piston rings.
The machine should be thoroughly inspected from time
to time, and bearings should not be allowed to become
excessively worn before being replaced.
•
Brushes should be replaced when worn out, and com-
mutators should be kept smooth, clean and round. Care
should be taken not to allow oil to come in contact with
the commutator or windings, as oil is injurious to in-
sulating materials.
1
SUBURBAN MOTOR CAR CATECHISM-
CAUSES FOR FAILURE OF TRAIN
MOVEMENT.
Question 1. If train fails to move after instructions
under train operation have been followed, what should
be done?
Answer. Light circuit switches should be closed to
ascertain if there is power in the contact rail, or motor-
man should note if trains in neighborhood are moved by
power.
Question 2. If it is found that there is current in
operating car, what should be done?
Answer. Master controller handle should be moved
to first point, then master controller switch opened to
ascertain whether the master control circuits are closed,
which will be indicated by the sound of slight arcing at
master controller switch.
Question 3. What would cause the failure of train
cable circuits?
Answer. First, imperfect master controller fuse.
Second, grounded train cable. Third, imperfect contact
in master controller. Fourth, loose coupler jumper.
Question 4. What should be done to detect imperfect
fuse?
Answer. Insert new fuse, and if this fails it is evi-
dent the trouble is elsewhere.
Question 5. What should be done when a grounded
train cable occurs?
867
868
ELECTRIC RAILROADING
Answer. The master controller fuse should be re-
placed and the controller moved to the "on" position to
determine if fault lies in construction of the fuse. If
this fails, an attempt should be made to locate the ground
in the train cable. The first thing to do is to throw the
CONTROL CUT-OFF SWITCH (Fig. 502) on the
operating car to the "off" position. If this proves inef-
fective, this operation should be repeated back through
the train, cutting out, however, the train cable jumper
between car tested and one to be tested.
Question 6. What should be done to detect imperfect
contact in master controller?
Answer. Motorman should remove cover from con-
troller and note the movement of contact fingers. The
action of the train is dependent upon the contact of these
fingers, and if it is found that the contact is imperfect he
should endeavor to readjust the contacts, and if he fails
in this it is then necessary to operate the train from the
next car.
Question 7.. What should be done to detect a loose
jumper?
Answer. Motorman should lose no time in going
back through his train to determine if the coupler plugs
are properly inserted in the sockets, and, if not, he should
insert them properly.
•
Question 8. What are the other causes that would
prevent the operation of a train or reduce the speed?
Answer. First, the blowing of third-rail shoe fuses.
Second, the blowing of main motor circuit fuses. Third,
the blowing of circuit breakers or main fuses. Fourth,
an imperfectly acting triple valve causing brakes to re-
main set on one or more cars in train.
MOTOR CAR CATECHISM
869
î
Question 9. How can enclosed fuse that is blown be
detected?
Answer. If an enclosed fuse has blown there is a
deposit or collection of greyish powder at the ends of
the box.
Question 10. What should be done in the event of a
third-rail shoe fuse blowing?
Answer. This fuse will blow only when there is a
short circuit on the car equipment, and fuse should not
be replaced but train continued in the regular manner,
and report promptly made to the train despatcher or per-
son in charge of nearest terminal.
Question 11. If a circuit breaker acts or blows, what
should be done?
Answer. The circuit breaker setting switch should
be moved to the "on" position.
Question 12. What should be done when a triple valve
acts imperfectly?
Answer. Air-brake instructions should be followed,
į. e., valves should be cut out and auxiliary reservoir
cock opened to release brakes.
Question 13. If a train is standing on crossover and
current cannot be obtained on the operating car, although
the other cars of the train and trains in the neighborhood
have current, what does this indicate?
Answer. This indicates that the bus line fuses be-
tween the operating and adjacent cars have blown, or
that bus jumper is loose or disconnected.
Question 14. What should be done to continue oper-
ation of train?
Answer. Motorman should go back to the first motor
car where current can be obtained and move train
through crossover, then go back to the first car again
870
ELECTRIC RAILROADING
and proceed in the usual manner until a point of inspec-
tion can be reached and inspector notified.
Question 15. If a fire occurs in any car in the train,
what should the motorman do?
Answer. Open all circuit breakers by moving the cir-
cuit breaker switch (Fig. 485) to the "off" position, and
if this fails he should then open the main or motor cir-
cuit switch and the main cut-out switch on the car on
which the trouble occurs.
Question 16. If smoke or fire is observed by the train-
men in any of the light or heater circuits within the car,
what should be done?
Answer. The trainman should immediately cut out
the light or heater switches, whichever the case may be,
and the trouble be reported to the despatcher in charge
of the nearest tèrminal.
Question 17. If an unusual noise is observed in the
movement of train, what should be done?
Answer. To prevent delay the motorman should have
the conductor stand beside the train to locate the noise
while he moves the train, after which, if the trouble is
with the brake rigging, same should be tied up.
Question 18. If the noise is located within the motors,
what should be done?
Answer. Motorman should open the cut-out switch
on the car affected, and proceed after reporting trouble.
to despatcher in charge of terminal.
Question 19. If a third-rail shoe support is broken,
what should be done?
Answer. Motorman should first pull the bus line
jumpers, at both ends of the car, insert wooden insulat-
ing slippers between the contact shoe and rail and then
proceed to detach or tie up remnants of device, exercis-
MOTOR CAR CATECHISM
871
J
ing extreme care that the contact device is kept clear of
the truck frame, contact rail, structure, or any grounded.
parts to prevent injury to himself.
Question 20. If either pilot or emergency air-brake
valve leaks badly, what should be done?
Answer. First try applying brakes by releasing the
knob in the controller handle several times, and if this
does not remedy the defect or difficulty cut the valves.
out by means of a cut-out cock located in the pipe lead-
ing to them from the train line.
ELECTRIC LOCOMOTIVE CATECHISM.
CAUSES OF FAILURE OF TRAIN
MOVEMENT.
Question 1. If locomotive fails to move after instruc-
tions under train operation have been followed, what
should be done?
Answer. First, after making sure that the overhead
and main master controller switches are closed, throw
controller on two or three points and off, and observe
by the sound whether any contactors are operating.
Question 2. If none of the contactors operate, what
should be done?
Answer. Turn on light circuit switches to ascertain
if there is power on the third rail or overhead rail.
Question 3. With current on the locomotive, what
would cause the failure of contactors to operate?
Answer. First, an imperfect master controller fuse.
Second, imperfect contact in master controller on some
of the fingers of the primary cylinder. Third, two or
more imperfect 4-ampere fuses in the control apparatus
circuits.
Question 4. What should be done to detect imperfect
master controller fuse?
Answer. Open main master controller switch and re-
new fuse, and if there is still no operation of contactors
the trouble is evidently elsewhere.
Question 5. How can an enclosed fuse that has blown
be detected?
872
ELECTRIC LOCOMOTIVE CATECHISM
873
Answer. A small circle in center of table is charred
and turned black when fuse is blown. This is termed
the "Telltale" of fuse.
Question 6. What should be done to detect imperfect
contact in master controller?
Answer. Cut out master controller switch, then re-
move controller cover and open arc deflectors; first on
the right-hand side. Turn on controller and see that
the controller fingers make good contact with their re-
spective cylinder segments. If any contact is imperfect
endeavor to readjust, if there is time. Failing in this
go to the other controller and operate from that, after
cutting in its overhead switch and the main master con-
troller switch again.
Question 7. What should be done to detect imperfect
fuses in the control apparatus circuits?
+
Answer. Remove cover from the cut-out switch on
back of No. 2 controller and inspect the five top fuses
and the eighth and ninth from top. If any one of these
fuses shows signs of being blown from the telltale being
black, renew the blown fuses.
Question 8. If some of the contactors close on the
first test without giving main current, what should be
done?
Answer. After opening main switch throw reverser
handle back and forth two or three times, throwing
controller to first notch at each reversal and note
whether both reversers respond, throwing over at each
reversal.
Question 9. If neither reverser responds, what should
be done?
Answer. Renew fuses eighth and ninth from top on
cut-out switch and then try.
874
ELECTRIC RAILROADING
Question 10. If one reverser responds to reversals on
controller and other does not, what should be done?
Answer. Throw over by hand the reverser that is
not operating, making sure after throwing that the re-
verser is properly locked by toggle. It would require
considerable force to lock reverser, but it is absolutely es-
sential that it be locked, and no attempt should be made
to operate before making sure of this.
Question 11.
What contactors should close on the
first notch of controller?
Answer. I, 2, 4, 19, 22, 25, 33, 41 and 42. Contact-
ors 1, 4 and 19 close after No. I reverser thrown; 25, 33
and 41 close after No. 2 reverser throws. Contactors 2,
22 and 42 are governed by the No. 1 circuit on master
controller.
Question 12. If contactors 2, 22 and 42 do not close,
what should be done?
Answer. First, renew top 4-ampere fuse on cut-out
switchboard. Second, examine main motor cut-out
switches. See that they are well closed, so that auxiliary
contacts are closed.
Question 13. If this is not effective what should be
done?
Answer. After closing main switch again throw con-
troller to eleventh notch, moving slowly from tenth to
eleventh, and begin operation in series multiple. Motor-
man should here move handle more slowly than ordinar-
ily, as the automatic feature may thus be cut out. Motor-
man should watch meter and should not exceed 2,000
amperes in multiple.
Question 14. If two locomotives are being operated
together and the master controller fuse blows again,
after being removed, what should be done?
ELECTRIC LOCOMOTIVE CATECHISM
875
1
Answer. Pull 20-point jumper between locomotives
and try renewing fuses, and then operate from locomo-
tive on which fuse does not blow again. If a new 20-
point jumper is available this may be substituted and
tried.
Question 15. If motors do not take current between
eleventh and seventeenth notches or between the eight-
eenth and twenty-fourth notches, what should be done?
Answer. Renew the second and fifth fuses for the
first case and the second and fourth fuses for the second
If this is not effective examine contact fingers for
the primary cylinder and adjust if any of these fingers
are not making good contact. Failing in this operate
from the other controller.
case.
Question 16. What are the other causes that would
prevent the operation of locomotives?
Answer. First, the blowing of the third-rail shoe
fuses. Example for this, if lights are not obtainable in
turning on light switches (see Q. 2). Second, the blow-
ing of an individual motor fuse.
Question 17. What would tend to reduce the speed?
Answer. First, in operating with two locomotives, if
either locomotive is inoperative from any of the causes
referred to, or if there is a loose 20-point jumper, or the
bus line jumper is loose or out, and the shoe fuses blow
on either locomotive, of course one locomotive would be
dead load. Second, imperfectly acting triple, as would
be indicated by meters showing excessive current.
Question 18. What should be done in the event of
third-rail shoe fuses blowing?
Answer. These fuses will ordinarily blow only when.
there is a short circuit on locomotive equipment. If the
cause of fuses blowing is evident, however, as from the
876
ELECTRIC RAILROADING
temporary grounding of a shoe, the fuse may be renewed
after the ground has been removed. To do this put slip-
per boards under all the contact shoes of both locomo-
tives and pull bus line jumper between locomotives and
release overhead shoes from overhead rail. In removing
slippers from under shoes, after renewing fuses, do not
stand nearer the fuse box than is absolutely necessary.
If one locomotive is grounded and the other is not, leave
out bus line jumper and operate from locomotive which
is free from ground.
Question 19. What should be done in case of an in-
dividual motor fuse blowing, as indicated by contactors
1, 2, 4, 19, 22, 25, 33, 41 and 42 closing properly on first.
notch without taking current?
Answer. After making sure that the motor cut-out
switches over reversers are all closed, open main switch
and see which motor fuse is blown, renew this and pro-
ceed. If this fuse blows again open cut-out switch for
this motor and start train from the eleventh notch.
Question 20. If a third-rail shoe support is broken,
what should be done?
Answer. Motorman should first pull bus line jumper
if two locomotives are coupled together, insert wooden
insulating slippers between the contact shoes and rail
on the crippled locomotive and retrieve overhead shoe
upon rail and then proceed to detach or tie up remnant
of device, exercising extreme care that the contact de-
vice is kept clear of the contact rail and kept clear of
truck or any grounded part to prevent injury to him-
self.
if
Question 21. What should be done in case air pump.
fails to operate?
Answer. Renew fuse in pump switch which is located
ELECTRIC LOCOMOTIVE CATECHISM
877
in "A" end cab. Open the pump switch before doing
this. If this does not remedy the trouble inspect the
governor contacts and adjust them if necessary.
While many of the conditions referred to are some-
what imaginary and may never arise in practice, the
questions and answers given should, however, serve to
give the motormen familiarity with the circuits and the
operation of the control.
After the motormen have acquired familiarity and ex-
perience in electrical operation, they may on occasion
exercise their own judgment and common sense to better
advantage.
AUTOMATIC AIR-BRAKE CATECHISM.
MOTOR CARS.
A.-General.
Question 1. What is the power used to operate an
air-brake?
Answer. Compressed air.
Question 2. How is the air compressed for use in the
brake system?
Answer. By air compressors on the motor cars.
Question 3. How does it apply the brake?
Answer. By being admitted to a brake cylinder and
forcing a piston out, which, by means of connecting rods
and levers, pulls the brake shoes against the wheels.
Question 4. How is the brake released?
Answer. By allowing the air in the brake cylinders to
escape to the atmosphere. A spring in the brake cyl-
inder then shoves the piston back and the brake shoes
are forced away from the wheels by the brake release
springs on the trucks.
Question 5. What is the form of air-brake now gen-
erally used?
Answer. The quick-action automatic brake.
Question 6. Why is it called an automatic brake?
Answer. Because if anything, no matter what, causes
a reduction of pressure in the brake pipe, the brake will
apply automatically.
878
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AIR-BRAKE CATECHISM
879
Question 7. What parts has the quick-action auto-
matic brake on a motor car?
Answer. An air compressor, pump governor, two
main reservoirs, safety valve, slide-valve feed valve, con-
trol pipe, two brake valves, two air gauges, brake pipe,
triple valve, auxiliary reservoir, brake cylinder, con-
ductor's valve, two air strainers, one bleed cock, two pair
of hose and couplings, six cut-out cocks, one double cut-
out cock, one air strainer with check valve, and one
branch pipe air strainer (Fig. 524).
Question 8. Where are the brake valves and air
gauges located?
Answer. In the motorman's cab at each end of the car.
Question 9. What parts has the quick-action brake on
a trailer car?
Answer. Auxiliary reservoir, brake cylinder, triple
valve, brake pipe, control pipe, conductor's valve, two air
strainers, one bleed cock, four cut-out cocks, two pair
of hose and couplings, one double cut-out cock, one air
strainer with check valve, and one branch pipe air strainer,
Question 10. Is there any difference between the
reservoirs, triple valves, and brake cylinders used on
motor cars and trailer cars?
Answer. No.
Question II. Where is the pressure that supplies the
brake cylinder stored or carried with the automatic
system?
Answer. In the auxiliary reservoir under each cab.
Question 12. What has to be done to apply the auto-
matic brake?
Answer. Reduce the brake-pipe pressure, which re-
duction causes the triple valve to admit the pressure from
the auxiliary reservoir to the brake cylinder.
880
ELECTRIC RAILROADING
B.-The Air Compressor.
Question 13. Where is the compressor installed, and
how?
Answer. It is placed under the car, suspended from
the sills by a cradle. (See Fig. 525).
Question 14. Does it make any difference in which
direction the compressor rotates?

Fig. 525. Suspension Cradle of Air Compressor.
Answer. The shaft must always turn so that the com-
pression part of the stroke is on the upper half revolution.
This will be assured if the rotation is the same as the
hands of a clock when looking at the compressor at the
gear side.
Question 15. How are the pump parts lubricated?
Answer. The crank case is filled with oil (preferably
Arctic Ammonia Oil) up to a point determined by the
oil fitting 18, Fig. 526, on the side of crank case. When
the level of the oil is visible in this fitting, the cap being
removed, the oil level in the crank case is correct. As

AIR-BRAKE CATECHISM
881
88
89
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Fig. 526. Air Compressor on Motor Cars.
25-

882
ELECTRIC RAILROADING
the shaft turns and the connecting rod heads are forced
downward, they drive the oil over the inside of the crank
case and such parts of the cylinders as are exposed. In
this manner all the crank-shaft bearings as well as the
cylinders themselves and wrist pins are thoroughly lu-
bricated.
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82
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83
69
86
87 88
AIR DISCHARGE.
84
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AIR
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82
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BRUSH HOLDER.
59
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Fig. 527. Air Compressor on Motor Cars.
68
AIR-BRAKE CATECHISM
883
Question 16. How often should the oil in the crank
case be replenished?
Answer. Once a week.
Question 17. How often should the suction box be
cleaned?
Answer. This depends largely upon the locality in
which the car operates. Generally it is not required more.
than once or twice a month. In very dusty localities it
may be required oftener.
Question 18. How is the suction box cleaned?
Answer. The outer perforated plate 4 (Fig. 527) cov-
ering the air inlet on the lower side of chamber H should
be removed and the pulled curled hair taken out and thor-
oughly cleaned by beating in a bag, by the use of com-
pressed air or some other efficient means. It may then
be replaced and the outer perforated plate put back in
place.
Question 19. How is the motor lubricated?
Answer. By removing plug 65 (Fig. 526) in both
end bearing housings and filling with oil until the level
can be plainly seen. These bearings should be replen-
ished at the same time as the crank case.
Question 20. Should a compressor which frequently
blows fuses be sent out temporarily with a heavier fuse
than that prescribed?
Answer. Not under any circumstances. Such a prac-
tice is almost sure to result in burning out the motor.
C-Electric Pump Governor.
1
Question 21. What is the purpose of the electric pump
governor? (Fig. 528).
Answer. It starts and stops the compressor automati-
cally when certain predetermined minimum and maxi-

ELECTRIC RAILROADING
884
mum air pressures occur in the main reservoir by alter-
nately making and breaking the circuit to the air-com-
pressor motor.
Question 22. Where is this governor located?
Answer. It is placed in a sheet-iron box under the
to
67
66
74
77
78
63
80
56
54
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52
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TO HIGH PRESSURE
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Fig. 528. Air Compressor Governor on Motor Cars.
TO CUT OUT
PISTON
AIR-BRAKE CATECHISM
885
car on the motor compressor side. This box is located
between the grid resistances.
Question 23. At what pressure is the governor set
to start the compressor?
Answer. One hundred and five pounds.
Question 24. At what pressure is the governor set to
stop the compressor?
Answer. One hundred and twenty pounds.
Question 25. Why is there such a difference between
the maximum and minimum pressures?
Answer. By having this difference a number of ap-
plications of the brake can be made before reducing the
main reservoir pressure to the cutting-in point. This
gives the compressor a longer rest between periods of
operation, thereby allowing it more time to cool.
D.-The Main Reservoirs.
Question 26. From the compressors where does the
air pressure go?
Answer. To the main reservoirs.
Question 27. Where are the main reservoirs located?
Answer. Under each motor car.
Question 28. How much main-reservoir pressure
should be carried?
Answer. One hundred and twenty pounds maximum
and 105 pounds minimum.
Question 29. How often should the reservoir be
drained?
Answer. Daily.
Question 30. From the main reservoir where does
the air go?
Answer. Through the feed valves to the control pipe
and thence to the motorman's brake valve.
886
ELECTRIC RAILROADING
E.-Safety Vale.
Question 31. What is the purpose of the safety valve?
(Fig. 529).
Answer. It prevents overcharging of the brake sys-
tem in case the electric pump governor fails.
Question 32. Where is it placed?
Answer. In the end of the main reservoir.

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Fig. 529. Safety Valve.
F-Slide-Valve Feed Valve.
Question 33. From the main reservoir, where does
the air go?
Answer. To the slide-valve feed valve (Figs. 530 and
531).

AIR-BRAKE CATECHISM
887
Question 34. Where is it located?
Answer. In the box under the car between the re-
sistances on the motor compressor side, in which the elec-
tric pump governor is also located.
58
61
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59
64
67
66
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62
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Fig. 530. Slide Valve-Feed Valve Open.
Question 35. What is meant by the slide-valve feed
valve?
Answer. It is a device in the pipe from the main res-
ervoir to the control pipe which automatically reduces

888
ELECTRIC RAILROADING
main-reservoir pressure to a constant control-pipe pres-
sure.
Question 36. What tends to lower the control pipe
pressure, thereby causing the slide-valve feed valve to act?
58
54 55 56
E
b
51
53
59
64
67
i
66
60
61
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57
63
62
65
Fig. 531. Slide Valve-Feed Valve Shut.
Answer. Reinstating the brake-pipe pressure at re-
lease; recharging the auxiliary reservoirs; maintaining
an air pressure of 90 pounds in the system against leak-
age, when the brakes are not applied.
AIR-BRAKE CATECHISM
889
Question 37. What care should be given this feed
valve?
Answer. The piston and its slide valve should occa-
sionally be taken out, all dirt and gum removed from
them and the chambers where they work, being careful to
leave no lint and to avoid bruising the parts removed.
A very small amount of some light lubrication oil (en-
gine oil will do in the absence of a better) should be
applied to the piston, the face of the slide valve and the
spring on the latter. In replacing the parts move them
back and forth a few times to insure that they work
freely. Next, remove the regulating valve, carefully
clean it, its valve seat and the bushing through which the
valves extend, using no metal to do this, so as to avoid
scratching, and replace the valve dry.
Question 38. Must the main reservoir be drained to
do this?
Answer. No. Close the cut-out cock between the
feed valve and the main reservoir.
Question 39. When properly regulated, what can
cause pressure to feed too high in the control pipe?
Answer. A leaky slide valve.
Question 40. What will tend to prevent the feed valve
properly maintaining the pressure in the control and
brake pipes?
Answer. A leaky regulating valve, leakage past cap
nuts. If this leakage is great enough the effect will be
the same as opening the regulating valve.
Question 41. What will tend to prevent the feed valve.
from opening promptly?
Answer. The piston becoming heavily coated with a
greasy deposit, which prevents rapid equalization of the
890
ELECTRIC RAILROADING
pressure on both sides of the piston, thus reducing its
sensitiveness.
Question 42. Should the feed valve be carefully reg-
ulated?
Answer. As there are a number of these valves in a
train they should all be regulated alike as nearly as pos-
sible, since that valve which is regulated the highest will
stay open the longest and furnish the most air, thus mak-
ing the work imposed on the compressor of that car more
than that done by the others.
G.-Control Pipe.
Question 43. After leaving the feed valve, where does
the air go?
Answer. Through the control pipe to the brake valve
that is being operated by the motorman.
Question 44. What is the purpose of the control pipe?
Answer. It is the means of conveying to the brake
valve that is being operated by the motorman the supply
of air furnished by all the main reservoirs of the train.
Question 45. What are the connections to the control
pipe?
Answer. From the feed valve; to the brake valve,
and to the triple valve.
Question 46. What pressure is maintained in the con-
trol pipe?
Answer. Ninety pounds.
Question 47. Does this pressure vary during the ap-
plication of the brakes?
Answer, No.
AIR-BRAKE CATECHISM
891
H.-The Motorman's Brake Valve.
Question 48. From the feed valves, where does the
air go?
Answer. Through the control pipe to the brake valve
being operated by the motorman.
Question 49. From the feed valves to the control pipe
to the brake valve is all what pressure?
Answer. Ninety pounds.
Question 50. It passes through the brake-valve into
what?
Answer. The brake pipe, and thence through the
triple valve to the auxiliary reservoir.
Question 51. What is the purpose of the brake valve?
Answer. To connect the control pipe to the brake
pipe; to release the brakes, charge the system and main-
tain the pressure; to connect the brake pipe through
suitable passages to the atmosphere to apply the brakes,
and to break all connection between the brake pipe and
control pipe or atmosphere; to hold the brakes applied.
Question 52. In what position of the brake valve is
there a direct opening from the control pipe to the brake
pipe?
Answer. In release or running position.
Question 53. In this position how would the control
pipe and brake-pipe pressure stand, comparatively speak-
ing?
Answer. Equal.
Question 54. What is the release or running position.
to be used for?
Answer. For recharging the brake pipe quickly, so as
to insure a prompt and simultaneous release of the
892
ELECTRIC RAILROADING
brakes; for recharging the auxiliary reservoir, and pre-
vent brake-pipe leakage from setting the brakes.
Question 55. What is the next position of the brake
valve and what does it signify?
Answer. Lap position; all ports closed.
Question 56. When is it used?
Answer. When holding the brakes on after an ap-
plication; or when graduating the release; or when they
have been applied by opening a conductor's valve. This
position should also be promptly used when train breaks
in two hose becomes uncoupled or bursts; when coupling
to air-brake cars or at any time a sudden reduction of.
brake-pipe pressure takes place when not made by the
motorman himself.
Question 57. How should the brake-valve handle be
turned to lap?
Answer. Slowly after making a brake-pipe reduction
so as to cut off the exhaust gradually, that the head
brakes will not be "kicked off" by the air surging for-
ward; quickly when going to the release position, to
graduate the release.
Question 58. Why should it be returned quickly when
graduating the release?
Answer. Because the longer the brake-valve handle is
in the release position the lower the brake-cylinder pres-
sure will reduce. In other words, the reduction of brake-
cylinder pressure is governed by the same principle as
the increase of brake-cylinder pressure during an applica-
tion, but oppositely. For example, the increase of brake-
cylinder pressure up to the point of equalization is pro-
portional to the decrease of brake-pipe pressure; on the
other hand, the decrease of brake-cylinder pressure is
proportional to the increase of brake-pipe pressure.
AIR-BRAKE CATECHISM
893
Question 59. What is the next position and its use?
Answer. Service application; should be used for all
ordinary stops.
Question 60. How is the air discharged from the
brake-pipe in making a service application?
Answer. Through ports in the rotary valve of the
brake-valve, and the "quick service" ports of the triple
valve. The further the brake-valve handle is moved in
the service-application direction the more rapid the dis-
charge of air.
Question 61. Would the blow, or escape, of air from
the brake-pipe be longer with a six-car train than with
a three-car train, the same reduction in pounds being
made in each case?
Answer. Yes; if the brake-valve handle is moved to
the same notch in both cases. The capacity of the long
brake-pipe being so much greater it would require a
larger volume of air to escape to make the same reduction
in pounds.
Question 62. How many service-application notches.
has the brake-valve?
Answer. Two: service and intermediate service,
Question 63. When should they be used?
Answer. With a six-car train the brake-valve handle
can be moved to the second service-application opening,
but with not more than three or four cars the first or
intermediate notch should be used.
Question 64. Why not use the service notch with a
three or four-car train?
Answer. Because owing to the comparatively short
brake-pipe the reduction of brake-pipe pressure would be
sufficiently rapid to cause quick action, resulting in a
full emergency application of all the brakes when only
partial service application was intended.
894
ELECTRIC RAILROADING
Question 65. What is the next position?
Answer. The emergency or quick-action; in this posi-
tion a large direct opening is made from the brake-pipe
to the atmosphere.
Question 66. When is this position to be used, and
how?
Answer. Only in case of emergency; and then the
handle should be moved directly to that position and al-
lowed to remain there until the train stops or the danger
is passed.
I.—Brake-Pipe.
Question 67. What is the purpose of the brake-pipe?
Answer. It is the connection between the brake-valve
and the triple valves, auxiliary reservoirs and brake.
cylinders.
Question 68. What is the difference in pressure be-
tween the brake-pipe and the control pipe?
Answer. When the brake-valve handle is in full re-
lease there is no difference; during an application of the
brakes the brake-pipe pressure is lower than the control
pipe, an amount depending on what brake-pipe reduction
is made by the motorman.
Question 69. What special devices are placed in the
connection from the brake-pipe to the triple valve?
Answer. The double cut-out cock and the branch-
pipe air strainer.
Question 70. What is the double cut-out cock?
Answer. It is a cock having two entirely separate
passages through it, one tapped at each end for one-inch
pipe and the other for three-eighth-inch pipe. The larger
one is for the branch pipe from the brake-pipe to the
AIR-BRAKE CATECHISM
895
triple valve, and the smaller one for the branch pipe
from the control pipe to the triple valve. The turning of
the cock handle shuts off communication from both the
brake-pipe and the control pipe to the triple valve. (Fig.
532).
Question 71. Why should it be arranged to shut off
communication from both the brake-pipe and the control
pipe to the triple valve at the same time?

1-PIPE TAP N PIPETAP
A
B
1-PIPE JAP PIPE TAP
Fig. 532. Double Cut-out Cock.
6
Answer. It makes it impossible in case anything
should happen to the brake cylinder, reservoir or triple.
valve to cut them out from one of these pipes and not
from the other, which might easily occur if a single cock.
were placed in each of the branch pipes separately.
Question 72. When is the double cut-out cock to be
closed?
Answer. Only when the brake apparatus on that car
becomes out of order sufficiently to make it inadvisable.
to use it.
896
ELECTRIC RAILROADING
Question 73. What is the purpose of the branch-pipe
air strainer?
Answer. It prevents dirt and scale from entering the
triple valve, where it might result in cutting the slide
valve and piston; or during an emergency application
lodge on the emergency valve and hold it open.
Question 74. How are connections made between the
cars?
Answer. By hose and couplings.
Question 75. What is it necessary to do when coupling
or uncoupling hose connections between cars?
Answer. To uncouple it is necessary first to close the
cocks at the end of each car, both for the brake-pipe
and the control pipe, before attempting to uncouple the
hose. In coupling it is necessary to see that the hose
couplings for both the pipe lines are securely made before
opening the cocks in each pipe on the cars; open the
cocks of the control pipe FIRST, and AFTERWARDS
those in the brake-pipe.
Question 76. In making up trains what should be
done with the hose couplings at each end of the train?
Answer. They should be fastened up to the dummy
couplings which are supported on the end of the car in
order to keep any dirt or foreign matter from getting
into the couplings and pipes, and to prevent anything
lying in the track from striking them. Also, to reduce
the wear due to the swinging of the hose when free.
J.-The Triple Valve.
Question 77. To what is the brake-pipe connected
under the car?
Answer. The triple valve.
Question 78. Where is it located?
AIR-BRAKE CATECHISM
897
Answer. On a bracket in a special box underneath
the car, between the grid resistances, on the side opposite
to the box containing the electric pump governor and
feed valve.
Question 79. Why is it called the triple valve?
Answer. Because of the three distinct operations it
performs in response to variations of brake-pipe and
auxiliary reservoir pressures. It (1) charges the auxili-
ary reservoir; (2) applies, and (3) releases the brakes.
K.—Auxiliary Reservoir.
Question 80. What is the auxiliary reservoir?
Answer. It is a wrought steel reservoir in which is
stored the air for applying the brakes on the car to
which it is attached.
Question 81. To what is it connected?
Answer. Its only connection is to the triple valve.
L.-Brake Cylinder.
Question 82. What is a brake cylinder?
Answer. It is the cylindrical casting secured to the
car framing at the side of the auxiliary reservoir. It is
provided with a piston having an air-tight leather pack-
ing and a hollow piston rod. This piston, together with
the cylinder and the head on the packing leather side,
form a chamber into which the compressed air is ad-
mitted from the triple valve, and by forcing the piston
outwardly applies the brakes to the wheels by means of
foundation brake gear and brake shoes to which it is
attached by a loose push rod; a head on the other end of
the cylindrical casting forms the guide for the piston and
a seat for a coiled spring by which the piston is forced-
898
ELECTRIC RAILROADING
back to the inner end of its stroke when the air pressure
is exhausted from the brake cylinder by the operation of
the triple valve.
M.-Levers.
Question 83. How is the piston rod connected to the
brake shoes?
Answer. By a system of levers generally called "foun-
dation brake gear." When the piston is pushed out the
levers are so arranged as to draw the shoes up against
the wheels. (Fig. 533).
Question 84. What is especially necessary in arranging
these levers?
Answer. That the retarding effect on each wheel
should be in proportion to the weight of the car bearing
upon it and that it should be equal for both wheels on
the same axle. When a car weighs equally on all the
axles the brake-shoe pressure should be equal on all the
wheels.
Question 85. How is the necessary brake-shoe pres-
sure against the wheels determined?
Answer. By the light weight of the car.
Question 86. What proportion of light weight is taken
as a basis for the brake-shoe pressures?
Answer. The total pressure of the brake-shoes against
the wheels should be 100 per cent of the weight of the
motor cars and 90 per cent of the light weight of the
trailer cars.
Question 87. What is the general arrangement of
foundation brake gear?
Answer. Fig. 533 shows the general arrangement of
brake rods and levers and their relation to the brake

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Fig. 533. Arrangement of Brake Levers.
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AIR-BRAKE CATECHISM
899
cylinder. To the push rod is connected the PUSH-ROD
LEVER. A similar lever, called the CYLINDER LEV-
ER, is attached to the slack adjuster and connected with
the push-rod lever by the CYLINDER ROD. Through
these two levers the pressure developed in the brake
cylinder is carried to each of the trucks. As the piston
is pushed out by the air pressure the upper end of the
push-rod lever is forced to the left. This transmits the
force through the cylinder rod to the cylinder lever, and
as a result the lower ends of both levers are drawn
together, transmitting a pulling force through both of the
TRUCK PULL RODS. The push-rod and cylinder
levers are so proportioned that the amount of force trans-
mitted to each truck is in the same proportion as that
of the weight of the car resting on each truck. The
amount of pull transmitted to each of the truck pull rods
is equal.
The truck pull rod engages with the upper end of the
LIVE TRUCK LEVER. The lower end of the live
truck lever is connected with the lower end of the DEAD
TRUCK LEVER by a TIE ROD. These truck levers
are proportioned, so that each brake beam gets an amount
of pressure in proportion to the weight on that axle.
Question 88. What is the total leverage?
Answer. It is the ratio* of the sum of the pressures
on all the wheels of the car to the pressure on the push-
rod.
Question 89. How is the hand-brake connected to the
lever system?
Answer. Through the HAND-BRAKE ROD,
HAND-BRAKE LEVER, HAND-BRAKE CONNEC-
*Ratio: The quotient obtained by dividing one into the other
is obtained. Suppose it is 7. Then we say the ratio is 7 to 1.
900
ELECTRIC RAILROADING
TION, MULTIPLYING LEVER, and the chain which
connects the multiplying lever to the push-rod.
Question 90. What is the use of the chain?
Answer. It provides a flexible connection between the
hand-brake and power-brake rigging, so that when the
power brake is in operation the hand-brake levers do not
move, thus reducing the amount of friction to be over-
come by the air pressure and also reducing the wear on
the hand-brake rods and levers.
Question 91. What is the object of the multiplying
lever?
Answer.
To increase the power of the hand-brake to
that ordinarily obtained by the air pressure.
Question 92. When applying the brakes by hand does
the piston in the brake cylinder move out?
Answer. No. The push-rod is loose in the push-rod
holder and can be forced out by the piston, but cannot
pull the piston out when it is pulled out.
N.-General Operation.
Question 93. How should brakes be tested in prepar-
ing trains for service?
Answer. First, see that hose coupling cut-out cocks
on the head and rear end of train are closed and those
between the cars are opened. Next, that all the brake
valves are lapped with the exception of the one that is
to be used, and this must be placed in release position.
Then start the compressors, charge the brake-pipe and
auxiliary reservoirs, allowing the compressor to operate
until the governor cuts it out. Motorman will then apply
brakes by moving handle of brake valve to service-appli-
cation notch until a reduction of ten pounds has been,
AIR-BRAKE CATECHISM
901
made in the brake-pipe. Then after placing handle on
lap, remove handle, and carrying same, motorman will
proceed throughout length of train and see that each
cylinder piston of every car has moved out such a dis-
tance as to indicate that brakes are properly applied on
all cars of the train. The brakes are then to be released
from the last cab at end of train. Then again remove
handle, and return to other end of train, examining all
cylinder pistons. Be careful to see that they have moved
back to full release, thus indicating that all brake shoes
hang free.
Question 94. In making an application of the brakes
for any purpose, except testing brakes or emergency
applications, what is the least pressure that should be
drawn from the brake-pipe at the first reduction?
Answer. Five pounds.
Question 95. Why not less than this amount?
Answer. Because the reduction might not be sufficient
to force the brake piston against the release spring and
friction of brake rigging.
Question 96. What reduction of train-line pressure is
necessary to fully apply the brakes on service application?
Answer. From eighteen to twenty pounds.
Question 97. Why should the reduction, as stated in
the last question, fully apply the brakes?
Answer. Because eighteen to twenty pounds reduction
in brake-pipe pressure causes an equalization of auxiliary
reservoir and brake-cylinder pressure, thus fully applying
the brakes. A further reduction in the brake-pipe is
simply a waste of air.
Question 98. What is the possible result of this waste
of air?
Answer. The brakes are slower in releasing, fail to
902
ELECTRIC RAILROADING
release simultaneously, cause a shock to the train upon
stopping, and seriously overtax the compressor.
Question 99. How many applications should be made
in making the ordinary service stop?
Answer. As a general rule, one.
Question 100. What is meant by one application?
Answer. From the time the brakes are applied until
they are fully released, no matter how many brake-pipe
reductions or graduated releases, is one application; after
the brakes have been fully released, and are reapplied, is a
second application.
Question 101. How is the application to be made for
an ordinary service stop?
Answer. A fifteen to eighteen-pound brake-pipe re-
duction should be made obtaining a full cylinder pressure
at once, if at fair speed and gradually reducing same as
the speed of the train decreases.
Question 102.
be followed?
Should this plan of operation invariably
Answer. No. If the train is drifting or running at
very low speed it is not necessary to have such a high
cylinder pressure.
Question 103. Why is it that the cylinder pressure
should be gradually released as the speed of the train
decreases?
Answer. Because the friction between the brake-shoes
and the wheels is less for high speed than for low, having
the same pressure in both cases. Consequently, if maxi-
mum cylinder pressure is used at a high speed it is neces-
sary to decrease it as the speed decreases; also to make
stop in less time and to avoid rough stops; also stops can
be made much more accurately; otherwise, skidding of
the wheels would be likely to follow at low speeds,
AIR-BRAKE CATECHISM
903

SPEED
CYLINDER PRESSURE
CYLINDER PRESSURE
VELOCITY
VELOCITY
J
CYLINDER PRESSURE
TIME
Fig. 534. Diagram of Stops.
ר־י
904.
1
ELECTRIC RAILROADING
Question 104. What would be the result if the cylinder
pressure should be gradually increased during the appli-
cation?
Answer. Pressure would be least when the speed was
greatest, and, therefore, have a much smaller retarding
effect than it ought to; and would be greatest when the
speed was considerably reduced, thereby making the skid-
ding of the wheels very probable and bring the train to
a stop with a sudden jerk.
Fig. 534 illustrates the proper and improper method
of handling the brakes in a service application. The
brakes are applied at o and the train comes to a stop at
S or T. The curve shows the decreasing velocity after
the brakes are applied. The diagram shows the varia-
tions of cylinder pressure during the stop. The full lines
show the proper method of handling, and the dotted lines
the improper. It will be seen by the dotted diagram and
curve that the retardation of the train during the first
part of the stop is comparatively small. The motorman.
is afraid to put on his brakes, and as a result applies them
little by little, till at the end of a stop he has full cylinder
pressure, and the retardation of the train is very sudden
and dangerous. Often motormen will find, when using
such a method, that he has to make full release of the
brakes and then reapply, as shown on the diagram, in
order to keep the train from stopping short of the station.
This causes jerks and uneven motion throughout the
train and a great waste of air, resulting in overworking
the compressor and causing unnecessary wear on the
train apparatus.
On the other hand, if the motorman throws full pres-
sure at once into the cylinder the retardation during the
first part of the stop is much greater, and as the speed
AIR-BRAKE CATECHISM
905
gradually decreases, the motorman gradually releases the
cylinder pressure in such a way as to keep the retardation.
of the train at a maximum. The amount gained in re-
tardation during the first part of the stop by the proper
method of braking makes the time required for the entire
stop much less than in the other case, the time saved
being represented by the distances S T.
Question 105. What other reason is there besides mak-
ing quicker stops for using the proper method of braking
outlined above?
Answer. By gradually releasing the brakes the auxil-
iary reservoirs are partially recharged at each partial re-
lease, till when the train comes to a stop the auxiliary res-
ervoirs are almost completely recharged. In the other case,
when the train comes to a standstill the brake-pipe pressure
is the least, of any time during the stop, so that the entire
system has to be completely recharged after the train
comes to a standstill. This means, in the latter case, more
time is required for the brake system to be fully prepared
for subsequent applications. Also with proper method
start can be made quickly if desired, as there is little, if
any, cylinder pressure remaining. This is also true if
grade necessitates holding brake on during stop, as it can
be graduated almost off.
Question 106. In making partial release during a
brake application, how should the brake valve be handled?
Answer. It should be moved to the release position.
for a moment and immediately returned to lap.
Question 107. To make a complete release of brakes,
how should the brake-valve be handled?
Answer. It should be moved to the full release posi-
tion and allowed to remain there.
1
906
ELECTRIC RAILROADING
1
Question 108. If brakes release after a service-appli-
cation, where should cause be looked for?
Answer. Examine brake valves in train until trouble
is located. Either a brake-valve has not been fully lapped
or has a leaking rotary valve.
Question 109. In case of emergency, when it is es-
sential to stop the train in the shortest possible distance,
how should the brake-valve be handled?
Answer. The handle should be thrown to the full
emergency position and left there until the train has
come to a stop, or the danger is passed.
Question 110. Would it not be better to return the
handle to lap position after a quick reduction has been
made? The object to save brake-pipe pressure to assist
in releasing?
Answer. No. The first consideration in a case of
emergency is to stop and to do that as quickly and surely
as possible. The handle should be left in emergency
position.
: Question III. If the motorman has the brake par-
tially applied with service application and should be sud-
denly flagged, what should he do?
Answer. Put the valve handle in the emergency posi-
tion and leave it there until stopped, the same as before.
Question 112. Would he get quick action under those
circumstances?
Answer. That depends on the amount of reduction
made in service and the length of the piston travel. With
only a slight reduction he would get partial quick action,
but would not get full quick-action brake-cylinder pres-
sure.
Question 113. Could anything be gained by placing
AIR-BRAKE CATECHISM
907
the handle in release position for a moment before going
to emergency position?
Answer. No; it would be dangerous to do so. Such
an action would release the brakes when they were most
needed and would make them slower to apply.
Question 114. If the motorman had the brakes applied
with a thirteen to fifteen-pound service application, and
was flagged, would it be policy for him to put the brake-
valve in the emergency position?
Answer. Yes; if it were a case of emergency. Pos-
sibly some of the brakes have partially leaked off; the .
emergency application would set them fully.
Question 115. In the case of emergency should a
motorman reverse his motors?
Answer. Yes. As a last resort to prevent collision
or to save life he may reverse his motors. Handle on
master controller should be thrown into opposite direction
to the first, or switching notch, which notch is usually
found to have the greatest retarding effect. Motors
may also be reversed in the event of brakes being inoper-
ative, but in ordinary service conditions motormen must
never reverse motors.
Question 116. In case the brakes are applied suddenly
from the train, what should the motorman do?
Answer. Place the brake-valve handle on lap position
until a signal is given to release the brakes.
Question 117. Why is this done?
Answer. To maintain the main reservoir pressure and
to prevent its escape, thereby providing for a prompt
release of the brakes.
Question 118. How should the conductor's valve be
operated when necessary?
Answer. It should be pulled wide open and allowed to
908
ELECTRIC RAILROADING
remain or be held in that position until the train stops,
and then before leaving it the valve should be closed.
All cars have a conductor's valve which, when opened,
remains in that position until closed by hand.
Question 119. Why is it necessary to leave the con-
ductor's valve open until the train has stopped, if it is
used?
}
Answer. Because if it is closed and the motorman
fails to place the brake-valve on lap position the brakes
will release.
Question 120. What does this valve do when it is
open?
Answer. It makes a direct opening from the brake-
pipe to the atmosphere, the same as when the brake-valve
is placed in the emergency position.
Question 121. Can the brakes be released with the
conductor's valve?
Answer. No. It must be remembered that to release
brakes it is necessary to either put air into the brake-
pipe or take it out of the auxiliary reservoirs. The con-
ductor's valve will not do either of these.
Question 122. Should the brake apply suddenly, with-
out the aid of the motorman or train crew, what should be
done?
Answer. Place the brake-valve handle on the lap posi-
tion as before.
Question 123. What would be the probable cause of
this?
Answer. Either a burst hose, burst brake-pipe, or
train breaking in two.
Question 124. In the event of a burst brake-pipe hose,
what should be done?
Answer. Close the flat handled cut-out cock imme-
AIR-BRAKE CATECHISM
909
diately ahead of the burst hose and release the brakes back
of the burst hose by closing the double cut-out cocks and
opening the bleed cocks in the auxiliary reservoirs,
leaving them open. The brakes ahead of the fractured
hose can be released, provided the brake is still operative
upon at least half of the cars in the train. If the motor-
man has control of less than half of the brakes of the
train, the hand brakes on the cut-out cars must be applied
to assist in controlling the train.
Question 125. In the event of a control-pipe hose
bursting, what should be done?
Answer. Close the round-handled cut-out cocks imme-
diately ahead and behind of the disabled hose, the brakes
may then be operated in the usual manner until the train
reaches the terminal, when the fractured hose must be
replaced.
Question 126. Should the cross-over pipe connecting
the brake-pipe and triple valve be broken, what should
be done?
Answer. If the break is between the double cut-out
cock and the triple valve, the double cut-out cock should
be closed and the release valve opened under the disabled
car. If the pipe is broken between the double cut-out
cock and the brake-pipe, the flat-handled cut-out cock
on the front end of the disabled car should be closed,
release valves in all auxiliary reservoirs behind disabled
car, as well as on that car opened, and the brakes oper-
ated the same as with the burst hose.
Question 127. If the brake pipe should be broken or
burst, what should be done?
Answer. Close the cut-out cock on the front end of
the car and operate brakes as per Answer 124.
>
910
ELECTRIC RAILROADING
Question 128. In setting off cars, what should be
done?
Answer. The cut-out cocks should be closed first and
the hose parted by hand and hung up properly.
Question 129. Should the hand-brake be set before.
releasing the air-brake?
Answer. No.
Question 130. What is the proper way to release a
brake with a bleed cock?
Answer. The bleed cock should be held open until
the exhaust air commences to escape from the triple
valve; it should then be closed, as, if it is held open
longer, it results in waste of air and has a tendency to
set the other brakes.
Question 131. When it is permissible to cut out brakes
on cars?
Answer. Only when they are in such condition to
render it impossible to operate the brakes on such cars.
Question 132. Are small leaks sufficient cause for
cutting out cars?
Answer. No.
In Fig. 535 is given the arrangement of the apparatus
on a motor car of the West Jersey and Seashore R. R.
Fig. 536 shows a slightly different arrangement of the
apparatus on the motor cars of the New York Central.
The wiring of the apparatus is the same in both roads,
and is proven by Fig. 537.
The arrangement of apparatus on the locomotives of
the New York Central is shown by Fig. 538, and the
wiring diagram in Fig. 539.
SWITCH BOARD
B
TROLLEY
TROLLEY SWITCH AND
LIGHTNING ARRESTER IN BOX
IN

TROLLEY FUSE
MAIN SWITCH
MOTOR, RESISTANCES
$
MAIN FUSE
CONTACTOR BOX
REVERSER
CIRCUIT BREAKER
Bus LINE
CONNECTION BON
BUS FUSE_
G
GOVERNOR)
AIR COMPRESSOR
ARRANGEMENT OFAPPARATUS ON CAR
Fig. 535. Pennsylvania Equipment.
JUJ
TRAIN CABLE
CONNECTION BOX
CIRCUIT BREAKER SWITCH
TRAIN
CABLE COUPLER
SOCKET
MASTER
CONTROLLER
SWITCH
BUS LINE COUPLER
SOCKET
MASTER
CONTROLLER
MOTORS
BUS LINE
CONNECTION BOX
SHOE FUSE-
THIRD RAIL SHOE

+
SWITCH PANEL
POWER CONNECTION
BOX
MOTOR RHEOSTATS
MAIN FUSE
MM
CONTROL
CONNECTION BOX
TROLLEY CONNECTION
BDX
CIRCUIT BREAKEP
BUS COUPLERSOCKET
BUS CONNECTION BOX
POWER CONNECTION BOX
CONTROL COUPLER SOCKET
CONTACTOR BOX
REVERSER
G
G
QUC
CIRCUIT BREAKERSWITCH
MASTER CONTROLLER SWITCH
BUS BUS
MOTOR RHEBSTATS BUS
FUSE RHEOSTAT
FUSE
AIR COMPRESSOR
MOTOR NO.!,
GOVERNOR
MOTOR NO.2.
SHOE FUSE
THIRDRAIL SHOE
ARRANGEMENT OF APPARATUS ON CAR
Fig. 536. New York Central Equipment. ·
MASTER
CONTROLLER
Blow-out
Coil
Forward
P
5
Reverse
5,

43
0 Coupler
oyono
Sockets
༑་།་
Bus Line
Couplers
Fuse's
10
M S-11
Switch
MS40A Set Trip
Moster
Controller
Switch hamm
OH-15 Cut-out
Switch
Main
Switch
No.1
lohool
no
Jan 2007
Wire Colors
No I Red
**
- White
Green
Green & White
Yello
Reds Black
Black
10B-112-B Relay [From this cable No. 4 wire
connects to No. S
No.5 connects to No 4
Let connection Box NO. 2
BJ-348
Connection Box
No.?
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G
78
78
ardh
CA
G
51
AC
40
78
3C
835 Ohm
Tubes
035 Ohm
DB-102-A-12
Tubes
Circuit Breaker
D8·1136
Relay
15
Third Rail Shoes
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R-118
IP
H.14
R/S
G
ht
го
3A
38
24
2m
72
IM
A23 R·24
18 10
28
26
7A
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30
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43
30
Im
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57
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Fig. 537. Wiring Diagram. New York Central Motor Car.
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Trolley Fuse Boxes
Trolley
Moster, Controller Switch
Headlight Switor
Main Master
Controller Switch
Cantoctors
Motor Cut-out Switch
Nal Na2
Current
Limil
Relay
Master Controller
Motor Rheostats
No. Reverser
No. 1 Motor Fuse Box
'B'End of Third Rail Shoe
Locomotive
Fuse Boxes
Bus Line
Socket
Contactors
Train Cable
Socket
Motor Rheostats
Third Rail Shoe
Fuse Boxes
ལུས་
Main Switch
No. 2 Motor Fuse Box·
Air Compressor
Trolley
Trolley Fuse Boxes
Moster Controller Switch
Headlight Switch
Motor Cut-out Switch
Na 3 Nad
Negative Control Switch
Air Compressor Switch
Contactors
Na 2 Reverser
Motor Rheostats
Control
Rheostat
-No 4Motor Fuse Box
Master
Controller
Cut-out end.
Connection Box
Third Roil Shoe
Fuse Boxes
A*End of
Locarnative
Air Compressor
Governor and Contactar
Contactors
To Contactors
Control
Rheostàt
VISHENG
Motor Rheostats
Bus Line
Socket
Trom Cable
Socket
-----
No. 3 Motor Fuse Box.
Third Rail Shoe
Fuse Boxes
Third Rail Shoes
aljajajar
Motors
Fig. 538. Arrangement of Apparatus on Locomotive.
4
Third Rail Shoes
о
12
Lock Coll
18
من
Trolley
Forward
10 1
Revers
10 11 12 13
A·47·8
Sochets
M S· 2 ·A Switch
Kicking Coil
G
ms Lightning Arrester
D·A·48.8
Bus Line
Couplers
୧୨
18
Main Switch
MEN
81
Blow-
out
Cail
AB
M-29
\DBYINAH
Relay
04-12-1
M22
Ms
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76
P¼¿ RIS RIARIS
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For NYC & HARR Locomotive

7
Irw
BJ.349
Connection
Box No./
04/
35
Green
Control Cable
Red
-Green
One End
Other End
Na's
From
From this cable No wire connects to No.0
No. Owire connects to No.8 at connection Box No 2
A
RAS RASPA€ R$3 P&
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by by by by by by by
|A31732 755 734 756 756
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MA-10-B
Fuses
EJ
SAA
у
807
Am
0:25
M-A-12-B Fuses
Third Rail Shoes
Fig. 539. Wiring Diagram. New York Central Locomotive.
SA
T-159-K-12
10-0
lig.
ગ
18
15
16
S
10
など
​匹
​T-125-0-7
AAA
Fuses
18| |24
DH-13-A
Cutout ona
Connection
Box No. 2
GENERAL INDEX.
'Accumulators
Acceleration
Acceleration, Automatic
Air brake
Alternating current
Alternator
Ampere
Ampere-hour
Ampere- turn
Ammeters
Amalgamation
Anode
·
Armature calculations
Armature cores
Armature windings
Armature reaction
Arrangement of cells
Arresters
D
Atmospheric electricity
Auto transformers
•
Base
Battery fluid
Batteries, primary
Batteries,
storage
Bearings
Bonding
Bridge
Brushes
·
Building up
•
A
B
•
242 to 264
•
.597
630, 679
.756 to 762
..356
.387, 456 to 464
•
300
.252
189, 195
320 to 331
·
.239
.276
.393
391, 421
.425 to 428
.455
.315
96 to 146, 556
80 to 95
...375
418
..235
218 to 241
.242 to 264
420
.579
636, 705
401, 430
400
911
912
GENERAL INDEX
•
Capacity
Cars
Car equipment
Catenary
Cathode
Cells, descriptions
Cells, primary
Cells, storage
Centigrade
Choke coil
Circuits
Circuit breakers
Circular mil
Commutator
•
Commutating switch
Compass
Compensated motor
Compensator
Compound dynamo
Condensers
Conductivity
Contactor
Control, systems of
Controllers
· •
Consequent poles
Converter, see Rotary
Cooling transformers
Counter E. M. F. ..
Corrosion
CR loss
C2R loss
Current
4
Current limit relay
Curves
Cycles
Dead circuit
Declination
་
•
•
•
• •
1
·
C
• · • 轉
​D
M
•
·
•
► •
·
•
•
•
•
•
•
•
*
..48, 360
702, 722
749 to 762
568 to 573
.276.
*
•
223 to 264
218 to 241
242 to 264
..53
.138
282 to 300
.342 to 355
304
.386, 427
643, 719
.157
637 to 656
661
407
48 to 59
..305
621
604 to 615
604 to 615
.154
366
.375
·
.414
"
.280
•
312
.341
11
12
.673, 704
.213 to 217
..388
..85
.157
GENERAL INDEX
913
Delta winding
Density
Dielectric
Dip
Divided circuits
Drop
Drum armatures
Dry cells
Dynamo
Dynamo, general information
Dynamic electricity
Dynamotor
Eddy currents
Efficiency
Electro-magnetism
Electro-magnetic induction
Electro-motive force
Electro-plating
E. M. F..
Electroscope
Electrophorous
Electrolysis
Electrolyte
•
1
Electrical machines
•
Energy
Equalizer
Exciter
Exciting current
Fahrenheit
Feeders
[
Field coils
Flux
Force
Formulas
D
Frequency
Frequency, changer
Fuller cell
མ
E
F
.462
188
•
48
.158
.308
.312
.391, 398, 425
.238
418 to 438, 378 to 408
464 to 469
12
364
.424
.341, 373
175 to 209
.368
..285
278
· ·
.285
.20, 36
.17, 39
276 to 281
.253, 276
60 to 79
338
..500
•
459
1
373
.52
559
.435
.188
.335, 33S
210 to 212
.86, 358, 38S
•
486
.234
914
GENERAL INDEX
Galvanometers
•
Gantry
Generator
General Electric control
German silver
•
Gravity cell
Grouping of cells
Ground wire
"
Ground connections
Ground plates
Heaters
Helix
Henry
Horn lightning arrester
Hydrometer
Hysteresis
Idle Current
Impedance
Inclination
Induced magnetism
Induction motor
Induction regulator
Insulators
G
•
H
I
J
Joints, insulated
Joint resistance
K
Kicking Coil
Q
L
Leyden jar
Lightning
Lightning arresters...
319
.579
386, 388
616 to 620
..303
226 to 234
.315
128
•
.141
•
.141
.753
.181
J.359
•
133
..231
.423
363
.358
158
+
170
449
493
•
.559 to 579
581
.307, 314
138
18
..80
80 to 95
.96 to 146, 556
GENERAL INDEX
915
Lightning rods
Limit switch
Line of force
Line of magnetism.
Line relay
Live circuit
Loaded circuit
Local action
Locomotives
Lode stone
·
• •
Magnet core
Magnetism
Magnetic calculation.
Magnetic circuit
Magnetic field
•
Magnetic induction
Magnetic needle
Magnetising force
Magneto-motive force
Making magnets
Manual control
Mass
Master controller
M. C. B...
•
Megohm
Mesh winding
'Meters
Mho
氤
​Motors in general...
Motors, general information.
Motors, parts of.
Motors, generator
Motors, induction
Motors, railway
Motors, series
*
Motors, synchronous
•
•
M
91
.673
..167
.188
.676
•
85
85
239
681, 706, 722
·
147
•
.418
147 to 209
302 to 209
·
..198
.169
169, 368
}
.152
189
189
.149
•
614
•
.336
624, 631, 669, 700
.740, 746
301
462
319 to 334
•
.
.307
409 to 417
.446 to 469
418 to 438
364
449
439 to 455
44S
491
•
916
GENERAL INDEX
Motors, compensated.
Multiple, see parallel...
Multiple unit control.
•
..637 to 656
..296
616, 657, 702
N
New Haven, general information.
New Haven locomotive.....
New York Central motor cars.
New York Central locomotives.
NOSE rule....
• •
•
•
..681
..683
.702-705
706-721
179
Ohm
Ohms Law
Oil switches..
Oil of vitriol..
Panels
Parallel circuits
P. D.
•
Permeance
Permeability
·
Permanent magnetism.
Phase
Polarity
Polarization
Poles of magnet.
Polyphase
Potential control
Power
督
​D
Power factor
Power houses
·
•
•
Reactive coil
Reactance
Regulation
Reluctance
O
P
R
a
ย
•
•
.301
311 to 318
•
543 to 553
.218, 251
.497 to 540
296
.312
•
..196
162, 194, 196, 216
147 to 174
460, 461
155
222
.153
463
.604
337, to 339
362
470 to 480
.138
..358
.400
•
196
*
GENERAL INDEX
917
Reluctivity
Residual magnetism
Resistance
Resistance in series.
Resistance in parallel
Retentivity
Reverser
Reverse switch
Reversing a motor
Rheostatic control
Right hand rule..
Ring armatures.
Rolling stock..
Rotary converter
Rotor
· +
.
•
Saturation
Schedule speed
Self exciting
Self induction
Series circuits
Series_dynamo
•
·
Series parallel circuits
Series parallel control
Series motor
Shafts
Short circuit
Shunt circuit
Shunt dynamo
Single phase
SNOW rule
. •
•
S
Solenoid
Sparking
Sprague control
Sprague control for A. C. and D. C..
Star winding
Starting box
Starting motors
*
·
196
197
301 to 310
.307
..307
162, 197
623
674
.452
604
.179
391, 425
722 to 748
366
449
*
194
.598
400
..359
283, 291
}
406
314
604
448
.421
284
284
406
460
.177
190
403,
454
616 to 620
657 to 668
462
.412
.411
918
GENERAL INDEX
1
Static electricity
Static on circuits.
Stator
Storage batteries
Storage batteries, care of..
Storage batteries, diseases of.
Sub-stations
Supersaturated
Surge
Switches
Switch boards.
Synchronising
Synchronous motor
1
Three phase
Third rail...
Thunder storms
Toepler machines
Train cable
•
Transforming current.
Transformers
Transformers, auto
Transformers, cooling
Transmission line..
Trolley
Trucks
Turbines
Turbine-generators.
Turn tables
·
Two phase
Type M control.,
Volt
Voltage, detector
Voltmeters
•
*
氤
​.
*
•
·
11, 16 to 79
84
449
242 to 264
.254
.257
480 to 491
...197
85, 88
542 to 553
497 to 540
495
.491
T
.461
.574 to 581
V
*
"
81
64
619, 626
364 to 377
369 to 377
..375
..375
·
559 to 576
..566
.740 to 746
474 to 480
474 to 480
264 to 275
461
616 to 626
•
311
554
320 to 331
GENERAL INDEX
919
Watt
Wattless current
Wattmeters
•
Waves
Weight
Westinghouse control
Wimshurst
machine
Wire measurement
Wire table
Work
W
Y
Y winding
لم
.339
.363
.331 to 334
12
336
669
$69
.304
..306
.336, 338
.462
SPECIAL INDEX
FOR NEW YORK CENTRAL AND PENNSYLVANIA EQUIPMENTS
Air brake, general
Air brake hints
A
Air brake test ..
Air brake cut out..
Air brake broken cross over pipe.
Air brake conductor's valve
Air brake emergency use.
Air brake emergency attachment
Air brake releasing
•
Air brake, list of parts.
Air brake, arrangement of levers.
Air, failure of
Air, discharged from brake pipe.
Air gauge and brake valve..
Air pressure, reduction
Air compressor, location, etc.
D
Air compressor, control, parts.
Air compressor, increased speed
Air compressor crank chamber.
•
•
-
•
•
•
►
Air compressor crank chamber oiling.
Air compressor and reservoir.
•
Air compressor frame
Air compressor governor
•
•
·
Air compressor operation
Armature, (compressor), direction of rotation.
Armature, removal of
Auxiliary reservoir
·
Automatic acceleration
Application, service.
•
•
•
·
·
•
•
.858, 900
858
900
.910
.909
..907
.894, 906
.797, 820
.859, 878
..879
.898
.859
..893
..879
859
.861, SS0
848
864
863
.865 ..
858
•
861
.848
863
·
.S63, 880
..S63
.897
822
.892
920
SPECIAL INDEX
921
B
Brake pipe and purpose.
Brake cylinder
Brake cut out cock, double..
Brake, sudden application
Brake, hand
Break in hose..
Brush holders (compressor).
·
Bus line coupler socket.
Cable, train
Cable, train jumper
Cable, train, failure of....
Cable, train, grounded
Circuit breaker, blow
Circuit breaker
Contact shoes, third rail.
•
C
Contact device, overhead
Contact, imperfect, master controller.
Contactor and box....
Contactor, table of numbers..
Contactor pump motor circuit.
Connection box, train cable..
Control pipe
Coupling hose
Coupler plug, train cable.
Coupler socket, bus line..
Coupler socket, train cable.
Cleaning suction box...
Current limit relay
·
·
•
• •
1 •
Current direction
Cylinder pressure
•
...894
.897
894
.907
..858
858, 908, 909
..862, 864
.779, 813, 838
778, 816, 843
..791, 843
..868
•
.
.803, 868
...869
773, 812
768, 836
...836
.868, 873
768, 811, 827
.853
849
R
•
.791, 818, 843
890
..896
.843
.779, 813, 838
.789, 818, 843
.S83
791, 818, 847
856
.902
E
Engineer's valve (see Motorman's valve).
...891
+
Electric pump governor..
...883
922
SPECIAL INDEX
Failure of locomotive
Failure of train
Fire
•
Fuse box, shoe
F
Fuse box, motor
Fuse box, third rail
Fuse, detection of blown..
Fuse, in case of imperfect..
Fuse, protection of
Fuses, control
Fuses, bus line
Fuses, blowing on 2 locomotives..
Fuses, main
Fuses, motor
Fuses, shoe
Governor, pump
ปี •
.872
.802, 867
807, 870
.834
.833
83-1
.869, 873
..867
.825
*
•
796, 820, 847
815
..874
776, 813
833
834
G
.848
.859
Graduated release, failure of....
Hose, burst
H
I
Imperfect contact
Imperfect fuse
J
Jumper, bus line
Jumper, train cable
Jumper, loose
•
Junction box, bus line.
•
Levers and rods..
Liners, amature bearing.
Lubrication of motor..
Lubrication of pump parts,
·
L
1
.858, 908
.868
.867
•
•
780, 813, 838
•
791, 818
.868
782, 815
•
•
.898
..864
.883
865, 880
$
t
SPECIAL INDEX
923
M
Master control
Master controller
Main reservoir pressure.
Motor control
Motor fails to take current.
Motormen, hints to..
1
Operation in general...
•
О
Oil replenished in crank case.
Potential relay
P
Pressure, reduction in train line.
Reverser
Rheostat, motor control.
Relay, current limit
Relay, potential
Resistance tube
►
Sanding rails
Starting locomotives
Starting trains
Shoe support, broken..
Switch, control cut out.
Switch, negative control
Switch, circuit breaker
Switch, main motor cut out:
Switch, main
Switch, main sander
Switch, master controller
R
S
ហ
• •
·
•
1
.783, 815, 833
.785, 816, 839
.885
.765, 811, 826
..869, 873
858
.800, 821, 851
865
794, 819
901
771, 812, 827
771, 812, 828
.791, 818, 847
794, 819
791
.857
..851
800, 821
..808
.788, 794, S12, 847
..841
775, 794, 819
..832.
777, 813, 829
849
.839
Switch, master controller, overhead.
· •
787, S16, 840
Switch, pump motor
Switch, sander operating
Switch, third rail
.848
.850
779
Switch, trolley
•
779
924:
SPECIAL INDEX
Train operation
Train breaking in two.
Train cable
Track sander parts.
Trolley fuse box..
•
•
•
Valve, brake
Valve, brake, use of
Valve, brake, leaky
Valve, conductor's
T
0
799, 821, 851
.824
788, 816, 843
849
782, 834
V
1
•
•
•
Valve, compressor
•
•
Valve, electro pneumatic
Valve, motorman's brake
Valve, motorman's brake pressure.
Valve, safety
Valve, sander
Valve, slide valve, feed valve.
Valve, triple
1
W
Wires, train cable..
1
• • •
•
幂
​·
·
.
..891
.:.891
..871
.907
.865
.850
..879
891 to 893
.886
849
1
•
.886
.896
...816, 843

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