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HANDBOOK
USE OF ELECTRICIANS IN THE OPEEATION AND CASE
OF
ELECTRICIL MACHINERY AND APPARATUS
U. S. SEACOAST DEFENSES.
PREPARED UNDER THE DIRECTION OP THE LIEUTENANT GENERAL
COMMANDING THE ARMY.
WASHINGTON:
GOVERNMENT PRINTING OFFICE.
1902.
JUN 5 1902
OiSfDi
r4'
y
PREFACE.
The installation and management of the electric machinery in United States
battleships merit the attention of electricians in forts. Its character and object
in the two situations are similar, and the conditions of dampness, limited space
changing personnel and reliabilitj' are equally severe.
Every implement or portion of the fortification plant mnst be simple, certain
in operation, effective, proved in the industries as standard in its class, and it
should only be intrusted to the care and management of an efficient engineer.
To be efficient he must have ambition, intelligence and the skill gained by care-
ful handling. The good order and working of his machinery at all times furnish
the only reliable testinaonial regarding his fitness.
The preparation of the Handbook was suggested and aided by the electricians
of the class of 1900, Fort Monroe. It contains in fiill the latest instructions,
issued by designers and constructors. The portion relating to land and sea
mines is intended for separate publication. The diagrams were drawn by First
Sergt. Karl P. Runa. Notice of errors in this first edition will be thankfully
received. — G. L. A.
Boston, 1903.
(3)
1. United States Navy D. C. Set Constructed by General Electric Company. 5
HANDBOOK FOR ELECTHTCIANS.
SPECIAL INSTRUCTIONS TO ELECTRICIANS.
1. Your special duties are to secure the cleanliness and the best working order
of every part of the fortification electrical equipment given to your care, whether
it be a Schukert 60-inch projector or a glass insulator.
2. Upon taking charge of a plant, inspect it very carefully, and for your future
protection, in a letter for file report everything found not in order, even to the
tool marks on the machinery.
3. For ten days, if practicable, the retiring engineer should operate, in your
presence, all apparatus to be turned over and you, in turn, in his presence.
4 . Take written notes in your notebook of the information he gives you. Secure
all diagrams, plans and instructions relating to the machinery.
5. Keep posted on boards, or in frames, in a lighted and frequented place as
soon as convenient :
(1) Oil Engine Directions obtainable from The De la Vergne Companv,
East 138th Street, N. Y.
(2) The exact order of operating valves and switches in starting, running
and stopping made out by yourself.
(3) Instructions, Electric Storage Battery Company, Philadelphia, Pa.
(4) Diagram of pipe connections. Engineer Office or yourself.
(5) Wirings of dynamo and switch board, Engineer Office or contractor.
( 6 ) Blue print of emplacements showing wires, lamps, etc. , Engineer Office.
(7) Diagram of search-light connections, General Electric Company or
Engineer Office.
(8) Diagram of each outside independent circuit under your charge.
6. Take care of the equipment in the following order of importance :
(1) Storage batterv. (9) Firing, night apparatus.
(2) Steam boiler. " (10) Telephones.
(3) Generating set, steam or oil. (11) Telegraphs.
(4) Switch board. (12) Night signals.
(5) Searchlight. (13) Anemometers.
(6) External and internal wiring. (14) Lines.
(7) Lamps and outlets. (15) Electric bells.
(8) Motors and hoists.
7. Keep all machinery rooms clean, dry, ventilated and well lighted; all sur-
faces free from rust and dust, even if a banked fire or a kerosene burner is
necessary.
8. Do not delay work or repairs because exactly what you need is not at hand.
Proceed with that which is obtainable and do the best thing possible so as to
avoid making excuses. Even a good excuse is unfortunate.
9. Make timely requisitions for only the necessary and the best stores. Use
best mineral oil only.
10. If boiler, engine, dynamo or any iron piece or tool is to remain unused, its
polished surfaces will be thoroiighly cleaned in fiill light in a dry room on a dry
day and covered with a thick, uniform coat of cosmic, with 25 per cent of resin
added if interval will be long. Every three months clean off, repolish and re-
new.
11. " Prevention " is the rule for machinery troubles, not ' ' Cures. "
12. In case of accident, ' ' the other man " can not be pleaded by the electrician.
The clearest evidence regarding his capacity is furnished by a single boiler
fixture leaking, dirty water, incrustation or corrosion in boiler, an unsteady
(5)
6 HANDBOOK FOR ELECTRICIANS.
steam gauge, water glass, or fire, an unusual noise in engine, a hot bearing or
coil, a scratched or sparking commutator, an oil engine's chronic cough or thick
exhaust, density, voltage or gassing of storage cells not uniform, battery stand-
ing at low voltage, burn-outs and tool marks on search light or other apparatus,
dust, rust, or damp on any part, unsoldered joints or leaky circuits, and by other
things.
13. A neat and well-fitting uniform will invariably be worn outside of the
emplacements.
14. Always charge a storage battery at its given normal rate to full charge
(density, 1.200;- voltage, 2.5 per cell) ; do not discharge above the normal rate
except in emergency, and never below density of 1.175 and voltage of 1.8 per
cell.
15. Keep density, voltage and gassing of all cells uniform. To cover plates
I inch, water (or solution, 1.400, rarely) is added at the top directly after charg-
ing begins. If little used, the battery is partially discharged and regularly
charged once each week.
16. Blow off boiler in starting at 10 pounds from water high, one or two
gauges; oftener if necessary. Maintain uniform fire, water level, and pressure.
Frequently inspect fire tubes for dirt, and boiler interior for deposit and corrosion.
17. Handle all machinery and apparatus with great care. Let their loads be
increased and decreased uniformly and slowly. Guard against sudden rise of
temperatures. Never hesitate to allow a machine to take its full load under
these conditions, but not to exceed it.
18. An engine is always started as slowly as possible. A good engineer turns
valves and switches deliberately while watching the effect; his order of starting
and stopping is always the same.
19. Keej) exposed conduit, cut-out, switch, junction and lamp boxes cleaned
and painted, and all openings tightly sealed, so that the whole system is essen-
tially air-tight.
20. For more complete information, electricians are referred to Crocker's (two
volumes) Electric Lighting, Sheldon's Dynamo Electric Machinery, General Elec-
tric Company's Bulletins and Instructions, Westinghouse Company's Bulletins,
Dawson's Electric Traction, Treadwell's Storage Battery, Goldingham's Oil
Engines, Miller's Telephony, Maver's Telegraphy, Cushing's Wiring, Strom-
berg's Steam Engine, Hawkins' Catechisms of Electricity and Steam Engine.
21. The efficiency of all your machinery was long ago proved. The opinions,
sometimes heard, that search lights, for instance, can not be controlled from a
distance, that storage batteries are inefficient, that telephones near guns are
inoperative, that oil engines and submarine mines are unreliable, result from
the kind of knowledge which is dangerous.
22. In more than nineteen cases out of twenty in which a standard machine or
apparatus, properly installed, fails, the fault rests with the attendant.
23. Remember that if there is any portion or piece of the fortification electrical
equipment under your charge not in perfect working order, or not clean, and not
reported as irreparable, and if you being for duty, are working less than ten
hours daily on week days, you will be held blamable.
I HANDLING AND CARE OF STEAM FIRE=TUBE BOILERS.
(A) RAISING STEAM.
1. To start the fire in a small furnace, clean the grate of clhikers and the pit
of ashes. See that grate woi-ks freely. Cover it evenly with shavings and
wood and light the fire. When the Tipper stratum of hard wood is blazing well,
throw on a uniform 2-inch layer of soft coal, closing furnace and ojiening the pit
doors. When the coal is red, add a second similar layer. A third feeding should
leave a greater depth of coal around the sides than in the center.
2. If the furnace is large, cover the grate all over wnth a 2-inch layer of hard
coal, except a space in front for wood and shavings. Cover the coal at the back
with a little heavy wood and light the fire. Add coal to the upper hard wood
when aglow, as above, and so continiie.
3. Regulate coal and draft for at least one hour's rise to full pressure in a small
warm boiler, two hours for a small cold water boiler and five or six hours for a
large cold boiler.
Horizontal Boiler for a Stationary Engine.
f., ,g-7^
2. Horizontal Return Fire^Tube Steam Boiler.
4. After lighting the fire see that :
((/) Gauge glass agrees with gauge cocks and is not choked.
(h) Water stands to upper gauge at least.
(c) Safety valve is in working order by raising it once or twice.
(d) Steam feed, throttle, and blow-off cocks are closed.
(e) Pump is oiled.
(/) Upper gauge is temporarily open to equalize the pressure within.
5. At 10 to 15 pounds pressure blow off to second gauge to drive out mud and
create circulation for even temperature.
(B) fiiii:n^g.
1. Before opening the furnace door have plenty of coal at hand — no piece
larger than the fist. Spread the coal by throwing to the rear first and so on to
the front in a thin uniform layer. Most firemen heap on too much fresh coal.
2. The thickness of coal fire is from 5 to 8 inches. If the necessary thickness
makes too hot a fire, reduce the grate area by putting in fire brick, 8 inches high,
around the sides of the furnace.
3. If the fire bums unequally, fill the vacant spots. Allow no air holes in the
bed of fuel.
4. The cleaning tools are: The hoe for pulling or pushing the fire over the
bars, slice bar for breaking lap the fire, clinker hook and the T-bar for raking
lengthwise of the bars beneath the fire to cause the ashes to fall through, and
scoop shovel.
5. Clean or rake the fire as rarely and as quickly as possible, but always when
clinker and ash are closing the grate, usually two or three times a day if coal is
(7)
8 HANDBOOK FOR ELECTRICIANS.
hard. Dark spots, heavy smoke, and bine flame give warning. But leave the fire
alone so long as it is at uniform glow and its light shows in the ash pit beneath.
6. To clean a fire, have plenty of water in the boiler, open damper and one fur-
nace door, pack half of the fire to one side, raking out the dead clinkers and ash ;
then move the whole fire to the exposed grate and clean the other half ; finally
spread the fire evenly and throw on fresh dry coal. Cleaning reduces the depth
of fire and lowers the boiler pressure. Shaking the grate is the best way to clean
when it can be done.
7. The most effective and economical fire is moderately thick, steady, uniform
and regulated, as far as possible, by the chimney damper. Enough air should be
admitted above the fire through the door air holes to consume the rising gases
and thereby increase the heat. With a steady fire the combustion is more per-
fect and there are less clinkers, less cleaning and less cold air.
8. The construction of a damper should not admit its closing the chimney
entirely, as gases may otherwise collect in the flue and cause explosion.
9. To bank a fire, have three gauges of water. Allow fire to get low, clean
and piTsh it to the rear in a compact pile and cover it thickly with small coal or
wet ashes. Leave clinker and ash on the fi-ont of grate. Leave fire doors
open and close the pit doors tightly and the chimney damper partially. If the
fire is fomid too cold the next morning less grate should be uncovered and the
pile of fire be less compact. Banking the fire preserves the boiler by keeping its
temperature anore nearly even, saves time in starting, but is dangerous if not
properly done.
10. To start a banked fire, clean out ashes and clinker or shake the grate,
spread the fire evenly, feed a little wood for draft and add coal gradually.
11. Ashes left high in the ash pit may cause warping or burning out of grates.
12. When fuel and water are irregularly fed, or pressure is always changing,
or the safety valve is now and then popping, or dampers and doors are being
frequently opened and closed, or if there is a leaking of water, steam or oil, or
room is dirty, the boiler's tender is outside of his sphere of usefulness.
13. Give the last two or three minutes in a boiler room to its inspection to
make sure that everything will be left in order. Then close and lock all doors
and windows.
(C) CARE AXD MA?^AGEME:N^T OF STEAM BOIIiERS.
1. The steam boiler is the most important element of an electric plant.
2. An indifferent or intemperate fireman and a cheap boiler are alike dangerous.
3. The first thing on taking charge of a boiler is to inspect its safety-fitting
and feeding apparatus.
4. Let the ear aid the eye in detecting troubles.
•^. Never exceed the working pressure given by the builder or in.spector.
6. Never open nor close a throttle, a blow-off or other steam outlet suddenly,
nor leave it before it is closed.
7. Repair a leak or a damage in boiler or fitting as soon as jwssible. See that
furnace, combustion chamber and smoke flue are tight.
8. Much smoke from the chimney .shows that combustion is not perfect. All
air must go through the grate bars or the little smoke burners.
9. The boiler room should be day lighted, well ventilated, spacious and dry.
Never leave it while boiler is under steam.
10. Dry steam only is wanted. If a small jet from the upper gauge cock, close to
the orifice, is transparent or even has a grayish-white color, the excess of moist-
ure is less than 1 per cent. If the jet is strongly white, the excess is 2 per cent or
more. Steam containing less than 3 per cent excess of moisture is fairly "dry."
11. Empty a boiler working daily once a fortnight. If water is muddy blow
out 6 inches daily and use the surface blow-out more frequently. To avoid
serious results examine blow-out and check valves whenever the boiler is filled.
12. Procure the manufacturers' directions of boiler and its fixtures.
13. Blisters and cracks may occur in the best boiler plate. Then put the boiler
out of service and repair.
14. In case of low water, immediately open furnace doors and chimney damper,
close pit doors tight and quickly cover the whole fire with ashes, soil or coal
(wet if possible). Leave all steam outlets as they are. Do not draw fires until
the ])ressure has dropped, nor turn on feed water, nor start nor stop engine, nor
lift safety valve imtil the fires are out and the boiler is cooling. If water has
only just disappeared there is no immediate positive danger. If the water gets
too high, carefully open blow-off and let otit gradiially a gauge of water.
15. Foaming or priming is due to forcing the boiler or to small steam space
or to other bad design or to dirty or high water or to opening the throttle
CARE OF BOILERS.
9
suddenly. There is rumbling in the boiler, the glass gauge jumps up and down
and there is danger of water being carried over with the steam and of bursting the
cylinder. Partially closing the throttle may stop it. If high or dirty water is
the cause, blow off and pump. If the foaming is violent, check the draft and
fires. The true water level can only be seen by closing throttle or supply-pipe
valve long enough to observe.
16. If a boiler stands unused for a few days, fill it to the top ; adding a little
common washing soda is excellent. If it remains idle for some time, empty it
and dry thoroughly with live coals inside the man or mud hole, allowing draft
through the safety valve. Sometimes quicklime is used. Disconnect the feed
steam and blow-off and finally seal the boiler air-tight by closing all openings and
coating the joints with cosmic. Finally coat the boiler and fittings with
linseed oil.
17. A boiler must be cool when filled. Never allow water from leaky joints or
other source to come in contact with the exterior of the boiler. Feed water should
enter in the direction of the boiler's circulation, and not near a heated surface.
18. A good engineer maintains a steady fire burning as slowly as the reqiiired
pressure will permit, tmif orm height of water at the middle gauge and a uniform
pressure. The safety valve, gauge .ylass, injector, valves, etc., are always in
the best working order and constantly watched. All joints, connections and
packing are tight. He knows the extent of scale, corrosion, and soot. All of
his machinery and rooms are kept in order.
(D) THE STEAM BOIT^ER AXD ITS FITTIIS^GS (FIG. 3).
1. Every steam boiler requires the best material, the highest grade of workman-
ship, correct setting, economy of maintenance, capacities for steam, water and
fire, heating surface to maintain the max-
imum iDressure, free circulation of water, all
parts accessible for cleaning, and repairs,
complete combustion of fuel, joints and
weak parts not exposed to fire, minimum
I'epairs, constant vigilance, and care.
3. The piping is water-tight, smooth inside,
direct, and so arranged as to take iip expan-
sion and not to collect water. All flanges
and fittings are carefully put together. Rub-
ber gaskets are essential between flanges to
prevent leakage from pressures under 100
pounds ; soft copper for higher pressures.
(o ) Pipes conveying live .steam are covered
with asbestos or other nonconducting and
noncombustible material, by which the loss
of heat is often reduced three-fourths.
(b) All valves of brass or bronze are globe
or gate, operating automatically or by means
of an outside handle. Leakage is often caused
by dirt or sticks in the water. Never close a
valve or a cock so loosely as to leak nor so
closely as to bind. The last half turn in clos-
ing is made very slowly, if, like the throttle,
it checks a heavy pressure. Valves lift about
one-fourth their diameter.
3. The safety valve is raised daily by hand
to guard against sticking or tampering.
4. (Fig. 4.) The main valve F is held down
on the two circular seats il/and A^ against the
steam pressure by the spring S acting on the
rod T. The outer seat N is formed on the
body A of the valve, while the inner and
smaller seat M is formed on the tipper edge
of a cylindrical chamber B which is con-
nected to the body A by arms containing the
passages C C. The hollow chamber B forms
a guide for the valve V. Ordinarily the steam
exerts a pressure on the annular si^ace between
ikf and N; when the valve rises a little the
steam rushes over the seat iV into the air, and
over the seat M into the chamber B, whence
3. Upright Boiler.
1. K, smokestack ; H, weight safety valve ;
G, feed pipe ; S, steam space ; P, pressure
gauge \ c c c, gauge cocks ; I', water line ; / t,
fire tubes; N, feed pipe with stop valve;
iir M M, hand holes ; a a, stay bolts ; F, fire
box ; E, grate ; D, ash pit ; k, ring ;
10
HANDBOOK FOR ELECTRICIANS.
it escapes through the channels C, C The channels are, however, not large enough
to allow the steam to escape from the chamber as fast as it enters, and hence the
pressure in the chamber rises and acts on the area inside the seat M. This addi-
tional pressiire throws the valve wide open and
qviickly relieves the pressure in the boiler.
(a) Steam escaping from a safety valve is a sig-
nal of safety. It is set to open at 5 pounds above
the working pressure. Changing, overloading or
neglect is dangerous. About 1 square inch of valve
opening is necessary for 3 square feet of grate sur-
face.
(b) To set a weight safety valve : Steam pressure
in lbs. X valve area in sq. ins. X dist. from fulcrum
to center of valve = lbs. required to raise lever X
length of lever.
5. The i^ressure gauge is a brass circular tube of
oval cross section having the open end connected
with the boiler space by a pipe so bent as to retain
water in the tube. The steam pressure on the
water tends to make the oval section circular and
therefore to straighten the hoop, whose free and
closed end in moving turns a pointer by means of
gearing. The pressure shown is that above atmos-
phere.
It must be accurate over the whole scale, should
stand at when there is no pressure and agree
with the safety valve at blow-off. If not, compare
it at once with another gauge and correct. The
length of the invisible jet from the upper gauge
cock is a rough check.
6. The gauge glass is the boiler fixture most
closely Avatched. A majority of accidents are
attributed to a choked water gauge which is never
to be relied upon, especially when the boiler is
foaming, unless verified by the three gauge cocks.
Before firing and occasionally during the run, blow
out the glass twice to see that water returns to the same level and both pas-
sages are clear.
Cold drops of water or currents of air or scratches in cleaning are liable to
fractiire the glass. Then close lower and upper stopcocks, replace from stock
always on hand by a new glass and soft rubber gaskets, taking care that the
glass does not touch metal.
7. The three gauge cocks are tried many times every day as a check upon the
indications of the glass and pressure gauge and are more reliable. The upper
cock should show dry steam ; the middle one, steam and water ; the lower, water
only.
8. The scum cock, for blowing out dirt from the surface of the water, is opened
and closed alternately and quickly to prevent clogging. Continue so long as
scum appears.
9. The blow-off cock of gun metal with metallic packing is opened at least once
a day to guard against sticking. To insure against the blow-off being left open,
the handle is a removable spanner or key which can only be put on or taken off
when the cock is closed.
Blowing down at about 10 pounds pressure while raising steam drives out
impurities on the bottom and equalizes the temperature throughout the boiler.
If the pressure is high, open deliberately and keep the hand on the spanner
while watching the glass. Make sure to close the cock. If water falls unac-
countably in glass, look to the blow-off.
10. The feed jjunip (fig. 5) is an engine to be cared for and handled much
like the main engine. It must be simple, double-acting, quiet, without leaks,
i:)Ositive under varying pressure, and have a suitable location, no dead center, a
full supply of water, both a check and a stop valve in the delivery and a check
valve and strainer at the sviction extremity.
(«) The pump end is in good order if the pet cock, when opened, shows full
stream at forcing and weak at suction. Streams on both suction and forcing
strokes show that the pump valves are not closing. If there is no stream, look
for air leakage in the suction or no water supply. If the receiving valve does
not close, the pet cock shows hydrant pressure.
4. Pop Safety Valve,
CARE OF BOILERS.
11
(&) If pump goes slow, the packing may be too tight or suction maybe closed
or steam has fallen. The packing is tight enough if on closing the delivery
valve the plunger makes a stroke up and down and then stops.
(c) If the pump gets hot, water may be backing into it past the check valve
from the boiler.
(d) If an accident happens to a pump and there is no injector, stop the engine,
close boiler valves, draw the fire, raise the flue caps, and close the damper.
(e) If the suction pipe leaks, wrap sheet-rubber over the opening and bind it
tight with string or copper wire as a temporary repair.
(/) A steam boiler requires both a pump and an injector, each capable of sup-
plying 1 cubic foot of water per horsepower per hour.
END VIEW OF STEAM CrLINDERS
PISTON PATTERN WATER END
5. The Worthington Pump.
1.
Steam cvUnUer (Nu. 1 aud
23.
Piston rod.
42.
Casing.
No. 2).
24.
Valve-rod head pin.
43.
Binder.
2.
Steam-cvlinder lieail.
25.
Valve-rod link ( long or short) .
44.
Plunger hub.
3.
Slide valve.
26a.
Long lever.
45.
\\ ater-cylinder
hand-hole
4.
Valve-rod nut.
27a.
Short lever.
plate.
n.
Valve rod.
276.
Fork end.
46.
Force chamber.
6.
Valve-rod gland.
28.
Rock-shaft key.
47.
Force-chamber
hand-hole
7.
Valve-rod bead.
29.
Upper rock shaft.
plate.
8.
Steam chest.
30.
Lower rock shaft.
48.
Valve guard.
9.
Steani-cbest cover.
31.
Crank pin.
49.
Valve spring.
10.
Steam pipe.
32.
Spool.
51.
Valve.
VZ.
Piston rinp.
33.
Spool position pin.
52.
Valve seat.
13.
Piston follower.
34.
Spool key.
53.
Delivery tee.
14.
Piston-follower bolts.
35.
Cradle.
54.
Air chamber.
15.
Piston bod v.
36.
Cross stand.
65.
Suction flange.
16.
Piston tongue.
37.
Blow cock.
57.
Piston nut.
17.
Piston-tongue spring.
38.
Water cylinder.
58.
Plunger nut.
IK.
Piston-tongue bracket.
39.
Water-cylinder head.
61.
Vi atcr-c.ylinder
foot.
19.
Piston-rod slutting box.
40.
Plunger.
63a
Solid water piston ring.
20.
Pistou-rod stuffing-box gland.
41.
Plunger ring or cylinder
65.
Packed water piston body.
21.
Steam-cylinder foot.
lining.
66.
Packed water piston follower
22.
Exhaust Uauge.
12
HANDBOOK FOR ELECTRICIANS.
11. The injector lifts, heats, and forces the water into the boiler but it is not
so easily regulated to a small continuous flow as the pump.
(a) It has four nozzles: The steam nozzle 4, through which a jet of steam
from the top of the boiler first passes ; the combining nozzle C at whose extrem-
ity the steam and the water from the supply unite ; the condensing nozzle D
in which the steam's
^®" condensation is com-
pleted, and the deliv-
ery nozzle, seen just
above 3, to the bot-
tom of the boiler.
(b) There are four
openings — steam, wa-
ter, overflow and de-
livery.
(c) The Hancock
injector (fig. 6) with
40 pounds dry steam
will lift water below
100 F. up 25 feet and
force it hot into the
boiler. It has globe
valves at 4, 5 and 3
and a check and globe
valve to boiler not
shown.
(I) To lift the water
and to inject it, open
valves 3, 1, 5 and 4 in
order. Steam rushing
through 4, C and D
toward overflow 8
drives out the air.
Water rises in 5 to C
and the steam jet is condensed by it at D. The re.sulting hot water jet has less
cross section than the steam, but equal energy at the overflow. When the flow
of water here appears steady, close 1 to turn the stream through D, open 2 one-
half turn and close 3 to direct the flow into the boiler. The ear will recognize
proper action. The jet into the boiler can be somewhat reduced by partly
closing the water supply 5.
(ii) To inject simply (the svipply being above the injector) leave 1 always
closed and open 3 and 5. When cold water appears at overflow, open 2 and 4
and close 3.
(m) Metropolitan, Rue and Korting are other good injectors similar in action.
(iv) Failure to act is due to improper handling, leakage of air, water insuffi-
cient or too hot, pressure too low or too high, or to obstructions in the tubes. If
the stream breaks unexpectedly, look first to water and steam supply for the
cause of the trouble.
(V) If hard scale forms on the nozzles, scrape it off or soak the injector in a
one-tenth solution of muriatic acid or boil it in a mixttire of vinegar and salt.
(VI) All pipes, valves and fittings of piimp or in-
jector must be air-tight and agree in size with pump
or injector openings. The suction pipe is larger if long.
Keep the fine wire strainer at its extremity clean.
Injector and pump require each its own check valve and
a stop valve in common in the delivery. Neither will
lift hot water. There ought to be a water heater
between the pump and boiler if the supply is cold. Use
injector if the pump can only inject cold water.
] 2. A fusible plug (fig. 7) screwed into the crown sheet
of a furnace, may not act unless examined and scraped
clean on both furnace and fire sides whenever the boiler
is cleaned, li is the fusible metal in the uiiper part of
the plug P, so that when it melts from low water there
is still water covering the crown sheet Q.
13. Several manholes arc placed in large boilers, and hand-holes in small, for
purposes of inspection and cleaning. Gaskets are liable to get hard or to become
torn so that at least one extra set should be kept on hand.
14. The grate clogged with clinkers or ash stops the draft.
7. Fusible Plug.
CARE OF BOILERS.
13
(E) THE FEED WATER.
The feed water ought to be pure and hot. Rain water is iisually satisfactory ;
well water is often good, sometimes very bad for the boiler. When the source
is untried or the boiler is new, the man or hand holes are freqiiently opened to
see if incrustation, corrosion or both have occurred. These maladies are the
two greatest evils that operate against the life and safety of steam boilers and,
unless prevented, will burn, granulate or distort the plates and tubes or cause
pitting, grooving or wasting which results in explosions.
1. Incrustation.
(a) Well water generally contains salts of lime, magnesia, silica and alumina.
When the water is heated under pressure they are liable to separate from the
water forming at first a soft deposit. Heat further bakes the sediment iipon
the boiler's interior into a nonconducting stone-like or glass scale which sepa-
rates the water from the plates and leads to dangerous overheating; -jJ^-inch
scale makes 15 per cent more heat necessary.
(&) To maintain 90 pounds pressure, water must be heated to 320' F., and a
clean boiler fire surface to 325' F. If ^-incli scale intervenes, the fire surface
must be raised to 700° F. Above 600" F. iron becomes granular and is liable to
bulge or crack under pressure.
(c) Incrustation can be prevented (i) by an expensive piirifier which heats
the water before entering the boiler until the salts are precipitated; (ii) often by
chemicals of pure quality such, for example, as caiistic soda for lime carbonate
deposit, or carbonate of soda for lime sulphate deposit, or good kerosene, etc.,
Avith more frequent blow-oflis; (iii) sometimes by frequent iise of surface and
bottom blow-offs alone.
The chemicals (ii) simply make the hard deposit soft. Thej' should be uni-
formly added in weak solutions to the boiler by way of the jiump, gently at first,
and the effect carefully watched by an experienced person. Excess may cause
boiler leakage. Let the first trial be at the rate of I pound salt jjer horsepower
per month, or one quart daily of kerosene per 100-horsepower. Avoid all nos-
trums. Where the supply is poor, a good remedy lies in a large cistei-n and a
wide roof, from which the first water of every rain is not collected.
(d) When the hard scale has been once deposited, the most certain remedy is
to chip or pull it off by hand.
(e) Some waters having magnesia, etc. , throw down a fine floury deposit which
with little grease from the exhaust, and itnder ijressure, often strains seams and
rivets, causes leaks and bulges furnace plates. Oil filters and sjiare use of oil
are remedies.
2. Corrosion.
(a) Corrosion is internal or external. Few boilers after some service are
wholly exempt from pitting, grooving or wasting away in irregular and ill-defined
patches. Internal corrosion (fig. 8) is the most destructive of all boiler diseases
and serioiis enough to demand a remedy
at once and subsequent careful watch-
ing. Stay bolts and rivet heads are
sometimes attacked.
(b) It may be due to acid from vege-
table matter in feed water, or decom-
Ijosition of acid salts in the scale, or
other impurity in hot water under high
pressure, or to galvanic action. The
ill effects can generally be reduced by
pure soda ash, in solution, uniformly
added by the pump. If galvanic action
is suspected, fasten blocks of zinc into
good metallic contact with boiler parts
and near the patches. Change of water
may cure. Or, let a chemist discover
and apply a neutralizing agent.
(c) To prevent external corrosion,
allow no water to come in contact with
the boiler's outside, or dampness from
8. Corrosion Next a Lap.
leaking to remain in the seatings and coverings. Finally coat with linseed oil.
(d) A sensitive hydrometer, finely graduated above unity over a short range,
will aid in detecting the waters which cause scale or internal corrosion.
14
HANDBOOK FOR ELECTRICIANS.
(F) CLEANING THE BOIEER.
1. While cleaning, watch for faults.
2 The heating surface, first of all, should be kept clean on both sides. Never
allow scale or soot to exceed yV inch in thickness. A chisel may be used for
scale ; a scraper, chain or wire brush, and not steam, for flues.
3. The water in the boiler is changed every two or three weeks.
4. Empty and thoroughly clean once in five hundred working hours, of tener
if tiie boiler is new or the water is bad, or the work has been intermittent. The
interior, after it has cooled, is washed down with a hose and dried, all scale is
removed and the boiler again washed. A small chain is sometimes dragged
around the tubes to clean them. Before closing the manholes remove crust and
tools that they may not choke the blow-off.
(G) TIIE Il^SPECTION OF A BOIEER.
1. By a legalized inspector, once a year, extends to every part and fixture of the
boiler, first empty and then under steam, after the defective parts have been
replaced. , . . , . ■, , -,
2. Boiler, flues and mud drum are first cleaned and dried m order to be seen.
3. The inspector ascertains the soundness and thickness of the platesby the sound
and rebound of a very light hammer. The hammer test is usually sufficient.
Henotesthelocationandamou.it of incrustation and corrosion, and searches for
blisters, cracks, loose rivets, broken or corroded stays, fractured joints, etc. All
seams, head, and tube ends are examined carefully. A doubtful spot is exam-
ined with the aid of a magnifying glass. Sometimes a small hole is drilled
through and, after inspection, plugged.
4. A loose rivet is replaced. A stay, brace, or fastening found defective, or a
tube cracked is taken out and a new one is put in. A blister or a bulge is cut
out and a patch is riveted inside if possible.
5. The hydraulic test is made w-hen the boiler is new or extensively repaired
or can not be thoroughly examined inside and out. Fill the boiler with water,
close all outlets and use the force pump very slowly and evenly until the pres-
sure is one and one -half times the working pressure. Or a gentle fire may be
started under the filled boiler to get the desired pressure, but the temperature of
the water should not exceed 212". There is no danger of explosion if boiler is filled.
Watch the gauge closely for any drop in pressure due to the boiler's yielding.
By fixing points of sticks or wire close to the outer surface of furnace sheets,
shell and ends, any deformation due to pressure may be detected. Any leakage
in seams, rivets or joints is calked before continuing the test.
6. Under steam, the pressure gauge is compared with a standard along its entire
scale; the safety valve is raised, operated, and, if necessary, reset. Look for
leakage in cocks, valves, joints, and all fixtures, and for any faulty action in
gauge glass, pump and injector.
7. The inspections of a boiler begin at its manufactory and continue so long as
it is in use.
(H) EXPEOSIOIS^S.
About 250 steam-boiler explosions occur annually in the United States, mainly
due to preventable causes. Vigilance and execution of the foregoing rules will
prevent them. When the first symptom of a disorder appears, apply the remedy.
" In 1893, a single American insurance company examined 163,000 boilers, in-
spected 67,000, tested hydrostatically 8,000 and found 600 unsafe. In all, 123,000
defects were discovered, of which 12,000 were dangerous, as classified below:
Nature of defects.
Deposit of sediment
Incrustation and scale
Internal s''""ving
Internal corrosion
External corrosion
Defective braces and stays
Settings defective
Furnaces out of shape
Fractured plates
Burned plateS
Blistered plates
Defective rivets
Defective heads
Whole
No.
Dan-
gerous.
548
865
148
.WT
63r)
4S5
352
254
G40
325
164
1,569
350
Nature of defects.
Leakage around tubes
Leakage at seams
Water gauges defective
Blow-outs defective
Deticiency of water
Safety valves overloaded
Safety valves defective
Pressure gauges defective
Boilers without piessure gauges
Unclassified defects
Total.
Whole
No.
21,211
5,424
3,670
1,620
204
723
942
5,953
115
755
122, 893
Dan-
gerous.
2,909
482
660
425
107
203
300
552
115
4
12, 390
CARE OF BOILERS. 15
The various causes are :
1. Excessive pressure, due to carelessness of the engineer who ought to have
been intelligent, well paid and legalized ; and to defective pressure gaiige, safety
valve and observation of water gauge — all three combined. The working pres-
sure should not exceed two-thirds of the water test or one-fifth the safe theoreti-
cal pressure.
2. Overheating of plates due to low water or scale. While boiler is under
steam the water line should always stand at the middle gauge, and the water
glass should be cleaned and watched.
To stop scale, inspect and clean boiler regularly, blow off sufficiently often,
use the scum cock, seek the proper solvent and change the water, if necessary.
3. Corrosion in patches and holes. After some explo.sions, plates are found
wasted in places to the thickness of paper. Vertical boilers are more liable to
explode from corrosion at the ends of tubes. Keep boiler full of water if it lies
idle a few days.
4. Bad construction in material, design, or workmanship. There is no remedy.
The prevention lies in purchasing boilers from a standard maker. There is only
one gi-ade of boiler to be selected, i. e. , the best.
II.— THE STEAM ENGINE.
The type generally used in isolated plants is a simple, double-acting, single-
slide or piston valve, automatic cut-off, high-speed, high -pressure, horizontal or
vertical, direct-connected, steam engine. All types involve similar principles
and require the same kind of care.
(A) ITS OPERATIOlSr.
STARTING.
1. Drain water out of steam feed pipe and close the drain.
2. Make stire that every part of the plant is in order.
3. See that both cylinder drains are open.
4. If the engine is not too large, turn it over by hand to see if it runs smoothly
without play and leave the crank at 45 degrees, leaning toward and moving from
the cylinder.
0. Open the throttle a small fraction of a turn to drive out water and to warm
the cylinder while oiling.
6. In a regular order fill the oil cups and oil all bearings, and make sure that
oil is not choked by gumming anywhere.
7. The cylinder must be warmed some time to allow free motion of the valve
and piston.
8. Widen throttle slightly to start engine as slowly as possible during the first
dozen turns.
9. Bring engine to fiill speed very gradually, standing ready to close instantlj''
if a blow is heard.
10. Then turn throttle wide open.
11. Close the drain.
12. Adjust the oil cup and lubricator feeds, two to five drops per minute
RUNNING.
1. The engine should run without noise. Lost motion is taken up gradually
as soon as it is detected.
2. The ear may aid the eye in detecting troubles.
3. Watch for heating especially in crank, crosshead, cylinder, stuffing boxes,-
main bearings and eccentric. When found, ease away on nut or key when
possible and increase oil to which melted tallow may be added. Correct the
fault at the first stop.
4. Uneven speed indicates sticking of the valve or governor parts or loose
connections in the valve motion.
5. See that oil cups feed properly and that no bearing surface is dry. Guard
against the use of too much oil.
6. A click in the cylinder from water should be quickly recognized. Open
both drains until it stops.
7. An engine running retjuires constant vigilance and labor on the part of its
attendant. There is no place for company or a chair in an engine room.
STOPPING.
1. Slow down engine gradually, especially if pressure is high, and be deliber-
ate in last half turn of throttle. Leave the crank on outer dead center.
2. Close all oil cups.
3. Open drains and loosen belt.
(16)
THE STEAM ENGINE. 17
4. Feel crank, crosshead and other parts for heat.
5. Clean the engine thoroughly while warm.
6. Close the room tight, locking doors and windows, that engine may cool
slowly.
(B) GEISTERAI. CARE AND MANAGEMENT.
1. Never attempt to adjust a key or part without first marking its original
position with a pencil or a metal point.
2. After making an adjustment run at first slowly on no load and on light
loads. Experimental changes should never be allowed.
3. If the engine is unexpectedly stopped and the steam pressure is high, throw
fresh coal on the fire, close damper to grate, open the furnace door, and start
the pump.
4. Keep steam at uniform pressure while running.
5. If engine is new or just overhauled, run it slowly without load and with
light loads for hours to let it wear to its bearings.
6. A cleanly kept engine in good order attests its engineer's capabilities. All
bearing parts are kept free, smooth, oiled and without lost motion.
7. The new man gains all the information possible from the retiring engineer
and should possess the manufactiirer's directions.
8. No loose garment should be worn around an engine in motion.
9. Do not tinker with the engine. If it is necessary to repair some part, do it
thoroughly and look over all other parts.
10. Inspect at least once a month for leakage in piston, valves and cocks.
Watch gauge glass for leakage from boiler when engine is not running. See if
piston and valve rods are in alignment, if cylinder is scored, if all bolts are
secured, if shoulders are forming in the cylinder, if there is acid in the oil, etc.
11. If cylinder, valve, rod or guide is scored, graphite put on will fill the
scratches and may restore the smoothness.
12. Always add oil to the graphite.
13. Packing allowed to become hard will flute the rods.
14. Packing, waste, iron parts, etc. , temporarily laid on the floor, may carry
dirt and grit to the bearing i^arts.
15. Every bearing surface requires a drop of the best mineral oil applied not
often but regularly— a thick oil for cylinder and thin for other parts. Most
engineers use too much oil. Never allow surfaces to get dry. Dirty oil from
boxes may be filtered and reused.
16. Thin grease mixed with cylinder oil is the best lubricant for governors.
17. If there is not a belt tightener, put the belt partially on the pulley at rest,
then run it on the engine pulley to be started with very slow motion.
18. The practiced ear can generally tell if the exhaust is regular. If the puffs
are long and short alternately, the exhaust is freer at one end than the other.
One exhaust may be heavier, yet the two may be equally timed. Equalizing
the cut-off and exhaust is a partial remedy,
19. It is difficult often to locate knocking. Therefore, seek the place and
cause, biit proceed cautiously before making any changes intended to remedy
the evil. It is usually due to the following causes :
(a) Lost motion in crank, crosshead, valve rods, main journals, etc. Try the
hand on the suspected part at rest or in slow motion.
(b) Valve not set or the sli^jping of eccentric which admits steam suddenly;
if due to valve, an indicator diagram is necessary.
(c) Engine out of line. See remedy elsewhere.
(d) Crank pin not parallel to main shaft. Disconnect connecting rod from
crosshead and clamp to this end of the rod a spirit level parallel with the shaft.
As the crank is turned the bulb will show if pin is not parallel with the shaft.
(e) Leaky piston rings, poor lubrication, water in cylinder.
20. Relief valve on cylinder is set at 5 pounds higher than the safety valve.
21. Heating is due to lack of good lubricant; dirt, grit, or filings in journals;
bearings too tight ; reciprocating or revolving parts out of line ; improper fitting ;
too heavy load ; too high velocity ; too great pressure.
22. To feel for heating at crank pin in motion, stand in front of the engine
and lower slowly the hand, palm down, until the crank barely touches it on the
up stroke ; or, starting from the crosshead end of the connecting rod, slide the
hand along the rod to the ci-ank.
23. Never permit the heating to reach a degree uncomfortable to the hand.
If it remains moderate, oil and wear may stop it.
1714—2.
18
HANDBOOK FOR ELECTRICIANS.
34. In case of smoke from overheating, slow down the engine as quickly and
as far as possible, but do not stop it until the part has cooled. Then dismount
quickly, clean off the brass from the steel, and correct
the fault.
25. Piston rings should clear the cylinder at both
ends a fraction of their width for smooth running.
26. Remember that the pump is a second engine.
27. If a valve leaks, clean it, reground the seat, but
do not increase the pressure.
(C) THE CYLINDER I.UBRICATOR (FIl}. 10).
To refill with oil, close L, C and K in order. Unplug
F to drain off reservoir, allowing air to enter at E.
Close F and take out E to fill with oil. Replace E,
open C and K, and regulate L from two to five drops
a minute, depending upon the qualtity of oil and the
amount of work.
If a glass breaks, close C and K and drain out.
Loosen the packing nuts, replace with new glass and
gaskets, taking care that the glass does not touch metal.
(D) THE FOUR CRITICAL POSITIONS OF
VALVE AND OTHER MOVING PARTS.
1. When, as in fig. 11, the valve Xis in the middle
position, and the eccentric arm is nearly vertical, ^4 a
is the steam lap and B b is the exhaust lap of the
valve. The lead of a valve is the distance the steam
port is opened at the beginning of the crank's stroke
(fig. 12). Full port opening (fig. 15) occurs at the end
of the eccentric's stroke.
2. Lap, lead, or full port angle, or arc, is that made
half; c, upper valve ; ' e" fiufng by either crank or eccentric while a point of the valve
piug;F,drain; A', discharge valve; travels Over lap, lead, or full port opening.
giasr^p St-feecTgiass^' ^''""'' ^- Travel = total distance valve moves = two times
' ' ' ■ length of eccentric arm. Stroke=total distance piston
moves = two times length of crank. Angle of advance = amount of angle the
eccentric is ahead of crank.
4. If we consider what takes place at one port, say the left, and on the left
side of the piston during one fiill stroke and return, it will be seen that there
are four critical positions of valve, piston, etc., during the one turn of the fly
wheel, say clockwise, as in figs. 13, 16, 17, 18.
Sight Lubricator to
Cylinder.
R, reservoir, oil shown in upper
Laps.
(t ) Admission of steam begins when ^ is at a going to the right.
(2) Cut off of steam begins when A is at a going to the left.
(3) Release of steam begins when B is at />, going to the left.
(4) Compression of steam begins when B is at b, going to the right.
These four events similarly occur on the right side during a stroke and return,
and so on.
THE STEAM ENGINE.
19
12. Lead.
Fig. 13 shows admission of steam to head end of cylinder before the end of a
stroke, in order to form a cushion.
In fig. 14 the piston (also crank) is at head dead center luider fnll boiler pres-
sure, and valve is at lead by definition.
In fig. 15 steam iwrt is full open. Eccentric arm is at crank dead center.
In fig. 16 steam is cut off. Pressure on piston will now be due to expansion
only of the steam in the cylinder. Eccentric makes nearly the same angle with
vertical through O, as at admission.
20
HANDBOOK FOR ELECTRICIANS.
In fig. 17 inside edge of valve going to left has reached port's inside edge.
Release of steam or its exhaust to atmosphere begins.
In fig. 18 inside edge of valve going to right has reached the port's inside edge,
and compression of steam in the cylinder follows. Eccentric makes about the
same angle with vertical through O as at release.
Admission (fig. 13) next follows, and so on,
18.
(E) TO CONSTRUCT ACCURATEirr IN ONE FIGURE (19)
THE FOUR CRITICAL POSITIONS.
Given, travel = 8 inches ; steam lap = 1^ inches : lead = ^^ inch, and exhaust
lap = i inch.
On H i = 3 inches, draw eccentric's circle in i n: outside, crank's circle 31 1 N.
O m is the eccentric arm's position at valve's mid travel.
Lay off O E = exhaust lap, J inch, O L = steam lap, L T = lead, erect verticals
to get points d, c, o, 6, and t. The radii O a, O b, O c, and O d are by definitions
the positions of the eccentric at admission, ciit-off, release and compression.
d m = en = exhaust-lap arc ; m a = n b = steam-lap arc ; a t = lead arc.
d O m = exhaust-lap angle ; m O a := steam-lap angle ; a O t = lead angle.
Lay oQ. H F = at, and through F draw O A. AO a are the positions of crank
and eccentric at admission.
The eccentric is always in advance of the crank by an arc = m a -\- 90° + « t,
or in angle = m O a + 90" + H O F — angle of advance.
Steam lap O L + full-port opening L i = i valve travel = li inches ; full-port
arc a i = 90° — m a.
Lay off from b, arc b x = m a + 90° + a t, or, since b i = a i = 90° — m a, lay
off from / the difference (2 m a -\- a t) to get x. Bob are the positions of crank
and eccentric at cut-off.
Lay off from c arc c y = m a -{- 90° + a t, or, since arc c i = 90° -f c n, lay off
from i the difference {m a + at — d m) to get y. C O c are the positions of
crank and eccentric at release.
Lay off from d, arc d z = via -\- 90° + at, or, since arc d 11= 90° — d in, lay off
from Hthe difference (m a -\- a t -\- d m) to get z. D o d are the crank and
eccentric positions at compression.
Therefore the crank is —
At admission, the lead angle distant from first dead center.
At cut-off, two steam lap angles + lead angle from second dead center.
At release, steam lap -f lead — exhaust lap (angles) from second dead center..
At compression, steam lap + lead -|- exhaust lap (angles) from first dead
center.
THE STEAM ENGINE.
21
19. Four Critical Positions of Crank and Eccentric Arm.
(F) TO EQUAIiIZE THE FORWARD AND RETURN STROKES
OF THE PISTON.
The foregoing would only be true for very long connecting rods. The angular
position of an actual rod (about six times longer than the crank) delays the
events on the stroke from the head end and produces them too early on the
return. If, for instance (fig. 20), the pis-
ton is at ^4 and C when crank is at the
dead centers, it will be to the right of B,
midway of A and C, when the crank is
vertical ; that is to say, the piston travels
faster in the head end half. For a partial
remedy equalize the leads of the valve and
slightly alter one exhaust lap for equal
The valve position is less disturbed than that of crank
Crank Moves Uniformly, Piston
Does Not.
release and compression.
because the eccentric arm is relatively short.
22
HANDBOOK FOR ELECTRICIANS.
(G) EFFECT OF CHANGING STEAM EAP, EXHAUST LAP,
TRAVEL AND ANGULAR ADVANCE.
]iy increasing.
Steam lap
Kxliaust lap
Travel 111- eccentric
arm.
Angular advance
Begins later, ends
sooner.
Unchanged
Begins sooner, lasts
longer.
Begins sooner, pe-
riod same.
Kxpansiou.
Begins sooner, lasts
longer.
Begins same, lasts
longer.
Begins later, ends
sooner.
Begins sooner, i>e-
riod same.
Compression.
I'uchanged Begins at same
point.
Begins later, ends
sooner.
Begins later, ends
later.
Begins sooner, jie-
riod same.
Begins sooner, lasts
longer.
Begins later, ends
sooner.
Begins sooner, pe-
riod same.
(H) PRINCIPLE OF THE WHEEL-GOVERNOR AUTO-
MATIC CUT-OFF.
1. If the angle of advance .4 a (fig. 19) is increased, full port L i is made
less, h approaches i, the cut-off h O occurs earlier and the period of admission of
steam against the piston is lessened. But the lead would thereby be increased.
To keep it the same, the eccentric arm is, by the automatic cut-off, shortened at
the same time the angle of advance is increased. The valve travel is thus less-
ened and the lead is preserved.
Or, admission may be prolonged by automatically decreasing the angle of
advance and increasing in effect the eccentric's arm.
2. Wheel governors accomplish the
above in different ways in order to keep
uniform the speed under a varying
load —
(a) If load decreases, speed increases,
governor weight is thrown out by cen-
trifugal force, valve travel and admis-
sion period are diminished.
(6) If load increases, speed decreases,
governor weight is drawn in by the
spring, valve travel and admission
period are increased.
3. The governor (fig. 31) of the
straight-line engine affords a typical,
simple, and accurate automatic con-
trol of steam to load.
The eccentric is screwed to a plate,
A C, pivoted at a on the fly-wheel, re-
volving clockwise. As the weight TT'
flies out, the end d of the eccentric
arm is shifted about a as a center
toward c by the links / / moving with
the arrow against the spring >§. Govern-
ors usually have two opposite weights actuating the eccentric arm like the above.
Fig. 22 gives by the same letters the relative positions above of crank h e,
eccentric arm c d, center of shaft c and center of governor motion a. Angle of
advance = /* c d. Describe arc through d to center a.
When too high speed throws W outward, the free
end of the eccentric arm is moved to some iioint e,
the angle of advance becomes Ji c t^and the eccentric's
length c e. The valve travel is shortened, the lead
is preserved, cut-off occurs earlier, admission of steam
and speed are less.
4. To adjust the governor for increase of speed,
slide the weights, if movable, toward the center
equally ; or tighten the springs equally ; note that the
spirals' do not touch each other. To run slow, loosen
them, but seldom more than an inch.
5. To make sure that the tensions on both springs remain eciual, count the
turns made 1)y the nuts in tightening, or listen to the sounds of the springs when
struck after tightening.
6. For larger changes, procure other weights and springs. The governor can
usually be changed to run reverse. If it ever works irregularly, look for a
gummed or dry joint or a surface that binds.
c h = general direction of crank and i
c d = eccentric arm.
\
k_
J-
22.
Wheel Governor's Auto-
matic Control of Steam
Valve.
I»^
22a. Sturtevant Double Engine.
THE STEAM ENGINE. 23
(I) A FITI.L INSPECTIOI^ OF AI^ ENGINE.
A full inspection extends to proving the level of its base ; the alignment of
cylinder, shaft, crank pin and guides ; of valve rod and eccentric ; trueness of
cylinder bore, fly wheel, and l3earing surfaces; equality of clearance; the fit
of piston to cylinder ; of crosshead to guides ; of connecting-rod brasses to crank-
pin and crosshead journals ; of main shaft to its bearings ; of packing to rods ; the
setting and critical positions of the valve ; lengths of rods and the general order.
Tools required: Spirit level, inside calipers, plumb line, straightedge, ruled
square, very fine stout string, stick slotted for a cylinder-head bolt. The rules
given below for a horizontal engine suggest the course for a vertical.
1. To prove the base level, apply the spirit level in two positions at right
angles on the base, always reversing the level.
2. To get the dead center, place a fine pointer from a fixed rest close to the
fly wheel's outer rim in front. Turn fly wheel to bring the crosshead to aboxit
i inch from the outer end of its travel. Mark accurately the guide at the end
of crosshead and the rim opposite the pointer.
Continue the turn of the engine until the same end of crosshead returns
exactly to the mark on the guide. Mark the pointer's place on the rim and
turn the wheel so that the pointer stands midway of the two marks on the
rim. The engine is now at its outer dead center. A fine straight line drawn
on the guides along the crosshead end marks the position. Next find and
mark the inner dead center.
3. To line up an engine (horizontal) is to find if cylinder's axis prolonged inter-
sects the axis of the main shaft at right angles, and the axis of the ci'osshead
pin in all positions, and if the main shaft is level.
Disconnect and remove all parts from crank pin to and including back cylin-
der head. To any bolt of this head, bolt the slotted stick across the head to hold
one end of the fine string in the axis of the cylinder. Draw the string taut
through the cylinder to an adjustable upright in front of the engine. With
inside calipers carefully adjust the string to the centers of the two counterbores.
This is the center line of the engine, to which other parts are adjusted.
(«) Put one leg of the square against an inner crank face so that the outer
edge of the other leg is in the shaft's axis See if the edge just touches the line
as the crank is turned.
(b) To square the shaft, turn the crank pin forward so that it almost touches
the center line of the cylinder. Caliper between line and crank or disc. Turn
crank pin backward to line and likewise caliper. If the two distances are equal
the shaft is sqiiare. If not square, move the out-end pillow block.
(c) To level the shaft, apply the spirit level on top and reverse it. Or, better,
drop a plumb-line in front of the crank face and caliper at the xij> and down
half stroke similarly as in squaring. If the shaft is oiTt, shift it by liners, babbitt,
thicken or thinner brasses, or by using a file, as required.
To verify both the level of shaft and trueness of fly wheel, drop a plumb line
from the ceiling past the wheel's outer rim and center and turn the wheel.
(d) To line the guides, lay a straightedge across the two guides and caliper
between it and the center line the whole length of the guides. Likewise caliper
between line and the inside edges. Measurements will show if center line inter-
sects the axis of the crosshead pin. If necessary, dress the guides with file or
sandpaper, or insert shims.
(e) To verify {b and r?),key up the connecting rod snug to the crank pin, and while
turning the crank see if the free end of the rod moves parallel with the guides.
4. To align A-alve rod and eccentric, less liable to derangement, will require
like expedients.
5. To find whether cylinder has worn out of true, caliper all around the center
line in one circle, then another, and so on along the inside of the cylinder.
6. To test the fit of the piston: (a) Loosen the connecting-rod keys, and, by
turning the fly wheel, bring the piston to the head end. Take off cover, also
the follower on the piston, and see that the piston rings press against the cylin-
der bore all around without binding.
(b) For a check, put the engine to the other dead center and admit a little
steam. Leaking, if any, can be seen at the open end.
(c) Or, without removing the head end, if the cylinder is piped for indicator,
relief valve, or exhaust to air, turn crank to either dead center and open the
cock at the end opposite from that at which steam is very slowly admitted.
Steam will appear at the cock if the piston leaks.
(d) The split of a piston ring is down in a horizontal engine. If two rings,
they break joints on the lower half.
24
HANDBOOK FOR ELECTRICIANS.
THE STEAM ENGINE.
25
7. The crossliead. — It ie essential to keep the piston rod exactly in the center
line. Give the gibs an easy sliding fit without lost motion. Ease away on the
crosshead pin inside the connecting rod to prevent undue wear (fig. 34).
8. To get the true length of connecting rod: (a) Move piston, with crosshead
disconnected, against one cylinder head, i. e., the striking point, and mark the
guide opposite crosshead end. Do the same for the other head. Suppose the
distance between both guide marks = 25 inches ; between centers of crank pin
and shaft = 12 inches. Then full stroke = 24 inches, and clearance at either
end = i inch. Now move crosshead + inch back from the striking point
mark, bring crank to dead center, and with a tram measure between the outside
centers of crank pin and wrist pin for the required length.
(b) To lengthen the rod insert liners between its brasses and stud ends.
(c) To put on the rod move the piston slightly toward the crank and adjust
the keys so that the bores of the brasses easily fit without play.
(d) To take up lost motion loosen the set screws, drive down the key, and
tighten the set screws. It is a good plan to drive in the key until the brasses
bind, mark the key and slide it back to a proper fit, marking it again for later
adjustment, if necessary.
(e) To equalize clearance, usually i to i inch, in the cylinder, lengthen or
shorten the connecting rod.
9. To adjust main shaft bearings, the shaft is shifted on either side, or both,
by the use of thicker or thinner shims, babbitt or brasses. If the brasses meet,
tighten the nuts to an easy bearing. If not, lay in a sufficiently thick wire of
lead to take the compression and screw the nuts to a bearing. Then replace by
a shim gauged to the same thickness and screw the nuts home.
If the lead wire is thicker at one end, the shim will be made the same.
10. To set a common slide valve, is to make the leads at both ports equal, and
the full-port openings as nearly equal' as possible. Leads are made equal or
unequal by changing valve or eccentric rod's length ; but if both leads are equal,
change of amount is gotten by changing the angle of advance. Always com-
pare the openings by inserting a long, thin wedge.
23. Anninsrton & Sims D. C. Set.
(a) Take off the steam-chest cover (fig. 23), give all connections a close working
fit, place crank at either dead center, and measure the lead for each port ; if the
leads are equal to each other and to the amount given by the builder, the valve
is properly set. If not, change the valve rods length by the half difference, and
repeat the operation, which will probably first reqiiire a change of the eccentric's
position to bring the lead right at the first dead center.
Suppose the valve has proper lead, ^V i^ch with crank at first dead center, and
shows a lap of f inch at the other port with crank at second dead center, the
26
HANDBOOK FOR ELECTRICIANS.
THE STEAM ENGINE.
27
valve rod's length is then changed by /^ inch. Now put crank at first dead
center and change eccentric's position to give -jJ^-inch lead and move crank
(always in its working direction) to second dead center, and so on,
(b) If the valve is controlled by a wheel governor, block the weights ont to
their positions at normal speed and proceed as above. Both length of rod and
angle of advance are successively changed in setting valves.
(c) In vertical engines with cylinder above, the lead at the crank-end port is
given slightly increased lead over the upper to compensate for weight of moving
parts and the wear downwards.
(J) TO PACK THE PIST0:N^ ROD.
(1) Cut the rubber or other material into four or more rings of square cross
section Avith beveled split to fit rod and box so closely that the finger can push
them into place. The first split is up ; the others, break joints. Rub graphite
or chalk on the outside to prevent its sticking to the iron.
Screw down the gland evenly, first one nut a partial turn and then the other
a little more, and so on alternately.
(2) To stop a leak, tighten little at a time. If several trials fail, reverse the
packing, or, better, renew with soft packing always kept in stock.
(3) The troubles with packing result from ill-fitting rings, engine out of line,
rough rods, not correcting the first small leak, too long or too short or too few
rings, or too small stuflfiug box. The valve rod is similarly packed.
(k) the pisto?^ valve iis^ commojf use is
bai.a:n^ced.
This valve is cylindrical and usually hollow. Steam passes over its edges on
all sides and does not force the valve against its seat witn unnatural pressure
as in the case of the D-slide valve. Its action is precisely the same and the fore-
going principles apply, whether the piston valve admits steam at the ends of the
chest and exhausts at the middle, or admits steam from the middle around the
valve and exhausts at its ends.
^^ id O,
24a. The Cylinder and Valve.
To the latter class belongs the valve (fig. 34a) of the Armington & Sims
engine, shovni in the lead position. Live .steam surrounds the valve and
fills its interior through one or the other of its end openings. Steam has
already started into the head-end port from the middle of the chest and from
the interior of the valve by way of the right-hand opening. The exhaust
occurs quickly at either end of the cylinder through direct passages. The valve
carries check rings at both ends.
The Rites governor (fig. 24b) is extremely simple, sensitive and powerful.
The eccentric arm at its greatest elongation is short, so that the valve's travel
is small. The cut explains better than words its mode of operation.
28
HANDBOOK FOR ELECTRICIANS.
24b. A. and S. Governor.
The main journals have chain continuous oilers ; the crank pin, a centrifugal
oiling device ; and the crosshead runs in oil, all supplied from a central reservoir.
There is no throwing of oil.
Fig. 22a shows the new Armington & Sims wheel governor and ils con-
nection with the valve.
24c. End View Oiling Device.
III.— THE HORNSBY=AKROYD OIL ENGINE
Has no ignition apparatus and is, when properly attended, reliable. One
pint kerosene maintains one horsepower for one hour.
(A) THE ENGIIS^E.
1. The engine (fig. 26) is four cycle, i. e., in its propulsion four different
operations occiir behind the piston in the four strokes which cause two complete
turns of the pulley. They are —
First stroke. — ^ Admission (or suction). During the first outward stroke air is
drawn into the cylinder and a thin, momentary jet of kerosene oil is sprayed
into the adjoining hot combustion chamber or vaporizer (fig. 36a).
Second stroke. — Compression. In the following inward stroke the air is driven
through the narrow neck into the vaporizer to form with the oil vapor a mixture
which at the end of the stroke is ignited by the heat in the chamber.
^ ITT
— I — I — 7*
^>
^^
V
s^
-» ^
g" '
^vLI
c^-xx»^>^
Beau de Rochas Cycle of H
and most Explosive Engines.
Third stroke. — Explosion plus expansion of the gas through the neck into the
chamber then drives the piston outward with a maximum pressure of 130
poiinds per square inch and a mean of 40 to 75 pounds.
26a.
Fourth stroke. — Exhaust of the products of combustion from the cylinder into
the exhaust chamber and pipe occiirs during the next inward stroke, or final
cycle.
During the first outstroke the thin stream of oil is instantly vaporized on
striking the heated interior surface of the vaporizer, and the proper amount of
(29)
30
HANDBOOK FOR ELECTRICIANS.
THE HORNSBY-AKROYD OIL iiJNGINE.
31
air heated en route by the hot exhaust chamber, is drawn into the cylinder.
Mixture and compression follow on the following instroke, at the end of which
ignition is caused by the heating effects of compression, friction, and vaporizers
combined. The impulse is given only during one stroke in four. The vapor-
izer is protected from cooling air currents by the hood, and its heating is con-
trolled by the damper on top. Cylinder and valve box are cooled by a Avater
jacket.
2. Number and names of parts :
1. Cylinder liner.
2. Cylinder casing.
3. Vaporizer.
4. Vaporizer cap.
5. A'aporizer-cap joint ring.
(!. Vaporizer coAer.
7. Vaporizer-cover lid.
8. Vaporizer-cover filling piece.
9. Valve-box journal.
10. Valve-box sleeve.
11. Spray nozzle.
12. Horizontal valve.
13. Horizontal-valve spring.
14. Vertical valve.
15. Vertical-valve spring.
IC. Valve box.
17. Valve-l)Ox screw cap.
18. A'alve-Uo.x coupling.
19. Overflow glass.
20. Half union.
21. Oil-pump can.
22. Oil-pump plug.
23. Oil-pump plunger.
24. Oil-pump plunger spring.
2.5. Oil-pump plunger lock nut.
26. Oil-pump plunger head.
27. Oil-pump plungor-liead guide
28. Oil-pump gauge.
29. Oil-pump body.
30.
Oil-pump gland.
58.
31.
Bed plate.
59.
32.
Bearing cup.
60.
33.
Splasher.
61.
34.
Oil tank.
02.
35.
Oil filter.
63.
30.
Filter cock.
64.
37.
Worm gear.
65.
38.
Gear wheel.
66.
39.
Gear guard.
67.
40.
Crank shaft.
68.
41.
Crank-pin oiler.
69.
42.
Oiler elbow.
70.
43.
Piston.
71.
44.
Piston rings.
72.
45.
Wrist pin.
73.
46.
Connecting rod.
74.
47.
Connecting-rod head end.
75.
48.
Connecting-rod crank end.
76.
49.
Compression plates.
77.
50.
Cam shaft.
78.
51.
Governor wheel.
79.
52.
Governor pinion.
80.
53.
Governor-gear guard.
81.
54.
Governor bracket.
82.
.55.
Governor spindle.
83.
56.
Governor counterpoise.
84.
57.
Governor-counterpoise lever.
85.
Governor balLs.
Governor counterweight.
Governor-counterweight lever.
Governor-regulating plate.
Governor fork.
Governor-fork spindle.
Governor connecting rod.
Governor connecting-rod lever.
Valve lever.
Air-valve cam.
Exhaust-valve cam.
Cam rollers.
Lever fulcrum.
Lever-fulcrum pin.
Air-valve lever.
Exhaust-valve lever.
Cam shifter.
Locking handle.
Air-exhaust valve box.
Air-exhaust valve-box cover.
Air-exhaust valve spring.
Air valve.
Exhaust valve.
Cylinder lubricator.
Cylinder-lubricator cover.
Cylinder-lubricator pulley.
Fly wheel.
Fly-wheel key guard.
27a. Cylinder End Projection.
32
HANDBOOK FOR ELECTRICIANS.
THE HORNSBY-AKKOYD OIL ENGINE.
33
34
HANDBOOK FOR ELECTRICIANS.
3. The oil pump (fig. 28), actuated by the same lever as the air-inlet valve
(fig. 30), performs the double office of suction on the upstroke and of forcing on
the downstroke. The suction as well as the forcing side has two check valves
in series for certainty of action. On the downstroke oil is forced direct to the
valve box.
4. Valve box (fig. 29). — Here are two valves, the "horizontal" or check valve
for keeping the oil from flowing back and preventing the possibility of prema-
ture explosion, and the "vertical" or by -pass valve for regulation.
2
(L OVtRFLOW
TO TANK
H OR. VALVE
28 Oil Pumn ^^' ^^eck and By=Pass Valve Box.
5. The regulation of the engine is effected by altering the supply of oil in two
ways: first, by changing the length of stroke of the pump, i. e., the oil supply,
and, second, automatically by a sensitive ball governor which opens the by-pass
valve in the valve box, and deflects a portion or all of the oil jet from the vapor-
izer through the overflow outlet back to the tank. During the piston's first or
suction stroke the pump injects the oil (opening the ' ' horizontal valve " ) through
the spray nipples (see "oil jet," fig. 29) into the vaporizer ; but if the by-pass valve
is partially or wholly depressed at this time, part or all of the oil will overflow.
6. The air-inlet and the exhaust-poppet valves (fig. 30) close at the proper
times the exhaust chamber to their respective pipes. Always under the tension
DA M P £R
30. Exhaust=Chamber Side of Engine.
THE HORNSBY-AKROYD OIL ENGINE.
35
of springs tliey are actuated by levers moved by cams on the auxiliary shaft.
Through the port (marked in the figure) leading from the exhaust chamber to the
rear interior of the cylinder, the air passes on
its way in and the exhaust products on their
way out.
8. Fig. 30a gives the crank positions at the
instants when the poppet valves open and close.
The air valve closes just after the crank has
passed out-center. The exhaust valve opens at
about 85 per cent of full stroke and closes just
after the air valve has opened.
9. The piston (fig. 21b) should make a good
fit top and bottom, and not rub hard on the
sides, as ascertained by inspection and turning
the fly wheel. The three or five rings break-
ing joints on the underside must not leak. Their
close fit and the good ll^brication of the piston
are absolutely essential. Mechanical or sight
feed lubricator is always used.
(B) ENGII^E-ROOM INSTRUCTIONS.
STARTING.
1. Before starting see that oil and water tanks (fig. 31) are full, and that the
three cocks w^hich supply water to the water jackets are fully open.
2. Heating the vaporizer.— Fill the lamp with oil outside of the engine room,
to avoid smoke, and put a piece of wick into the cups which are formed round
the pipes. These wicks which should consist of a piece of ordinary asbestos
packing, will last for several weeks.
30a.
WATER
COOLING
TANK
Water-Cooling Connections.
A little kerosene should then be poured into the cup under the coil and lighted.
When this is nearly burnt out, pump up the reservoir with air by the air pump,
when oil vapor will issue from the small nozzle and give a clear flame. Then
place the lamp on the stand so that the coil is one-half inch from the vaporizer.
Turn the damper for draft.
When it is required to stop the lamp, turn the little thumbscrew on the reser-
voir-filling nozzle, and let the air out. Should at any time the nozzle, where
36
HANDBOOK FOR ELECTRICIANS.
the vapor comes out, get choked up, it can be cleaned with the small prickers
which are sent for that purpose.
The heating up of the vaporizer is one of the most important things to be
attended to, and care must be taken that it is made hot enough at starting.
The attendant must see that the lamp is burning properly, and that a good clear
flame is given ofif from five to ten minutes according to the size of the engine.
If, however, the lamp is burning badly, it may take longer to get up the proper
heat. It is most important that this should be carefully attended to, as, though
the engine may start if the vaporizer is not as hot as it ought to be, the engine
will run badly, and perhaps soon stop altogether. Failure to get engines to run
properly can in most cases be traced to the above.
If the vaporizer is' partly jacketed, close the valve on the inlet water pipe
before heating up, and open or partially open while running.
3. Oiling. — See that the oil cups on the two main crank-shaft bearings are fitted
with proper wicks and filled with oil. Adjust the lubricator of the large end
of the connecting rod and oil the small one which is inside — also the bearings
on horizontal shaft and the skew gearing — the rollers at the ends of the
valve levers and their pins, and the pins on which
the levers rock— the governor spindle and joints,
the bevel wheels which drive same, and the joints
that connect the governor to the small relief valve
on the vaporizer— twenty places in all. For such
bearings none but the best engine oil should be
used. Oiling should always be done during heating
up the vaporizer, and the lamp should be left burn-
ing for a few minutes after starting.
4. To start. — Turn the small regulator on the
governor bracket (fig. 276) to position "Shut," and
work the pump lever up and down until oil is seen
to freely pass the overflow glass. Then turn the
small regulator to position ' ' Open, " work the pump
lever up and down again one or two strokes, then
give the fly wheel one or two smart turns, when
the engine will start readily. The engine will
often start better by first turning the fly wheel the
reverse way, when an explosion will sometimes be
obtained which will start the engine, and in any
case the rebound thus obtained from the com-
pressed air will help the fly wheel to be tiirned forward more easily.
The handle upon the cam shaft, before starting engine, must be ijlaced in the
position marked "To start, "in order to relieve a part of the "compression,"
and immediately the engine has got up sufficient speed to affect the four cycles
this handle should be placed in position marked ' ' To work. "
No time should be lost in starting the engine after the vaporizer has been
sufficiently heated, as the engine will not run satisfactorily if the vaporizer is
allowed to cool down after heating it. If too much oil is pumped into vaporizer
it will be difficult to start up.
Starting gear is not necessarily required except for the larger engines, say
35-horsepower and upwards ; 35-horsepower engines can, however, be started by
two men. Release the air from the lamp directly the engine starts.
In turning over the fly wheel there is a certain knack by which a skillful
engineer exerts his force only once or twice, and usually on a certain one of the
spokes ; it is the one which he reaches by stooping down to effect the compres-
sion. If the engine starts in the wrong direction it will generally reverse itself
after a few turns, when give it assistance. To avoid accident, never put a foot
or a leg on a spoke to assist in starting.
5. Failure to start is generally due to vaporizer not being hot enough (barely
perceptible red in the dark). If the oil tank is full, if piston is clean, and if
reheating the vaporizer again fails, examine the engine :
(a) Oil piiftnp. — Turn the regulator to "Shut" and work the pump by hand as
in starting to see if a full stream of oil free from air, passes the glass as it
should do.
(t») If the stream is not a full one, open the three-way cock from oil reservoir;
if oil flows oxit freely the filter is in order. If not, clean it.
(c) If the pump is still un.satisfactory, see if air is in the pump or pipes by
disconnecting the oil-supply pipe from the vaporizer valve box, pumping until
oil overflows, then pressing left thumb tightly over outlet, pump down once
quickly. If the pump plunger yields, air is in the pipes. Or, pump several times
32.
THE HORNSBY-AKROYD OIL ENGINE.
quickly and then remove the thumb suddenly ; if air is in the pipes, its elastic
force will cause a long jet (fig. 32a).
(d) If there is no air in the pipes, inspect the action of the valves by pressing
the pump steadily down while closing the outlet with the thumb. If the plunger
yields under a steady pressure but not under a sudden jerk, the suction valves
are not tight. To stop leakage , wash out valve
hoxes with oil ; if this fails, tap the steel ball
valves on their seats with a copper punch.
(e) To examine the vaporizer valve box,
take it off, reconnect it with its pipe, stroke
the pump as in regular working and observe
the jet. If the jet is full, positive and clear,
and begins with the downstroke and does
not dribble after the the end of it, the jet is
normal — a very important condition. Watch
the effect of partially and wholly depressing
the vertical valve while pumping.
RUNNING.
32a. Pump Detached.
(a) Good action requires three things —
(1) Oil and air delivered to vaporizer in
right amounts at the right time.
(2) Sufficient compression of the mixture before ignition.
(3) Ignition of gas complete at the proper time.
(b) Regulation. — (1) When the engine is working at its full power, the dis-
tance between the two round flanges on the pump plunger (fig. 28) shoiild be
such that the hand gauge will allow the part stamped " 1 " to just fit in between
the flanges ; and if at any time the positions of these flanges be altered, they can
always be readjusted to this gauge. The other lengths on the hand gauge are
usefiTl for adjusting the pump to economize oil when running on a medium
load " 2 " or a light load " 3 " of the gauge. Still, familiarity with an engine is
hetter than the gauge for regulation. If overflows show of tener than once in
5 or 6 strokes, the pump stroke may be shortened.
32b. Qovemor With Overflow Glass.
(2) The governor (fig. 325) is adjusted to reduce the oil jet occasionally. At
normal speed it revolves about i inch clear of its seat. When it runs too fast
its connecting mechanism depresses the vertical valve and diverts more or less
oil to the overflow. Moving the weight out from the fulcrum slows the gov-
ernor's action. " Governor lum ting, " causing the engine to run unsteadily, is
due to joints or spindle becoming bent, dirty or sticky.
When engines are required to run empty or light, it is best to alter the stroke
of the pump to just the amount of oil that will keep the engine running, and
can even be reduced so that the speed of the engine is a few revolutions under
the usual speed (so that the governor can not cut out any oil, which allows the
vaporizer to get a small charge of oil each time), and thus keep it from getting
cooled down. Also the cock on the return or lower water circulating pipe and
38
HANDBOOK FOR ELECTRICIANS.
32c.
the cylinder jacket can be nearly closed, so as to keep the cylinder warmer.
The above remarks do not apply when the work is intermittent, and the engine
is not running light very long together.
(c) In the valve box Ctigs. 27i^, 29). if the horizontal valve is not working prop-
erly, vapor from explosion will be found passing the overflow glass whenever the
little lever or the finger presses down the vertical valve. Unscrew the cap and
turn the valve by its tail arovmd to dislodge any dirt in the seat of the valve,
and see that the spring is closing the valve. If this does not stop leaking, take
Gilt the valve, ground it on its seat with a little emery flour and water, and
take care in replacing valve and sleeve to preserve the same thickness of jointing
material, and hence same valve opening.
(d) The spray hole or holes (figs. 276 and 29) are liable to get clogged. The
valve box is taken off and each hole is cleared by the little wires supplied for the
purpose, so as not to increase the size.
(e) If the pipe to the vaporizer valve box does not rise all the way from the
piimp, or if it gets bent down, an air pocket will be formed in which air will be
compressed upon each stroke of the pump, and thus allow the oil to go in slowly
and not, as it should do, suddenly. Also if the oil tank gets emptied of oil at
any time, air will get into the suction
and delivery pipes of pvimp, and it will
take some time before the oil going through
the punap and pipes will get rid of this air,
so that for a while the engine would not
work properly, as the air, by getting com-
pressed as the pump works, will interfere
with the oil being pumped in suddenly, as
it should be. It is best, if ever the oil get&
below the filter in the tank, to work the
pump by hand for say ten miniites, hold-
ing open the relief valve on the vaporizer
valve box so as to get air well out of the
pipes. Derangement of the pump rarely
occurs. If the packing is renewed it should not be screwed so tight as to bind
the plunger.
(/ ) The air inlet and exhaust poppet valves (fig. 32c) must always work freely
and definitely and drop on to their seats. They can at any time, if required, be
made tight by grinding in with a little flour of emery and water. The set screws
(fig. 32cZ) at the ends of the levers that open these valves must not be screwed up
so high that the valves can not close ; this can always be ascertained by seeing
that the rollers at the other end of the levers are just clear of the cams, that is,
when the projecting part of the cams is not touching them.
ig) Cylinder's proper temperature lies between 110° and 130° F. The cooling
tank is kept full of fresh water below 130° F. If the temperature tends to rise
above this, cold water must be added, or a
pump capable of delivering 10 gallons per hour
per horsepower of engine is connected with
the shaft to maintain from another soiirce cir-
culation around the cylinder. If a cheap sup-
ply under pressure is available, use it. If the
supply is above 70° F., as at many southern
posts, much more water will be necessary.
Sea water, if unavoidable and if circiilated
rapidly, can be used, but the water jacket
should be watched for deposits.
(/;) If the piston gets black and gummy, or
the exhaust gases are like smokC; or "cough-
ing" is continuous, combustion is incomplete, due chiefly to excess of oil or too
little air, or possibly to leakage over the piston rings.
{i) Ignition can be retarded by lessening the vaporizer's heat and slightly
reducing compression by increasing the clearance in the cylinder. In starting
or on light loads the water inlet to valve box may be partly or wholly closed ta
preserve the vaporizer's temperature.
ij) Heat in exhaust and vaporizer valve boxes sometimes causes the valves
not to seat or their stems to stick, and necessitates regrounding.
(k) If a little oil is sent into the heated vaporizer and the fly wheel is turned
forward, the engine should start freely. If not, test the spray by hand and turn
the fly wheel backward to test the compression. If this pressure is so slight
32d.
THE HORNSBY-AKROYD OIL ENGINE.
39
(the relief cam being out of action) that it can be overcome by hand, there is
leakage in the piston rings, the air or exhaust valve or some joint or gasket.
(l) Watch the temperatures and oiling of bearings, especially of the cylinder ;
use just enough oil for the load and listen for regular action after fifteen min-
utes' run ; keep every part clean.
(m) For subsequent reference in time of trouble, mark on the gearing or record
when engine rims well, the exact positions of crank when the poppet valves open
and close and for load and half load, or the usual load after an hour's satisfac-
tory run, the motion of pump stroke, heat of outlet water, frequency of oil over-
floAV, governor's rise, vaporizer's color in the dark, appearance of exhaust and
piston.
(n) The engine is working efficiently if, after getting warmed up, it runs on
its load smoothly to the eye and ear. if the piston shows no carbon deposit, if
the exhaust gases are invisible or nearly so, and if the explosions sound regu-
larly, except occasionally when the governor reduces the explosive charge.
33.
STOPPING.
(a) Turn the small regulator on the governor bracket to position marked
"Shut." To stop quickly, hold down the air- valve lever at the same time.
If the engine does not then stop readily, the spring of the horizontal check
valve is weak and oil is entering the vaporizer instead of all coming through
the overflow valve, as it should at "Shut." If the stop is for a brief period, but
more than five minutes, it will be necessary to start the lamp under the vaporizer.
(b) In frosty weather do not omit,
before leaving the engine, to run all
water out of the pipes and water jackets
by first closing the main water-pii^e cock
and opening the floor cock. The small
water cocks to the valve-box water jacket
are usually left open.
Fundamental Alterations. — (a) If
air or exhaust valves appear to be open-
ing or closing at the wrong time, take
off the nut on the end of the lay shaft
which holds the skew when on, and see
that the chisel cuts on the shaft and on
the skew wheel are opposite to one an-
other, as shown in fig. 33. The lay
shaft is coned where the skew wheel is
fixed, and is held on simply by fric-
tion, the nut being tightened against it.
Should it at any time be necessary to
take out the crank shaft, always be sure
that the skew wheel gearing is put
together so that the tooth marked O
on the crank-shaft skew wheel fits in
between the two teeth marked O on the lay-shaft skew wheel, as shown on the
sketch (fig. 33).
(6) To reverse the direction of rotation, exchange the relative positions of the
cams actuating the air and exhaust valves and the fuel supply.
33a. Belt Pulls on Lower Run.
40
HANDBOOK FOR ELECTRICIANS.
THE HORNSBY-AKROYD OIL ENGINE.
41
Fig. 33a gives also the positions of the crank at the moments when the air and
exhaust valves open and close.
The pressure in the cylinder during four consecutive strokes and the impor-
tant action of valves and other parts and the time of ignition during a run,
can best be seen by means of cards taken with
the Crosby or other indicator (fig. 34). If these
show faults, adjustments may be made to correct
them. Unless the indicator is properly set, its
drawing will be misleading. The cut shows its
attachment to the engine and the means for get-
ting the brake horsepower and the amount of oil
consumed.
All cylinders are tapped for indicator tests.
The operation is similar to that for steam engines
and the importance of getting a correct card is
even more important.
In the A card ignition took place slightly before
the piston reached the end of its stroke, and the
pressure during the first third of the expansion
stroke fell off too rapidly. The exhaust was not
free and the compression was too great.
Diagram B shows good action on a load. The
ignition line should be nearly perpendicular to the
atmospheric. The exhaust opened at 90 per cent
of the full stroke, and the pressure during exhaust
and suction was 0. There is good area between
the expansion and compression lines, and all lines
show steadiness.
In the third card C the suction line below the
atmosphere indicates that the inlet of air was
hindered. The low compression line points to
leakage past the poppet valves, oil inlet, or
piston. From the waving in the lines and short-
ness of figure, the indicator may not be in proper
order.
In the D card the events are lettered in the
order of occurrence. The exhaust was choked,
and ignition took place too early. Compression ^
began too soon and became too great.
Full directions for erecting, testing, installing, running, and repairing this
remarkable engine will be found in G-oldingham's "Oil Engines," from which
the above cuts are taken.
IV.— THE DYNAMO.
(A) ge?^:eiiat. PRIN^CIPLES.
Magnetic Wind From
N. to S. Pole.
The short exploring magnetic needle will show that the space, or field, between
the poles of a horseshoe magnet has the strongest magnetic force and that the
imaginary lii:es therein which represent the direction and intensity of the force,
are approximately straight, parallel and uniformly distributed (fig. 35).
I. Laws of the induction of an electromotive force in a loop are as follows :
1. Induction. — An E. M. F. is induced or generated in a
coil whenever the number of lines of magnetic force
through it is changing — either increasing or decreasing —
by the motion of the coil or lines, or both.
2. Direction. — Its direction is clockwise when the num-
ber of lines through the coil is decreasing and contra-
clockwise when increasing — this to a person looking at
the coil from the side on which the lines enter it.
3. The amount of induced E. M. F. varies directly -with
the time rate (i. e. , the rapidity) of change of the num-
ber of lines inclosed by the coil.
II. Or, the laws may be otherwise stated for any
straight conductor as, for instance, any short length of
a loop :
1. An E. M. F. is induced in any conductor while it is
cutting across lines of magnetic force, by the motion of
the conductor or of the lines or of both.
2. Hold thumb, forefinger and middle finger of the
right hand, each at right angles to the other two. If the
middle finger represents the conductor, if
the forefinger points in the direction of
the lines of (fore) force, and if the thumb
points in the direction the conductor
moves, the middle finger will point in
the direction of the induced E. M. F.
3. The amount of E. M. F. induced varies
directly with the time rate (or rapidity)
with which the number of lines of force
is cut.
III. An alternating current is usually
generated in a revolving loop. The nega-
tive part can be rectified in the outer
circuit.
1. It follows from either set of the above laws that if the coil in fig. 37 revolves
uniformly as the brushes point, and if the external circuit is closed, (1) a current
will be generated in the coil due to the induced E.
(2) Its direction, during the entire half revolution of
which the coil's position is shown in the figure mid-
way, will be toward the brush marked -f ; in the
next half revolution, to the other half. (3) The
current strengths will be great-
est at both vertical positions,
and at both horizontals, where
their direction is revei-sed.
2. The current, or the E.M.F.,
induced during little more than
one revolution, is expressed by
the curve in fig. 38. That part of the curve below the reference line represents
the negative C generated.
3. The negative C may be rectified, i. e. , so turned as to go to line as a positive
C, by the device of a 2-part commutator (fig. 39) in place of the two rings of
(42)
The Three Positive Directions at
Right Angles.
37. Simple A. C. Dynamo.
THE DYNAMO.
43
fig. 37. The two parts of the commutator are the terminals of the coil, and
so disposed that each brush shall pass from one jjart to the other at the instant
the induced current changes or is zero. This is the simplest form of a direct
current, self -exciting dynamo, such as the fuse-
firing dynamo.
4. The current thus sent to the field and the
external circuit consists of positive pulsations or
waves, shown in fig. 40.
5. In order to render the
positive waves less abrupt,
that is, to make the dynamo
current more nearly like a
battery current represented
by the broken line in fig. 40, it is only necessary to
increase the number of armature coils and of com-
mutator strips.
6. Principle of self-exciting dynamos
39. Simple D. C. Dynamo.
There is
usually suflBicient liiagnetism in the field of the
soft-iron field magnet core to give rise to a small
current in the armature coil when revolved. This current flowing, wholly or in
part, through the winding of the field magnet, increases its magnetism and
therefore the number of lines of force in the field between the poles. The cur-
rent in the armature coil thereby is increased, and so the operation continues
mtil the magnet is saturated and the dynamo gives its fiill current.
IV. The two principal armature windings are the ring and drum.
1. Fig. 41 is a 2-pole, 4-coil, ring, vsdnd-
ing around core of annealed soft iron
wires or washers. Two circuits be-
tween brushes. Nearly all cores, ring
or drum, are now made from soft-iron
sheet in washer shape.
Fig. 42 is a 2-pole, 4-coil, drum, lap
winding over annealed soft-iron wash-
ers starting from 1. Coil a b is firsi
wound, then c d, e f, g h in order.
Back pitch, + 3; front intch, — 2.
43.
44.
Fig. 43 is a 2-pole, 8-coil, ring wind-
ing. Arrows show direction of cur-
rents.
Fig. 44 is a 2-pole, 8-coil, lap, drum
winding. Back pitch, -|- 7 ; front pitch,
— 5.
u
HANDBOOK FOK ELECTRICIANS.
Fig. 45 is a 4-pole, 20-coil, ring, four
windings through armature, making
its resistance between poles = ^V of
that of the single winding. By con-
necting each bar of the commutator
with the one opposite, two brushes
90° apart will be sufficient.
Fig. 46 is a 4-pole, 17-coil, wave, drum
winding. Back pitch, 9 ; front pitch. 9.
Two circuits between brushes. Short
lines having arrowheads represent
wires along the length of the cylinder ;
outside wires are back connections,
inside wires, front connections.
2. An armature winding is more readily followed by considering the wires,
bars and poles rolled out upon a plane surface as in fig. 47, for the armature
shown in fig. 48. Or, iipon paper, draw rectangles to represent all poles, in a
parallel row show all of the bars, and then draw single lines from the bars to
represent the coils as they are foiind on the cylinder in one position.
48. Drum Wave Winding — 4=Pole.
Drum Wave Rolled Out.
3. The features of recent slow speed armatures are—
(a) The core is composed of japanned washer-
shaped discs stamped out of sheet iron and solidly
assembled on a spider (fig. 52). Air ventilating
ducts run radially and longitudinally through the
core, and deep slots in which the coils are to be laid
run longitudinally along the cylinder surface.
(b) The copper coils (figs. 51 and 53) are forged or
formed on a collapsible block, then covered with tough
and moisture-proof insulation and laid in lap form
(fig. 50), or in wave form (fig. 52) in the slots between
the teeth of the cylinder core where they are so firmly
wedged by fiber and bound by band wires that no part
can vibrate.
(c) Opposite active parts of the same coil occupy as
nearly as possible corresponding positions (figs. 50 and
52) under the poles. Ends of coils are mechanically
fastened and soldered to their proper bars so that open
circuit may not occur. Back and front wires are
eqiaal. The air space is everywhere the same and the
pull of all field magnets, alike. This method of wiring
requires a minimum of length and allows any injured
SI. One Lap Coil. coil to be easily replaced.
49. W=e M. P. Generator Armature, with Winding Unfinished.
50. G. E. Core. Lap Winding Begun.
44
THE DYNAMO.
45
(d) The bars of the commutator (fig. 54), of H. D. copper insulated by amber-
colored mica, are sufficient in number to keep the P. D. between any two adjacent,
below 10 volts.
(e) The bearings (fig. 55) are self -aligning, also self -oiling by means of revolv-
ing rings on the shaft.
OuCer- nnics cor-ie&
Inner- mica cones
-mica collar- oncJen seo^nenLs —
Clampini^ r-in<5
• Cap
54. General Electric Commutator.
v. Field unndings. — There are five methods of exciting the magnet which
in turn render magnetic the space or field in which the armature coils revolve :
Permanent Magnets (fig. 60), Separately Excited (fig. 56), Series (fig. 57), Shunt
(fig. 58), and Compound "Winding (fig. 59).
^ ^ W
56.
57.
58.
59.
46
HANDBOOK FOR ELECTRICIANS.
The series winding is regulated by varying the "resistance of a coil in shunt
to it. The shunt winding is regulated by varying the resistance of a coil in
series with it. The compound winding uses both methods of regulation.
(B) SPECIAI. SERVICE GENERATORS.
I. The telephone call box dynamo (fig. 60) has
three permanent magnets 31 to create its field.
The single Siemens armature coil C, of fine wire,
has one end fastened to the soft-iron core at a and
the other end to the insulated pin c. The alter-
nating current generated passes out through c to
a spring in contact with it and returns through
frame and bearing to a.
II. United States fuse-firing dynamo (fig. 61)
is series wound, self -exciting. The Siemens
armature coil is revolved eight times by means
of its pinion gearing into the ratchet bar B when
pushed down. At the end of the stroke the bar
strikes and opens the short-circuiting key P and
allows the full current to rush into the external
circuit. No. 3 (16 by 8 by 5 inches) weighing
18 pounds, has 0.05-inch wire in magnet (If ohms),
and 0.032-inch wire in armature (0.9 ohms),
develops 15 volts and will fire eight fuses in
series.
C'=15-^ (3.7 + i2).
-^
■.rsTL
— ^
61. Dynamo for Firing Fuses. Second View of Circuits.
Ill — General Electric Direct-Coupled G-enerating Sets.
1 . Foundations — Installing. — The generating set (fig. 62) should be provided with
a foundation of ample proportions and mass to absorb the vibrations produced
by the reciprocating parts of the engine. When placed upon a good foundation,
the set will give the best results, require the least amount of attention, the bear-
ings will run perfectly cool with a small amount of oil, and, in general, operating
expenses will be reduced to a minimum.
63. Governor.
THE DYNAMO.
47
The engines should run without perceptible vibration or noise if properly
installed and given a reasonable amount of attention. When a generating set
is installed in a building for isolated liglit or power, care should be taken to
avoid having the engine foundation connected in any way to the foundation
of the building or its adjacent walls. Pipes leading to the engine should also
be as free as possible from connection to walls. A wooden base frame is some-
times found desirable under the generating set when installed in a building, as
it will, to a large extent, prevent the transmission of noise and vibration.
2. Steam. 2>ipes, lyressare and speed. — Sharp bends in the steam and exhaust
pipes should be avoided as much as possible, and the steam pipe should be
covered with good nonconducting material. A drain pipe with valve should
be provided just above the throttle valve in order to drain the pipe line of con-
densed water. A separator should be installed on the steam pipe close to the
engine, to protect it from water that is occasionally cari'ied over with the
steam. Often considerable trouble is experienced ^vith foaming boilers, and
62.
M. P. 6=20=305=125. Form of O. E. Generating Set, with Single
1 1 by 8 inch Cylinder.
accidents are liable to happen if no separator is used. When the engines are run
noncondensing, a drain pipe ^ inch to | inch in diameter, depending upon the
size of the engine, should be placed at the lowest point of the exhaust pipe.
3. The engine. — (a) The engine and generator are tested for several hours
with the full rated output of tlie generator, and the engine is regulated to the
proper speed, which is stamped on the name-plate. The valves of single engines
are set to operate economically at a steam pressure of 80 pounds, and the ratings
of single engines are based on 80 pounds steam pressure, noncondensing. Ver-
tical tandem compound engines (fig. 73) are adjusted to operate at 125 pounds
steam pressure, condensing, or 140 pounds noncondensing, and the sets are rated
on this basis. Both single and compound engines give the best results when
operated at their rated pressures, and if an engine is desired to run at a steam
pressure lower than standard, it may be necessary to adjust the governor (fig. 63)
by tightening the spring until the rated speed is obtained. Single engines may
be run on a steam pressure up to 100 pounds without difficulty, but for higher
pressures use reducing valves.
48
HANDBOOK FOR ELECTRICIANS.
(b) If the speed of the engine is unsteady, the cause is probably sticking of
the valve or parts of the governor, or loose connections in the valve motion.
The governor should be taken apart, bearings thoroughly cleaned, and the lubri-
cant removed. Only the best quality of thin grease — mixed with cylinder oil if
desired — should be used in the governor.
64. Piston Rod and Crosshead.
65. Governor Connecting Rod.
66. Piston Valve— 20 KW. and Over.
67. Piston Valve— Below 20 KW.
(c) The governor (fig. 63) has few moving parts and minimum friction. As
the load is decreased, the fly weight, by increased centrifugal force, is moved
out and the eccentric pin (seen near the center hole of the fly wheel) is moved
toward the center of the shaft. This reduces the throw of the valve, changes
the steam admission and compression to suit the load, and preserves the engine
speed wnthin small limits.
The governor can change the cut-off from f to 0, and the speed can be changed
within certain limits by tightening or loosening the spring. It will not allow,
with 80 pounds steam, a variation exceeding 21 per cent in the number of its
revolutions for a change from full load to one-fifth of the same ; nor exceeding
3i per cent for a change from 80 to 100 pounds pressure ; nor exceeding 5 per
cent for both changes.
THE DYNAMO.
49
(d) The relief valves for taking care of the water that enters the cylinder
should be adjusted for the working pressure at the engine, and should open freely
at a pressure 5 pounds greater.
(e) If any valves leak, they should be taken out and cleaned, and the seats
reground. The leak shoiild not be stopped by increasing the pressure on the
valves.
(/) The engine will run without noise, A'ibration or heating in any of ito parts
when given proper care and attention. All working surfaces are liberally pro-
portioned, and wear is very slight, but as soon as any loss motion appears, it
should be immediately taken iip by the adjustment provided for that jKirpose.
Use only Garlock square or other iirst-class packing, and the best quality of
cvlinder oil.
Counter^C'ockwise Rotation. 69. Engine Side.
4. The generator — (o) To place the sjjools. — Observer is supposed to be inside
of frame and looking at faces of two lower pole pieces. Large arrow indicates
direction of rotation of lower half of armature. Small arrows correspond to
arrows on spool flanges, the spools being so placed that the arrows point in oppo-
site directions on each sxicceeding spool. Arrows on bearings must point in
direction of rotation.
(b) To adjust the compounding. — Every compound generator is provided
with a shunt consisting of strips of German silver with suitable terminals
attached, which should be connected to the series field terminals on the right-
hand side facing the commutator (fig. 68). Any degree of compounding ui) to
70. Freeing the Pigtail from the Brush Holder.
60
HANDBOOK FOR ELECTRICIANS.
10 per cent may be obtained by changing the length of this shunt. The arma-
ture and field coils are, during winding, subjected to an insulation test with a
voltage many times higher than the normal and their resistance is watched to
locate short or open circuits.
(c) To set the. brushes, place the brush holder on the studs so that the boxes
A (see fig. 70) which hold the brushes, shall be about i inch from the surface
of the commutator, aiid clamp them firmly in this position. From time to
time the brush holder should be turned slightly on the studs to compensate for
the wear of the commutator.
Place the brushes in the holders, as sho-v\ai in fig. 71, and screw down the
pressure spring B by turning the nut C, so as to give about H pounds pressure
for l^-inch brushes and f pound for finch brushes. Nothing is gained by
increasing the pressure per square inch on a carbon brush above 2 pounds, as
the resistance per square inch beyond this point is practically not reduced,
whereas, the friction is increased in direct proportion to the pressure.
Fit the carbon brushes carefully to the commutator by passing beneath them
No. sandpaper, the rough side against the brush and the smooth side held
down closely against the surface of the commutator. Move the sandpaper in
the direction of rotation of the armature, and on drawing it back for the next
71. Correct Position of Brushes in Brush Holder.
cut, raise the brush so as to free it from the sandpaper, then lower the brush
and repeat the operation until a perfect fit is obtained. If the brush requires
considerable sandpapering, No. 2 sandpaper may be XTsed at first, but the final
fitting must be done with No. 0. If an attempt be made to fit the brushes
without raising them when drawing the sandpaper back, it will in every case
fail to give satisfactory results. When thick brushes are used — say f-inch — in
addition to following the above instructions, the machine should be run as long
as convenient, without load in order to improve their surface. As soon as the
brushes of a set ai)pear to make a good fit one of them should be removed from
the brush holders in the following manner, to determine if they are worn to a
surface :
Unscrew the stud D, thereby freeing the end of the pigtail E, and push the
spi-ing B forward so that there will be plenty of room to draw the tip E on the
end of the pigtail through the slot F (see fig. 70). Then draw the pigtail
through the slot F, bend it forward and turn the spring B to one side as showna
in fig. 72. The brush may then be withdrawn from the box. In replacing the
brush these directions should be followed in reverse order.
Care should be taken not to disturb the nut C after it has once been set, as it
is not necessary to alter the pressure of the spring B in remo^dng or replacing a
brush. By this means a practically constant pressure may be kept on the brush.
(d) To adjust the brush yoke. — The design of these machines is such that no
movement of the brushes is necessary when load is thrown off or on. The
brushes should be set at no load, so that the reference mark on the pedestal is
in line with the reference mark on the brush-holder yoke. With the brushes in
this position generators will compound according to the name-plate stamping.
(e) To take care of comviutator.— The commutator, brushes and brush holders
should at all times be kept perfectly clean and free from carbon or other
73. Small Direct=Coupled M. P. 6=25=450, with Vertical Tandem
Compound Engine. 50
THE DYNAMO.
51
dust. Wipe the commutator from time to time with a piece of canvas, lightly
coated. with vaseline. If vaseline is not at hand, use oil, but lubricant of any
kind should be applied very sparingly.
If a commutator when set up begins to give trouble by roughness with
attendant sparking and excessive heating, it is necessary to immediately take
measures to smooth the surface. Any delay will aggravate the trouble and
eventually cause high temperatures, throwing of solder and possibly displace-
ment of the segments. No. sandpaper fitted to a segment of wood with a
radius equal to that of the commutator, if applied in time to the surface when
running at full speed (and if possible, with brushes raised), and kept moving
laterally back and forth on the commutator, will usually remedy the fault. If
this does not suffice, it will then be necessary to tighten up the segments and
turn them off true. A machine tool will not leave the surface smooth enough
to give perfectly satisfactory results. It is always necessary before putting on
the load after the commutator has been turned, to carefully smooth the surface
with the finest sandpaper, thus removing all traces of the tool point.
72. The Brush Ready for Removal.
5. Starting and running the set. — (a) Before starting, see that all screws and
nuts are tight, that the oil cups are filled with oil free from dirt and grit,
and that all working parts are well oiled. The feed should then be adjusted to
give the required amount of oil to each bearing. The waste oil collects in the
base and may be used again after running through a filter with some new oil
added, but no advantage results from using too much oil. Turn the armature
by hand to see that it is free and does not rvib or bind at any point. The drain
valves on the cylinder should all be opened to allow the condensed water to
escape. Turn the steam on slowly at first, allowing the cylinder to get well
warmed up and giving the condensed water a chance to get out before turning
on full steam pressure. The piston valve will heat up as soon as the steam
enters, but the cylinder requires some time before it expands sufficiently to
allow the valve to move freely. When the engine has started, see that the oil
rings in the bearings are in motion.
(b) As soon as the machine is set running see that it excites itself to full volt-
age. If it does not, trace out the field connections and test the polarity.
When the machine is to run in parallel with others and its polarity is wrong,
raise the brushes and excite the fields by closing the main switch from the
bus bars.
(c) A continuous run of four hours on full load should not raise the tempera-
ture of an armature or field coil 60' F., or of the commutator 73° F., above the
air as determined by placing the bulb of a thermometer surrounded by waste
upon it after the machine is stopped. Directly following the above, the machine
will sustain a heat run continuously of two hours on 33 per cent above its full
rated load without injiiry to the engine or dynamo. After this run which
should only be done by an experienced person, it is a good time to make the
insulation tests and to look for mechanical defects.
(d) To remove the armature, unbolt and lift off the upper field half, take off
the brush holders, brush yoke, pulley and bearing caps, and put a sling on the
armature.
52 HANDBOOK FOR ELECTRICIANS.
(C) DISEASES OF DYNAMOS.
The DISEASES are stated in small capitals, their causes in italics ; the remedy-
follows the cause when it is not evident and not structural. Dr. F. B. Crocker
gives the following systematic statement :
I. — Sparking at the Commutator is caused by:
1. Armature carrying too much current. — Due to overload, loose connections,
reversed polarity, excessive voltage of current, short circuit or grounds in
dynamo or external circuit.
2. Brushes not at the neutral points. — Shift the rocker to a point midway of
those which give sparking.
3. Commutator rough. — Apply No. sandpaper (not emery) laid inside a
wooden form to fit the commutator, and before replacing brushes take care to
remove all traces of sand or copper dust.
4. Commutator very rough or eccentric or having a flat bar. — Turn the commu-
tator down, revolving slowly in its place ivithout i^lay, by means of a sharp-
pointed tool, and finish in turn with a smooth flat file and emery ; preferably put
armature in a lathe. A flat is often caused by an open coil.
5. A high &ar.— Tap it down and tighten up the clamping ring, or, if it can
not be done, file the bar down.
6. Brushes making bad contact. — Due to roughened or bui'ned ends, improper
bedding, to oil, carbon, dust, or to insufficient pressure.
7. A short or broken circuit in armature or field ; a reversed coil.
8. A ground in the armature. — Locate and rejilace the coil.
9. A iveak field or excessive shunt field resistance.
10. Unequal x>oles due to armature reaction being relatively too great.
11. Too high brush 7'esistance, as with certain carbons.
12. Vibration, from unbalanced armature or pulley or faulty belt.
13. Chatter of carbon brushes. — Clean commutator and apply vaseline or oil.
14. Surging current, from uncertain engine governor action.
15. Break in armature, only while running due to centrifugal force.
II. — Heating of Commutator and Brushes is caused by :
1. Heat from adjoining bearing or front armature.
2. SjJarking.
3. Black carbon film from the brushes, which offers resistance.
4. Bad connections in brush holder.
■ 5. Arcing between bars or other parts of the commutator.
6. Heating of carbon brushes from current. — Coat the carbons with copper
deposit.
III. — Heating of Armature or Field Magnet is caused by:
1. Excessive current. — Same as cause 1 of sparking.
2. Coils short-circuited permanently, or due to contact in armature only tohile
running.
3. Moisture. — Showing vapor driven off after a short run. Bake in an oven or
send full current until vapor ceases.
4. Foucaidt currents in iron core or Eddy currents in the coils, structural.
5. Reversed coils.— S>end a current through armature or field and note the
deflections of a compass needle all the way around.
6. Heat from adjacent j^arts.
IV. — Heating of Bearings is caiised by:
1. Lack of good mineral oil.
2. Grit or dirt.
8. Shaft bearing rough or cut.
4. Bearings too tight.
5. Shaft sprung, so that it turns harder at one point of a revolution.
6. Bearings out of line or proportion.
7. Side thrust of shaft against bearings.
8. Too tight belt.
9. Armature closer to one pole than to another.
10. Heat from adjacent part.
V. — Abnormal Noise is caused by:
1. Armature or pidley out of balance. Bad foundations.
2. Armature striking a pole piece ; rebabbitting, new liners, or reducing the
projecting part.
THE DYNAMO. 53
3. Side thrust of shaft due to bad alignment.
4. Rattling of loose so'eics o)' other parts.
5. Humming or squeaking of brushes. — Lift one of a set off at a time and,
when found, apply a drop or two of oil.
6. Flapping or slipping of belt, or striking of a belt joint on the pulleys. —
Tighten or loosen the belt ; never apply resin.
7. Humming of armature teeth passing the edge of pole p)ieces.
8. Straining of coupling in direct connected sets. Reline and readjust.
VI. — Speed too Low is caused by:
1. Overload.
2. Short circuit in armature.
3. Armature striking pole pieces.
4. Shaft not free to revolve.
5. Engine too slow or slipping belts.
VII. — Failure to Generate is caused by:
1. Residual magnetism too iceak, due to (a) vibration, (b) proximity of another
dynamo, (c) earth's magnetism, (d) accidental reversed current through field
coils, but not sufficient to reverse the magnetism. Send a current from a few cells
through the field coils in the proper direction.
2. Reversed conu'ections, or direction of rotation.
3. Short circuit to a shunt dynamo.
4. Field coils opposed. A compass needle will show.
5. Open circuit in dynamo, at a brush contact, switch or fuse, or in the exter-
nal circuit to a series machine.
6. Brushes not in proper position.
VIII. — Variation of Voltage is caused by:
1. Irregidar speed.
2. Lap or other bad. belt joints.
3. Short or open circuits in armature or field.
4. Incorrect connections.
5. Engine governor out of order.
(B) THE CARE A.^J) MANAGEMENT OF D. C. DYNAMOS.
It is assumed that the machinery is properly constructed and installed. The
engineer on taking charge and subsequently at intervals makes an —
1. Inspection and adjustment. — Every part of an electric plant is kept scrupu-
lously clean if well managed.
The caps of bearings are taken off : all dirt, grit and old oil are removed ; oil
passages are cleared ; the journals are examined ; the caps are screwed back with-
out binding ; the boxes are filled with the best mineral oil.
The armature, rotated by hand, is examined for injured insulation, a bulge,
loose coil or binding wire, contact with pole piece, unequal distance between
armature and pole pieces due to wear or bent axle, contact between lug, tendency
to stop in the same place.
A good commutator is cylindrical, smooth, and clean, and has a dark-brown
polished appearance. A high bar must be tiled down. For a low bar or flat,
the whole commutator must be turned down. A rough surface from excessive
sparking can be smoothed by fine sandjiaper (not emery) laid inside a wooden
form cut out to fit the cylinder which, after the brushes are raised, is given a
slow speed ; before letting down the brushes, make sure that no metal dust or
filings lie in the insulation between the bars. If the commutator has worn
eccentric or in ruts, it must be turned down by a tool on a sliding rest fastened
to the bed.
The brushes, copper or carbon, with ends alike beveled and evenly bedded on
the commutator, should set with tips exactly 180 degrees apart in 2-pole machines,
90 degrees in 4-pole, etc. , in j)erf ect alignment and at equal lengths from each
rocker arm along which the brushes are, as a rule, unevenly spaced so that the
wear on the whole commutator will l>e as nearly uniform as possible. In the
absence of setting marks, adjust the tips of one set of brushes carefully to the
edge of a bar and count the bars for the exact position of the other set.
The brush springs are next adjusted to a uniform, light, yet reliable, contact
sufficient to take the full current without sparking. Too great pressure will
soon wear and heat the commutator and cause sparking ; too light pressure will
54
HANDBOOK FOR ELECTRICIANS.
cause vibration, sparking and heating. Pressure of carbons seldom exceed 1
pound per square inch of contact surface and is usually less ; of copper brushes,
is much less.
See that the rocker can with steady force be moved over its range, can be locked
in any position, and that no side play of it disturbs the bedding of the briishes.
Oil, water, grit or dust on any conductor insulation or part of the machine,
a wrong or a bad connection, an unsoldered joint, a loose nut or bolt, or a tin
oil can, tool, or loose iron near the machine will be quickly detected by a capable
engineer and removed.
Dynamos usually run counter clockwise to a person at the commutator end.
To reverse the rotation, shift the positive brush with its connections 'to the posi-
tion of the negative, likewise shifted. To reverse the current, exchange the
leads or reverse the polarity,
A belt should be heavy, single, or link, ^-inch narrower than pulley, without
lace or lap, and just tight enough to prevent slipping. The pull is always on
the lower run. It remains on the pulleys in intervals between daily runs of the
dynamo slid back 6 inches.
N and S are labeled or marked by the engineer on magnets ; -r and — , on
terminals; "on "and "off," on rheostats; initial letters of connections, on volt-
meter switch points ; currents on feeders, etc. , for his aid in case of trouble.
The inspection extends also to a run of the plant.
STARTING.
2. See that all parts, screws, and nuts are tight; turn the armature by hand
to see that it is free and does not rub or bind; put on the belt, tightening
gradually after starting. Note that the main switch to line is open for shunt
or compound machines and closed for a series ; that the field rheostat is open
and the V. switch is turned to dynamo + and — ; fill oil reservoirs and start
lubricators if sight feed; start the machine very slowly, noting that the oil
rings turn and belt runs smoothly ; bring it gradually to full speed ; drop the
brushes down if not there permanently ; close field rheostat and, cut out resist-
ance for a gradual rise of potential, as shown by the voltmeter or pilot lamp,
to the proper limit ; stand ready to stop if anything goes wrong ; shift the brushes
at the first sign of sparking.
To light lamps raise the dynamo to its voltage and close in order and deliber-
ately the overload, main, and feeder switches, watching the ammeters whose
deflections should be anticipated. Of the feeders, close smaller first, if there is
a choice, to increase the load as steadily as possible.
Before closing a feeder on a storage battery, find the battery's voltage and
make sure that the voltage of the dynamo is 5 to 10 volts greater, while at the
same time the lamps are kept at their normal voltage by the heavy current
regulator.
A new or a repaired machine is first run empty, or on light load several hours
with slack belt and plenty of oil.
If two compoiind machines are in parallel (fig. 75), start and close one on the
main circuit as above ; bring the other to normal speed ; close its field rheostat
Switch or Rheostat
to excite its shunt field ; next close equalizing switch and regulate with shunt
field rheostat to the potential of the first machine; then close main switch.
Ammeters will show if either is doing its share of the work. To stop, reverse
the above steps.
THE DYNAMO. 55
RUNNING.
3. A dynamo properly started and subsequently watched requires little care.
Any trouble should be detected at its beginning and corrected, if possible,
without stop{)ing. Sparking is the worst trouble. Allow no unusual or
unnecessary noise to continue, nor change of voltage or speed, nor abnormal
heating of bearings, field coil, armature or commiitator. The heating of any
part w^hich the hand can bear indefinitely without discomfort is safe. The
limit in modern dynamos and motors is 80° F. of any part above the room; if
greater than this, something is wrong.
Feel the air near the armature revolving. The commutator should not be
more than 10 degrees warmer than the armature.
Overloading is the cause of most troubles.
Handle a conductor with a stick or insulated tool. Use one hand only around
a dynamo. Wear rubber gloves and shoes for 500 volts or more.
Stop the dynamo if violent armature sparking can not be suppressed or smok-
ing appears.
In good dynamos the "lead'" is small and the rocker has a wide range with-
out sparking. Its proper position is midway of the two points which shows the
first sparking or at that point which gives the highest voltage. Leave the
rocker always clamped.
The lead of dynamo brushes advances slightly with rotation as the load
increases.
One of two or more brushes in a set may be removed and cleaned while run-
ning. If carbon brushes "chatter," clean the commutator.
The oil on a new or repaired djaiamo is drawn off after each run for three or
four days to get rid of the grit. Afterwards draw off and add a little fresh oil
every three or four weeks.
In case of a hot box, do not shut down unless the following alternatives have
failed : Slacken the belt, loosen the cap, piit more oil on, lubricate with vase-
line or cylinder oil. If the heating is reduced, polish the shaft with crocus
cloth and scrape the boxes after shutting down. But if the heating continues
to increase take off the load, slow down, loosen caps, get the belt off as soon as
possible, keep the armature moving to prevent sticking, take off the caps, then
stop the revolving, take out the linings and allow them to cool in the air. Do
not throw them into water. Scraping the linings can only be done by an
experienced person. The shaft is also polished with crocus. Do not use ice or
water to cool a hot box.
Occasionally hold a small piece of clean white cotton cloth — never waste — on
the commutator to vripe it clean ; then put on two or three drops of vaseline.
Keep printed directions and diagrams of all circuits posted.
4. If the dynamo is alone and not charging a battery or supplying a motor,
slow down the engine to a few revolutions ; open main switch ; raise brushes
if copper ; hold clean white cloth on commutator until no dirt shows ; stop the
engine ; open the feeders and field rheostat ; feel the armature vnnding for heat ;
loose the belt.
If a battery is being charged, reduce the charging current to a few amperes
and open the battery switch, then slow down the engine and proceed as above.
If a motor is being supplied, it must first be gradually cut out by its rheostat.
If the dynamo is working in parallel, reduce its current to nearly and open
its switch before reducing speed.
To prevent mechanical shock, never open a main switch carrying more than
a few amperes except in case of emergency.
After stopping, dust the dynamo and clean it thoroughly while warm with
cotton cloth — never waste. Remove any trace of oil or metallic dust, especially
from brush, brush holder, or commutator. Every part is kept scrupulously
clean. A bad joint or a loose nut is detected. Cover the machine. The room is
then swept and dusted and, if not sunlighted, a lamp is maintained to keep it dry.
v.— THE SWITCHBOARD.
(A) ARRANGEMENT AND CONNECTIONS.
1. The switchboard is the electrical center of an installation. Its distributing,
measuring, regulating and protecting apparatus are systematically and con-
veniently arranged on the front of one or more slate panels lield in a metal
frame. On the back the bus bars and all copper wires connecting the apparatus
are accessible, insulated, rigid and straight between supports except where they
are bent out 1 inch in crossing
"Wires running from the switchboard are neatly aligned and run horizontally
or vertically along ceiling and walls in conduit or taut between large porcelain
insulators on asphalted strips. Connections are sweated and bolted ; small wires
may be jointed and soldered. As a rule, the drop from a dynamo post to any
feeder on the same leg is less than one-fourth of 1 per cent. Fig. 78 suggests
the entire system where cells are charged and discharged in series.
2. The switchboard connections should permit four conditions — first, the
dynamo, or dynamos in parallel, to feed directly all lamps, motors, searchlights,
etc., or any part of them, and in large installations to leave one spare unit idle;
second, to charge the battery or batteries alone ; third, to do both simultane-
ously ; fourth, the battery to supply in case of a breakdown to the machinery,
all current to the circuits of its emplacements except motors and searchlights.
3. There will then be one generator panel or board of panels in the power
room centrally located, and a panel for each battery reserve near its emplace-
ment, but not in the same room with the battery. If there is only one battery
and the dynamo is near it, the two panels will be mounted together in the
dynamo room.
The panel is of best slate, 1^ inches thick, held vertically 2 feet from the wall,
1 foot from floor by a metal frame from which it is insulated by ebonite bush-
ings and washers. The dynamo pane], about 6^ by 2^ feet, will, when
necessary, be mounted with others like it in a continuous board. The battery
switchboard is about 6*^ by 3+ feet wide and its bus bars will receive their supply
either from a dynamo feeder or battery. A searchlight must have its own
switchboard, supplied by a feeder from the dynamo board's bus bars.
4. The simplest and best form of switchboard arrangement affording, with the
least apparatus, ample control and protection for one or any number of emplace-
ments and batteries, is given for both generator and battery panel fronts on
page 74. It will no doubt be adopted in the course of a few years. For a single,
compact plant the arrangement may be as on page 75.
On account of the diversity of switchboards which will be met with, several
diagrams are given below.
(B) GENERAL DESIGN.
The general design and apparatus ought to allow :
Separate feeders from dynamo board to battery panels, motors and search-
lights ; from each battery panel to its centers of distribution.
Such regulations that all centers of distribution may be kept at the same poten-
tial, all batteries may have their normal charging and discharging currents, and
the charging of two battery halves may be equalized.
Magnetic protection to every dynamo, motor, and battery against overload and
underload.
Measurements of C and V of any part desired and of leakage.
The details of apparatus are given in figs. 79 and 80. The same api)aratus is
indicated by symbols for other boards. The best switchboard arrangement
to be found in forts appears on pages 58, 59.
1. Weston voltmeters, V, reading to 150 ; a recording volt gauge for the battery
is advisable.
2. Weston shunt ammeters, A, reading to one-half excess of the maximxim
current.
(56)
78. W=e Switch Board Front.
66
THE SWITCHBOARD. 57
3. 6-point voltmeter switch on battery panel connected to give at will the
voltage (a) between bus bars, (b) of first half battery, (c) of second half battery,
(d) of whole battery, (e) between + bar and ground, (/) between — bar and ground ;
4-point switch on dynamo panel to give the voltage (a) between supply mains,
(b) bus bars, (c, d) either bus and ground.
4. Main regulating rheostat 31 Rof noncombustible, nonabsorptive material is
necessary to reduce the bus bar voltage while charging the battery. It has range
and capacity to carry indefinitely with less than 200° F. rise, the chai-ging cur-
rent of both batteryhalves within 5 per cent of the normal while the bus bars
remain at 112 volts ; enough stops are provided to keep the bus bars within 1 volt
of the potential necessary to supply the lamps.
5. Equalizing rheostats, E R, E R' , have each ten steps for a total drop of 10
volts, and in construction are like the above.
6. The field rheostat, F R, supplied with the dynamo, can lower its maximum
voltage on load to 110.
7. All rheostats are required to have :
Capacity to carry its ma :imiim current indefinitely with less than 200° F. rise,
and 30 per cent overload for one minute.
Contact arm on a spindle and touching one point before it leaves the other.
All material fire and moisture proof and conductor nonoxidizable.
Compactness, ventilation, and abundant radiating surface.
Insulation of 1 megohm between conductor and frame iinder A. C. test.
Words "high," "low," or "raise," "lower," to indicate the turn of contact
arm to change the voltage.
8. Its overload circuit breakers, O L, operate with certainty and excess of force
within 5 jier cent of adjustment. This is usually made to open automatically
the circuit at one-fourth increase of the normal current.
9. Its underload C. B's. operate within 5 per cent of adjustment, and is usually
set to open the circuit with a fall of 5 or 10 amperes if the C. B. is "no current,"
and of voltage 30 per cent if the underload is "low voltage." It should not
catch if the current or voltage is lower than that of the adjustment. Both O L
and U L circuit breakers have carbon protection to the main contacts, and if
combined on one base, have but one trip-catch.
10. Fuses have copper tips stamped with 80 per cent of the amperes which
they can carry indefinitely, and will therefore blow at one-fourth excess of their
normal current.
11. Knife switches are oO amperes or larger, double pole, single or double
throw, quick break, fused, carbon -tipped, hinged, and so constructed that con-
tact will occur along the entire edge of the jaw at the same time, and no current
can pass through a hinge or spring. Single-throw are closed by an upward
motion to avoid accidental closing.
12. All conducting parts of the switch board are of drawn copper and have a
cross section of about 1 square inch per 400 amperes; all joints are sweated and
bolted with a contact area of 1 square inch per 180 amperes; all sliding contact
surfaces have 1 square inch per 40 amperes. Bearing parts are phosphor-bronze
or brass.
(C) THE U. S. ENGINEER SWITCHBOARD.
1. Figs. 79 and 80 give the details of apparatus and wiring of the dynamo
and battery panels. The feeders, h to the latter, come from F S o&. the
dynamo panel's bus bars.
Fig. 81 shows the connections on the battery switchboard panel (fig. 80), while
the storage battery is being charged, and fig. §3 while being discharged. The
three figures are lettered to correspond.
2. By this arrangement, the battery of 58 cells is charged, 29 in series and 2 in
parallel, by the throw of the triple-pole double-throw switch, T P D T, on the
battery panel to the right and is discharged, 58 in series, by its throw to the left.
The plan allows other and distant batteries, each with its own switch board, to
be supplied by feeders from the same dynamo board's bus bars, permits the
djTiamo to feed all lamps, etc. , at the same potential, offers little chance for
mistakes or accident and fulfills the four conditions imposed in par. (A) 2, for
isolated D. C. plants with battery reserves. But the apparatus is extensive and
current is lost in dead resistance while charging and lighting at the same time.
3. Details of the apparatus :
(a) In the Weston voltmeter V, (fig. 79) a pivoted coil, of which only three
turns are shown in cross section, is held in position between the poles iVand S of
a strong steel magnet by a light spiral watch spring F, seen in front, and one, R,
58
HANDBOOK FOR ELECTRICIANS.
+
1^ I^Lgl +
79. Present Generator Panel Apparatus in Detail.
THE SWITCHBOARD.
59
■h|.|.[.|.|.H ...
80. Engineer Battery Panel.
60
HANDBOOK FOR ELECTRICIANS.
like it, in rear, but drawn on the left in order to be seen. When a current passes
through the coil, it revolves on its pivots on the same principle as the armatiu'e
of a motor and carrying with it the pointer along the scale. The Fcoil has
many turns of very fine wire and a large fixed resistance in series, which is kept
in the instrument case.
81 and 82. Diag:rammatic Sketch of Engineer Switchboard Battery Panel.
(5) The "Weston ammeter ^4 is similarly constructed, but has fewer turns of
coarser wire in the coil, which carries a very small but a fixed fraction of the main
current through the shunt A S of German-silver strips in the main circiTit.
Ammeters and voltmeters are inclosed in iron cases to shield their fields, and
they should be handled with care, so as not to disturb the pivots or weaken the
magnets.
(c) The voltmeter switch T »S' has two brass arcs which are the terminals of
the F circuit; also (fig. 79), four double brass points connected as shown. The
83. G. B., D. P. Overload Togg^le^Joint C. B..
THE SWITCHBOARD.
61
brass ends of the lever (not shown) are insulated from each other and bear upon
the arcs and two opposite points at the same time. The voltmeter can thus be
switched in between (1) dynamo posts, (2) bus bars, (3) — bus bar and ground,
or (4) + bus bar and ground. The V S
on dynamo panel has six points.
(d) In the overload switch O L the'
knife edge kept open by a spring is,
when pushed into the jaws by its han-
dle (thus closing the circuit), held in
that position by a trigger catch. Be-
neath the catch and on the other side of
its pivot is a plunger R over a vertical
soft-iron movable core I (fig. 84), sur-
rounded at its upper end by a coil car-
rying the main current. When the
current becomes too great the core is
drawn tip, strikes the plunger and catch
and releases the knife. The spring over-
comes the friction of the jaw on the
knife which then opens the circuit far
more quickly and surely than is done by
a fuse wire. The hand-screw shown
below I, which moves the core up or
down, affords regulation.
The figure (85) gives back connections
of Ite C. B. and protected terminal fuse.
(e) 01/ and UL{fig. 79) is a combina-
tion overload and underload automatic
circuit breaker. In addition to the over-
load cut-out, described above, there is a
straight horizontal magnet with end
pole pieces. It may be wound with fine
wire connected for a fall in voltage as
represented in the diagram, or with
coarse wire in series with the O L coil
to open for a fall in current. The arma-
ture is a horizontal soft-iron cross piece at the upper extremity of a vertical lever
pivoted below and held by a sj)ring normally away from the magnet. When
84. Ite Automatic Cut=out or Circuit Breaker.
Diagram Nu. I.
Diagram Mo. 2.
the knife of the switch is closed by the handle, the armature is automatically
moved into approximate contact vsrith the pole pieces and held by their magnet-
ism. If the voltage falls to the adjustment, the armature lever is released and
strikes the trigger catch, releases th6 knife and opens the main circuit.
62
HANDBOOK FOR ELECTRICIANS.
(D) THE PREBLE SWITCHBOARD
(Fig. 86), for a single plant with a battery reserve, requires little apparatias,
loses very little energy in regulation, gives little chance for accident, and it is
simple. Lamps are 110 volt ; dynamo, 110 to 150 volts ; 58 cells charged and dis-
charged in series vary from 110 to 145 volts. 1. Dynamo to light lamps — close
O L, MS, and FS only; 31 R is cut out. 2. Dynamo to charge battery — close
TPD Tto right, O L, O' L, U L, and 31 S only. 3. Dynamo to do both— same
as last and close F S. 4. Battery to light lamps— close O L', T P D T to left
and F S.
86. Preble Switchboard.
(E) KEY WEST SWITCHBOARD.
The relative sizes of wires, fuses, switches, etc., and the divided bus bars are
shown in fig. 87. A shunt switch on the dynamo to the series field may be opened
to raise the voltage.
The ten end cells, active or nonactive, may be gradually added or subtracted
from the main battery, as required, by an end cell switch. Its arm consists of
two parallel brass bars sliding on the stops and on two dijBferent brass rings con-
nected by German-silver resistance. By this device the battery circuit is never
opened and no cell can be short-circuited
FIRI
NG B.B.
15 u
foH.
O
\o\
iM yj 7* iOO /CO
LIGHT B.B. I I 'i°h MpOWER B.B
87. Key West Switchboard.
THE SWITCHBOARD.
63
(F) THE GOIiDEN^ GATE BOARD.
The Golden Gate board (fig. 88) distributes current to three points, 1,500 and
2,000 feet apart, each having its own battery for a reserve. The generator and
No. 2 stations are together. Battery and lamps can be supplied simultaneously,
but not battery and motors.
88. Golden Gate Switchboard.
(G) SWITCHBOARD ARRANGEMEIST.
The switchboard arrangement in fig. 89 for dynamo, single battery, with 15
end active cells and 100 lamps, is economical. It fulfills the four conditions and
the dynamo and battery can be placed in parallel to supply 400 lamj)s for three
hours.
89. Shunt Dynamo, 45 Cells and 15 Active End Cells.
64 HANDBOOK FOR ELECTRICIANS.
(H) TO OPERATE.
1. No one should be allowed to touch the switchboard unless he is familiar
with all circuits connected with it, the strength of main and feeder circuits,
the insulation of each part. Records of these are kept.
2. Always close a switch deliberately and firmly, while watching the ammeter
and voltmeter, whose deflections were previously known, and while standing
ready to open. Main switches loaded are opened only in an emergency.
3. The rule is to close feeder switches when practicable, so as to change the
load as gradually as possible — the smaller first.
4. Guard against dust or wet, overheating in any part, unsoldered joints,
loose nuts, wires or other parts, bad contact of rheostat arm on any stop, instru-
ment not holding its zero, switch twisted or dirtied so as to not make good con-
tacts ; apparatus out of adjustment.
5. Leave all switches and circuit breakers open after a run.
90. As Shipped and Prepared for Mounting.
VI.— STORAGE BATTERY (CHLORIDE).
{A) UI^PACKIXG, SETTING UP, AND INITIAI. CHARGING.
1. Great care shotild be taken in unpacking and all subsequent handling.
2. Open boxes and crates on the "up" side. Lift contents out, verify their
number and condition, and never slide them by turning box on its side.
3. The construction of the stand is shown in fig. 91. Dimensions change
with, size of .jar. When jars are 15 inches high by 13 inches wide by 11
inches deep, the cross section of the timbers are 5| inches deep by 3f inches
wide. When each shelf carries two rows of cells, there will be foiir longitudinal
stringers to each shelf instead of two stringers, as shown for the single row
of cells.
•4. The battery room should be so located or arranged that the temperature
will be moderate and the air dry. If the room is damp there is danger of leak-
age from grounds and solution running over from absoi'ption.
5. Usually, natural ventilation is sufficient if the proper inlets and outlets
for the air have been provided, but in some cases forced draft is necessary. To
obtain the best results and life from the battery, the temperature should be
91. Method of Mounting. Working Plan 6f Frame.
.\ Glass jar.
B Wood tray.
C Glass insulator.
D Stringer.
E Iron bolt.
F Crosspiece.
G Wood dowel pin.
H Post.
I Leail-covered bolt connector.
J Lead strap lug.
K Positive plate.
L Jfegative plate.
M Eulibcr ring separator.
N A'itrili.-d brick.
Li'iiil terminal lug.
P Copper connecting conductor.
between 50° and 80° F. If the room is excessively hot (over 80°) for any great
length of time, the life of the plates is very considerably shortened. If the
temperature is low, no harm results, but the available capacity is reduced.
6. Place the jars, after they have been cleaned, in position on the stands
which should be so situated in the room that each cell will be easily accessible.
If the floor space is available, it is often preferable to install the cells on one
tier, in which case a set of stringers properly fastened together and the
insulating bricks will be all that is required.
7. Place the elements as they come from the packing cases (see fig. 90) on
a convenient stand or table (the elements are packed positive and negative
together, the positive having plates of a brownish color, the negative of a light
1714-5 (6,5)
66 HANDBOOK FOR ELECTRICIANS.
gray; the negative always has one more plate than the positive), cut the strings
that bind them together and carefully pull the positive and negative groups
apart, throwing the packing aside. After carefully looking over both elements,
to see that they are free from dirt and other foreign matter, place two hard
rubber separators on each positive plate, about an inch from and parallel with
each vertical edge, and then slip these plates into position between the nega-
tives, which have been placed crosswise on a board about two-thirds the width
of the plates, so as to allow of easy readjiistment of the separators, which may
become disarranged (fig. 91).
8. To facilitate the lifting of the elements into the jars and to prevent the
disarrangement of the separators when doing this, a short strip of webbing
should be used; lay this on the board under the element (fig. 90). When
putting into the jars, be careful that the direction of the lugs is relatively the
same in each case, thus causing a positive lug of one cell to always connect
with a negative of the adjoining one and vice versa. This insures the proper
polarity throughout the battery, bringing a positive lug at one free end and a
negative at the other.
9. Just before bolting or clamping the lugs together, they should be well
scraped at the points of contact, to insure good conductivity and low resistance
of the circuit; this should be done before the elements are taken apart and
directly after unpacking, if the battery is to be set up at once. The jars rest on
sand in wooden trays on glass insulators standing on framework as shown
above.
10. Before putting the electrolyte into the cells, the circuits connecting the
battery with the charging source must be complete, care being taken to have
the positive pole of the charging source connected with the positive end of the
battery, and so with the negative poles.
11. The electrolyte is dilute sulphuric acid of a specific gravity of 1.200 or 25°
Baume as shown on the hydrometer at normal temperature (60° F). If it is
not convenient to procure this from the Battery Company, already mixed and
ready for use, it should be prepared by diluting suitable commercial sulphuric
acid, or "oil of vitriol," as it is more commonly called, with pure water. The
acid, as well as the water, must be free from impurities, such as iron, arsenic,
nitric or hydrochloric acid; this is absolutely essential. When diluting, the
acid must be poured into the water, not the water into the acid ; the propor-
tions of acid (of 1.840 specific gravity or 66° Baume) aiid water are one part of
acid to five of water (by volume). The acid must be added to the water slowly
and with great caution, on account of the heat generated ; the final density of
the solution (1.200 specific gravity) must be read when the solution has cooled.
The vessel used for the mixing must he a lead-lined tank, glazed earthenware
or one of wood which has not been used for other purposes ; a new washtub or
spirits barrel is recommended.
12. The electrolyte should cover the top of the plates by i inch and must be
cool when poured into the cells, wliich then should never be allowed to stand
for more than two hours, before the charging is started.
13. The initial charge should be continued uninterruptedly, or as nearly so as
possible, for about thirty houl's at normal rate, or until the positive plates
become a deep brown or chocolate color, the negative a light slate and the
potential of each cell 2.5 volts (with current flowing), gas being freely given off
from all the plates. The density of the electrolyte should again be 1.200 sp. gr.,
having fallen considerably after being put in the jars.
14. At the end of the first charge, it is well to discharge the battery about i;
and then immediately recharge it. Repeat this treatment two or three times
and the battery will be in jjroper working condition.
15. When the battery is in regular service, the discharge should not be car-
ried below 1 . 8 volts per cell at full load ; the charging should be started at once
after a discharge and continued until the battery is full, as indicated by the
four signs given above, i. e., potential, specific gravity, color, and gassing, the
first two being most important. The cells must never be allowed to stand dis-
charged. If, by chance, this should happen, then the charging must be pro-
ceeded with at half rate ; the potential in this case at the end of charge should
be 2.4 volts (0.1 volt less than normal) and the density of the electrolyte 1.200
sp. gr. , the same as when the charge is at normal rate. Upon discontinuing a
charge the'potential of each cell will immediately fall to about 2.2 volts, and
then to 2 volts when the discharge is started.
16 In order to determine whether the battery continues in good condition, it
is essential that potential and density readings be taken at least once a week
jiist before beginning the charge and also near the end.
STORAGE BATTERY,
67
(B) GENERAL INSTRtrCTIOJ«rS FOR CARE AND OPERATION
OF chijOride storage battery.
To obtain the best results in the operation of the battery, it is absolutely essen-
tial that proper, careful, and methodical attention be given to all the details of
its operation, the same as is necessary with the generating machinery, and for
this reason the following information and rules should be most carefully noted
and followed ; if this is done the total work in connection with the operation of
the battery will be reduced to a minimum :
1. Charging. — In the charging of the battery, which should preferably be at
the normal rate, it is most important that it be continued until complete, but it
is equally as important that it should not be repeatedly continued beyond that
point, as not only will an unnecessarily rajiid
accumulation of sediment and excessive evapo-
ration of the electrolyte result, but what is more
important, the life of the plates will be very
much shortened.
At weekly intervals, however, it is advisable
to slightly prolong the charge, in order that the
electrolyte may be thoroughly stirred iip by the
prolonged gassing, and also to correct any un-
evenness in the working of the cells, which may
have developed.
2. A complete charge which in general should
exceed the previous discharge by from 12 to 15
per cent (in ampere hours) is determined by the
voltage and specific gravity of the electrolyte or
solution in the cells reaching a maximum (not
necessarily a fixed value), also by the amount of
gassing, and by the color of the plates, the first
two being the chief guides.
3. Determination of maximum voltage and
specific gravity. — With all of the cells in the
battery in normal condition, with no impurities
in the electrolyte and no material lodged between
the plates or sediment touching them at the bot-
tom, the maximum voltage and maximum specific
gravity of tlie electrolyte is reached, when, with
the charging current constant at the normal rate, no further rise or increase in
either (voltage or specific gravity) during a period of one-half hour is noted.
For instance, if the charge has l)een continued for five hours with a gradual
continued rise in the voltage and specific gravity during that time, but with an
additional one-half hour of charging there is no further rise in either, then the
charge is to be considered complete.
If the charging is at a rate lower than the normal, the interval during which
no perceptible rise shoiild occur must be proportionately increased.
4. The voltage at end of charge is not always the same throughout the life of
a battery, being dependent chiefly upon two conditions, namely: the age of the
battery and the temperatiare of the electrolyte, and for this reason it is most
important in determining the completion of a charge, that these conditions be
taken into consideration.
When first installed, the end of charge voltage will be 2.5 volts per cell, or
higher, at normal rate and at normal temperature (70' F. ), but as the age of the
battery increases the point at which it will be fully charged is gradually lowered
for corresponding rates and temperatures (see below) until, in many cases, with
both normal, it will have fallen to 2.40 volts, or even less, per cell.
If the charging ciirrent is at the maximiim rate, which should never be used
except in cases of emergency, where a rapid charge is necessary, the final
voltage will be approximately O.Oo volt per cell above that of the normal rate.
With rates lower than the normal, the voltage at end of charge will be approx-
imately 0. 05 volt less for each one-fourth decrease in the rate, viz :
If 2.50 volts at normal rate (100 amperes for illustration), then 2.45 volts at
three-fourths normal rate (75 amperes for illustration), and 2.40 volts atone-
half normal rate (50 amperes for illustration).
The eifect of changes in temperature on the final charging voltage is that it
is noticeably lowered with an increase in the temperature above the normal
(70°) and correspondingly increased with lowered temperatures, irrespective of
the age of the battery.
92. Type E=ll in Glass Jar.
68 HANDBOOK FOR ELECTRICIANS.
5. Voltage after charge and before discharge. — After the completion of a
charge and the current is off, the voltage per cell will fall immediately to about
2.15 volts, and then to 2.00 volts when the discharge is started. If this is not
begian at once, then the pressure will quite rapidly fall to 2.05 volts, and there
remain while the battery continues on open circuit.
6. Specific gravity of electrolyte at end of charge and conditions affecting
it. — As with the voltage, the specific gravity for complete charge is also affected
more or less by the varying conditions during the progress of the life of the
battery, in addition to the changes due to the evaporation and replacing of the
water in the solution — the sulphuric acid not evaporating.
In the beginning it should be between 1.195 and 1.205 sp. gr., at normal
temperature, and with the solution at the proper height (| inch) above the top of
the plates.
Gradually there is a slight loss of the acid from the electrolyte, through very
small quantities being carried off in that portion of the minutely divided spray
that is thrown up during gassing at end of charge, which is prevented from
falling back into the cell by the air currents in the room. In addition, some of
it is absorbed by and acts iipon the sediment which slowly accumulates in the
bottom of the tanks, and so can not go back into the solution again.
7. Restoring loioered specific gravity. — When this loss has become such that
the highest reading that can be gotton at end of complete charge, all indi-
cations of such being present, is ten points below the standard or what it was.
when first put into regular service, i. e., if it has fallen from 1.200 sp. gr., the
original reading, to 1.190 sp. gr., then this loss should be regained by the addi-
tion of dilute acid instead of water, when replacing evaporation. Under ordi-
nary conditions it should not be necessary to add fresh acid oftener than once
every two years, or possibly only at such times as the sediment is removed. A
convenient density for this purpose is 1.400° sp. gr., because the proper density
of the electrolyte will be more quickly and easily attained by the use of this
heavier solution, it containing double the amount of pure acid, in comparison
with that of 1.200, so that, for instance, if foxir carboys holding ten gallons
each, of 1.200 sp. gr. solution, would be required in any particular case, the
same result could be gotten by using two carboys holding ten gallons each, of
1.400 sp. gr.
As it is essential for the successful operation of the battery that the electro-
lyte be free from impurities (see under "Electrolyte" below) and as the ordi-
nary commercial sulphuric acid is not of the proper degree of purity, it is very
strongly recommended that all solution be purchased throiigh the Storage
Battery Company, which will undertake to supply the proper quality.
If, for any reason, the required supply is not procured, the solution may be
prepared by diluting specially treated sulphuric acid, or oil of vitriol as it is
more commonly called, v.nth pure water.
In any case, a carefully collected sample (at least 8 ounces) should be sub-
mitted for test. For water analysis one quart is required.
8. Gassing and color of plates — Additional indications of state of charg-
ing. — At the end of complete charge, in addition to the voltage and specific
gravity reaching a maximum, gas will be given off freely from all of the plates in
the battery, and the color of the plates should be a deep chocolate or dark brown
for the body of the positives and a uniformly light slate or gray for the nega-
tives. Provided the body of the positive plates is of the proper color, no atten-
tion need be paid to the lodgment on the top of these plates or their projecting
buttons, of a fine white powder that may be easily brushed off, the dark color
then showing underneath. In fact, if these parts are of the deep chocolate color
and no white powder is noticeable, it is an indication that the battery is being
overcharged.
This white powder is composed of particles from the plates, thrown off by the
gassing at end of charge, which become sulphated and of a light color while in
suspension in the electrolyte.
9. If there are end cells in the battery, i. e., if some of the cells are so con-
nected with the switchboard, that by either cutting them in or out. the pressure
can be regulated, those that may have been successively cut into circuit on the
discharge, should be cut out again on the following charge, as soon as they come
up to a state of full charge and not be allowed to continiially overcharge. If
any of these cells are not used regularly or stand idle, they should be given a
complete charge once a week.
10. Counter electromotive-force cells. — In some of the smaller plants it is at
times more suitable to provide for the adjustment of the pressure by means of
STORAGE BATTERY.
69
■what are known as coiinter electromotive -force cells, instead of connecting a
number of the cells of the battery to the regulating switch on the board. These
cells are made up of plain grids or plates without active material (storage
capacity not being required), and do not receive anj^ of the charging current,
nor do they require the careful attention that end cells do. They should, how-
ever, be examined from time to time, to see that they are not short-circuited, and
if found so, the cause should be removed, the same as in the case of the regular
cells in the battery.
11. Discharge. — As from the voltage and specific gravity readings the degree
of charge can be determined, so likewise can the amount of discharge.
12. Drop in voltage and specific gravitij indication of amount and safe
limit.— Dnrmg the greater part of a complete discharge the drop in voltage is
slight and very gradual, becoming greater with marked rapidity near the end.
The limit of discharge is reached when the voltage has fallen to 1.75 volts per
cell with current flowing at ordinary rates ; in usual service, however, it is
advisable to stop the discharge considerably above this point, more especially to
insure a reserve in case of emergency. The fall in density of the electrolyte also
serves as an indication of the amoxint taken out, and is in direct proportion to
the ampere hours discharged, thereby differing from the drop in voltage, which
varies irregularly for different rates and degrees of dis-
charge, and for this reason, under ordinary conditions, is
to be preferred in determining the amoimt of discharge.
The actual amoxmt of the variation in the strength of
the electrolyte between a condition of full charge and of
complete discharge is dependent upon the quantity of
solution in the containing vessel, compared to the bulk
of the plates.
If a cell contains the full number of plates, the range
will be about 35 points, or from 1.200 sp. gr. down to
1. 165 sp. gr. With fewer plates, in the same size contain-
ing vessel, the range will be about proportionately lessened.
13. The color of the plates is also a guide, as it is when
charging.
As the discharge progresses, the ijositive plates become
lighter, and the negatives darker.
14. Interval between discharge and charge. — When a
battery is discharged it should be allowed to stand but a
very short time (not more than an hour), if at all, before
beginning charging again.
15. Instruments for use 2cith the battery. — For the
successful operation of the battery, there should be pro-
vided a portable low-reading voltmeter, reading to three
volts and calibrated to 0.03 volt, for taking the individual
cell readings ; two or more hydrometers, with scale read-
ing from 1.150 up to 1.250 sp. gr., and a portable lamp
for inspecting the individual cells, in addition to the
switchboard instruments, consisting of a voltmeter read-
ing approximately three times the number of cells in
series in the battery, a two-way ammeter and a recording
voltmeter with a scale that will clearly show the total
range in voltage for both charge and discharge, of the
cells usually in circuit on the discharge.
The recording voltmeter is especially desirable, because
it enables the attendant to easily and accurately note the
progress of charge and discharge, and determine, in con-
junction with the hydrometer readings, after the manner
noted above, the proper time to stop either.
In addition to being a guide for the charge and dis-
charge, it furnishes a permanent record of the working
of the Ijattery.
An ampere hour meter, for recording the amount of
both the charge and discharge, is also valuable, and will act as a check on the
readings taken with the other instruments.
16. The electrolyte is dilute sidphuric acid, and should be prepared by mixing
suitable commercial sulphuric acid with pure water. It is absolutely essential
that both acid and water should be free from impurities such as iron, arsenic,
nitric acid or hydrochloric acid.
93. Long Flat Hy=
drometer.
70 HANDBOOK FOR ELECTRICIANS.
If the tiser mixes liis own solution, care must be taken to pour the acid
into the water, not the water into the acid. The acid must be added to the
water slowly and with great caution, because of the heat generated ; the final
density of the solution must be read when the solution has cooled.
The proportions of acid (of 1.840 sp. gr., or 66° Baume) and water are one
part of the former to five of the latter (by volume). The vessel used for the
mixing must be a lead-lined tank, one of glazed earthenware, or one of wood
which has not been used for other purposes.
The water used in replacing evaporation should be of the best quality. If it
is natural water, drawn from the city or town supply or other source, it should
be submitted from time to time for test.
The water should be added to the top of the cells shortly after starting the
charge ; not after finishing a charge or during discharge. Do not insert a hose
into the cell with the idea of stirring up the electrolyte ; this may result in
lulling up the sediment, and so short-circuiting the plates.
The electrolyte must never be allowed to get below the tops of the plate.
Should it be known that any impurity has gotten into the cell, steps should
be taken to remove it at once. In case removal is delayed and any considerable
amount of metal becomes dissolved in the sohition, this solution should be
replaced with new immediately, thoroughly flushing the cell with water,
before putting in the new solution. The change should be made when the
battery is discharged, and just before charging. If in doubt as to whether the
electrolyte contains impurities, a sample taken at end of discharge should be
submitted for test.
17. Maintaining the battery in proper condition. — In order that the battery
may continiTe in the best possible condition, it is essential, in addition to care-
fully following the points noted above, that each individual cell in the battery
be regularly inspected with a view to reducing to a minimum the chance for
any of them working irregularly or getting low; also that cell readings be
taken and recorded at fixed intervals in such form that consecutive readings
can be easily compared and any trouble that may have developed be detected
and remedied at once.
For the individual cell inspections a portable lamp is reqiiired, so that any
tendency for an accumulation or lodgment of material between the plates can
be easily noticed and located. If the elements are in glass jars an ordinary
lamp with extension cord attachment vdll be found most convenient and satis-
factory, but if they are in lead-lined or other opaque tanks, then a lamp suitable
for immersion in the electrolyte to the bottom of the tank will be necessary.
When examining a cell, great care should be taken to look between all the
plates. Any accumulation of material found between them should be removed
at once. If it is from the plates themselves, remove by pushing down to the
bottom of the containing vessel with a piece of hard rubber or wood, but if
foreign matter is present, it should be withdrawn from the cell. Metal of any
kind miist never be used for the purpose in either case.
These inspections should be so arranged that each cell is examined at least
once every month ; if it is not convenient to go over the entire battery all at
once, a sufficient number of cells may be looked into, say on one day a week, to
get over them all within the month.
In addition to the examination of the cells with the lamp, and to noting near
the end of each charge whether all the cells are gassing equally well, readings
of the voltage and specific gravity of each cell should be taken once a week at
the end of the prolonged charge and so recorded, preferably in a book gotten up
for the purpose, that consecutive readings can be compared.
STORAGE BATTERY.
Rule a large sheet in the following form :
71
Page 1.]
SPECIKU' GRAVITY.
[Page 2.
VOLTAGE.
Date, 1900. 11-26
12-2
12-9
12-16
Date, 1900.
11-26
12-2
12-9
12-16
Cell No.
Rate.
100
amperes.
95
amperes.
100
amperes.
1
2
3
4
5
6
1201
1202
1199
1200
1200
1199
1201
1198
*1185
1200
1200
1202
1200
1201
1199
1
2
3
4
5
6
2.51
2.52
2.50
2.52
2.50
2.49
2.51
2.50
*2. 27
2.50
2.50
2.52
2.50
2.50
2.49
-59.
60
61
59
60
61
1198
. 1202
1200
1204
1200
1201
2.50
2.51
2.52
2.52
2.61
2. 50
From the above readings it will be noted that on 13-2, cell No. 4 is unusually-
low, being 15 points in specific gravity and 0.25 points in voltage lower than at
the previous readings, thus indicating something WTong with the cell, and on
examination it would probably be found that the cell was short-circuited. After
a good charge the cell again came up, as is indicated by the reading taken on
12-9, no acid having been added.
These readings should be taken at the end of charge ; the voltage readings
always when the current is flowing ; open-circuit readings are of no value.
If any of the cells show readings lower than the normal and do not gas freely
at end of charge, then they should be examined at once with a cell lamp to deter-
mine the cause of the falling off.
18. Getting low cells into normal condition. — A cell which has been found to
have gotten low will generally need more than the usual amount of charging to
get it back into normal condition again, after the cause of the trouble has been
removed. This may be accomplished in several ways.
The first and simplest being to overcharge the whole battery, but care should
be taken not to carry this to excess.
The second, by cutting the low cells out of circuit over one or two discharges
and in on the charges.
The third, by giving an individual charge while the other cells in the battery
are on discharge ; this may be done from a small dynamo, usually motor-driven.
Before putting a cell that has been in trouble into regular service again, care
should be taken that all the signs of a complete charge are present, viz : the rise
in potential and specific gravity to the proper value, the gassing from the plates
and the normal color.
19. Sediment. — Another cause for cells working irregularly, especially after
they have been in service a considerable time, is the accumulation of sediment
in the bottom of the jar or tank, to such a depth that it touches the bottom of
the plates which then become short-circuited.
For this reason the gradually increasing amount of sediment should be care-
fully watched and removed before it gets dangerously near the plates. It must
never be allowed to get up to them.
As the accumulation is usually greatest under the middle of the plates of a
cell, care should be taken not to be guided by an examination under the end
plates only.
To remove the sediment, a convenient method, provided there is sufficient
free space at one end of the tank, is to "rake" it out from under the plates and
then ' ' scoop " it up, always using a device containing no metal in its construction.
If, however, this method is impracticable, the electrolyte should be drawn off
into clean containing vessels, the battery previously having been fully charged,
and the cells then flushed with water (the city supply may be used for this pur-
pose) in such a way as to thoroughly stir up the sediment, the whole then Ijeing
drawn off, the process to be repeated as often as necessary to remove all the
sediment. If there is not sufficient drop to allow of siphoning, a pump should
be used. Pumps most suitable for this purpose are of the rotary type, with
bronzed parts.
After the tanks or jars have been thoroughly cleaned, the electrolyte should be
quickly replaced, to prevent undue heating and drying of the negative plates, and
also the long charge required by dry plates to bring them to a state of full charge.
72
HANDBOOK FOR ELECTRICIANS.
In addition to tlie electrolyte withdrawn from tlie cells, new must be provided
to make good that displaced by the sediment. This should be of 1.300 or 1.400
specific gravity to connteract the effect of the water which was absorbed by the
plates during the washing, and also to reduce the bulk of the new supply.
20. Keeping electrolyte free from impurities. — Still another cause for irregu-
larity in cells would be the presence of foreign matter in the electrolyte. If it
is known that any impurity, especially any of the metals (except lead) or other
acids, has gotten into a cell in other than very minute quantities, the electro-
lyte should be replaced by new immediately, after the manner noted above under
"Electrolyte."
21. Battery used but occasionally. — If, for any reason, the battery is discharged
but occasionally, or the discharge is at a very low rate, a weekly freshening charge
should be given.
22. Putting the battery out of commission. — If the use of the battery is to be
discontinued for a time, say six months or more, it is vei"y often best to take it
entirely out of service by drawing off the electrolyte.
This should be done as follows :
After a complete charge, siphon off the electrolyte (which maybe used again)
into convenient receptacles, preferably carboys which have previously been
cleaned and have never been used for other kinds of acid, and as each cell is
emptied immediately refill with water. When water is in all the cells begin
discharging and continue until the voltage falls to
or below 1 volt per cell at normal load ; when this
point is reached draw off the water ; the battery may
then stand without further attention until it is again
to be put into service.
23. Putting the battery into commission again. —
To do this, proceed in the same manner as when the
battery was first put into commission. After first
determining that the polarity of the charging source
has not been altered, so that its positive pole will
still be connected to the positive end of the battery,
put in the electrolyte and start charging at once at the
normal rate, continuing until the charge is complete ;
from twenty-five to thirty hours at this rate will be
required. The completion of this charge is determined
in the same manner as are those when the battery is in
regular service, as noted above.
24. The attached form is recommended for recording the readings, which should
be taken in duplicate, carbon paper being used to obtain the second copy which
should be forwarded to the Company's office.
94.
Type G=19 in Lead=Lined
Pine Tank.
(C) FORMS FOR KEEPING RECORDS AND MAKING TESTS.
1. Storage Battery Weekly Inspection Report.
I);itc, ,100 Time I"
_A. M.
-P. M.
Consisting of cells, type " Chldriilc Accuiiiuliitor."
Battery {gSfci:!'^* -- -">--•
liuurs iit average rate of amperes.
(date).
Battery had been {gSrlingi::} f^'
Battery last inspected with lamp
Cells (Nos. ) especially worked on during week
Height of electnilyte aliove top of plates inch.
Water was aildcd to replace evaporation (date).
Temperature of electrolyte °r; of air of battery room °F
Cell.
Volts.
Specific
Gravity.
Cell.
Volts.
Specific
Gravity.
Cell.
Volts.
Specific
Gravity.
]{eiimrks.
1
2
3
i
5
6
7
Ktc.
31
32
33
34
35
36
37
Etc.
61
62
63
64
65
66
67
Ktc.
STORAGE BATTERY.
73
2. Test of Battery of "Chloride Accumulator"
Consisting of cells, type Located at
<
Date.
Time.
No. of
Cells
in
Cir.
Total
Volts.
Volts
per
Cell.
Amp.
Amp.
Hrs.
Pilot Cell.
Remarks.
Volts.
Sp.Gr.
Temp.
Note. — Readings to be
taken half hourly. All of
the cells to be in as near-
ly uniform condition a.s
possible before the test
is started.
Pilot cell should be
representative and in the
main part of the battery.
1
3. Test of Battery of "Chloride Accumulator.
Consisting of cells, type Located at_
CHARGE.
DISCHARGE.
CHARGE.
DISCHARGE.
Test taken by
Time.
TO
A.M.
~P.M.
Time.
TO
A.M.
~P.M.
TO
A.M.
-"P.M.
TO
A.M.
"P.M.
P.M.
"A.M.
A.M.
--P.M.
A.M.
— P.M.
A.M.
— P.M.
A.M.
— P.M.
A.M.
-"P.M.
KEMAKKS.
Cell. ; Volts.
Sp. gr.
Volts.
Volts.
Sp.gr.
Cell.
Volts.
Sp.gr.
Volts.
Volts.
Sp. gr.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
IG
Etc.
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
Etc.
The readings to be taken at
the end of charjje and dis-
charge; the voltage with the
current (lowing, as recorded on
the CJ) sheet; the specific
gravity immediately after the
current is oif.
Two columns for "Volts"
under **■ Discharge '* are pro-
vided in case the fir!i.t set of
readings is taken before the
battery is " down," or in case
"check '' readings are desired.
The time when readings are
started and finished to be
recorded at head of columns.
74
HANDBOOK FOR ELECTRICIANS.
(D) GENERATOR AND CIRCUIT PANEL AND BATTERY
PANEL.
Generator and circuit panel (fig. 95) and battery panel (fig. 96) for use in
connection with chloride accumulators as designed and manufactured for the
U. S. Gov't by the Storage Battery Company, Phila. V. M. switch: 1, bus;
2, A + B discharge ; 3, A charge ; 4, B charge ; 5, + ground ; 6, — ground. The
back connections will be evident.
THE SWITCHBOARD. 75
(E) COMBi:N^Er> GEI^ERATOR ANI> BATTERY PAIVEI.
For use in connection with chloride accumulators where battery is charged
and discharged in series, as designed and maniifactured for the U. S. Gov't by the
E. S. Battery Company, of Philadelphia. Voltmeter switch: Point 1, dynamo-
point 2, battery ; point 3, + ground ; point 4, — ground.
I#l#l'l|i-^'lll#lt|i|'r
7ti HANDBOOK FOR ELECTRICIANS.
Fig. 95a gives the S. B. connections when a booster and end cells are employed
in large installations. It is the most economical disposition shown.
(F) PRECAUTIOIN^S.
1. Sulphating, buckling, and disintegrating of plates (positives are more sus-
ceptible than negatives) are the three most serious troubles with storage cells in
general, but they may be avoided ; if not too far gone they can be cured.
2. Sulphating is a whitish scale that forms in patches due to overcharge ; to
standing too long partially discharged, or to too strong electrolyte. It is also
shown by loss of capacity and a higher voltage than the charge warrants. If
slight, repeated slow charge below one-half the normal rate and discharge is the
remedy ; if considerable, carefully scrape off the white scale prior to slow charge.
No attention need be paid to a whitish loose precipitate which does not extend
into the plate, as found by cutting into the skin with the point of a knife.
'6. Buckling or warping of a plate from unequal action on its two surfaces is
caused by excessive charging or discharging rate or sulphating. To remedy,
steadily press the plate between two boards.
4. Disintegrating of paste from plate results from sulphating, biTckling, or old
age and, if well started, new plates are the only remedy. It seldom or never
occurs in chloride plates.
5. The office of the storage battery is to form a reserve for feeding lamps,
operating night signal sets, igniting fuses, etc., in case of accident to the
machinery, and to illuminate the magazines for short periods, so as to avoid
starting the engine.
6. A well-managed chloride storage battery will last indefinitely on 6 per cent
allowance of the cost for amortisation each year. Watt efficiency should be
about 85 per cent ; quantity efficiency, 90 per cent.
7. The normal rate of charge and discharge is about 13 amperes per square
foot of ijositive plate counting one side only. The charge rate need not be
exceeded ; the discharge rate, only in emergency.
8. Gruard against disturbing the plates in jars while connecting or disconnect-
ing the lugs, and against solution falling from the hydrometer or stick, outside
of the jar.
9. Dry plates will keep indefinitely in a dry place.
10. The deflection of a voltmeter across a connection should be no greater than
for an equal length of lug.
11. To charge a portable battery of few cells from a 110-volt lighting, a 5o0-
volt trolley or an arc-lighting circuit by placing in series with the battery a bank
of lamps or a rheostat, is well explained in figure 98.
(a) The connection with an arc circuit, as in D, requires experience. The
switch is so made that the contact arm A when thrown to the charging (two
dotted lines) position shall not open the light circuit nor short-circuit the bat-
tery A. Heavy wire resistance R has terminal C so spaced between B and D that
the arm must touch C before leaving B or D.
Or, R may be permanently placed in the arc circuit, its E. M. F. verified before
switching in the battery and after the charge is finished and battery is opened,
R is shunted out of circuit. The caution seems unnecessary that while being
charged the switch should be opened at the first sign of fluctuation or stoppage
of the current.
THE SWITCHBOARD.
77
In the case of a battery of three cells or 6 volts requiring a charging C of
amperes from an arc circuit of 7 amperes, R = & ^ {1 — 5)=;3 ohms.
. l»OS.Tlvt WM.
II
TT?T
Di^56^^il_S •
Ql^gg^^lJD .
BVT.-B*«TTCRY.
Oa^COMSUMEPlS SWlTC^^
98. Charging Few Cells.
\h) In the case of the same battery charged from a 110-volt circuit the total
resistance of lamps hot = (110 — 6) ^ 5 = 21 ohms.
(c) In all cases the polarity and potential of the charging circuit must be
known to be correct by means of the voltmeter before closing it on the battery.
If no voltmeter is at hand, the polarity can be ascertained by dipping the termi-
nals in salt water, when the greater flow of gas will appear at the negative
terminal which is the one which should be connected with the negative of the
battery.
VII.— D. C. ELECTRIC MOTORS.
(A) ESSEJ^TIAL PRIKCIPIjES A2fT> CLASSIFICATION^.
1. Any D. C. dynamo supplied with current from an external source will
operate as a motor. The lead of a motor, if any, is backward, not as in a
dynamo, forward or with the rotation.
2. To get the direction of rotation of any conductor on the motor arma-
ture's surface, hold the left hand with its thumb and first two fingers extended
99. W=e Multipolar.
at right angles to each other, so that any one of the three lies parallel with the
conductor pointing in the direction of the current through it, and so that
another points in the direction of the lines of force of the
field magnet ; then the third will point in the direction the j ^1S-^"?°l"
conductor is urged.
3. Back electromotive force. — The armature of a motor
revolving in a field, owing to an external supply, has an
E. M. F. set up in it precisely the same as if it were
revolved as a dynamo. This E. M. F. or (e) has (from the
rule with the right hand) a direction opposite to that (E)
which actuates the motor, and is therefore called back or
counter E. M. F. The motor's power varies directly with
the resultant E. M. F., i. e., with (E—e). Ex. If 100 volts
be applied to the brushes of a motor of 2 ohms internal
resistance, and if the armature be clamped to prevent ";i?,:r"-
rotation, the current would be 50 amperes. But if the iqq Motor Left Hand.
armature is allowed to revolve, a counter (e) will be set up
.X-, .1 1 ^1 4. ■ (100— 96) volts „
of say, 96 volts. The current then through the motor is ^ ^ ohms —^ amperes
and the power expended is 2x100=200 watts.
4. Efficiency.— The power input (C amperes X E volts) is always equal to the
useful output or power at the pulley (torque in lbs-feet X revs, per sec.)
plus the energy wasted per second to overcome ohmic resistance, friction,
(78)
ELECTRIC MOTORS.
79
windage, hysteresis, Foticault and eddy currents. The total wastage amounts
to 10 or 15 per cent. Efficiency of a motor = tiseftil output h- input = 80 to 90 per
cent usually.
5. Modern D. C. motors are usually woimd for a constant potential supply of
500 volts for several miles transmission, 220 volts for a few thousand feet, and
110 volts for a few hundred feet as in
forts. Like modern generators, they us-
ually have 4 or more removable poles
projecting inwardly from an outer field
steel casting support toward an iron-
clad armature, i. e., one in which the
conductors are sunk and bound below
the surface in slots parallel with the
axis. Displacement of the winding is
therefore impossible.
In the construction both field and
armature coils are formed on moulds,
insulated and laid without bending on
their cores, which are laminated trans-
versely to their main currents. The
armature core has air ventilating ducts
parallel and perpendiciilar to the axis
to which it is rigidly held by a spider.
The commutator has large diameter and
many bars insulated by mica. The
brushes are carbon, radially placed with
little or no lead and are sparkless from
full load to no load without adjustment.
6. Each class has a special use. —
For constant current supply, motors are
always series wound ; for constant potential, they are series, shiint or compound
wound.
(a) The series motor (fig. 101) has great starting torque (force X lever arm),
changes its speed greatly for small changes of load, does good work at the dif-
ferent speeds, races dangerously without load, and is regulated by a rheostat in
series with it. If its supply is constant current, it may be safely overloaded to
the point of stopping ; if constant potential, it may run one-half hour on 25 per
cent overload. It is suited to variable speed work as in railroads, automobiles,
hoists and machines which require increased torque when slowed down from
overload and have an attendant. Series motors run parallel across constant
potential mains, work well on separate work; on joint work each must be geared
{not belted) for a speed corresijonding to its share of the voltage.
100a. W=e Core of M. P. Motor.
101. Series Wound.
(h) The shunt motor (fig. 102) has moderate torque at starting, gives nearly
constant speed with varying load, falls in speed only a few per cent from to
full load, is largely self-regulating, and suited to blowers, lifts, and lathes. The
armature and field circuits lie in parallel across the mains, and the speed can be
regulated by a starting box in either one or in both ; the rheostat in the arma-
ture circuit is essential at starting to prevent a destructive current. Several
shunt motors of like voltage may be placed in parallel, even of unlike power.
80
HANDBOOK FOR ELECTRICIANS.
either to work separately or each to do its part on one shaft ; or in series, to work
separately.
(c) A compound motor (fig. 103) is cumulatively or differentially wound — a
compound dynamo as a motor has the latter winding. The former kind is com-
ing into use. It has increased torque at slower speed, is partly self -regulating.
5tirt'*^g Rheostat.
I f ? f l
Counter Clochwlsg
102. Shunt Wound.
and is adapted to work where heavy overloads occur and close regulation is not
important, such as for printing presses and hoists. Their supply is constant
voltage only.
(B) REGULATING AND PROTECTING APPARATUS.
1. When a motor armature is at rest there is no counter E. M. F., and if the
potential of the supply were closed upon it, the current would be destructive.
Hence, a starting and stopping rheostat (fig. 103) is always put in series with the
motor and its resistance is gradually cut out as the
motor gains speed and counter E. M. F.
When a starting box has not wire of sufficient
cross-section to carry the motor current for any
length of time without overheating, the switch must
not remain on a point longer than two or three sec-
onds. When the rheostat wire is large enough to
carry the current indefinitely, the box is a speed
regulator or controller.
2. The motor is slowed down and finally stopped
by turning the same contact arm to throw resistance
into the motor circuit and thus gradually to dimin-
ish the current from full strength to zero. To open
the circuit as at the main switch while full current
is flowing would endanger the insulation from the
induced extra current.
3. In addition, a motor requires to be protected
against sudden excess of current by an overload
automatic circuit breaker in one or both of its feed-
ers, which is quicker and more certain than a fuse ;
also by an underload automatic circuit breaker against
the fall of the current or of the potential below a
certain limit due to a cross or other accident which
is liable to be followed by a rush of full current that shunt
would destrov the motor at rest. »03. Compound Motor.
ELECTRIC MOTORS.
81
(a) Diagram of General Electric S. and S. rheostat (fig. 104) with automatic
release (underload C. B. ) in armature circuit of small series motor. Box is
shown for small shunt motor.
Release rnagrtet
'momr
Field /^i-T-natAJT-©
104. Diagram of S. and S. Rheostat.
(&) Diagram of General Electric S. and S. rheostat (fig. 105) for larger series
motor with underload release magnet in the armature circuit and magnetic
blow-out at the first step ; stops on left-hand side are connected with middle
pivots of coils on right-hand side.
OTMKT
105.
Diagram of S. and S. Rheostat for Larger Series Motor.
(c) The armature of the retaining magnet is adjusted by means of the screw
and nut to hold at a current equal to aboiit 55 per cent of the full-load amperes
of the smallest size of motor with which the rheostat is used. Therefore these
series motors must be loaded to about one-half their capacity, or the armatiire
will not be held by the magnet.
Boxes for S. and S. rheostats (fig. 106) for shunt motors, two larger showing
magnetic blow-out.
1714—6
84
HANDBOOK FOR ELECTRICIANS.
(d) Reneivals. — If the first step which is of copper and hexagonal in shape
becomes burned, it may be removed by iinscrewing it and substituting another.
The arm may also be easily taken off and smoothed or renewed.
(C) OPERATIOK AND CARE OF MOTORS.
STARTING.
1. See that all nuts and parts are tight, that connections are correct, that
the commutator is clean, that the brushes are properly set, and that the
starting switch is in the "Oif " position. Turn, if possible, the armature by
hand, to see if it is free. Close the main switch. Turn the rheostat switch
steadily clockwise until it strikes the automatic release, so that the motor starts
.slowly and increases uniformly to full speed, taking about one-half minute to
turn the switch. If the motor is new, run it empty for a time and see that all
parts operate properly when the motor is partially and fully loaded.
If a motor fails to start after beginning to cut out the resistance, tiirn the
switch off to prevent accident before beginning to explore. With a voltmeter,
or with the hands on low potentials, ascertain if the supply is present. If it is,
take off the load, close the main switch, and see if the armature moves. If it
does not, proceed from the mains with a voltmeter in search of a broken circuit.
The break may be in the rheostat.
112. W=e S. and S. Box.
If motor terminals show potential and poles have no magnetism, there is a
break in the field of a shunt or compound motor, or between the terminals of a
series. But if the poles are magnetized, see if brushes are at the neutral point
and pressed down, if commutator is clean, if adjacent poles are not alike, or if
coils have not a short circuit.
RUNNING.
2. («) See that the oil rings or feeds distribute oil properly, that the belt
runs in the middle of the pulley without tendency to thrust the armature
toward one end, and that no part gets overheated. The heating of any part
is probably normal if its temperature is 110° F. or less above that of the siir-
rounding air after several hours' continiious run on full load, as tested by a
thermometer placed upon it and surrounded by waste. The danger ijoint has
not been reached if the hand can bear long contact without discomfort. Hot
coils are usually due to overload, short or partly open circuit. Commutator and
brushes often get hot from sparking or friction.
(b) From time to time, or whenever the bearings show signs of heating, draw
off the oil and replace with new by bringing up the level until the rings flush the
shaft freely, care being taken not to overflow the bearings.
A hot box is due to poor oil, grit, rough-bearing surface, tight box or belt,
shaft bent or out of line, or overload.
ELECTRIC MOTORS.
85
(c) The usual load causes a certain rise of temperature in each part which is
well known to the watchful attendant, and any increase of that amount requires
immediate correction without, if possible, stopping the machine. If smoke
appears, damage has been done.
(d) Irregularity of speed may be expected in a series motor whose load varies.
But a shunt motor changes speed slightly for large variation of load ; if over-
loaded it heats. Abnormally low speed indicates overload, short circuit or a
defective contact.
(e) Keep all parts of the motor free from dirt, damp, waste oil and carbon diist.
STOPPING.
3. Turn steadily the rheostat switch contraclockwise to the open stop ; then
open the main switch. The order is the reverse of that in starting. Finally,
take the same precautions as in leaving dynamos.
4. ' ' Faults ' ' in motors, together with their causes and remedies, are for the most
part, the same as for dynamos (page 52). The motor on account of its duty is
not, as a rule, so accessible as a generator; its care, equally important, is more
likely to be neglected.
Prevention, not cure, is the rule for motor or dynamo troubles.
Dirt, sparking or overheating usually affords conclusive testimony regarding
the attendant's fitness.
Oil cans, tools, or loose iron near the motor in operation are liable to be drawn
into the armature.
To reverse a D. C. motor, reverse the current through the armatiire (usually)
or the field — not both.
The voltage of supply shoiald be within 5 per cent of that for which the motor
was built.
Excess voltage to shunt motors will heat the fields and somewhat increase the
speed ; scant voltage will heat the armature and lessen the sj^eed.
Remember main switch first, rheostat last in starting; rheostat first, main
switch last in stopping.
Do not keep the rheostat switch long on one stop, except the end ones, unless
the rheostat was biiilt to carry the full current indefinitely as a regulator or
controller.
Oil reser voirs may be half drawn every three or four weeks and refilled with new.
High-grade, dense, mineral oil, free from grit, is the proper lubricant ; after
filtration it may be reused.
Keep posted all motor circuits and manufacturer's directions.
A series motor always runs rever.se to its direction as a generator ; a shunt, in
the same direction ; a differential compound, according to the stronger field.
(D) SPECIAL rOKMS OF MOTORS IN SERTICE.
1. (a) The Leonard motor control for giuis, turrets, passenger elevators, etc.,
avoids violent stresses, bad sparking, and affords complete control with precision
of stoppage.
(b) In fig. 113, Mis the
motor whose field is con-
stantly excited direct from
the mains. G is the genera-
tor, likewise excited, but
through the reversing field
rheostat C. The brushes of
31 and G are permanently
connected.
(c) To start the motor the
generator's field is weakly
excited. As resistance is
cut out of C, G delivers
stronger current to M and
increases the speed. The
rheostat contact arm is
divided by insulation at the
pivot. Turning it to left
reverses the G field and il/'.s- < i^- System for Traininsr Quns.
motion.
2. The recording watt-hour meter (fig. 114) in general use is a compound
wound ironless motor, whose main field coil carries the main service current,
and whose armature of fine wire lies with dead resistance across the mains.
86
HANDBOOK FOR ELECTRICIANS.
The revolutions varying as the C and E of supply and therefore as their pro-
duct, are recorded as units, tens, etc. , on the dials. The shunt field is added to
compensate for friction. A copper disc on the armature shaft revolves between
the poles of an adjustable magnet, which can slow down the motion 16 per cent
or less as desired.
114. Measures Electrical Energy.
3. Dynamotors, motor generators, and boosters are rotating transformers of
direct current having a dynamo and a motor armature winding and two com-
mutators iisually on the same shaft.
(a) The dynamotor has two armatures, or two separate windings on one
armature revolving in one magnetic field. Its place in the Teazer system for
lis. Thompson's Recording Watt Meter.
116. One of the Special Motors.
starting a main motor without taking excessive starting current from the
mains is shown by "Teazer Armature " in fig. 116.
The left commutator belongs to the motor winding on the armature ; the
right commutator, to the dynamo winding which has about one-fifth of the
potential of the motor's winding. At starting, the Teazer dynamo supplies
about one-fifth of the main voltage to the main motor, giving proper torque -at
low speed without draining more than about one-fifth of the current from the
supply mains which would be taken without the dynamotor. When the main
motor has reached the highest speed attainable in this way, it can be switched
to the supply mains and the Teazer circuit switched out without excessive drain
from the mains.
4
^
-^M#^
I'fliHl ' i&s!^v
^^^^^o
■^ )
^^H
9
n^^^^^H
M^^^^
^■^^^.^jfl
rf
/^^^
ELECTRIC MOTORS.
87
(&) The motor generator (fig. 117) has two armatures revolving on one shaft
in sei)arate fields. The motor commutation is at one end, the dynamo's at the
other. It is not so efficient a transformer as the dynamotor, but its dynamo
voltage may be given greater range and its modes of construction and operation
are simpler in charging batteries, electroplating, supplying telegraph trunk lines
or current to laboratories.
117. Motor Generator.
(c) A booster is an electrically or mechanically driven transformer whose
dynamo commutator is in the main circuit at a distant point to raise the voltage
there. Both the main and generated currents flow together in the dynamo
armature winding, which has, therefore, very thick copper. Boosters are
placed, for instance, at the ends of long feeders running from the same bus bars
as short feeders, to keep the potential the same.
VIII.— ELECTRIC HOIST WITH AUTOMATIC SAFETY STOP.
It is applied to two platforms, G G, either of which is drawn upward, while
the other descends, by a winch driven by a motor through worm or train gear.
A 5-horsepower motor can raise 2,000 pounds counterweigh ted by 600 pounds of
the other platform at the rate of 1 foot per second. The design is simple, inex-
pensive, and the motor and hoist are fairly well protected.
1. il/isthe motor with both series and shvint fields, the latter being excited
when M S is closed. R S is a three-pole reversing switch shown in position for
the right-hand platform to ascend.
2. The controller has a starting rheostat, R h ; a hand lever, W; a spring lever,
T'; an underload release, U L : and an overload release, O L. The magnet U L
depends for its excitation upon the voftage of the motor terminals and also upon
the integrity of its circuit at any one of the four points — O L, R S, E, or F. The
main circuit from ill S is through the electro-magnetic brake E B, series fields
OL, to the contact piece b ; when the lever V is held down hjUL magnet, the
circuit is closed from h through cL V, W, R h (or direct after the motor has
attained full speed), to RS, 31 to 31 S.
3. The main circuit is broken either when the lever V is released (e and / taking
the spark), or when IT' is moved to the left (A; and Z taking the spark). The lever
V, when released by U L, is carried to the right by the spring at its axis until it
strikes TT'. The rheostat may be designed for running the motor continuously
at different speeds, or as a starting box not to be in the circuit longer than
thirty seconds.
4. S is a baby switch held open by a spring. Its object is to close, if desired,
the U L magnet circuit when open at E or F.
5. A and ^4. are the devices for automatically breaking the circuit through UL,
and thus the main circuit when the platform ascending strikes the lug g, which
is adjustable on the bar sliding in guides /;. On the lower end of this bar an
insulate copper wedge makes, when down, contact between two copper terminals
at E or F, and breaks it when up, thus making or breaking the circuit through
U L. E and F are alike and adjustable vertically 6 inches.
6. The right-hand platform is at its upper level, the left-hand is at its lower ;
the circuit through armatxire 31 has been broken and Fis up against W. If now
we try to start the motor without reversing R S, the circuit through Jf will still
be open at E. But throw R S down and the circuit through U L will be closed
at F, and the left-hand platform can be raised.
7. To start the motor at all, W must always be brought iip to the left, pushing
T' before it until held by the underload magnet U L; then irmay be moved to
the right, closing the circuit first through R h and at last withoiTt it.
8. When the left-hand jilatf orm, on nearly reaching its upper level, engages g
and opens F, the main circuit will be opened at h and the motor will stop.
9. If it is necessary to move the platform farther iip after the circuit has been
broken at E or F, the switch H may be closed and the platform may then be
moved by the motor. So long as S is closed V will not be released except for no
voltage or overload.
10. The motor may be slowed down or even stopped by moving W to the left,
provided R h is large enough to carry the current.
11. The electro-magnetic brake on the gear wheel next the motor armature
automatically clamps it whenever the main current ceases and the motor stops.
It gives a quick stop for heavy or light loads.
12. If the electric machinery is disabled the motor is quickly thrown out and
the Tilatf orm can still be raised by a crank handle and gearing.
(88)
ELECTRIC HOIST.
89
IX.— SEARCH=LIQHT PROJECTORS.
THE 60-INCH DIAMETER SCHUKERT SEARCH LIGHT
AT FORT MONROE (Fig-. 120).
With 150 ampei-es, at about 60 volts, it has 194,000,000-candlepower. On a
clear, dark night a person within its beam, 12 miles distant, can read ordinary-
print ; it lights np an object 2i miles distant with the brightness of the full moon,
and it will enable a person near the projector to distinguish, with the aid of a
glass, a vessel at 6 miles distance.
(A) THE U. S. GOVERNMENT PROJECTORS
Are supplied by the General Electric Company in the following sizes or
diameter of reflector :
Control.
(Hand, H: pilot
house, P; elec-
tric, E.)
Size.
Cl'RUENT.
Carbons.
Amperes.
Volts at Arc.
Positive- —
Cored.
Negative.
H. or P.
H., P. orE.
H. or E.
H. or E.
18"
24"
30"
36"
35
.50
SO
130
47-50
48-52
49-53
5f)-55
1 " X 12 "
1%" X 12 "
134" X 12 "
%" X 5" solid.
•V" X 7" cored.
%" X 7" cored.
1" X 7" cored.
All are fitted with true parabolic ground glass, silver-plated mirrors, as speci-
fied for .standard use in the Navy Department. The light reflected from the
parabolic mirror is whiter and more penetrating than from a s]3herical mirror.
121. Rheostat for U. S. Government Projector.
(90)
120. 60=inch Diameter Schukert Search Light at Fort Monroe.
SEARCH-LIGHT PROJECTORS.
91
All projectors are fitted with horizontal automatic ratchet-feed focusing lamps.
The lamps are designed to throw the greatest possible amount of light on the
reflector, and screen shutters are provided to prevent the direct rays from leaving
the projector, so that all the rays of light are reflected and sent out parallel.
Both positive and negative carbons are fed automatically at the same time,
and are so proportioned that the arc remains in the focus of the mirror until
they are entirely consumed.
The carbon holders or carriages are designed for vertical and horizontal adjust-
ment of the carbons, and by means of a magnet fastened on the inside of the
projector and surrounding the arc on all sides but the top, the arc is made to
burn steadily near the center of the carbons and in focus with the mirror.
In order to obtain the best results the carbons must be hard, homogeneous,
and of the best quality. Soft carbons fuse and make " mushrooms" which cut
out a large portion of the light and prevent the arc from burning steadily.
All projectors are designed to operate on direct current incandescent circuits.
A regulating resistance of G. S. ribbon (fig. 131) is placed in series wuth the lamp
to reduce the voltage, 80 or 110, to the proper potential, which varies from 40 to
60 volts, according to the size of the lamp and current consumed.
(B) METHODS OF CONTROIj.
1. The beam of light from the hand control projectors can be trained
vertically or horizontally by the operator standing at the projector and moving
the barrel in the desired direction with the handles. A star wheel, mounted on
the arm, clamps the quadrant part of the
trunnion and acts as a locking device by
means of which the barrel of the projector
may be held at any desired angle.
2. The pilot-hoiise control projectors, en-
tirely of brass (fig. 122), are mounted on top
of the pilot or other house and operated from
within. Both horizontal and vertical move-
ments of the beam of light are accomplished
by means of the same lever which is located
conveniently within reach of the pilot. The
projector may be locked at any desired angle
by turning the handle of the lever so that it
screws against the quadrant like a set screw.
It has conductor rings and brushes in the
base so that the projector can be rotated in
a horizontal plane. If the projector is to be
located at some distance, the above mech-
anism is adapted to rope belting.
3. Electrically controlled projectors (fig.
123) may be operated from a distance. They
have two electric shunt motors mounted in
the base of the projector, one motor operat-
ing a train of gears controlling the vertical
movement, and the other motor operating
another train of gears controlling the hori-
zontal movement of the projectors. These
motors are regulated by a controller con-
veniently located and connected to the pro-
jector by seven condvictors. The movement
of the beam of light corresponds to the
movement of the handle of the controller,
and both horizontal and vertical movement
can be obtained at the same time. On
releasing the handle of the controller, it is
brought back by a strong spring to the
neutral position, short-circuiting the arma-
tures of the motors and holding the projector locked in position. An electrically
controlled projector can also be operated as a hand control projector, by open-
ing the circuit switch on top of the controller and releasing the clutches con-
nected to the motors in the base of the projector.
The drum rotates on its trunnions and can be elevated 70' above and lowered
30° below the horizontal position. The turntable can be revolved freely in
either direction in a horizontal plane.
122. Pilot^House Control.
93 HANDBOOK FOR ELECTRICIANS.
With electrical control, the highest speed obtainable in the horizontal plane
is a movement of 360° in thirty seconds, and in a vertical plane 100° in sixty
seconds. The motors may be operated at four slower speeds and also by steps,
the angle of each step being less than a degree, that is to say, about one third
of the area covered by the beam.
4. In general the projector is designed to take either a spherical or a parabolic
mirror. The trunnions being mounted on slides, allow the drum to be balanced
with either mirror. The mirror is so mounted in a brass frame that it is securely
protected against concussion and provision is made for expansion due to heat.
The plciin front door, used when long range and small area of beam are
required, is composed of strips of plate glass.
When i)rojectors are required to furnish a beam of light covering a wide area,
at shorter range, the front door is made iip of strips of glass ground i^lano-convex,
each strip being a lens, with the convex side outward. The beam of light pass-
ing through this door is diverged, making it wider but not increasing its height.
These diverging doors are for either 10% 20°, or 40° divergence for any projector.
(C) IS^UMBER A:N^D IN AMES OF PARTS.
1. The hand -control U. S. projector is complete with the following parts:
The base with all the gears; turntable with arms and drum; 1 mirror; 1 front
door with plain glass ; 1 front door with diverging glass ; 1 box for front doors ;
1 lamp; 1 rheostat; 1 canvas cover; 125 positive carbons in tin boxes; 125 nega-
tive carbons in tin boxes ; 1 extra set of plain glass front door strips in plain
wooden box. One tool box containing the following articles : 1 crank-handled
socket wrench for lamp feed; 1 wooden -handled socket wrench for ad j listing
carbons ; 1 smoked glass with frame ; 1 dust brush ; 1 small dusting brush for
lamp ; 1 chamois skin for polishing mirror ; 1 spare spring for starting magnet ;
1 spare spring for feeding magnet ; 1 contact spring ; 1 contact screw ; 2 round
smoked glasses ; 1 round ground glass ; 2 pairs of carbon holder clamps, screws,
and washers; 43 extra lava insulators ; Ismail wrench for 8-32 and 10-32 nuts.
2. The pilot-house controlled projector has the same apiiaratus, except pedes-
tal, but in addition rope and guide pulleys.
3. The electrically-controlled projector is' furnished complete with the same
parts as the hand-controlled projector, together with the following additional
parts : 1 controller stand and canvas cover ; 1 controller cable 25 feet long, with
connecting plugs at each end ; 1 controller receptacle ; 2 pairs of carbon brushes
for motors ; 2 20-ampere fuses for controller ; 6 8-32 nuts.
(D) INSTALLING PROJECTORS.
The arrowhead, which is cast or painted on the base or the pedestal of the
projector, should point aft. Otherwise, the maximum allowable motion of the
projector can not be obtained on account of the stop pin which is inserted to
prevent twisting the cables.
The current should be led directly from the switch board in the dynamo room
to a switch which should be mounted near the projector. A rheostat should be
placed in series in the circuit, and also an ammeter to indicate the current.
1. Hand control projectors are shipped assembled, so that they may be imme-
diately bolted to their place. When the lamp is inserted and the necessary con-
nections are made to the supply wires the projector is ready to operate.
2. For i)ilot-house control projectors, select a desirable position on the house
roof for the location of the projector, and cut a hole through the roof nearly the
diameter of the inside of the low base ; disconnect the handle and bow from the
lower end of the rod and shell, and bolt the projector over the hole in the roof,
using a gasket between the base and the roof to keep out water. The arrow-
head on the base should point aft. When the projector is in place, the bow and
handle can be replaced, and care should l)e taken to see that the handle points
in the opposite direction from the beam of light ; for example, when the beam
is thrown forward the handle should point aft. The studs and terminals are
marked -f- and — . The operating mechanism of the rope control consists of two
small drums which are connected to the operating drums on the projector by
ropes.
3. The E. C. projector, mounted upon a low truck, stands by itself under can-
vas cover in a dry, dust-proof, sun-lighted room, from which it may be run out
to any desired point within 1,000 feet of the switch board and dynamo, and is
sui)plied by means of twin-core cable. The controller cable should permit the
controller to be operated at 150 feet distance from the projector. The connec-
tions and installation appear under head (F) page 97.
SEARCH-LIGHT PROJECTORS.
93
(E) liAMP MECHANISM OF AEI. PROJECTORS.
1. Parts of lamp mechanism are as follows (fig. 124) :
A, negative carbon holder. 31, fixed nut for focusing screw.
B, positive carbon holder. N, stud of lamp switch for cutting out
C, clamping screws for carbon clamps. feeding magnet.
D, vertical screw positive carbon clamp. O, ratchet and pawl.
E, horizontal screw positive carbon P, feeding magnet armature.
clamp. Q, contact of circuit breaker.
F, negative carbon support. R, adjusting screw for ratchet arm.
G, positive carbon support. S, starting magnet.
H, lamp frame. T, feeding.
K, main lamp contact shoes. U, adjusting spring for feeding magnet.
L, hand feed screw.
2. Placing the lamp in the drum. — The lamp may be lifted by the top plate,
but it should never be lifted by the carbon supports, as the strain due to its
weight is liable to spring them out of their correct position. The 18-inch and
24-inch projectors have obturators which prevent carboning the lamps before
they are placed in the drums. The drums of these projectors are, however,
sufficiently la;-ge to readily permit adjustments of the carbons after the lamps
are in place. When inserting the 18-incli or 24-inch lamp in the drum, the
125. Obturator.
shutters of the obturator should be opened and the arc magnet turned so that
the opening is downward. This adjustment may be made after removing the
pin on the side. The lamp may now be placed in the i^rojector, the arc magnet
returned to its proper position, and the shutter of the obturator closed.
3 Carboning the lamp. — The carbons are placed horizontally in the focal
axis of the mirror. The positive carbon should have its crater toward the
mirror. The projectors are intended for use on circuits of 1 10 volts, and a regu-
lating rheostat is furnished with each i^rojector to provide the necessary voltage
at the lamp terminals. The rheostat is shipped to conform with the voltage of
the circuit, which should be stated when the projector is ordered. To obtain
the best results, the rheostat should be adjusted once for all according to the
volts and amperes given in the table at the head of this article.
94
HANDBOOK FOR ELECTRICIANS.
The carbons must be of the best quality. Hardtiuuth and Schmeltzer carbons
are satisfactory.
In placing the carbons in the lamp, separate the carbon holders as far as pos-
sible by turning the feed screw. The larger, or positive carbon, should be
placed in the clamp nearest the ratchet mechanism. Adjust the carbons so that
they come in contact with each other exactly above the white line on top of the
lamp. This line should coincide with the white line inside of the drum when
the lamp is in place. The carbons should also be adjusted so that 'their axes
coincide. Readjustment of the carbons is necessary from time to time so as to
keep the crater in the center of the positive carbon and not allow it to burn
off at the edge. If the crater becomes displaced on account of impurities in
the carbons, the carbons should be readjusted so as to form a new crater in the
correct position.
4. Operating the lamp mechanism (figs. 126-7-8). — (a) After closing the main
switch, the carbons will begin to feed toward each other until they touch, and
the circuit will be completed, so that the starting magnet will draw the carbons
apart about \ inch, thus striking the arc. As the carbons burn away the arc
becomes longer and the voltage across the arc increases. More current is thus
compelled to pass through the feeding magnet in shunt with the arc. Its armattire
immediately breaks the circuit through the coil and then flies back, thus mov-
ing the pawl and turning the ratchet at the end of the feed screw.
STARTirOG MAGNET
negative Car-foo Can-ier Positive Car-borv Carrier
W U U)
Coils f"or the starting magriet of^ ZA' lamps ai~G
connected in multiple as sl-iowo
Coils Tor IO'30'ancJ 36' lamps sx'e connected in series-
Contact Snos
FEEDING MAGNET
Feeding magnet Circuit Breahof
SvA/itcn to cut out
reeding magnet
126. Connections of 18, 24, 30 and 36 inch Automatic Projector Lamps.
(b) Focusing the lamp. — After starting the lamp, focus it with relation to
the mirror by watching the rays. When the rays diverge, the arc is too near the
mirror, and when they cross at some distance from the projector, the arc is too
far from the mirror. The proper distance between the arc and mirror is
obtained 1)y moving the lamp backward and forward by means of the focusing
screw. The light will not be satisfactory unless the lamp is in focus, and the
operator must, therefore, never neglect to focus the lamp before using the
projector.
(c) When the arc is in the focus of the mirror the image of the carbons will
fall on the ground glass of the vertical peep sight (see S, fig. 128a) so as to show
the positive or larger carbon just touching the vertical line.
(d) In the 18-inch and 24-inch projectors the focusing screw is arranged to
screw into the back of the lamp and is fastened permanently to the projector.
The lamp should, therefore, be so placed that the thread of the focusing screw
catches and draws the lamp into focus.
SEARCH-LIGHT PROJECTORS.
95
(e) If the carbons are placed as described and the lamj) placed in the drum so
that the two lines referred to under "Carboning the Lamp" coincide, the arc
will be so nearly in focus that but little adjustment will be necessary.
(/) The lamp should be kept clean and free from carbon dust which occa-
sionally drops from the carbons while burning.
(g) The feed screws may be oiled when necessary with a small amount of
good clock oil, but care should be taken to carefullj' wipe them after oiling, as
otherwise small particles of carbon dust may adhere and cut the thread. The
carbon carriages and parts carrying current should never he oiled.
(h) As a few slight changes will be found in lamps constructed in different
years, reference is made to figs. 127-8, alike lettered, from which the plan of oper-
ation of all will be readily understood.
127. G. E. Search Light.
The springs A take current from leads to the contact rings of the pedestal,
the path of the current being shown in fig. 128.
The carbons are secured in clamps B on supports C, the supports being mova-
ble in guides of the frame and controlled by screw-bars I) and E. The larger
clamp is for the positive carbon, in which the crater is formed and which will
therefore be the farther clamp from the projector mirror, i^is the automatic
feed, shunted from the lamp leads, having an electro-magnet G, which controls
the armature H, and which in turn operates the screw-bars D and E through a
pawl -ratchet -F, and gearing J, when the voltage in the magnet is above 60 to
52 volts. K is the series-striking arc magnet which operates only when the cur-
rent is much in excess of that required for the lamp. A lug on its armature
embraces the screw-bar D between two collars. The screw has a small play at
L which is independent of the control of the automatic feed. Owing to the gear,
the screw-bar D revolves but one-half as fast as E. E can also be turned by a
removable crank socket wrench at T.
The naethod of operation is this: The carbons are first adjusted by the crank
wrench to a separating distance of about half an inch. The automatic switch
M should now be closed. The main switch is closed next, and, as no current
can pass until the carbons touch, the voltage across the carbons up to that
moment must be 110 volts. The shunt magnet (called the feed) commences to
vibrate, the voltage being greater than 52 volts, and feeds the carbons together
by means of the pawl and the gear wheels of the screw bars. "When the carbons
touch a heavy momentary current passes (since the resistance is small and volt-
age at 110), the armature of the striking arc magnet is attracted, pushes back
96
HANDBOOK FOR ELECTRICIANS.
of itself. Horizontal lamps
a tendency to flame at the
the negative screw bar and forms ("strikes'") the arc. The resistance of the
rheostat, in circuit when first set iip, causes a drop of 50 to 60 volts as soon as
the current passes, and should be adjusted by the lever to the voltage necessary
for running the lamp without flaming and hissing. The voltage required in
practice is usually from 45 to 49 volts ; the feed will frequently operate at 50
volts. The working current for the lamp varies with the size of the lamp and,
incidentally, with the size of the carbons ; it is as great as 75 to 90 amperes for
the 30-inch projectors, and from 25 to 35 amperes for the 18-inch type.
There is often some flaming of the carbons which can not be controlled by the
rheostat ; it is unimportant except from the fact that it decreases the intensity
of the light; it will usually disap-
pear
have
upper edge of the crater, thereby
forming the crater on the upper
edge of the positive carbon and dis-
torting the reflection ; this tendency
is corrected in some projectors by a
horseshoe magnet, attached to the
diaphragm in the projector, which
draws down the arc by magnetic
attraction.
Some hissing will occur when
starting up, especially with new
carbons, and the lamp will not quiet
down until a good crater has been
formed in the positive carbon. This
can be obviated by reaming out a
crater in the positive carbon with a
penknife before putting it in the
clamp.
Flaming and hissing are promoted
by inferior carbons and are much
increased if the carbons have ab-
sorbed oil. Those now provided are
of the Schmeltzer manufactiire and
are very homogeneous ; the positive
carbon is iisually bored axially and
cored with a soft carbon, which
materially assists in maintaining
a good crater. Negative carbons
are sometimes cored, but it is an
open question whether this expe-
dient does not conduce to the forma-
tion of mu.shrooms. Carbons are
128.
Lamp Details Showing Method of
Operation.
packed in tins and should be kept povered in a dry place, as they readily absorb
moisture.
The momentary current of short circuit, when the carbons touch, is ordinarily
heavy and quite sufficient to throw the pointer of the ammeter clear across the
scale and against the stops ; it need occasion no apprehension if it does not con-
tinue ; if it does, the switch at the switch board should be qtiickly opened. This
current may be as much as 50 per cent above the working current.
Any abnormal current of the searchlight ammeter is usually traceable to
either a mushroom on the negative carbon or careless handling of the socket
wrench. In most cases of fusing of the contact plungers in the pedestal there
is direct evidence of an attempt to regulate the feed by hand when the auto-
matic gear is switched on. If the lamp does not feed, it is for the reason that
there has been a burn out, or that the lamp itself is not clean, and in 90 per cent
of the cases dirt is the cause ; any attempt to remedy matters by use of a socket
wrench, while the current is on, is quite sure to short-circuit the lamp and pro-
duce overload.
The mushroom appears as a small protuberance on the end of a carbon and is
of a pasty consistency. It can readily be removed by the end of a screw-driver.
Ordinary attention to the working of a lamp should guard against its forma-
tion. It will caiise the carbons to adhere.
SEARCH-LIGHT PROJECTORS.
97
(F) CO:N^:n:ECTIOI^S A:N^I> i:N^STAIiI.ATION of U. S. EliECTRIC
COlS^TROLIiED PROJECTOR.
128a. Parts of Projector and Controller.
1. Parts of jirojector and controller are as follows:
hand star wheel for slow vertical movement,
wheel for throwlnji out split nut used for connect-
ing or disconnecting the drum from the base
mechanism.
wheel for slow horizontal movement,
hand star wheel for clamping turntable to center
pin for electrical control.
wood handles on drum for moving drum b,y hand,
hand wheel for clamping hand star wheel .1 when
electric control is used,
controller switch,
controller handle,
controller fuse bo.\.
controller coupling for connecting cable from the
projector,
focusing screw
i,
socket for inserting wrench to operate lamp switch
used for cutting out feeding magnet,
socket for inserting wrench when feeding by hand,
door used for adjusting the carbons and for clean-
ing the front door.
door used when carbons are to be a.
held by drop of coiio- 3. In a dynamite or gelatine cartridge ( 147), punch with ahard-
dion ; k, plug of beech- wood pin a hole in the lower end or middle, 1 inch longer than
^°°'^" the detonator and without removing the paper cover. Press
the cartridge to close the
mouth of the hole after
insertion, and lash with
string the wires along the
cartridge. Half hitches or
other tying of the wires
may cause short circuits.
IV. — To fire with a battery. — See that all persons are distant or protected;
attach the leads ; close the switch firmly'; detach the leads.
Before using the battery ascertain from its constants and external resistance
• if it can supply the necessary current strength to each fuse. In no case can this
be less than the current given for ignition, nor be more than 25 per cent in
excess. If the fuses are two in parallel, instead of all being in
series, double the current will be required.
V. — To fire until the service dynamo. — 1. If no one is near
the mine or gun, connect the leads to the posts ; seize the handle
with one hand ; steady the box with the other ; lift the ratchet-bar
to its full length, then press it down quickly with constant
force until the bar strikes the bottom with a thud, when the
fuses will be fired ; detach the wires. Churning the bar up and
down to fire is useless and harmful.
When there are three binding posts on the box (fig. 148) and
the number of fuses is small, join the leads to the middle and
either outside post ; when the number of fuses is large, join the
the main leads to the outside posts and run a third lead from
the middle post to a point midway of the fuses in series.
2. In case of failure to fire when the number of fuses does not
exceed the capacity of the battery or dynamo, there is probably
a break, a poor joint or a contact between the two leads. The
leads being detached, go over the whole circuit, lifting up the
wire in search of a break inside the insulation, examining the joints and watch-
ing for contacts. If this fails to reveal the open circuit, locate it by use of a
single high resistance cell and the fine wire coil of the detector or other Galv. of
sufficient resistance to keep the testing current below ^V ampere.
8. If trouble is suspected in the dynamo, try a fuse tlirough a resistance ; or, if
after removing the endboards, a spark is seen at the short-circuiting key when
the bar strikes it, the dynamo is in order. The resistance between the two bind-
ing posts should be zero when the bar is up and about 6 ohms when i^ressed
146.
147.
MISCELLANEOUS APPARATUS.
Ill
down hard. When there are three posts and the bar is tip, the R between the
left-hand and middle ones, looking at them from their side of the box is 0, and
between the middle and right ones, infinity.
YI. — Precautions in firing fuses are as follows:
The last thing done around a mine or a gun is the joining
of the fuse wires to the leads.
At the battery or dynamo just before firing, attach the
leads to the posts.
Place battery or dynamo in a safe place and as near the
mine as safety permits.
A rough test of the generator just before firing can be
made by its bringing for an instant to a barely perceptible
red, a certain length of platinum fuse wire ; or by firing a
single fuse through a given resistance.
The service dynamo will fire a very few fuses joined two
in parallel.
In jointing, scrape clean the ends, wind closely, solder
if convenient, with resin for the tius, and in all cases wrap
the joint with tape.
Fuses must be kept in a dry place remote from explosive
or strong acid, and should be tested before using.
Fuses varying 10 per cent or more from their specified
resistance are rejected.
Put detonators under test in a safety box ; never turn a
detonator toward a person.
A detonator must on no account be bent, struck, heated
or roughly handled.
Avoid strain on a fuse by hitching a tension string from
the charge case to the fuse wires.
For certainty of ignition of a single important charge,
two fuses are connected in parallel.
Always use fuses of the same kind in a circuit. Lead
wires have double the diameter of fuse wires.
Guard againtst injury to insulation in tamping, and bare
wire at a joint or other point in the circuit.
148.
30=Fuse Firing
Dynamo,
(C) EliECTRIC BELLS.
,/rT:.,
.^-
1. Electric bells are of two kinds — single stroke (fig. 149) and vibrating.
In the %Tibrating bell (fig. 150), the armature is held by a spring, C, against i?,
adjustable at D. The key K being closed, a current flows through L, P, B, F, C,
E, P', K and L, attracting the armature, striking the
gong and breaking the circuit at B. As no current
now flows, the spring at C throws the armature back
against B, reestablishing the current which acts as
before. Both contact points, B and F, are of platinum
to prevent corrosion by the spark.
2. Trouble in bell circuits is usually due to dirty
contacts at B and F, or to some part of the circuit
touching the metal frame or to a break in tlie circuit,
usuallj^ at a
binding
post, key or S~
joint. Use L.
insulated
wire only;
fasten wires
under composition staples without bending the wire ; keep parallel wires one-
half inch apart ; never run two wires under the same staple or through the same
hole ; solder splices, and cover with insulation.
To ring two or more bells, each with its own button, by means of one battery,
see fig. 151.
To ring one bell with one battery from two or more buttons, see fig. 152.
151.
112
HANDBOOK FOR ELECTRICIANS.
(D) THE ANEMOMETER (FIG. 153).
The anemometer measures the velocity of the wind in miles per hour.
1. It should be placed on top of a telegraph pole or other support without
vibration, erected on the highest site in the vicinity. Any obstruction within
500 feet of the site and 10° or more above it is objectionatjle, as the velocity of
the wind is diminished by friction from 20 to 50 per cent within 100 feet above
the ground. Two wires run from it to the distant register.
2. Four brass cups, C, on the ends of arms, in a wind, turn a vertical shaft,
A, whose screw thread, B, is geared into wheel, D. Two D-shaped lugs on the
wheel are arranged as shown to close momentarily an electric circuit every 25
revolutions on a single-stroke bell, every 500 revolutions on a self -register, and
permanently during 25 revolutions on the stop clock. The wheel must be spe-
cially constructed for each of the above registers ; for the stop clock the two
D-lugs are replaced by a semicircular ridge join-
ing their positions, which then closes the circuit
during one -half revolution of the wheel.
3. To get roughly the velocity of the wind in
miles per hour with the single-stroke bell, connect
up anemometer, bell, and battery, as in fig. 153.
Note by means of the secondhand of an ordinary
watch the number of seconds between two con-
seciitive strokes. Divide 180 by that number.
Example. — The seconds hand stood at 32 when
the anemometer rung the bell and at 47 at the
next stroke. Required, the velocity. Interval =
15 seconds; 180 -t- 15 = 12 miles an hour, approx-
imate.
4. Anderson's stop clock performs the above
avitomatically and more accurately, its electro-
magnet taking the place of the bell's magnet in
fig. 153. Its single second's hand moves over a dial
A S3? ('A c^ij having two scales — the inner one representing in
^ ^ ^ ?' ' '^ ^^^® usual way seconds to a total of 60, the other
-, ^\o Xh 1 1 ppale of unequal parts, velocities in miles per hour.
Experience shows that the velocities are a little
greater than those given by the above rule.
By means of a lever and cam, the seconds hand
can be brought to the vertical or position from
any other on the dial. A very light spring on the
movable end of the armature bears normally
against the balance wheel and thus keeps the clock from running ; when the
magnet is energized from the anemometer, the armature both releases and starts
the balance wheel, and the clock runs while the cups make 25 revolutions, or
the air, ^^^ mile ; the armature then released stops the clock.
To operate: Close the circuit; bring the hand to 0; if it then starts, the
anemometer has closed the circuit and it will be necessary to wait until the hand
stops, when reset it at 0. In a few moments it will automatically start and later
stop and register.
5. Gibbon's self -register (fig. 154) has an electro-magnet in the place of the
bell's magnet of fig. 153, and a 4-inch diameter drum revolved uniformly and
translated longitudinally by clockwork so that the point of a fixed pencil will
describe a spiral xipon a sheet of paper laid upon the drum's surface. The
pencil is held at the movable end of the magnet's armature. The paper is ruled
parallel with the drum's axis into five minute spaces.
Whenever the anemometer, after the connections are complete, makes about
500 revolutions, corresponding to points moving with the wind exactly 1 mile
apart, it closes the circuit and the pencil makes a sharp dent in the spiral.
To put the sheet on the drum, place the cylinder S on a table with the screw
rto the left-hand; place the paper on the cylinder with the top of it from the
screw. Let the line marked 12 noon come on the line of the cylinder, and place
a rubber band on each end. The lines at each end of the paper will then exactly
coincide. Place the cylinder S in its position, so that the end opposite to the
screw T will be near the post on which it rests. Slide the small sliding bar on
the horizontal bars O O until it fits on the ends of the screw-axle T; then
revolve the cylinder until the pencil rests on the end of the upper line marked
12 noon, or the line corresponding to the hour at which the instrument is set,
and tighten the thumbscrew N.
153. Anemometer.
MISCELLANEOUS APPARATUS.
113
To obtain the velocity from the self -register take the number of spaces and
parts of spaces between the mile marks recorded in the five minutes preceding
the time of observation and multiply the result by twelve.
TO ANEMOMETER.^ .iiiii i i n tii «|i|i
154
FROM ANEMOMETER.
Ex: Suppose the number of spaces indicating mile marks between 8.55 and
9 a. m. were li; then the velocity of the wind is 1^ X 13 = 15 miles per hour.
When the velocity is less than twelve miles per hour the velocity will be
determined as follows : If the interval between the last two mile marks is 7
minutes, then the current hourly velocity will be obtained by dividing 60 by
7 = 8| miles.
6. The velocity of the wind may be roughly estimated ^\dthout anemometer :
pe^H^...
Apparent Effect.
1 to 2
3 to h
fi to 14
15 to 24
25 to 29
40 to 59
60 to 79
No visible horizontal motion to inanimate matter.
Causes smoke to move from the vertical.
Moves leaves of trees.
Stoves small branches of trees and blows up ilust.
Gooil Kiilins lireeze, and makes white caps.
Sways trees and breaks small branches.
Dangerous for sailing vessels.
Prostrates exposed trees and frail houses.
Prostrates everything.
Li^lit _
Gentle
Fresh
Brisk
High
Gale
Hurricane
80 or more
To find the pressure of the wind in pounds upon a surface exposed perpen-
dicularly to the wind, multiply together, 0.005, the surface in square feet, and
the square of the velocity of the wind in miles per hour. Or, P = 0.005 .S'T"-.
7. Care of Anemomeier. — Keep mechanism clean and bearing parts oiled with
clock oil. The anemometer should be compared every season and found to
agree with at least two others supposed to be in good order.
1714—8
XII.— PRIMARY BATTERIES.
, (A) GENERAL DIRECTIO]PsrS.
1. When any two different metals are partially immersed without touching
in a liquid which acts more upon one than the other, the combination forms an
electric cell; if a wire joins the metals outside the liquid, a current of electricity
will flow around the circuit thus formed. Zinc is usually one of the metals or
plates ; copper or carbon is the other and its upper part is the positive pole of the
cell. Sometimes two liquids are used — each around its own plate — and kept
separate by a porous diaphragm or by gravity.
2. The current from an electric cell diminishes after a time more or less rapidly,
due chiefly to three causes : ( 1 ) impurities in commercial zinc, causing local
action ; (2) the production of new and hurtful compounds m the cell ; and (3) polar-
ization, or the formation on the copper or negative surface of hydrogen gas which
not only increases the resistance of the cell but tends to make the poles alike.
(1) Local action is remedied by coating the zinc surface with
•* fl 0/) ' ', -•, 1 r, mercury, a process called amalgamation; (2) hurtful compounds
«ULx.yJlJl!<>Lx.^ are removed from time to time; (3) polarization is partially or
|_ ^ -/vZfi wholly checked by enlarging and roughening the surface of the
vo e ' negative plate, or, preferably, by surrounding it with an oxide or
other substance, termed a depolarizer, which takes up the hydro-
gen as it forms.
3. Management. — (a) In mounting, see that all the parts are
clean, the bearing surfaces of connections brightened and the
connections made tight by using English binding posts, or doiib-
ling the wire througli holes too large, so as to fit. Use only rain
water and the best materials. Do not spill liquid or salt over
155. Typical, p^rts to remain dry. The two plates of a cell should not touch,
nor any two cells of a battery. Cells of different kinds are never joined in the
same battery.
(?)) For proper maintenance all cells should have covers to prevent evapora-
tion, all zincs in acids should be amalgamated to prevent local action, and rims
of jars should be dipped about an inch in melted paraffine to prevent salts from
creeping over. Keep cells well instilated on porcelain holders or paraffined wood
in a dry, cool and clean place, especially free from dust and change of tempera-
ture. The cells are preferably arranged in single rows on shelves accessible
on both sides and having a hood to carry off the gases. Direct sunlight on
glass jars may crack them.
The battery room, dry, light, ventilated, and with cement floor, should have a
sink with entrance and exit water pipes, and such facilities as spare jars, pitcher,
scales, brushes, syringe, hydrometer, funnels, graduated glass and mercury
dish. All trace of grease or soap must be excluded.
(c) After dismounting, all battery parts are cleaned while wet. Scrape off old
salt and crust, and nib with a brush until a bright surface appears. If plates
are greasy, soak in strong soda solution. Carbon plates and porous cups are
soaked in water several hours. Re-amalgamate the zincs. File or rub with
emery the connections, and finally dry, reparaffine and repaint with asphaltum.
Varnish the tops of plates.
4. Amalgamating ^/?jcs.— First clean the zincs, then dip in sulphuric acid
solution ( J(y), or any old acid solution, about one minute. Then transfer it to an
open shallow dish of iron or porcelain whose bottom is covered with mercury
and a little of the solution. While turning the zinc over so that every part
comes into the mercury, rub the surface with a swab made by winding cloth
around the end of a stick.
Or, mix, by weight, 1 part nitric and 2 parts hydrochloric (muriatic) acid and
add slowly i part mercury. When dissolved add 3 parts more of hydrochloric
acid and stir. Clean the zinc with potash and water; immerse in the above
solution for a few seconds. Rinse in clear water and rub ^\'ith battery brush.
T). Solutions are mixed in large jars to obtain uniformity by pouring in first
rain or pure water, and adding the acid slowly while stirring. Let the mixture
cool and settle and do not use the sediment.
(114)
PKIMARY BATTERIES.
115
156. Sampson.
up the
6. The desirable qualities of a cell are (1) a large and constant E, (2) a small
and constant R, (3) cheapness of materials, (4) no waste of materials when not
giving a current, (5) easily inspected, (6) easily refreshed, (7) no offensive
fumes, (8) first cost small. No one cell has all of them.
7. Several cells of the same kind and size may be united in series, parallel or
both, to form a battery. The two forms of battery are the primary and
secondary. .There are five different kinds of primary in general use — Leclanche,
dry. gravity, copper oxide, and bichromate.
(B) SPECIAL DIRECTIOl^S.
(«) Leclanche Cell (Fig. 156)
1. A zinc rod, or cylinder, and a carbon cup containing a mixture of nearly
equal amounts of broken carbon and manganese bioxide stand in a saturated
solution of sal ammoniac, j^ = about 1.48 volts; i? of 5
by 7 inch cell with zinc rod is about 1 ohm.
2. The Leclanche furnishes a strong current for a short
time, but it soon begins to polarize. Left on an open circuit,
it regains its strength without the consumption of material.
It is useful for intermittent work only.
3. Mounting. — Fill the jar about one-third full of water and
stir in about 4 ounces of sal ammoniac, so that there may not
remain an excess of the white salt. Put in the two plates
with cover. Liqiiid is about 2 inches from the top. If
porous cup, let the cell stand twelve houi's before using ; or
better, fill the cup with solution through the gas hole in the
seal. If prisms, they are held tight against the carbon by
two strong itibber bands.
4. Maintenance. — Add water as it evaporates and a little
salt as the current gets weak. Wipe off the first trace of
white salt forming on the tops of parts due to carelessness in setting
cell. Hard scale on plates shows that the solution is too strong.
Never leave the cell on closed circuit and for safety detach both poles when
the cell is not required. If a Leclanche fails, examine the connections, or add
a little salt, or replace the solution with new, or soak carbons in hot water for
three hours, or scrape off the hard scale, or fill carbon cup with fresh mixture,
or throw away all except the jar.
A green salt forming on a binding post is cleaned and the metal part is recoated
with asphalt. One carbon outlasts three zincs; one zinc rod gives 30 to 40
ampere hours.
{h) The Dry Cell (Fig. 1.57)
Belongs to the Leclanche class. A zinc can enveloped in pasteboard, and
always having a sealed cover, serves both as jar and plate.
1. The central cylinder of carbon and manganese oxide
is surrounded by an absorbent or gelatinous body well soaked
in an exciting solution of 1 part (by weight) sal ammoniac,
1 part Zn. chloride, 3 parts plaster, 2 parts water. The
ingredients are often kept secret.
2. £"=1.4 volts, and R = about 1 ohm for a 5-inch cell.
Its ampere hours is less than for a liqiiid Leclanche. But
it is cheap, portable, may be laid in any position, and kept
for a long time if not overworked and if the inside moisture
does not escape. A good dry cell may ring a door call bell
eighteen months.
3. If it fails, bore a small hole in the seal and inject
water. If its strength is regained, seal up the hole tightly;
otherwise throw the cell away.
(c) Gravity Cell (Fig. 158).
1. A zinc plate, Z, stands in a solution of zinc sulphate,
and a copper plate, C, in a solution of copper sulphate
(bluestone) , the copper being at the bottom. E — about 1.08
volts. i2 of a 6 by 8 inch cell in good condition is about 3
ohms. The gravity gives a steady current in a closed cir-
cuit and is employed for continuous work only. Good forms are Crowfoot
and Eagle.
157. Drv Cell.
116
HANDBOOK FOR ELECTRICIANS.
1S8. Gravity, Crowfoot.
2. Mounting. — Unfold the leaves of the crowfoot copper so as to form a cross,
place it in the bottom, bring its wire up straight and bend it sharply over the
edge for a clamp. Drop in crystals of copper sulphate, about three pounds, to
the top of the leaves. Pour in rain or soft water until it covers the zinc, put on
the cover and short-circuit for two or three days. If
wanted sooner, let the water come to within an inch of the
zinc and then pour carefully on top a solution of 3 ounces
of zinc sulphate in sufficient water to cover the zinc, or
zinc solution from an old jar, if clear, or a little sulphuric
acid.
3. Maintenance. — The cell is in good condition when the
lower copper solution has a deep blue color up to the point
midway between the plates and tlie upper zinc solution, of
1.1 specific gravity, is clear like water, and when the divid-
f^\ ^^ ing line between them is sharp. If the blue rises higher,
'^f\' I reduce the external resistance or short-circuit ; if it sinks
much below the middle, leave it on open circuit a few
hours. The cell normally should remain closed on a resist-
ance and never jarred nor the plates within be disturbed.
Copper sulphate crystals should always be seen in the bot-
tom. When the zinc solution becomes too heavj^ causing
salt to form on the upper parts and copper on the zinc, or
the specific gravity reaches 1.2, remove the top liquid by means of a syringe to an
inch below the zinc, and replace with water slowly, so as not to distiU'b the
solution below. When metallic copper forms on the zinc, take out the plate,
scrape off the mud, chip off any cake formation, and after dropping in large
crystals of bluestone (if needed), replace the zinc and cover.
4 Dismounting. — Take out the plates and save the top clear liquid to start the
new cells. With a hammer and knife remove the hard crust from the zinc and
the deposit from the copper. See that the attached wire
is firmly riveted to the copper plate and that there is no
break in the insulation.
5. The Eagle cell isfovportahility. — Fill the lead jar (fig.
159), whose inner surf ace has been brightened, one-third or
one-fourth full of cojjper siilphate and cover with two-
inch thickness of pressed excelsior, sponge or sawdust on
which rests the zinc. Wooden sticks suspended from the
rim prevent the zinc from touching the jar. Pour in
water until it covers the zinc and short-circuit for three
or four days. Let the jar stand on wood soaked in
paraffine or on glass.
(d) Copper Oxide Cell (Fig. 160).
159. Eagle.
1. Plates of zinc and of copper oxide stand in a one-
fourth sohition by weight of caustic potash. J5' = about 0.8 volt. R of the
5 by 8 inch cell with oxide between two zinc plates is
about 0. 07 ohm. The cell is for either continuous or inter-
mittent work.
2. Mounting. — Place the potash in the jar, and pour in
water until its level shall be i inch above the oxide plates
when in j)osition. Stir with a stick at intervals so as not
to cause too great rise of temperature until the salt is dis-
solved. Pour carefully on top heavy paraffine oil so as to
form a layer i inch thick.
Pass the ends of zincs, well amalgamated, through the
middle hole of porcelain cover and fasten them. Put the
copper oxide plates in their frames, slip on the hard riib-
ber separators, pass the ends of the frames through the
holes in the cover and fasten them. Put plates and cover
in position. If a strong current is wanted at once, short-
circuit for ten or fifteen minutes.
3. Maintenance.— If necessary, move the cell without
shaking. Glass jars are liable to crack. The top layer of
oil is very essential and the level of the dividing line previously marked on the
jar inside should be well above the oxide plates. There is no local action on
oi)en cii'cuit. All materials are i)roportioned to be consumed in i^ractically the
same time.
J 60. Copper Oxide.
PRIMARY BATTERIES.
117
(e) Bichromate Cell (Fig. 161).
1. Zinc and carbon plates stand in a solution of sulphuric acid and bichromate
of potassium or sodium. E = 2.1 volts. -R of 6 by 8 inch cell with zinc between
two carbons = about 0.08 ohm.
The Grenet zincs are submerged only when a current is required.
The current is very strong for a few hours.
2. Mounting. — To 1 gallon of water in an earthen vessel add from
1 to 2 pints of sulphuric acid, according to the strength reqiiired.
While the mixture is still hot stir in one pound of bichromate of pot-
ash pulverized. When cool it is ready for use and is known as elec-
tropoion fluid.
3. Maintenance. — Special care is taken to keep zincs well amalga-
mated; they should, when siibmerged, reach to the bottom of the
jar so as to toiich a little mercury. The zincs are
raised oiit of the solution when not in iise ; the carbons
may remain or not. DraAv off some of the old liquid
when it changes color and add fresh.
4. The Fuller bichromate (fig. 162) is used with long-dis-
tance telephones. Pour an ounce of mercury into the porous
cup, 3 by 7 inches, put in the zinc, fill the cup with water
and stand the cup with its contents in the jar containing, by
weight, 6 parts sodium bichromate, 17 sulphuric acid, and 56
water. Alongside put in the carbon with its cover.
The zinc remains continuously in the cell, which needs no atten-
tion for four or five months if not overworked ; otherwise once
162 F II amonth. There is very little local action on open circuit. When
the rich orange color becomes bluish, add crystals. If the color
is still orange and the cell weak, add acid. If the cell is still not active, renew
the whole solution.
XIII.— TELEGRAPHY.
(A) DIAGRAM OF MORSE RELAY TELEGRAPH FOR
E0:N^G lines (FIG. 163).
The main circuit is drawn full ; the local circuits, broken. The former lases
the ground ; the local circuits are metallic. The main battery of gravity cells
in series may be at any point of the main circuit, but a half is usually located
at each end ; if one of the halves has copper to line, the other must have zinc.
Niw York. —
16.5. Diagram of Morse Relay Telegraph for Long Lines.
All relays of the same circuit should be alike. Many operators read the relay
and dispense with the local circuit. For 5-mile circuits, 20-ohm soimders may
take the place of relays and local circuits ; both key and sounder have a com-
mon wooden base and the thin brass base of the sounder is raised \ inch for
greater clearness.
A 150-ohm relay has abotit 4,320 turns in 30 layers, No. 30 on each core.
A 4-ohm sounder has about 470 turns in 10 layers, No. 34 on each core.
A 20-ohm sotmder has about 938 turns in 14 layers, No. 25 on each core.
It is plain from the above diagram that all relays and sounders will respond
to any key in the circuit and to one key only at a time if
its switch is open. If a record is desired, a self-starting
tape register takes the place of the sounder.
(B) TELEGRAPH CODE.
The dot, dash and space are the three Morse signals,
and different combinations of them form the letters.
The dot (E) is made by a momentary downward stroke
of the key lever. This is the unit of time. The dash (T)
is made by holding the key down as long as it takes to
make 3 dots. A space as in A occupies the time of 1 tiot ;
a double space, as in R, eciuals 2 dots.
The space between letters is equal to 3 dots; between
words, 6 dots ; the sentence space is. filled in by a pei'iod.
(118)
164.
TELEGRAPHY.
119
The Morse Code.
I! _
s _
T _
Y __
W _
X _
Y _
Z _
—
; s I
: KO
( ) PN
■ " Q N
H
« sx
Abbreviations.
1 Wait a iruDmeut.
4 Start me.
5 Have you anything?
7 Are you ready?
8 Busy on other wire.
9 Important, give way.
13 Do von understand ?
18 What's the matter?
30 Close station.
44 Answer quickly.
92 Delivered.
134 AVho is at the kev?
Ahr
Another.
Ans
Answer.
Ck
Cheek.
Col
Collect.
D
Degrees.
Fm
From.
D H
Deadhead.
a A
Go ahead.
G B
Good bye.
a M
Good mornin
G N
Good night.
G K
Gov't rate.
Msk
Mistake.
N n
No more.
OB
Official business
OK
All right.
Opr
Operator.
I'd
Paid.
QK
Quick.
K
Kepeat, are.
S
Station.
Sis
Signature.
u
You.
1
Keady.
(C) FORMS OF MESSAGE.
Between operators whose calls are S and J :
Smith. — "Come down on twelve o'clock train if you are off duty."
Jones. — "Shall take six p. m. train."
The call, message, and acknowledgment in which Jones fails at first to receive
the word "twelve," and missends the word "take," occur thus:
Smith.— J JJJSJJJSJ
Jones. — III J
Smith. — II Come down on twel
Jones. — Gr A on.
Smith. — On twelve o'clock train if u r off duty
Jones. — O K Shall taken _^_ _ _ ____ _ take six p m train J
Smith.— O K S
Regular commercial or military message;
Fort Monroe, Va. , Jubj 30, 1901.
John B. Thomas, 80 State street, Richmond, Va.
When will you reach Old Point? Telegraph collect. W. J. Bodell.
It would be telegraphed as follows :
No 45 F S 7 Paid Fort Monroe Va 30 to John B Thomas 80 State street, Rich-
mond Va. When will you reach Old Point. Telegraph collect Sig W J Bodell.
"No 45 F " indicates that this is the forty-fifth message sent from Fort Mon-
roe whose office call is F. "S" is the sending operator's personal call. "7"
indicates the number of words in the body of the message to follow. "Paid"
indicates that the message has been paid for ; otherwise the word is ' ' collect " or
"DH" (deadhead). The year and month are omitted. A period immediately
precedes the body of a message and "Sig" always follows it. The receiving
operator whose call is " A " sees that the message is apparently correct, verifies
the number of words and telegraphs, "OKA."
(D) ADJUSTMENTS OF INSTRUMENTS.
1. Key. — Loosen the binding nuts and turn the trunnion screws close up so
that the platinum contact points will touch squarely, then turn each slightly
back so that the key lever moves freely up and down without lateral movement.
If necessary rub the contact points with fine emery occasionally to prevent
120 HANDBOOK FOR ELECTRICIANS.
"sticking." The vertical screws of the key should allow a small movement of
the key lever with a moderate spring pressure. See that all the binding screws
are tight and that the switch is firmly pivoted by its screw and scrapes well
into its position when closed.
2. Relay {or sounder). — The trunnion screws, as in the key, should allow free
motion to and fro (or iip and down) without lateral movement. Next adjust
the front (or lower) contact screw that the armature may not strike the magnet
cores or approach nearer than the thickness of writing paper ; withdraw it even
further if the armature "sticks." The back (or iipper) binding contact screw
should allow small play, but sufficient to give a distinct sound. Adjust the
screw of the spiral spring until the relay (or sounder) strikes with the key.
Finally see that all of the binding screws are tight.
(E) instructio:ns for operators.
1. Keep key closed except when sending. If no current is on make sure that
the trouble is not in your station ; for this purpose touch a short piece of copper
wire across the main wires entering the station to observe a spark or taste with
the tongue. If a spark is seen or a current is tasted, the trouble is probably in
your station.
2. Keep instruments screwed to the table and constantly in adjustment so that
relay, sounder and key strike together ; that all binding posts and screws are
tight; that the ends of wires entering posts project through them and are bent
around; that no dust, books, papers, etc., accumulate on or about the instru-
ments The table should be screwed down, and large enough to rest the elbow
in sending. Never put instruments on a window sill or expose them to the
weather.
3. To prevent instrument from working when not required, shunt it out.
Never screw down the armature lever nor alter the spring nor detach the wires.
4. To call a station, first adjust to make sure the line is not in use ; if not, open
the key, make the call three or four times and sign your own call. Repeat until
answered, when close the key.
5. To answer a call, wait until you hear the signature, then open the key and
as soon as the distant key is closed repeat the letter "I " two or three times, or
"O K " once, signing your own call. Close the key.
6. To send a message, call the station as above. When it is answered, open
the key, send the message and close the key. If a mistake occurs make inter-
rogation or six dots and begin with the last Avord sent correctly. Invariably
observe the "forms" of message above. If no "O K" is received, the call,
answer, and message are repeated.
7. To receive a message, answer the call and preiiare to write down the mes-
sage. The instant a word is missed, break and telegraph "G A" (go ahead) and
the last Avord received. But if all that precedes is desired, telegraph "R R."
In a regular message verify the number of words in the body before sending
"O K. " If the check does not verify, the sender must give the initial letter of
each Avord until the mistake is found.
8. In the body of a message abbreviations do not occur, numbers are spelled
out, periods occur between sentences but not at the end, and compound words
and names of places count for one AA'ord.
9. Care should be taken to send iiniformly. It is more difficult to send well
than to receive well. Few operators send and receive 40 words per minute ; 30
words is very rapid ; the average speed does not exceed 20. Five letters count
for the length of one word.
(F) DIRECTIONS FOR BEGIIVNERS.
1. (1) Memorize the alphabet. (2) Learn Avith the aid of an instructor to
write Morse A\'ith the key. (3) Send and receive alternately with a companion
at the same instrument. (4) Send and receiA-e Avitli a companion at a distant
station. (5) Complete the practice in a regular telegraph office. A good oper-
ator should often be consulted to avoid acquiring a faulty sending.
2. To write, grasp the button with thumb under the edge and first tAvo fingers
aboA'e it; alloAV the wrist to be perfectly limber; rest the arm on the table at or
near the elbow; let the grasp be firm but not rigid; never allow the fingers or
thumb to leaA'e the key nor the elboAV to leave the table ; avoid too much force.
The motion to be imparted is directly up and doAvn, principally at the wrist.
Guard against rigidity of the muscles, graduate your writing to the capacity of
the receiver and never croAA'd him.
TELEGRAPHY.
121
3. To receive, always write with pen or pencil the words as they come from
the sounder ; do not attempt to anticipate. A tendency to anticipate causes
errors and delays progress. It is good practice to have messages sent backwards
from a book. Break in as soon as a word is missed and do not wait until several
words are lost in the hope of catching a sufficient number to guess at the mean-
ing of the message. Always break in at the first word missed and telegraph
"G A" and the last word received; this will regulate the sending. In a short
time words like "and," "the," etc., will always be recognized and later whole
phrases without effort.
4. In the first practice take the following exercises in turn : (1) Make dots in
siiccession until a imiform rate of about 120 per minute is acquired. (2) Make
dashes in succession until a imiform rate of about 60 per minute is obtained.
(3) Practice E, I, S, H, P, 6, until each can be made at will correctly. (4) Make
the spaces uniform in O, C, R, Y, Z, etc. (5) Be careful to proportion short and
long dashes accurately in T, L, M, 5, 0. (6) Avoid leaving too long space between
the dash and the dot next to it in A, U, V, 4 and inN, D, B, 8. (7) Practice the
mixed combinations in F, G, J, K, Q, W, X, 1, 2, 3, 7, 9, period.
5. Follow "instruction to operators" given above.
(G) U. S. ARMY AXD I^AVY SlGlS^AIi CODE.
(1) WIGWAG ALPHABET.
A
22
B
-- 2112
r
121
T)
222
F,
12
F
--. - 2221
H
2211
-123
T
1
a. ..
b.-
c
after.
.--before.
- - can.
h...
have.
J-
K.
L-
M.
N.
O-
P.
Q-
R-
1122
.2121
-221
.1221
.--11
-_21
1212
1211
.211
S..
T..
U.
V-.
W-
X..
Y-
312
-112
1223
1121
2122
-111
2 2233
l.'.V-'.V-V-llll
.2222
.1112
.2231
.1122
.3311
.1332
.3111
.1221
.2113
(2) ABBREVIATIONS.
n -. not. ur your.
r are. w word.
t the. wi with.
u you. y why.
End of a word 3
End of a sentence 33
End of a message 333
Aye, ' ' I understand " 22. 22. 3
Cease signaling 32. 22. 23. 333
X X 3 " numerals
follow" or ' 'numer-
als end."
sig. 3 signature.
3
3
3
Repeat last word 121. 131.
Repeat last message __ 131. 121. 121.
Error 1.- 13. 12.
Move to the right 211. 311.
Move to the left 331. 331.
C. A. U. Cipher "A" Use.
C. B. U. Cipher "B" Use, etc.
N. L. U. Navy List Use.
V. N.U. Vessel's Numbers Use.
(3) CODE CALLS.
A. S. U. Action Signals Use.
I. C. U. International Code Use.
T. D. U. Teleg. Dictionary Use.
G. L. U. Geographical List Use.
G. S. U. General Signals Use.
(4) INSTRUCTIONS FOR SIGNALING WITH FLAG, TORCH, HAND L-4NTERN, OR
BEAM OF SE.VRCH LIGHT.
There are but one position and three motions.
The first position is with the flag held vertically in front of the center of the
body, butt of staff at height of waist, signalman facing squarely toward the
station with which it is desired to communicate.
The first motion, or " 1," is a motion of the flag to the right of the sender, and
will embrace an arc of 90°, starting with the vertical and returning to it, and
will be made in a plane exactly at right angles to the line connecting the two
signal stations.
The second motion, or "3," is a similar motion to the left of the sender.
To make the third motion, "front," or "3," the flag is waved to the ground
directly in front of the sender, and instantly returned to the first position.
Numbers which occur in the body of a message must be spelled out in full.
Numerals may be used in signaling between stations haviiag Naval Signal Books,
using the Code Calls.
122 HANDBOOK FOR ELECTRICIANS.
(5) TO SEND A MESSAGE.
"To call" a station, signal its initial or "call letter" nntil "acknowledged."
"To acknowledge," signal "Aye," followed by its initial or "call letter."
Make a slight pause after each " letter," also after each "front."
(6) FOG SIGNALS.
To apply this code to the "fog whistle " or "fog horn :"
One (1) toot (aboitt one-half second) will be "one" or "1."
Two (2) toots (in qnick succession) will be "two" or "2."
A blast (about two seconds long) will be "three" or "3."
The signal of execution for all tactical or drill signals will be one (1) long
blast, followed by two (2) toots in quick succession.
The ear and not the watch is to be relied upon for the intervals.
(7) TO SIGNAL WITH FLASH LANTERN, HELIOGRAPH OR SEARCH-LIGHT SHUTTER.
Same as in fog signals; substitute "short flash " for "toot," and "long steady
flash" for "blast." The elements of a letter should be slightly longer.
"To call" a station. — Make the initial or "call letter" until "answered."
Then turn on a steady flash until answered by a steady flash. The station
called will "acknowledge" and cut off its flash and the calling station will pro-
ceed with the message.
No abbreviations will be used in the body of the message.
All other conventional signals are the. same as for flag or torch.
(H) ARTII.LERY FIRING CODE.
T A = Target angle.
S A = Shot Angle.
T A D 23 M 45 = Target angle is 23 degrees and 45 minutes.
F F = Fire.
C S = Close station.
T T A = Take target angle.
T A 3 = Target angle No. 3.
2 R F = No. 3 gun is ready to fire.
R T A 2 = Repeat target angle No. 2.
R S A 4 = Repeat angle No. 4 shot.
R U R = Are you ready '?
R U R F = Are you ready to fire ?
(I) setti:n^g up the hbt^tograph.
1. Always spread the tripod legs -wdde enough for a good base and press them
firmly into the ground so that the top is level.
2. The sun mirror has a peephole at the center ; the station mirror, a paper
disc. Both in position on the bar can be tiirned horizontally or vertically by
tangent screws.
3. When the sun is in front of the operator while facing the distant station,
the sun mirror only is required ; with the sun in rear, both mirrors should
be used, although a single mirror may often be worked to advantage with the
sun well back of the operator. In the former case, the rays of the sun are
reflected from the sun mirror direct to the distant station ; in the latter, they
are reflected from the sun mirror to the station mirror, thence to the distant
observer.
4. With one mirror. — Attach the mirror bar to the tripod; insert and clamp
in their appropriate sockets the sun mirror and the sighting rod, the latter ^vith
its disc turned down. Sight through the center of the mirror and turn the
mirror bar, and raise or lower the sighting rod until the center of the mirror,
point of sighting rod, and distant station are accurately in line; then clamp the
mirror bar firmly to the tripod, taking care not to disarrange the alignment.
Turn up the disc of sighting rod.
Move the mirror by means of slow-motion screws until the "shadow spot"
from the unsilvered peephole falls upon the disc of the sighting rod. The
flash will then ])e visil)le to the distant observer.
The shadow spot must be kept in the center of the disc while signaling.
Attach the screen to its tripod and place it, close to, and in front of the sight-
ing disc, so as to intercept the flash.
TELEGRAPHY.
133
J Jjli««| .^ba. .i*'~45—
165.
5. With hoo mirrors. — Clamp the mirror bar diagonally across the line of
vision to the distant station; clamp the sun mirror, facing the snn, to the end
of mirror bar with tangent screw attachment ; and the station mirror, facing
the distant station, to the other socket. Stooping down, the head in rear of
and near the station mirror, turn the sun mirror by means of its slow-motion
screws until the whole of the station mirror is seen reflected in the sun mirror,
and the unsilvered spot and reflection of the paper disc accurately cover each
other.
Still looking into the sun mirror, turn the station mirror until the reflection
of the distant station is brought accurately into line Avith, or is covered by, the
unsilvered spot and the reflection of the disc; after this, the station mirror
must not be touched.
Now stepping behind the sun mirror, throw iipon the station mirror a full
flash from the stin mirror so that the "shadow spot" falls upon the center of
the paper disc. The flash will then be visible at the distant station.
The shadow spot must be kept in the center of the paper disc while signaling.
The intercepting screen should allow room for adjusting the sun mirror.
(J) LOCATING FAUIjTS.
Most line faults are of three kinds — a break, an escape, or a cross.
1. The break may be: (1) complete, as when the line is severed or a key left
open, etc. — all instruments in the circuit cease to work; or it may be (2) partial,
as from a rusted joint or a loose contact, etc., which increases the conductor
resistance — all instruments work equally feebly or
not at all. A complete break, as in fig. 165, is found
by inserting at either end a battery, one side of which
is to earth, as shown. The lineman then laroceeds
along the line froni the other side of the battery con-
necting, temporarily, at different points, the line to
earth through the tongiie or galvanometer. Near the battery he gets the full
current. If at any point he fails to get it, he has passed the complete break.
It is important to note the current strength from the taste or deflection near the
battery ; if, then, at any jilace it suddenly diminishes, but is still noticeable, a
partial break has probably been passed.
2. An escape (fig. 16off ) arises from defective insulation at some point, as when
a bare wire falls to ground or touches a tree or building, or the covering of an
insulated wire is injured, etc., and allows a por-
tion of the current on the line to escape. Instru-
ments work unequally. Those near the battery
are stronger, those beyond the escape are weaker
jgja than usual..
The lineman may inspect the line to see if any
pole, tree, building, etc. , has come in contact with the wire. If it can not be found
in this way he may open the line at some point. If an examination at the bat-
tery end still .shows the escape the fault is on the side of him towards the battery ;
but if it has disappeared the fault is on the other side of him. He proceeds
accordingly to open the line at another point, having closed the first.
3. Across (fig. 166) is a fault caused by two parallel lines coming in contact;
the instruments on one line respond to those in the other. Inspection of the
line may reveal the fault. Or open both of the dis-
tant ends. Starting from the battery the lineman
opens the line at some point ; if he gets a current he
has not reached the fault.
Generally on a long line having several stations
the fault is first located, as between two stations, *^<^-
from one of which a lineman is sent out.
Periodic tests of the conductor and insulation resistances of every important
line should be made regularly and the results kept in a record book.
tliaHr'
ir-
rti^cir-
(K) THE TELAUTOGRAPH.
(a) DESCRIPTION, PRINX'IPLES AND OPERATION.
1. Transmitter —By means of two light rods attached to the transmitting
pencil near its point the arbitrary motions of writing or drawing are resolved
into simple rotative or oscillatory motions of two pivoted arms, located on either
side of the writing platen. These arms are included in the line circuits and
124 HANDBOOK FOR ELECTRICIANS.
carry at their extremities small contact rollers wliicli move to and fro upon two
rheostats, or resistance coils, these l^eing so connected through the arms to the
line and to the source of energy as to act both as adjustable shunts and as
rheostats in the line circuits. By this method the voltage supplied to the line
is made to vary with the position of the pencil upon its writing platen and
definitely variable writing currents are transmitted.
2. The I'eceiver principle is equally simple. The variable line currents com-
ing in over the line wires are led through two vertically movable coils, each
suspended in a strong uniform magnetic field by a well-sweep arrangement,
from which they derive the name of "buckets."
Each coil is supplied with an adjustable retractile spring which tends to
oppose the movement of the coil downward through the field. It is evident
that for given values of the line currents each coil will have a definite position
in its respective magnetic field, depending upon the tension of its retractile
springs. The vertical motions of these receiver '■buckets," due to the varying
line currents, are used to cause rotative motions in two pivoted arms, similar to
those at the transmitter, which motions, through another system of light rods,
compel the receiving i^en to exactly reproduce the motions of the transmitting
pencil.
3. To accomplish the pen-lifting at the receiver an automatic device is used,
consisting of an induction coil at the transmitter, having two secondary wind-
ings and performing the double function of pen-lifting and reducing friction.
The prin^ary circuit of this coil is entirely local at the transmitter, and includes
an interrupter and a shunt circiiit controlled by the platen.
4. The vibratory secondary currents are superimposed upon the writing cur-
rents, and serve to keep the receiving -pen in continual though imperceptible
vibration, reducing friction in the moving parts to a minimum. The normal,
writing pressure of the pencil upon the transmitter platen opens the shunt
circuit and causes an increase in the strength of the secondary vibrations.
This operates a vibratory relay inserted in one of the line circuits at the receiA^er,
opens a local circuit, and causes the armature of the pen-lifting magnet to be
released and the pen is allowed to rest upon the paper.
5. Lifting the transmitting pencil from the platen decreases the strength of
the vibrations, closes the local receiver circuit, the pen-lifting magnet attracts
its armature and raises the pen clear of the paper.
6. The shifting of the pajier at the transmitter is done mechanically by means
of the master switch. The same motion of the switch operates an electro-mag-
netic device over one of the line wires, which automatically and positively shifts
the paper at the receiver a corresponding amount.
The paper, 5 inches wide, is supplied in conveniently detachable rolls, which
are mounted in brackets attached to the backboard of the instrument. For
signaling, a push button at the transmitter operates a call bell at the receiver.
7. The transmitting pencil is a simple adjustable lead pencil. The receiving
pen is made on the principle of the ordinary right-line drawing pen, so modified
as to make perfect lines regardless of the direction of motion, and capable of
holding an ample supply of ink.
8. The inking device consists of a bottle or supply well, with a hole and stopper
for refilling, and also with a second small hole in the side of the well. This hole
is below the siirface of the ink, and the toj) of the well being corked and air-
tight, the ink is prevented from flowing out by the pressure of the external
atmosphere.
The small hole is located at the unison point, and whenever the paper is shifted
the pen returns to this position and automatically dips its point into the ink
which stands at the mouth of the hole. Capillary attraction is siTflficient to
completely fill the pen, and, resting in the hole as it does, the point does not
clog up with dry ink when not in use, but is always ready to start writing with
a full fresh supply.
(b) EXPLANATION OF DIAGRAM.
1. Transmitter. — The motions of the transmitting pencil A are conveyed
through the pencil arms B B , and pencil arm levers C C to contact arms DD',
which carry contact rollers E E' , these contact rollers bearing upon the periphery
of rheostats F F' , the terminals of these rheostats being connected through
master switch G to the positive and negative poles of a suitable source of elec-
trical energy, indicated by battery H. The contact arm D' is connected to the
right line through one of the secondaries of the induction coil 1. and through
the right-line contacts G' of master switch, when the master switch is in the
167. Telautograph, with Cover Removed to Show the Working Parts. 124
TELEGRAPHY.
125
e^:n..
Tl^f\Kf>MlTTE;(\
169. Transmitter and Receiver.
126 HANDBOOK FOR ELECTRICIANS.
writing position as shown. The contact arm D is connected to the left line
throiTgli the other secondary of the induction coil I through the left line con-
tacts G2 of master switch. The writing platen J is pivoted at K K , and when
pencil is off, the platen closes upper contacts L L , shunting resistance 1 around
the primary winding of induction coil /. The vibrator 3J is in circuit with the
primary of induction coil / and battery H, and rapidly vibrates, the current
passing through the primary of the induction coil, thus causing a vibratory
current to traverse the right and left line wires, the strength of this vibratory
current depending upon the position of the platen J; when this platen is
depressed by the pencil in the act of writing the shunt around the primary of
induction coil / is open, consequently the strength of the vibratory currents on
line is increased ; this increased strength of vibration actuates the pen-lifting
relay m (in receiver). The paper at the transmitter is shifted by moving the
handle N of lever O, which is connected to shaft P, which carries the pawl Q.
engaging the ratchet wheel R, mounted on shaft of paper-shifter roller S.
Each movement of this handle A^to and fro causes the roller ,S' to rotate, which
moves the paper forward. The shaft P also carries master-switch contact
plates G, Gl. G2, which open and close the line and battery circuits, according
to the position of handle N; circuits being closed and instrument in sending
position when handle N rests in position shown by arrow. The movement of
the handle N in the opposite direction cuts the instrument out of circuit. The
handle is locked in either position by lever P, and can not be released except by
pressing point of pencil A on button T . A signal-switch push button is shown
at U\ this switch when operated throws cvirrent of positive polarity through
right line, which rings receiver bell u, as hereafter described.
2. Receiver. — The motions of receiver pen a are caused to duplicate the motions
of transmitting pencil A through the pen arms h b', pen-arm, levers c c'., which
are mounted on shafts carrying sectors d d'. Light metal bands e e' are attached
to the peripheries of sectors d d' and carry at their lower ends coils (or "buck-
ets ") // , and their upper ends are attached to springs g y . The coils / / are
movable in the annular spaces between the poles of the magnets /( and i, and /;
and i'. Coil /is in circuit with Morse relay j and the left line, and coil/' is in
circuit with pen-lifting relay m and the right line. As the transmitting pencil is
moved its motions are transmitted to contact rollers E E' , the strength of cur-
rent on line is varied, the currents becoming stronger as the rollers approach
the positive ends of the rheostats F F , these currents traversing line and pass-
ing through coils//, causing them to take different positions in the magnetic
fields, opposing the pulls of the springs g g' , these springs being so adjusted that
the position of the receiving pen in the writing field will always be the same as
the position of the transmitting pencil on its writing platen.
3. The depression of platen J, causing a strong vibratory current to traverse
line, causes the armature of pen-lifting relay m to vibrate and interrupt the
circuit of pen-lifter ;»', thus releasing the armature of pen -lifter and lowering
the pen-arm rest so as to allow the pen to come into contact with the paper.
Upon raising the transmitting pencil from its platen the vibratory current will
be weakened, the armature of pen-lifting relay m ceases to vibrate, closes the
circuit of pen-lifter m' , which attracts its armature and thus lifts the pen from
the paper.
4. The paper-shifter o' is an electro-magnetic device and is controlled by the
Morse relay J, the armature of this relay closing the circuit of the shifter through
its forward contact when the relay j is energized by line current through the
master switch by the movement of handle N in the position shown by arrow.
5. The signal bell w, which is of low resistance, is thrown in parallel with the
right-line coil, or "bucket"/'' when no current is passing through the paper-
shifter, consequently when signaling current passes over right line the bulk of
the current passes through the bell, rather than through coil/'.
6. The ink well (an ordinary glass bottle) is shown at p, the receiver pen a
entering the opening li ' and receiving a fresh supply of ink every time the paper
is shifted, the pen resting in this opening and in contact with the ink when the
instrument is not in use.
(c) Installing.
The instriiments are furnished with a suitable backboard, the connections
being made between the instruments and the circuits on the backboard by auto-
matic contact pins, so that the instruments can be put on and taken off readily.
The terminals on the backboard for connecting to line and battery are plainly
marked so that the proper connections may be easily made.
168. In Operation.
TELEGRAPHY. 127
(d) Operation.
1. To ivrite. — Depress button with pencil point and pull lever towards you a
full stroke ; release button with lever in this position, and write with firm pres-
sure on paper.
2. To shift imper. — Depress button, holding it down until you have moved
lever back and forth its full stroke as many times as you wish to shift paper,
then release button with lever in positiDn towards you.
3. To hang up. — Depress button, allowing lever to rest in position away from
you. Always, after writing, leave the lever in position from you.
{e) Care of Instruments.
The care of the instruments consists mainly in keeping the ink bottles properly
filled with the ink which is supplied for that purpose, the occasional cleaning of
the pen points, and the insertion of fresh rolls of paper which is siipplied for
that purpose.
XIV.— TELEPHONY.
(A) APPARATUS AXD COJ^^NECTIONS.
Fig. 170 gives details of the apparatus and connections of the bridge form of
the American Bell telephone :
1. Western electric call box, 500 ohms in armature, 1,000 ohms in bell magnets.
2. Long-distance induction coil, 1,000 ohms in the secondary.
3. Solid back transmitter, 3 ohms.
4. Two double-pole watch receivers with head strap, 75 ohms each.
5. A ijorous cup, or a carbon cup Leclanche, the latter preferred.
6. Warnock hook.
Full lines represent electric circuits ; those drawn heavy show the local or
transmitter circuit.
7. When one turns the crank shaft in the call box to ring, a cam thereon causes
the whole shaft to slide in opposition to a spiral spring, i inch to the left, into
contact at A. The generator's armature coil is thereby thrown into circuit; its
terminals are the insulated pin B bearing against a spring and the armature
shaft leading the current to metal frame and A.
8. When the receiver is off the hook, lever scrapes into good contact with both
springs at F: when on, it opens these points. Both posts of the watch receiver
T T are mounted on a triangular plate of ebonite inside the case.
9. Polarized bell. — The U-shaped, permanent magnet N 8 screwed at iVto the
backpiece of the electro-magnet, renders both poles of the electro-magnet north,
and by induction, the middle of the armature where it is pivoted, north. Both
armature ends are, therefore, south; i. e., either armature S-end stands opposite an
A"-pole. When a positive current enters the magnet coils, one iV-pole is neutral-
ized and the other is made stronger so that the latter attracts its armature end.
A negative C makes the other A^-pole attract its armature end, and so on. As
there is no spring to be overcome, a polarized relay is very sensitive and deserves
attention on account of its importance in the service. For the magneto which
generates the alternating + and — currents, see page 46.
(B) MAGXETO, BEEIi, AND SECONDARY COIES.
The magneto, bell, and secondary coils of each station are joined to main.s —
In parallel or bridge (fig. 171.) Ix series (fig. 172).
171. Parallel Telephone Station.
172. Series Telepiione Station.
The three main coils have f<'\v turns nf wire and
low resistance, anil ii|"
m series.
Magneto circuit, ncirnially short-circuited, has
tlie shunt opened automatically at A by the crank
shaft sliding to the right ^^s inch when rotated, so
that the ringing current goes to line.
1. All bells are permanently bridged. They will
respond to the magneto's slow alternations but
their impedance acts like an infinite resistance to
the rapidly alternating speaking current.
2. Magneto circuit, normally open at^l, isclosed
automatically by the crank shaft when rotated, So
that the generated current goes to line.
3. \Vlien the receiver is ou the hook lever for calling, the circuit between terminals is —
1. Bells, 3. 1. H, L, A, bells, 3.
4. When receiver is on and the crank is turned to call, the circuit is —
1. A, armature, 3.) 1. H, L, A, armature, bells, 3.
1. Bells, 3. I
5. When the receiver is taken uff lor talking, the circuit is —
1. Bells, 3.~> , , . ., . ' 1 . /?, S, F, .3. Local circuit is— i3, r, P, //^, X.
1 « p ■< [Local circuit is —
]:.'ii,F,tl ^' ^' -f'- ^'' ^■
(128)
TELEPHONY.
129
M
1
\ I
f
170. Complete Details of Bridge Telephone.
(Porous rup and Htiydeu cells shown ; use one kind only.)
130 HANDBOOK FOR ELECTRICIANS.
6. Five bridge or four series telephones are the limit on one circuit. When
more are required (as will rarely happen) a central exchange or a party line will
be necessary. The main circuit is always metallic. On short, busy lines, as
between range finder and four mortar pits, it will be advantageous to run four
main wires — two for talking and two for signaling. All telephones on the same
circuit must be alike.
(C) TO USE.
Give the bell crank one sharp turn, take the receiver from the hook, place it
firmly against the ear and when the unhooking at the distant station is heard,
give the number wanted if it is "Central" or the name desired if it is a party
line.
Speak directly into the transmitter, with the lips close to it, in a low, distinct,
and deliberate manner ; never shout. Be guided by the listener as to yoiir dis-
tance from transmitter and your articulation. When finished, hang the receiver
on the hook and give a half turn to the crank. During storms and when closing
for the day, shunt out the instrument by the lightning-arrester plug. Keep the
instrument free from dust, the cells clean, and the solution at normal strength
and height.
(D) TELEPHONE FAUETS A^^D THEIK EOCATIOiN'.
The three classes liable to occur are: (1) An open circuit at a joint, post,
spring contact, or where rust is seen; (2) a short circuit in a magnet coil, cord,
or where dust and filings collect; (3) derangement of magnets, bells, switch,
transmitter, receiver, or battery.
An intermittent fault is more difficult than a lasting one to find, as, for exam-
ple, when a line grounds only when swayed by the wind, or the resistance of a
joint keeps changing, or the two wires of a cord touch only when it is in a cer-
tain position. To locate a fault promptly, a knowledge of the circuit and experi-
ence are essential.
The first steps in locating a fault are to question the user, to look carefully
over the accessible parts, to try to ring, to listen for the characteristic noise in
the receiver from scratching on the transmitter, and to determine at once
whether the trouble is in the station or outside of it by cutting out the station from
the rest of the circuit if necessary. The symptoms differ somewhat in bridge
and series systems. Three cases arise ;
1. Station can not ring. — See if the bell's armature is free, if wire joints around
bell, hinges, hook, etc., are good, and if both shaft contacts at the magneto
operate. If a bi'idge telephone, there may be a short circuit between its mains,
in which case the crank turns with difficulty ; or there may be a break in its
magneto or its bell circuit, but not if the bell rings after detaching the line wires.
In a series telephone, there is probably an open circuit; it is outside if the bell
rings after connecting the line posts by a short wire or by the lightning-arrester
plug. If in this case there is no ring, the trouble is in the ringing circuit.
2. Station can ring but cannot hear. — The speaking circuit is open or shunted
at some point. If scratching or blowing into the transmitter is heard, the sta-
tion's receiver circuit must b3 in order and the fault probably lies in the trans-
mitter circuit of the distant station.
3. Station can ring but can not be heard. — The fault is probably in the local
transmitter circuit. But if scratching on the transmitter is heard, the fault lies
in the receiver circuit (receiver, secondary and lever contacts) of the distant
station.
TELEPHONY. 131
(E) IT^ GElVERAIi.
The tisiial induction noises heard in a receiver show that the main line and
your station receiver circuit are in order ; although the secondary may in this
case be short-circuited. If so, blowing into the transmitter can not be heard.
To verify, open the line and if the noises do not cease their cause lies within.
Cross talk, humming of motors, Moi'se clicks, etc. , show that the telephone
line runs parallel with a foreign wire for a greater distance on one side of it than
on the other, or that there is leakage through the ground terminals. To prevent
these noises, telephone lines are usually metallic, and if parallel with other wires
they should riin for equal distances on opposite sides of them. A twisted metallic
or a balanced line has no induction noises.
Creaking or boiling sounds in the receiver are often due to bad contacts in the
local or transmitter circiiit.
The set entire is not in good adjustment unless the bell hammer responds
promptly to slow turning, giving two strokes to each turn of the armature, and
unless light scratching on the backboard is heard in the receiver. The receiver
should be aiidible to a good ear at 10 feet distance from low, distinct talking at
the distant station.
(F) r>ERAN^GEME:NrT OF APPARATUS.
1. Li magneto. — (a) Short circuit from brass filings, dirt or burnt coils; (6)
dynamo shaft in the bridge telephone not closing on the spring contact and in
the series not opening when turned; (c) armature shaft not in contact with
spring; (d) weak field magnets ; (e) armature striking pole piece; (/) dust on
lightning-arrester.
2. 1)1 polarized bell. — (a) Armature striking pole piece, or too distant, or not
free to move, or not responding promptly; (b) bells not spaced to receive strokes
alike, in which case loosen and turn them ; (c) magnet too weak to hold by its
OAvn weight.
3. Jn liOoTc lever. — Not scraping into good contacts; weak spring.
4. In solid back transmitter. — (a) Breaking of mica disc, which allows carbon
granules to fall out ; (&) " packing " of granules, which renders speech inaudible,
and may often be remedied by moving transmitter quickly up and down ; (e)
diaphragm rusted, or its rubber hardened, or its spring too tight or too loose.
5. In receiver. — (a) Diaphragm too close, or too distant from pole piece. Its
distance is correct when after removing ear piece and holding the receiver side-
ways in one hand and tapping with the other, the diaphragm falls partially off ;
if it does not start it is buckled or too close ; if it falls entirely off it is too far
away ; (5) if diaphragm is buckled, replace it ; (e) dirt between it and the poles ;
(d) a break in the circuit, discoverable by touching the ends of the receiver's
cord to the poles of a cell ; (e) a short circuit in the cord itself through which
a series bell will ring and a bridge bell will not.
6. Inbattery. — See Fuller bichromate and Leclanche cells. One or two like
cells in series usually afford sufficient battery power.
7. In locating faults, an assistant, a detector galvanometer with dry cell, and
such tools as knife, small pliers, screw driver, file, and emery are useful.
8. Guard against dust, damp, unsoldered connections, loose wires under
screw washers or binding posts from shrinkage of wood, breaks or contacts in
the receiver cord.
(G) INTERCOMMU:N^ICATIiS^G TELEPHONY
1 Is suitable for twenty or less stations near each other, as in a large build-
ing or in any fort. A cable having one, and in some cases two more wires than
the number of stations, passes each station. There is no central (fig. 173).
Any one station can be put into communication with any other on that system
by the operator himself. The left hand figure at each switch designates the
number of station or instrument to which the switch is connected, and the lever
must always remain on left hand point except when another station is called.
No. 1 wishes to communicate with No. 3. He moves the lever of his switch to
the point marked 3, and after ringing him up can carry on conversation.
"When No. 1 has finished talking he replaces the lever of his switch to contact
132
HANDBOOK FOR ELECTRICIANS,
point No. 1. A similar action takes place when any of the other stations wish
to commtinicate. This system is specially adapted for communication in hotels,
factories, office buildings, or any place where wires are all under one roof.
When the distance between the terminal stations is over 500 feet the expense
becomes high, owing to the number of wires required.
COMMON RETURN
173. No Central.
2. A common battery is a feature of modern systems. In fig. 174 each of the
ten lines is connected with 10-springs jacks on each of the ten telephones (three
shown). P is plugged to the No. of the station called, c and c are impedance
64TTCRV'WI(!E
174. Common Battery, 10 Stations.
coils on either side of the transmitter circuit to prevent cross talk when more
than two stations communicate.
a. The Holtzer-Cabot system is extensively used (fig. 175).
TELEPHONY. 133
(H) A CEXTRAIi STATIOIS^ SYSTEM
1. Sometimes required, is shown for —
40 line drops, 1 per station, ^4.
10 clearing-ont drops, B.
10 plugs with double cords, C.
10 listening keys, E, for 10 connections.
10 sets ringing keys, F, for 10 connections.
Operator's transmitter.
Operator's receiver.
Operator's magneto.
Night-bell switch.
Operator's telephone battery.
176. Central.
2. On this board (fig. 176) ten stations can be i)ut in communication with ten
others in pairs at one time, by way of the ten twin wire cords (fig. 178), kept
from getting tangled by running weights. Plug C (fig. 176), or P (fig. 178), has
two insulated metal parts, knob and cylinder, which are the terminals of the
twin wires in the cord.
The line-drop magnet (figs. 177-8) on the board lets plate S fall and thus signals
the number of the station which calls and desires a connection ; its wires connect
with mains to station; wire u is for a night local call bell circuit.
3. The "clearing-out drop" magnet, CO, in fig. 178, is like the line drop except
in its winding of finer wire (500 ohms), soft-iron cover to prevent induction and
more closely adjusted armature; it is
bridged across the two wires in the cord
which connects the two stations placed in
communication and will, therefore, signal
when either station rings "off."
4. To illustrate the working of a board, it
is only necessary to take three line drops,
/, /', f'\ in fig. 178, two plugs, P and P',
and twin wire cord 1 and 2, one listening
key, K, also one ringing key, K' , whose but-
ton being pressed, throws the magneto, al-
ways running on a large board, into the
circuit of any pair of plugs.
5. When plug P is pushed into any spring-
jack, as at a —
Its small end knob raises tip spring e from the drop's wire and joins one of
the cord wires with one of the mains.
177. Gravity Drop.
134
HANDBOOK FOR ELECTRICIANS.
The insulated cylinder next the knob connects at the same time the other
conductor with the second main line to the station.
6. Suppose a call comes from station 1 —
The drop falls, displaying number " 1 " to the operator.
She then inserts either plug, as P, of any pair, say the fourth, in the jack,
closes the listening key, K, and learns that connection is desired With "40;" for
example, the circuit being main line, jack "1," plug Pand cord, key K, secondary
and receiver.
She next inserts the other plug P' of pair 4, presses key K' and rings her mag
neto, the circuit being magneto K' , plug P', jack to "40" and main line.
178. Three Jacks, Three Drops, One Clearing=out Drop.
On pressing K she hears station 40's response and then 40 and 1 talking.
Releasing K, she may give attention to other calls and connections.
The clearing-out drop C O. of high resistance and impedance, being perma-
nently bridged across the talking circiiit, signals when 40 and 1 have finished.
Their circuit was main line, jack, and plug 40, cord twin wire plug, jack and
main line 1.
XV LAWS, WIRE TABLES, EXAMPLES.
(A) ELECTRICAL QUAIS^TITIES, THEIR U:NITS, A:N^D THE
LAWS OF THEIR RELATIONS.
Each quantity has one unit and every amount is expressed in terms of that
unit by a decimal number.
Quantity, Sym-
bol, Law.
Defixition.
Name of
UXIT.
Talue of Practical
Umt.
Examples, Eqviva-
LENTS.
Difference of
With electricity pre-
1 volt, PIt_
= TI53 of the PD be-
2 volts P D between stor-
potential, P D.
cisely what difference
tween the plates of a
age plates ; 40 volts P D
r=Gxii.
of level is with water.
Clark cell at 15.5° C.
between arc lamp posts ;
10,000 volts for 1-inch
spark.
Electro - motive
The force which moves
1 volt, £„_
= } Jf § of the £ of a Clark
A gravity cell has 1.1 volt
force, E.
electricity through a
standard above = %
E; an inc. lighting dy-
E=CXB.
conductor.
of a Leclanche cell.
namo has about 125
volts.
Current
The time rate at which
1 ampere __
= the C which deposits
y^ ampere flows in a Hi-
strength, ('.
electricity Hows
in 1 second 1.1 IS
candle power, 110 - v o 1 1
C=E^R.
through a conductor.
mgms. of silver or
other metal equiva-
lent.
lamp; 10 amperes in arc
lamp.
Resistance, li
That property of a con-
1 ohm
= Res. of a mercury
1 mile trolley has 3 ohms;
R = E-^C'.
ductor which opposes
(true.)
column 1 sq. mm.
1,000' cop. wire, 1 mil.
the passage of elec-
cross section and 106.3
diani. has 1 ohm ; lii-
tricity.
cms. long at 0° C.
candlepower lamp fila-
ment hot, 200 ohms.
Quantity, Q
The total amount of
1 coulomb _
= the quantity deliv-
To deposit 1 pound copper
Q=CXT.
electricity which
ered by 1 ampere in 1
requires 1,500,000 cou-
flows in a given T
second.
lombs.
(seconds).
Capacity, A'
Measured by the Q re-
1 farad
= A' of container if 1
1 microfarad = one - mil-
k='q^e.
quired to raise the
coulomb raises its po-
lionth of a farad = ca-
container's potential
tential 1 volt.
pacity of J^ mile ocean
1 volt.
cable.
Work, W
The product of a force
1 joule
= 1 volt-c n 1 m b =
J^ ampere in 110- volt
W=EXQ
into a path ; also of
work of 1 ampere
"lamp for 1 minute does
= C^IiT.
quantity into poten-
through 1 ohm in 1
3,300 joules ; power ^
tial.
second=0.7373ft. lbs.
55 watts; heat = 1,375
calories.
Power, P
The time rate of work.
1 watt
= P when 1 jimle is
1 kilowatt = 1,000 watts;
P= TF-4-r.
A horse pulling T5
done uniformly in 1
1 horse p w e r = 746
(T in sees.)
lbs. at 5 miles per
second. Watts =
watts; 1 kilowatt =1
hour e.xerts 1 horse-
volts X amperes =
horsepower, approx.
power.
amperes ' X ohms.
Heat, H
772.5.5 ft. lbs. work will
1 calorie
= H required to raise
1 calorie = 4.16 joules = 3
H =-- .24 E Q
raise 1 lb. water 1° F.
1 gm. water 1° C. at
ft. lbs.; 1 joule = 0.24
= .24 eitr- T.
at 60° F., London sea
level.
0° C. = 1 gm. deg. C.
= 0.004 lb. deg. F.
calorie.
1 inch = 2.54 centimeters.
1 meter = 3.28 feet.
1 megohm = 1 million ohms.
1 micro. = 1 millionth.
1 kilo = 1,000.
1 milli. = „'5S-
(B) RULES, LAWS, AND EXAMPLES.
I. — If a current should floio through the forefinger of the right hand, in the
direction in tvhich the finger points, the north end of a magnetic needle in the
position of the thumb ivill point in the same direction as the thumb held perpen-
dicularly to the finger. {Figs. 180-1.)
II. — Ohms Law. — In every electrical circuit the strength of the current in
amperes floicing uniformly is equal to the electro-motive force of the generator
in volts divided by the total resistance of the circuit in ohms. Or, C = E -h R.
III. — The difference of potential between the ends of a conductor of a current
for the E. M. F. in it) equals the product of the strength of the current by the
resistance of the conductor. Or, E = CR.
(135)
136
HANDBOOK FOR ELECTRICIANS.
IV. — The resistance of a conductor varies directly ivith its specifi» resistance
and length and inversely icith its cross section or with the square of its diameter.
V. — The resistance of two or more wives joined in series equals the sum of
their separate resistances.
180, and 181. Magnetic Whirlwind around a Current.
VI. — The total resistance of tico or more wires joined in parallel equals the
reciprocal of the sum of their separate reciprocals.
a
nnnnnns
■yy a 6 "8 y f a aii'a a a ya-
3
ij = ^1 ohm between A and B.
Example.
VII. — The electro- motive force of a battery is equal to the E of one cell multi-
plied by the number of cells in series.
~ To find the E and R of foiir different batteries formed in turn from six
gravity cells of 1 volt and 3 ohms each, connected up (1) all
in parallel, (2) all in series, (3) three in series and two in
parallel and (4) two in series and three in parallel, thus :
■I'l'I'I'N
A ■i-n-i-n T
6 volts, 18 ohms.
3 volts, 4^<^ ohms.
2 volts, 2 ohms.
VIII. — To obtain the strongest current with a given number of cells through a
given externcd resistance, arrange the cells in such a way that the internal resist-
ance shall be as nearly equal as possible to the external resistance.
Ex. For an external R of 18 or more ohms, the six gravity cells above shoiild
be in series ; for 3 ohms external R, arrange cells two in series and three in par-
allel, and so on.
IX. — Each one of two or more parallel wires carries that part of the main cur-
rent which the reciprocal of its resistance bears to the sum of the reciprocals of
all the resistances.
Ex. A generator of 18 volts and 3 ohms, two leads of 11 and 3 ohms, and two
branches of 4 and 2 ohms are connected, as shown. Find R's, C's, and £"s.
Resistance between A and B = l^{i + i)=^ ohm. Total
R in circuit = |4-3 + 3 + f = 9 ohms. Main C = 18 -h 9 = 2
amperes. C in wire 4 = 2 X (i -^ f ) = t ampere : C in wire 2
= 2x(i-Hf)=t; sum of C's in both branches = 2 amperes.
PD of generator on open circuit = 18 volts; on closed cir-
cuit = 2x6 or 18 — 2X3 = 12 volts. Of JS: = 18 volts of the
generator, 6 volts are used to overcome its own resistance, 6
volts to maintain the 2-ampere current in lead 3, y volts in lead, 1| and f volts
in the two branches.
„,_. Ex. .E i? of branches 2, 3, 6 = 1 ohm. Total i? = 8 ohms. C = 2
amperes. C in branch 2 = 1 ampere, in 3 = ^ ampere, in 6, Jr ampere.
Eight volts i;sed in battery ; 4 volts in lead 2 ; 2 volts in branches
and 2 volts in lead 1. Total, 16 volts.
P D between ends of wire 2 = 1x2 = 2 volts.
183. p D between ends of wire 3 = ti X 3 = 2 volts.
X. — The quantity of heat in calories produced in a conductor is equal to the
continued j^roduct of j%%, the square of the current in amperes, the resistance
of the conductor in ohms and the time in ."teconds. Or, H=^0.24 C- R T.
Thus, 10 amperes flowing through a fuse of i ohm for 1 minute generates
360 calories = 1.44 lb. deg. Fahr. Power = 25 watts.
182.
LAWS, WIRE TABLES, EXAMPLES.
137
XI. — The poiver in watts in any live icire or circuit equals the total volts
Tmiltipliecl by the amperes or the square of the amperes times the ohms. Or,
P = EC=C- R.
Ex. A storage battery of 55 cells in lighting eighty 110-volt lamps falls from
112 volts on open circuit to 110, while the ammeter shows 40 amperes. How is
the power expended?
Ans.: In each lamp, 110 X + = 55 watts; in external circuit, 40^ X HO -^ 40 =
4400 watts; in battery (112—110) 40 = 80 watts; in entire circuit, 112x40 =
4480 watts.
XII. — The grams, W, of metal deposited, or gas freed, or electrolyte decom-
posed by C amperes in T sees, is W = 0.000010384. C T Z. Z is the chemical
equivalent of the metal, etc.
(C) WIRIJ^G TABLE.
1. Copper Wiring op U. S Underwriters.
Computed from — Weight 1 cubic foot copper = .555 lbs., and resistance 1 rail, foot commercial soft copper,
98f; pure, at 68° F. = 10^367 international or true ohms.
4
|[
Capacity.
5
o
1
f Strand
&
?£
K
Is
=13
11
m 5
o .
a-2
°,|
■ii
»■
Z
c
i'^
1^'
'4
S ~
a.
sl
■g"
.2
3.g
c-3
"o
■3
5
1
s
. o
3 ^
3S
3
O
3
O
^•
.=
c
^
<
iz;
?5
H
PL,
&<
»
"S
I.
II.
III.
IV.
\.
VI.
VII.
VIII.
IX.
X.
18
40
45
1,624
2, 048
5
6
3
4
6. 3880
5. 0660
4.92
6.20
18
21
49
58
Working formula
17
for res. of I feet
16
51
2, 583
8
6
4.0176
7.82
25
65
cop. of d mils. diam.
„ 10.4 X I
15
57
3,257
10
8
3.1860
9.86
31
72
14
64
4,106
16
12
2. 5266
12.44
38
83
Kes. increases 0.21
per cent for 1° F.
rise of temperature.
Res. H. D. cop-
per = 1.0226 X soft
cop.
For actual cross-
13
72
5,178
19
14
2. 0037
15.68
43
12
81
6, .530
23
17
1. 5890
19.77
48
tis
"109'
11
10
91
102
8,234
10, 380
27
32
21
25
1. 2602
. 99948
24.93
31.44
64
80
4-17
4-16
129
134
9
8
114
128
13, 090
16, 510
39
46
29
33
. 79242
. 62849
39.65
49.99
97
116
8-18
8-17
148
165
7
144
20, 820
56
39
. 49845
63.03
118
8-16
180
6
5
162
182
26,250
33,100
66
77
43
53
. 39528
. 31346
79.49
100.23
166
196
16-18
16-17
203
220
section multiply
Nos.in III by 0.78.54.
4
204
41,740
92
63
.24858
126. 40
228
16-16
238
For ohms per mile
multiply Nos. in VI
by 5.28.'
Nos. in \I give
also volts fall of po-
tential per ampere
per 1,000 feet.
From III \V6 cjvn
3
229
52, 630
110
75
. 19714
159. 38
265
32-18
259
2
258
66, 370
131
88
. 15633
200.98
296
32-17
1
289
83, 690
156
105
. 12398
253. 43
329
32-16
"",3(')0"
325
105, 600
185
125
. 09827
319.74
421
32-15
340
00
365
133, 100
220
150
. 07797
402. 97
528
32-14
380
000
410
167, 800
262
181
. 06184
508. 12
643
32-13
425
OOtM)
460
211,600
312
218
.04904
640. 73
815
32-12
454
Cables.
630
300, 000
405
273
. 03355
932
37-090
get e (J u i V a 1 e n t
strand cable tor any
727.3
400,000
503
332
. 02516
1242
£
37-1039
814.5
500,000
595
390
.02013
1.553
■g
61-0905
wire. Four No, 3's
891.9
963. 9
600,000
700,000
682
765
440
488
.01666
. 01438
1863
2174
3S3
61-0991
61-1071
may replace one 000(J
wire because 4 X
5 2 630 = nearly
1030. 5
800,000
846
540
. 01258
2474
3 ^
61-1145
1092. 6
900,000
924
585
.01118
2795
u ■"
61-1214
211600. For No. 0,
1152
1,000,000
1000
630
. 01006
3106
§ s
61-128
take two No. 3's or
1208. 7
1,100,000
1075
675
. 00915
3416
°-v
61-1343
four No. 6's.
1262. 8
l,200,0f)0
1147
715
. (K)838
3727
•^ M
91-1148
1314. 5
1,300,000
1217
755
. 00769
4038
91-1195
1364
1,400,000
1287
795
. 00715
4348
1 i
91-124
1413. 5
1,.5(M),000
1.356
8.35
.00667
4658
91-1285
1458. 6
1,600,000
1423
875
. 0062O
4968
~|C
91-1326
1503. 7
1,700,000
1489
910
.00588
.5278
O rs
91-1367
1547. 7
1,800,000
1554
945
.00556
5588
1^
127-1195
1571.9
1,900,000
1618
980
.00527
5898
127-1223
1630. 2
2,000,000
1681
1015
.00500
6208
^
127-1254
Rough ride. — One thousand feet of soft copper, one mil. in diameter (No. 10)
has one ohm resistance at the ordinary temperature of a room.
138
HANDBOOK FOR ELECTRICIANS.
2. Table for Taps, Bridge Wires, Etc., of Negligible Drop (0.15 of 1
per cent or less.)
1
9
3
4
.5
6
7
8 10
12
14
16
^9
300
1280
260
10Sf>
200
«IJO
160
080
130
5G0
1(10
43.5
80
345
66
280
50 38
220 160
24
100
15
60
4()
Feet tllO V
''!>
'S. Table of Sizes of Safety Fuses.
Fuse wires should be stamped with 80 per cent of the maximum amperes
which they can carry indefinitely, thus allowing i overload.
Amperes carried
Diam. in mils
17 20 25
^y2
45
8>^ n 143^
50 I 60 70
22 24 30
90 100 110
35 45
120 140
80 lOO
200 220
In testing, allow naked open fuses five minutes to blow; inclosed fuses not in
contact, a shorter period.
(D) GEiVERAI. FORMUIiA.
C= amperes.
i?=ohms.
£■= volts.
P= watts.
H P=horsepower.
C P=candlepower.
?i=No. lamps in parallel.
c= amperes in 1 lamp.
e= volts in 1 lamp.
I— feet on one side of circuit.
d= diameter of wire in mils.
tj= volts lost in wires.
A,-=motor efiiciency.
=ratio output to input.
=0.75 in 1 h. p. motors.
=0.80 in 5 h. p. motors.
=0.90 in 10 h. p. motors.
=0.95 in 50 h. p. motors.
1.— Ohm's km\—C=E -=- R; E=C R ; R=E -^ C.
2.—P=C-^R=CE=E-^-^R. 1 iTP=P^746=C-^P^746.
3. (a) Given the length, /, in feet and diameter, d, in mils, of copper wire, to
find its resistance at the same temperature ; P=Z x 10.4 -=- d'^
(b) Given the resistance, R', of copper or other pure metal at T ° F., to find
its R at any other temperature t°F ; R=R' [1 + 0.0021 (t—t)].
Ex. From the table the R of 1,000' No. 13, at 68 F =2 ohms- at 60° F.=2
(1 — 0.017)=1.97ohms; at 100° F. =2.13 ohms.
4. Given the voltage and candlepower of an incandescent lamp to find the
current strength to light it : c = C* P X 3.5 -h e.
Ex. A 32-candlepower, 52-volt lamp requires, therefore. 2.15 amperes. A
16-candlepower, 110- volt lamp requires i ampere.
5. To find the size of copper wire for feeders, mains, branches, service wires,
or inside work to feed n lamps in parallel taking each c amperes from a center of
distribution distant I feet, so that the total drop in both wires will be v volts :
d-' =
nxc X2lx 10.4
(from Ohm's law).
With the value of d'^ found, look in column III of the table for the next higher
value. If this wire has the carrying capacity in open (IV) or concealed (V) work,
as the case may be, it is taken; if not, the next larger wire.
Ex. What gauge of copper wire will supply fifty 110-volt, 16 candlepower
lamps at 150 feet distance from the center of distribution with only 2 volts loss?
Ans.: c = 16 X 3.5 ^ 110 = 0.51 ampere, d^ = 50 X 0.51 X 300 X 10.4--2 = 39780
circular mils. , No. 4 B and S.
6. Given the voltage e delivered to a lamp and the per cent drop (p as a whole
number) in the wires of the voltage received to find the number of volts drop
in the wires :
v-pe^ (100— jj»).
Ex. The leads to a cluster of 110-volt lamps are figured for a 4 per cent drop.
What is the actual number of volts lost in the leads?
Ans.: V = 4 X 110 -=- 96 = 4.6 volts. Voltage at supply end = 114.6.
Ex. What size of wire will carry with a 2 per cent drop, 30 amperes, 200 feet
to a 220 volt motor ?
Ans. : r = 2 X 220 -- 98 = 4. 5 volts drop, d' = 30 X 400 X 10. 4 -^ 4. 5 = 37733, No.
5 B and S.
Ex. Conversely, to find the per cent drop in the wire.s when the volts drop
and volts delivered are given :
p = 100 u -f- (e + v).
LAWS, WIRE TABLES, EXAMPLES.
139
M
f— W
Suppose there are 6 volts drop or loss in the leads to a 104- volt cluster or
motor; the per cent drop in the leads = 100 X 6 -7-(104 + 6) = 5.56 per cent.
7. To find the volts loss in a given copper wire carrying a given current :
■^iXt'XSZxlOl
V = -j^ : — '— ; or multiply the number in cohimn VI of the table by the
feet and amperes and divide by 1,000.
8. To find the sizes of feeder and mains in fig. 184, which give a drop or loss
between feeder switch and the 32 16 candlepower lamps of 2 volts or less, lamp
voltage to be as nearly uniform as possible.
On the plan mark all centers of clusters and measure along the wires the dis-
tances in feet between them. C is the heaviest main, having 10 X 33 = 330 lamp
feet. Its 10 lamps are supplied over 33 feet
of main and 1 00 feet of feeder. For a starter,
consider at first the drops to be in propor-
tion to the lengths, i. e., 0.5 volt in the
main and 1 . 5 in the feeder.
A 1.5- volt drop gives for the feeder
rr2=32x*X200Xl0.4^1. 5=22187, or No. 6
wire. But No. 6 causes a drop of 1.3 volts
either from (5) or from the proportion
L5 X If = 1.3, iTsing in the fraction the first
two figures only of d- as approximate.
Therefore, the drop in all mains will be j\
volt or less.
For main C, fr-'=10 X *X 66 X 10.4 h- 0.7 =
4903, or No. 13.
Likewise No. 13 is found for the main to
the 8 lamps in A, 40 feet from center.
No. 16 for B and No. 14 for D. Column
Fshows all five wires to have sufficient car-
rying capacity.
For a check, use column VI, which gives
the volts drop per ampere per 1,000 feet.
For example, in feeder, drop — 0.395 (No. 6)
X TiJinr (ft.) X 16 (amperes) = 1.3 volts; in
main C. drop =: 2 X 0. 066 X 5 = 66 volt ; in A, 0. 64 ; in B, 0. 64 ; in D, 0. 63. Be-
tween FS and the ends of the four mains the losses are 1 . 96, 1 , 94, 1. 94, and 1 . 93 volts.
If a problem gives the drop in yer cent, find the volts from v =pe-^ (100 — p)
and proceed as above. In extensive wiring, tables computed from above
formulas are used.
Any tap off the main D, for instance, having a drop greater than 0.07 volt
would cause the total to exceed 2 volts. For this limit, one lamp at 50 feet dis-
tance requires a No. 11 wire. But the sizes of tap wires may usually be taken
from table page 138.
9. To find d' of copper required to transmit HP (horsepower), I feet, with v
volts loss in the wires to a motor of e volts and k efficiency :
^ NO. 6
• FECDEFt
•
100' i
L
J
50'
184. How to Find Sizes of Conductors.
d-'
i7PX 746 X2?X 10.4
vxexk
Then increase d - by 50 per cent for overloading and look in the table.
Ex. A 110-volt hoist motor of 12 horsepower is 100 feet from the closet switch.
Select the tap wires to allow only 4 volts drop from switch to motor whose effi-
ciency is 90 per cent.
Ans.: d'— 47020. Add 50 per cent and the wire is No. 1.
10. The volts required for a constant current motor of iJP (horsepower) and
h (efficiency) are, ^ = 746 X -H" P-^ C k.
The amperes required for a constant potential motor of H P (horsepower)
and k (efficiency) are, C = 746 x HP-^ Ek.
Ex. The current to be supplied to a 220- volt motor of 90 per cent efficiency to
get 12 horsepower is C = 746 X 12 -r- 220 X 0.90, or 45 amperes.
11. The insulation resistance of a wiring sj^stem, including dynamo, or of any
part thereof, should be above 10,000,000 ohms, divided by the total amperes to
flow in the circuit or in the part considered. Or, I R = — '—j^ — ohms.
Ex. The IP of an 80-ampere installation is, then, 125,000; of a branch supply-
ing ten 16-candlepower, 110-volt lamps is 2,000,000 ohms.
140 HANDBOOK FOR ELECTRICIANS.
13. To find the H P expended in a wire, HP=C" R^ 746,
Ex. An arc light 10-ampere current flows in a 10-mile circuit of No. 6 B. and
S. i2 = 0.395X5. 28 X 10 = 20.8. The i?P lost is 100 X 20.8 ^ 746 = 2.8.
13. A storage battery, motor or arc lamp supplied by a generator E exerts a
back electro-motive force e in the circuit. The effective E. M. F. is then E — e
and the current, C = — ^ —
Jri
Ex. 1. Consider in simple circuit a dynamo of 3 volts and 0.02 ohm, a storage
cell of 2 volts and 0.005 ohm, leads of 0.1 ohm and compute what ammeter and
voltmeter should show.
Ans. : C — 8 amperes ; droi3-in leads = 0.8 volt ; PD between dynamo posts 8 —
8 X 0.02 = 2.84 volts ; P D between cell's posts. = 2.84 — 0.8 = 2.04 volts = (for a
check) 2 + 0.005 X 8.
Ex. 2. What is the E of a. dynamo of 0.02 ohm supplying 100 amperes to 54 cells
in series of 2.3 volts B. E. M. F. and 0. 0004 ohm each, the leads having 0.03 ohm?
Also P -D's at dynamo and battery terminals'?
Ans.: E= (54 X 2.3) + 100(0.02 -f- 0.03 -h 54 X 0.0004) = 181.4 volts. PD = 129.4
and 126.4.
Ex. 3. A dynamo of 135 volts and 0.015 ohm was charging for seven hours
through 0. 025 ohm leads, 53 cells each of 0. 0002 internal resistance and of 2. 1 volts
at starting and 2.35 at end of run. Find B. E. M. F., current and regulator
resistance to keep C at 200 amperes at starting and stopping.
Ans.: At starting e = 111.3, C = 460, R = 0.068; at end of rtm, e = 124.6,
C = 206 J? = 0.00165.
Ex. 4. What must be the E of a, dynamo of 0. 02 ohm resistance in order to
supply through 0.005 ohm leads, 7 brake HP to a motor of 90 volts back E. M. F.,
0.025 ohm internal resistance and 300 watts internal friction, etc.?
Ans.: C X 90 ^ 300 X 746 . •. C = 61.4 amperes, E = 90 + 61.4 (0.02 + 0.005 +
0.025)= 93.1 volts. If E of dynamo be raised to 95 volts, the motor will develop
11.6 i7 P.
Ex. 6. The 0.11 ohm leads from a 50-volt P D source are carrying 10 amperes to
an arc lamp of 39 volts, B. E. M. F., which has 0.09 ohm in the lamp coil, 0.08 and
0.12 ohm in the carbons and 0.1 ohm in the arc. What is the extra resistance
which keeps the current in the lamp at 10 amperes?
Ans.: Total P = ^^~^^ = 1.1 ohm. 1.1 — [0.11 + 0.09 + 0.08 + 0.12 + 0.10] =
0.6 ohm.
XVI.— ELECTRICAL MEASUREMENTS AND TESTS.
The apparatus required in the order of utility are : A ijor table Weston volt-
meter (150 — 3 volts) ; an inexpensive upright Weston, in a square hard-wood box,
having at middle, movable coil of about 60 ohms, both a shunt and series
coil to it such that two or three Leclanches will deflect the needle to the scale
end with either, and connections permitting the use of the movable coil alone
or with the shunt or series coil ; a London P. O. bridge ; a few fresh dry cells ;
a Weston milli-ammeter with shunts for heavy currents ; and, if at hand, a
storage battery and the switch board instruments.
CARE IN HANDLING INSTRUMENTS.
Do not send a current through a galvanometer, ammeter, or voltmeter with-
out first knowing its direction, and roughly its strength. Verify by striking
with one of the galvanometer leads before closing for a reading.
Clean metallic connections which scrape into contact are always made.
Set down an instrument of any kind gently.
If the needle is pivoted, tap the case lightly before taking a reading — especially
if the reading is small.
The pointer should stand at zero when there is no current.
A mirror beneath the pointer aids in getting a proper reading. To read,
place the eye over the end of the pointer so that the pointer covers its reflection.
When the box rheostat is used, be sure that all plugs remaining in the box
make such good connections a,s to cut out their coils.
Turn the plug clockwise both in plugging and unplugging to keep the con-
tact surfaces scraped, and never carry the plugs in the hand or lay them in a
dusty place.
If a galvanometer is not at hand, a telephone receiver or a telegraph relay
may take its place in rough testing and the tongue for continuity.
A magneto series bell whose capacity is known, is convenient and useful in
continuity and insulation tests.
Use a knife switch, not a contact key, to close a testing circuit.
The current from a storage battery ought not to exceed 13 amperes per square
foot of positive plate surface, counting one side.
The dynamo or battery which furnishes the testing current, must be well insu-
lated and care be taken not to short-circuit the generator or to heat a testing coil.
A Siemens detector galvanometer having a coarse and a tine wire coil, although
not so good as the Weston described, is more useful than a magneto in testing.
For a cheap W. B., string a Gr. S. wire of about 8 ohms up and down a hard- wood
board 30 inches long, on which brass pieces are screwed as in fig. 187 ; for the
third side prociire a few coils of known R.
I. — To measure the strength C of a e^irreni. — Insert in the circuit an
ammeter of sufficient capacity and of such low resistance as not to alter essen-
tially the quantity to be measured. Good connections are specially required.
II. — To find the difference V of potential betiveen tiro given points of an elec-
tric circuit. — Hold the positive voltmeter lead on the higher point and strike the
other with the negative lead to verify the proper swing — both direction and
amount — of the needle. Then hold the latter down and read. A high voltmeter
resistance is required so as not to alter appreciably the quantity to be measured .
III. — To test the continuity of a circuit by means of a detector
galvanometer and a few cells. — Connect this apparatus in series I I *
and strike terminals quickly to see that all is in order. Then L b^
join terminals to tho.se of the circuit under test. A deflection n < ^
shows continuity. If there is no deflection proceed along the
circuit touching across at convenient points with an extra wire
until the break is reached.
IV. — To measure an ordinary resistance R of a conductor
readily by the Substitution method. — Connect the unknown R,
a constant battery, a galvanometer (shunted if necessary) and jgg_ Substitution,
a key in series, and note the deflection. Take out R and insert
rheostat or G. S. wire from which throw into circuit a known resistance, r until
the deflection is the same as before. Then, R = r. Small resistances in G and
B and a large deflection of G are favorable conditions.
(141)
I
142
HANDBOOK FOR ELECTRICIANS.
V. — To measure an ordinary resistance x of a conductor accurately with the
Wheatstone bridge. — The Wheatstone bridge consists of three sets of known
resistances, a, b and c, joined in series. They and the unknown resistance x
form (for a picture) the four sides of a diamond-shaped figure. A galvanometer
joins any two opposite points of the diamond, and a battery the other two. Figs.
186, 187, and 188 represent three forms, which are lettered to correspond. Two of
the sides or sets, a and b, have usually three coils
each, 10,100 and 1,000 ohms, as in the London P. O.
pattern (fig. 188), or consists simply of a German
silver or a platinoid bare wdre, as in the wire bridge
form, fig. 187. The third set or side has usually 16
coils, so sized that any resistance expressed by a
whole number between 1 and 11,111 ohms can be
unplugged from it. Any resistance between y^u
and 1,111,000 ohms can be measured with the Lon-
don W. B. , and two infinity phigs permits its vise
as three separate rheostats.
To measure witJi, a W. B. — Connect, as in figs.
186-7-8, the unknown resistance x, with the three
sets, a, b and c, of the bridge so as to form a
simple closed circuit. There must be a certain
amount of resistance in each set, the more nearly equal the better. Connect a
sensitive galvanometer and key between any two junctions not adjacent and a
battery and key between the other two junctions.
While holding the battery key A', down, depress (or better, strike) the gal-
vanometer key An. If there is no deflection the bridge is balanced. If there is
a deflection, alter the resistance in one or more of the three sides, usually c, until
there is no deflection ; then the unknown resistance is equal to the resistance in
c multiplied by that in b and divided by the resistance in a. Or a- = c X b -^ a.
186. Student Form.
Si^
•CD-
.A.
(UUlUCUn ^ tiXBOB o Di
~~in iJi & i\ 12
e
. I . I , I , I . I , I . r . 1 , 1 , 1^
J looo IOC 10 3 10 100 1000 2^
» mim ^^ ^^ ^^ ^M Hit y
i-^— '— 1— '— '^
I ' e I'
.Sf^ 'v.?"J^
(hF
1
187. Workshop.
188. London P. O.
VI. — To measure a large resistance R like the insidation resistance of a con-
ductor by means of a sensitive galvanometer tvhose constant or deflections are
known and a battery of knoum V. — Detach the conductor from all others and
guard against leakage at its two ends over the insulation. Join in series either
end of the conductor, G, Fand the frame or ground plate as the case may be.
From the deflection the current C through the circuit is known. Then, E = V
■^ C — G'. G' is small enough, relatively as a rule, or can be made small by a
shunt, to be called zero.
VII. — To measure a small resistance R like a jiicce of cable, joint, armature
coil, etc., by means of a Weston ammeter a7id voltmeter. — Connect up as in the
_y figure and read the deflections. Then R = E -^ C.
r 1 Ex. When a storage battery, a heavy rheostat to prevent
- * ' •*• — 1 .short-circuiting, an ammeter and an armature whose resist-
ance was sought were joined in series the current was 15 am-
peres. The voltmeter (small coil) bridged across the two
commutator bars in contact with the brushes showed 0.09 volt.
R of armature = 0.006 ohm.
VIII. — To measure the conductor resistance R of the main or any feeder cir-
cuit flamps hot) by the sivitchboard voltmeter and ammeter. — Take the instru-
mental readings while current flows in the circuit to be measured and compute
from R — V -¥- C.
SZl
189. By Volt and
Ammeter.
ELECTRICAL MEASUREMENTS AND TESTS. 143
A conductivity test of a main or feeder circuit with a D G, or an R meastire-
ment by the substitution method, will preclude all danger from short circuit
when the feeder switch is closed.
IX. — I'o measure an ordinary resistance R by means of a
voltmeter and a single knoirn resistance r. — Connect as shown
(fig. 190). If the deflection is Fwhen the voltmeter leads are
ai>plied to the ends of R and v when applied to r, R — r V -r- r. T ' s?
Large and nearly equal deflections for V and v are favorable 190. Compari^
conditions. son.
X. — To measure a small resistance R by means of a voltmeter and a bare
German-silver ivire S of k)ioicn length and, resistance. — Connect R, S and a few
showed 3 volts. R of battery = 2 ohms.
For a large storage battery a heavy current rheostat and the
larger voltmeter coil would be necessary.
XVIII. — To measure the internal resistance R of a battery 194.
readily by means of a loir, resistance galvanometer G, and a
rheostat r. — Join R, G and r (well plugged) in series and note the deflection
which should be made small by shunting G, if necessary. Next unplug r ohms
from the rheostat until the deflection is halved. Then, R = i r. Close the bat-
tery for as brief a time as possible that its R may not change.
XIX. — To measure the resistance R of a galvanometer readily by means of a
knc-resistance battery and a known r. — Join R, B, and r well plugged in series;
note the deflection which should be small by arranging the cells of B in parallel,
if necessary ; unplug r ohms until the deflection is halved. Then, R = i r ohms.
The R of a galvanometer is preferably measured as an ordinary resistance.
XX. — To test the insulation R of a conductor by means of a magneto.^
Detach the conductor from the rest of the circuit. Join one terminal of the
bell to the conductor and the other terminal to the groinid, frame of instru-
ment, dynamo, etc., from which the conductor should be insulated. If the bell
rings feebly on turning the crank the insulation resistance is less than 25,000
ohms, or the capacity of magneto. If not, the insulation is greater,
XXI. — To select and label the conductors of a cable. — At one end connect any
conductor (insulated from the others) to the sheathing ; at the other end connect
the sheathing, a few cells, and a detector terminal in series ; tap rapidly with
the other terminal each conductor's end in turn until a deflection is obtained.
Tag this end and the other connected with the sheathing as wire "No. 1." In
like manner find No. 2, and so on.
A telephone receiver and a cell, or a magneto and bell, may be used in place
of the above and a separate wire in place of the sheathing. Conductors can
likewise be selected at the middle without cutting by piercing the insulation
with an ordinary fine needle, which is made the terminal of the detector.
XXII. — To test for crosses, grounds, and insulation of conductors in a cable. —
Dry both ends of the cable ; separate No. 1 for the test from the others at both
ends ; at the near end, bunch the others to the sheathing and connect the bunch
in series with two or three cells and a telephone receiver post. When an insu-
lated wire from the other receiver post is tapped quickly on No. 1, if well insu-
lated, a click will be heard from a charge flowing to the wire, but not at the
second or third succeeding tap. But if No. 1 is crossed or grounded the click
will be alike for all taps. Having properly labeled No. 1, repeat the operation
on No 2 withdrawn from the bunch, and so on.
XVII SPECIFICATIONS FOR REQUISITIONS, ALTERATIONS
AND REPAIRS.
Every electric machine or piece of apparatus for war uses shall be simple,
certain in operation, proved in the industries to be standard in its class and sup-
plied by one of the leading manufactories in the United States.
(A) POWER HOUSE.
1. Located centrally and 3 feet from protecting earth traverse or embank-
ment ; built of brick or old fortification granite ; floored with concrete ; roofed
with slate and iron in shed form or with low middle i-idge ; siipplied with at
leas'; five large, removable windows on three sides and with three large, window--
paneled doors on the front. In the rare cases where the power house can not be
protected, the machinery will occupy outer and sun-lighted rooms only, of the
work.
2. Partitioned laterally into (a) boiler, (b) generator, (e) battery rooms.
(a) holds an inclosed coal bin for three days' supply, with outside chute at top
and an inside shovel hole at the bottom accessible from furnace door. Large
plants have separate coal rooms. Door permits horizontal tubes to be with-
drawn. There is a ventilator at the highest point. For oil engines (a) holds
water tank, oil and supplies.
(b) affords at least 4 feet clear space around engine. and dynamo and in front
of switch board facing dynamo. Door between (a) and (b).
(c) contains two battery stands of two tiers or shelves each, solidly built from
one-size material (see '"Storage battery"). ' They extend along the lateral walls
and have 5 feet clear space between them, or preferably 30 inches or more clear
space on both sides. Distance between shelves = 2 x height of jars. Ventilators
at top and bottom.
(B) BOILERS.
A boiler is rated at 1 horsepower, which, with easy firing, moderate draft,
ordinary fuel, and good economy, can evaporate per hour 30 pounds (about i
cubic foot) of water at 100° F. into steam under 70 pounds pressure above the
atmosphere.
1. For 35 horsepower or less, procure from the standard factories only, verti-
cal fire tube ; for larger power or as space permits, vertical or Hor. return fire
tube without dome ; working pressure = 100 pounds ; water test = 150 pounds ;
safety factor = 5 ; requirements in practice in chapter I.
2. The shell is of mild, nontempering, open-hearth steel plate, f to | inch
thick, having 60,000 pounds tensile strength, 56 percent ductility, 20 per cent
elongation of a piece 10 by 2 inches wide. This data and firm name are stamped
on each plate. All holes are bored, not punched; all joints, lapped and double-
riveted longitudinally and single -riveted laterally.
The tubes of cold-drawn, seamless steel, 2-inch diameter in vertical boilers, 3-
inch in horizontal and at least i inch thick, closely fit holes drilled i diameter
apart in the clear ; the ends are expanded and flared.
3. Length, one and three-fourths to two and one-eighth times diameter;
capacity = one-third greater than maximum required by engine ; 13 square feet
heating surface per horsepower if boiler is vertical ; 15 square feet, if horizontal ;
36 square feet heating surface per square foot grate; one-third to one-half of
grate per horsepower ; total tube opening, one-tenth to one-seventh of grate area ;
grate air passage = one-fourth to one-half grate area ; chimney cross section =
one-fifth of tube opening; water feed = 1 to 1^ inch diameter; blow-off = 2 to 2^
inch diameter ; steam feed = engine opening.
4. Interior braces and stays of steel of 60,000 pounds, T. S., not welded nor
worked in the fire, riveted and bolted, shall have such cross section that the
1714-10 (145)
146 HANDBOOK FOR ELECTRICIANS.
strain ( = boiler pressure X area braced -4- cross section) shall be same as T. S.
above with same safety factor and firm-name stamp. Openings, 2 inches or larger
in the shell, shall be flanged. Manholes or hand -holes at bottom and top shall
permit thorough inspection and cleaning. All seams are calked inside and out.
Fire door has air inlet. Safety plug in tube is 2 inches below lower gauge and
near a hand-hole.
5. Fittings, except pipes, are brass.
(a) All piping, wrought iron or steel, are direct and short, with few bends
which must have large radii, and will be laid so as not to allow water to stand
in them. Steam pipes rise slightly toward the sluit-off valve next the boiler.
Boiler and steam piping are covered with asbestos. No piping is embedded in
concrete.
(b) Muffled pop safety valve, with lifting handle, has 1 square inch aperture
to 3 square feet grate, and opens at 5 pounds above working pressure.
(c) Steam gaiige, 6-inch face, has siphon and air cock.
(d) Three water-gauge cocks. Lowest is 2 inches above upper horizontal
tubes, or one -third of the distance between lower and upper flue sheets.
(e) Glass gauge, with two cut-off valves, drain cocks, guards, and extra glasses.
(/) Blow-off valves, with screw motion. Scum blow-off cock.
(g) Injector, lifting, lies direct as possible between svipply and the delivery
above crown sheet. Delivery tube is so bent that water entering will flow with
the circulation. Has both check valve and stopcock.
(/() Double-acting suction and force pump has air chamber, a branch in
suction for boiler compound and an independent and straight connection.
(?) Feed water, heater and purifier.
(j ) Steam separator.
{%) Exhaust directible into smokestack.
(C) GENERATING SET
1. Is either a (1) standard, direct-connected, simple, steam engine and dynamo
on a common iron bed plate effectively grounded, or (2) a Hornsby-Akroyd
oil engine, link -belt connected with a standard dynamo on wooden base and
having an inertia wheel.
(a) Supplied by General Electric, Westinghouse, or like standard company.
(t>) Stamped with name, volts, amperes, power, speed, + and -—posts, N. and
S. poles.
(c) Located with switchboard in a dry, ventilated, sun-lighted room used for
no other purpose, and kept dry by an oil stove if subject to dampness.
(fZ) Bolted to concrete foundations of dimensions given by the makers.
(e) Tested for two hours on one-third excess of its full rated load without
injury.
(/) Capable of long runs on full load without undue heat or wear.
(g) Perfectly balanced and runs true without vibration, noise or leaks.
(h) So efficient as to give by ammeter and voltmeter 0.80 of indicator's power.
2. It requires :
(a) A competent and devoted attendant.
(h) At least 4 feet surrounding clear floor space.
(c) Large windows on two sides.
(d) Fnil sets of tools, oilers, standard spare parts.
(e) Full working tracings and diagrams.
(/) If large, two or more like units with one spare.
((/) W. P. cover when not in use.
(h) Self -oiling of all bearing surfaces.
(i) Means to recover surplus oil.
(./) Guards to stop oil being thrown.
(k) Metal can for oily waste.
(/) That oil shall not run along shafts or spill.
3. (o) Engine, high-speed, double-acting, automatic cut-off, simple, vertical,
if 30-horsepower or less, horizontal if larger, compound if very large ; to work
most economically on 80 pounds pressure if simple, on 100 pounds if compound;
to allow, with economy, a variation of 20 pounds either way and fulfill condi-
tions on page 47.
(b) The piston, rods, crosshead, guides, shaft, nuts, bolts, of the best forged
steel, are accessible for repair, capable of realignment when worn and strong
enough to allow sudden throwing on and off of the whole load. The cylinder
and valve chest, of cast iron encased with nonconductor, have relief valves
removable for indicator connections.
SPECIFICATIONS FOR REQUISITIONS, ETC.
147
(e) At full pressure the governor prevents a variation less, than 2^ per cent in
the number of revolutions during a change from full load to one-fifth thereof,
and less than 5 per cent for a change of both steam pressure within limits given
above and of full load to no load.
(d) The engine will have cylinder, up-feed lubricator, automatic sight-lubri-
cation elsewhere, oil collectors and guards. The exhaust, directible to smoke-
stack and led outside and concealed, should be killed if flowing water is available.
(e) Ideal, Ball, Straight Line, Mcintosh and Seymour, Armington and Sims,
and Westinghouse are names of good engines.
4. The dynamo is direct current, multipolar, compound-wound, and has suffi-
cient potential to maintain during full load and normal speed, 110 volts at the
farthest lamp, and to charge 58 storage cells.
(o) It requires:
A ventilated, balanced armature; a laminated core of soft-iron disc rings;
P. D. between adjacent bars less than 10 volts; two or more brush carbons in
each set ; rocker locked in any position ; large self aligning and oiling bearings ;
field frame in upper and lower halves ; fuses on both leads ; equal magnetic
pull by all poles; all circuits of 0.99 cond. of pure cop. ; a field rheostat by
same builder.
(b) It is capable of running eight hours on full load, or three hours on 15 per
cent overload, without heating the commutator 50° F. or any other part 40° F
above the surrounding air as given by
a thermometer placed (in first case) on
the heated part and covered with
waste, and in the second case, 3 feet
from dynamo in line with the shaft.
(c) A change from full load to no
load, with brushes and rheostat fixed,
causes less than 2 per cent variation of
potential and no sparking. If the full
load is suddenly thrown off, the swing
of a Weston voltmeter from self-
induction is less than 10 volts.
(d) No insulating part can be injured
by moisture or 200 ' F. rise of tempera-
ture, and the insulation between cir-
cuits or between entire circiiit and
iron frame exceeds 1 megohm under
1,000 A. C. volt test both before and
after a run.
(e) Armature windings must be
symmetrical, systematic and replace-
able; end connections, short and
mechanically made to bars ; wires hav-
ing wide P. D. are kept apart ; no wires
cross in contact with each other. jpg^ Pj^u i^heostat W=e.
(D) SWITCHBOARDS.
Switchboards, preferably of slate, must not carry anything which is com-
bustible or absorptive.
Be free from moisture, dust and accessible from all sides.
Have a main switch, main cut-out and ammeter for each generator ; a D. P.
switch and cut-out for each circuit leading from board and a voltmeter and
gi-ound detector.
Meet all requirements of pages 56-7-8.
Be wired as sufficiently indicated on page 74.
(E) STORAGE BATTERY (RESERVE EXCEPT FOR MOTORS
JLND SEARCH LIGHTS).
1. Fifty-eight chloride storage cells of about 1 square foot positive plate (one
side) per 12 amperes of normal charging and discharging rate for eight hours
should show 85 per cent efficiency and conform with requirements in VI.
2. The glass jars rest on sand in wooden trays on glass or porcelain insulators
on shelves of paraffined solid framework.
3. Lead-lined strong wooden tanks are used when plates exceed li square feet.
148 HANDBOOK FOR ELECTRICIANS.
4. Connections ai'e lead-biirnecl, if practicable, or so bolted that they allow no
greater drop than an equal length of lead lug.
5. The jars, readily accessible on tv/o sides if possible, should stand free from
concussion and the direct rays of the sun.
6. Fully protected by an overload automatic cut-out and a D. P. switch near it.
7. Supplied with meters and facilities enumerated in VI and XII as necessary
for the care of batteries.
(F) ELECTRIC MOTOKS.
1. All electric motors should be —
Furnished by one of the leading manufactories in the United States.
Guaranteed to meet the general requirements given above for dynamos.
Located in a clean, dry, well-lighted place under oilcloth cover.
Insulated by moisture-proof wooden base frame if possible ; else dead-grounded.
Slotted ring armature; brush holder capable of fine adjustment and fixable in
the proper position.
Series wound (if hoist), multipolar and having 50 per cent excess of power.
If required, inclosed by frame against damp and dust. Hand-holes have covers.
Supplied with radial carbon brushes, two or more in each holder.
Constructed so as not to spark between no load and 15 per cent overload.
Fed direct through exclusive feeders having a cross-section to carry 50 per
cent excess of current.
Protected by rheostat, overload and underload circuit-breakers, fuses and D. P.
knife-switch within sight of motor.
2. Rheostats to motors constructed of fire and moisture proof material by the
builders of the motors, have the overload and underload releases, usually attached,
sufficient capacity without paralleling coils and 1 megohm insulation B. The
contacts should be ample, the resistance such as to drop the full potential 80 per
cent at the first point. Capacity and factory No. are plainly marked. There
are three types:
(a) Starting, capable of carrying line voltage 15 seconds.
(b) Regulating, capable of carrying full line voltage indefinitely.
(c) Regulating and reversing. C through armature only is reversed. All
springs are of bronze and carry no C. Points of control are clearly indicated.
Rheostats in damp positions are inclosed by a water-tight, fire-proof case.
/G) SEARCH EIGHTS.
1. The brass projector, painted dead black inside and out, holds the parabolic
glass mirror, 36 to 60 inches in diameter, |- to i inch thick, and is mounted ujjon
a low platform of a four-wheel truck. Its arc can be supplied at 1,000 feet dis-
tance from the dynamo through double cable.
2. The projector can be directed by hand or by means of a controller, multiple
cable and two shunt motors, so that the beam can be turned to any desired point
by a person 150 feet away from the projector, right or left, up or down, in agree-
ment with like motions of the controller's single handle, and with a rapidity
depending upon the amount of throw of the handle, or with as small motion as
desired.
3. The drum must be evenly balanced, well ventilated, and fitted vrith peep-
holes for watching and hand-holes for adjusting the arc.
4. In all the means of operation, in excellence of workmanship, and photo-
metric power, all projectors must equal or excel the Schukert and General Elec-
tric search lights of like size manufactured for the United States Government in
1900, as given on pages 90-102 of the Handbook.
(H) II^CAI^DESCENT LAMPS.
1. Sixteen-candlepower lamps, with Edison short base, screw into a brass out-
let box closed by a glass, screw-rim globe (fig. 199) for ordinary use. For pow-
der magazines, 32-candlepower lamps are clustered inside an air-tight, moisture
and fire proof lantern which is placed in the end wall nearest the gallery and
furnished with reflector and diffusing lens.
2. All lamps are 1 10-volt, and of standard size and make. Efficiency = 1 candle
per 3.1 to 3.5 watts; useful lif e = 800 hours; apportion one 16-candlepower
lamp to 1,000 cubic feet room space.
3. Filaments should stand centrally in a uniformly molded lead glass bulb
without tip, have two or three curls withoiit anchor, and show no dark or bright
spot when heated to a dull red. The vacuum should allow no glow when tested
on an induction coil delivering a |-inch spark.
SPECIFICATIONS FOR REQUISITIONS, ETC.
149
4. The mean horizontal candlepower obtained by revolving the lamp in a ver-
tical position 180 times per minnte should be within 1 candlepower of its rating,
and should not fall below 80 per cent of the initial candlepower after 800 hours' use.
5. Sockets of brass, never less than 0.013 inch thick, have solid construction,
standard screw threads, porcelain base, insulating lining fixed, tough and fire-
proof, and points of opposite polarity at least /y inch apart, unless separated by
reliable insulation. Except in special cases, they are keyless. If suspended, the
flexible cord enters the socket through strong insulating bushing, i inch inside
diameter.
(1) WIRIN^G.
1. The closet system of two-wire parallel distribution of direct current to
lamps, motors, search lights, storage batteries, detonators, etc., afford the better
control and protection, whether or not the wiring is partially overhead or
underground, or wholly interior. It takes more wire than the tree system, biit
allows switches and cut-outs to be safely and conveniently grouped and lamps
to be at more nearly equal voltage.
H^kTP
196. Distributing Current to Centers.
(a) Feeders run from bus bars to main centers in slate closets or to motors;
mains, from main centers to cut-out boxes (sub-centers) ; branches, from cut-
outs to places to be lighted, 12 or less lamps; taps, frona branches to lamps.
(b) The route to a lamp is: (1) Bus bar, (2) D. P. knife switch, (3) fuses to
protect feeder, (4) feeder, (5) bus bar main center distribution box, (6) baby
D. P. knife switch, (7) fuse to protect the main, (8) main, (9) inclosed fuse of
cut-off box to protect the branch, (10) branch, (11) tap to outlet, (12) snap
switch, (13) lamps.
(c) Search light, motor, or storage battery has its exclusive feeder.
2. Safety fuse cut-outs are placed in full view at centers and subcenters of
distribution, or where a smaller wire begins in a parallel system, or where a
motor, battery, etc., requires protection from overload and inside a building
where wires enter.
Safety fuse cut-outs are D. P. and mounted on insulating bases in a small
dust, moisture and fire proof box, held out from walls on porcelains. Fuse-
wires are in contact only with their connections and are f inch long for 50 volts,
1 inch for 110, to prevent arcing.
Cut-outs require copper tips stamped with maker's initials and 80 per cent of
the maximum C which the fuse will carry indefinitely, thus allowing one-
fourth overload.
Any set of lamps requiring more than 660 watts should be dependent upon
more than one cut-out between the lamps and dynamo.
Cut-outs and circuit-breakers are to protect and switches are to disconnect all
circuits beyond them.
3. Magnetic circuit-breakers protect automatically dynamos, motors and bat-
teries against overload with more certainty than fuses, also against underload.
Both kinds must operate with excess of power and within 5 per cent of adjust-
ment. Overloads are usually set to open the circuit at one-half excess of cur-
rent or one-fourth excess of voltage ; underloads, to open at 5 or 10 amperes of
current, or at one-fo\irth fall, if voltage. They must meet the requirements on
page 61 of Ite C. B's. (inverse time element). Magnet iron parts are copper-
plated.
150
HANDBOOK FOR ELECTRICIANS.
4. Switches and circuit-breakers are —
(a) Mounted on small slate, porcelain, or marble bases, or preferably on the
switchboard when used there, make sliding and secure contacts, make and
break rapidly without stop or spark.
Carbon-tipped and have threaded studs and flanged nuts to make back con-
nections.
Stamped with words "on" and "off," maker's name, and maximum C or V.
197. Cabinet Panel; Six Double Branches, Six F. S., One M. S.
(6) All conducting parts have such cross-section that heating from maximum
C can not be felt by the hand.
(c) All switches are double pole; snap for 10 amperes or less; knife for larger
but not smaller than 50 amperes ; in conduit not at centers, snap switches,
marine type, to 50 amperes may be used.
{d) Switches and cut-outs are located, and whenever possible grouped, inside a
fire and water proof insulated box centrally located in a dry, accessible place
which is free from inflammable material.
* ■ ' . . - ^^ '■■mMI HO' ^V
198. Cabinet Panel, Six Single Branches, at a Center.
5. General rules for loires. — (1) Coils purchased must show name of manu-
facturing company, date of manufacture, maximum voltage, and a guarantee
to be "National Electrical Code standard."
(2) All conductors are No. 14 B. and S., single, and above that size in strand
of 7, 19, 37, 61, 91, or 127 wares of one size— No. 19, 18, 17, 16, 15, or 14. One of
a strand lies in the center, and others, in layers, are twisted uniformly around
it, one turn in 20 or 30 inches, adjacent layers being wound in opposite directions.
(3) Copper is tinned. No variation of diameter greater than 0.002 inch
allowed.
(4) On poles — H. D. copper with R. C. and W. P. insulation or bare aluminum.
In conduit, ducts or on cleats — soft copper of 98 per cent conductivity of pure cop-
per, coated with rubber and its compounds to a total thickness of /j inch on No. 14,
increasing with larger sizes to ^-inch thickness on wire of 1,000,000 c. m. or larger.
(5) For all rubber-covered single conductors: (a) First layers are of 98 per
cent pure para rubber, tough, elastic, at least ^^ inch thick for all sizes, and
without flaws.
SPECIFICATIONS FOR REQUISITIONS, ETC.
151
(h) Next layers are vulcanized rubber of 40 per cent pure Para, smooth, con-
centric, continuous, at least /q- inch thick on No. 14 increasing to ^'^^ inch on wire
of 1,000,000 c. m., and without holes or flaws.
(c) All layers of cotton tape thoroughly impregnated with rubber compound,
lap tightly one-half of the width into an even circiilar section at least -^-^ inch thick.
(d) All exterior braid is closely woven and thoroughly saturated with an insu-
lating water-proof compound, uninjured by 200° F. dry heat, bending, or abrasion.
(6) Finished R. C. wires must show an insulation greater than 100 megohms
per mile during thirty days' immersion at 70°F ; also a dielectric strength such
that 1 foot, after seventy-two hours' immersion, will resist for five minutes 3,000
volts A. C. per ^^ inch thickness of rubber.
(7) When a cable has two or more conductors, each is insulated with rubber
and taped. Then all are twisted, usually in layers, aroimd the central wire, the
interstices often filled with jute, and the resulting cylinder is taped and sheathed.
15. Interior conduit. — (1) All interior wiring is drawn, for protection against
moisture and injury, into low steel conduit, f inch to 2^ inches inside diameter,
enameled outside and inside and "dead-grounded."
(2) Its lengths are coupled together like gas pipe and screwed into bronze
junction, closet, switch and outlet boxes having close-fitting doors or covers
which are screwed home on riibber gaskets. All ends of pipe are sealed iip.
The lamp outlet box is closed by a glass globe over the lamp,
screwing against a gasket (fig. 199).
(3) To the bottoms of all boxes is screwed a slate panel, or
marble board, or porcelain block, which carries and insulates
the switch, fuse, or socket.
(4) The conduit is either strapped to asphalt-painted wooden
cleats, 3 feet apart, so as to run with all of its boxes 1^ inches
out from ceilings or walls, or it is embedded in the concrete
2 inches from the surface of wall or ceiling. Its boxes lie on
the surface in the latter case.
( 5 ) The former or exposed conduit can be painted, repaired,
altered, and kept air and water tight.
(6) A good conduit system is rigid, continuous, and prac-
tically air and moisture tight throughout.
(7) Rounded insulated capping to the ends of pipe inside
of boxes prevents abrasion of the wire.
(8) Gfreat force in drawing in wires is unnecessary and
may cause leakage.
(9) Both positive and negative legs lie in one conduit
where either has less than 30,000 c. m. conductor; if larger, each has a separate
conduit. Clearance is j\ inch at least.
(10) Conduit wires require -^^ inch thickness extra fibrous covering.
(11) Every length of
good conduit is stamped
with maker's name.
(12) Snap switches,
being easily boxed, may
be used with conduit to
12 anaperes.
( 13) D.P.knife switches
are put in center of dis-
tribution closets.
(14) Wires are never
' ' fished "in forts. Flex-
ible iron armored con-
duit is permitted for re-
pairs and "droi) cords."
(15) Conduit is in-
stalled and all construc-
tion finished before wires
are drawn in. Bends have
4 inches radius at least.
(16) After the wires 200. Exterior, Wire Conduit in Forts.
are drawn in the ends of exposed conduit and outlets are sealed, all joints of
pipe and boxes are painted with asphalt and precautions are taken to keep the
interior air-tight.
7. Underground lines. — (1) Exterior electric wires will, as a rule, lie below
frost, often 4 feet underground, by being drawn into wrought-iron pipe or glazed
>-n
199. Water-tight
Outlet Box and
Glass Globe.
162
HANDBOOK FOR ELECTRICIANS.
201. Cross=section of lron=Pipe Conduit.
clay conduit set in concrete. Both of these ducts connect manholes about 350
feet apart and will last indefinitely.
(2) Wrought-iron pipe duct (figs. 201-3), in 20-foot lengths, of 3 to 4 inches
diameter, i inch thick, dipped in tar to prevent rust, are jointed by a screw
coupling, so as to be water and gas tight. The concrete is composed' of 1 part
Rosendale cement by volume, 2 parts sand,
and Si parts of broken stone passing U-inch
mesh ; is first laid between l|-inch planks on
the smooth bottom of the track and rammed
to li-inch thickness. Upon this is placed
the first layer of pipe, 1 inch apart, and con-
crete is rammed between them and above to
li-inch thickness. The process is repeated
until the section is completed with a 2-inch
plank cover. At a bend a manhole is built
or the curve is given a large radius.
(3) Glazed clay conduit 18 inches long, 3-
inch bore, with walls | inch thick and out-
side corners rounded, are laid, breaking joints
as in fig. 202. There is i-inch space between
the pipes of a layer and between layers, which
is filled with cement mortar, while a 3-inch
thickness of concrete mixed as above, sur-
rounds the whole. A 36-inch mandrel which
exactly fits the bore, preserves the alignment in laying the duct and prevents
mortar getting inside. The bottom of each 18-inch length duct is slightly curved
upward, so that the joints may not interfere with
the drawing in of the cable.
(4) Themanhole (fig. 203), about Si by Si by 7
feet deep inside, for allowing cable lengths to be
drawn into the iron or earthen duct and for con-
necting supply branches, is built of brick and
made water-tight. The masonry extends below
the duct level to form a catch basin, and is pro-
vided at top with a cast-iron ring frame support-
ing two covers, the lower being screwed down
upon a rubber gasket, and the other resting
loosely on top. Both covers permit ventilation.
(5) For means to draw in the cable, push through a duct a steel wire, or 4-foot
wooden rods, jointed, from one manhole to the next. This serves to pull through
a small rope, then a large rope, then a cleaning steel scraper and brush, and
finally the cable.
(6) Avoid twist and strain on the cable by
the use of a swivel clevis attached to several
iron vsdres wrapped spirally over the first 2
feet.
(7) Specimen underground cable (fig.
206) to be (a) No. 14 single or larger con-
ductor in strand of wires, iiniformly sized,
tinned and twisted ; (b) covered with one or
more layers of pure Para rubber, tape spi-
rally wound, half lapping; (e) then coated
^ T. two or more times with rubber compound,
"^ — J- each coat of two tapes laid on longitiidinally
and pressed into half -cylinder forms which
unite in good longitudinal joints; (d) tightly
bound with prepared rubber tape spirally
wound. Then the rubber is vulcanized, the
insulation is tested, and the outside tape and
braid or lead is laid on.
8. Overhead lines. — (1) Erected in forts
only where fully protected from fire or for
temporary uses.
(2) Never attached to trees, buildings or outside concrete walls.
(3) Wires. — Hard drawn copper. No. 14 and larger, of 60,000 pounds tensile
strength, 96 per cent conductivity of pure copper and tinned, is coated with -g^-
inch thickness of vulcanized riibber and covered with one or more cotton or
hemp braids saturated with moisture and fire repellant ; bare aluminum, 58 per
202. Clay Conduit in Cement
Mandrel.
203. Manhole.
SPECIFICATIONS FOR REQUISITIONS, ETC.
153
cent conductivity ; bare galvanized iron in uninhabited country for signal pur-
poses only.
(4) In contact only with double petticoat porcelain or glass insulators and run
at least 1 foot apart and in such manner that water can not cross-connect.
(5) Protected when necessary from accidental contacts with other lines by
insulated, dead guard, iron wires.
(6) Led into buildings through noncombustible insulating tubes slanting
upward toward the inside. Drip loops outside, safety cut-outs inside.
(7) Strain on wire for tying not to exceed one-third its tensile strength.
204, 205, 206.
(8) Sag = 1 to 2 per cent of distance between poles, depending on extremes of
heat and cold.
(9) Signal wires unavoidably paralleling heavy current lines are stretched
along lowest cross-arms. See Line Construction, page 155.
(10) A lightning-arrester in plain view is placed alongside of every overhead
line near the point where it has entered the building, and is connected with a
good ground (not gas pipe) by No. 6 copper wire direct as possible to ground.
A choke coil is between arrester and dynamo.
(11) Poles. — (a) Wrought-iron tubing ; or wood of cedar, chestnut, pine, or
spruce, round or octagonal, tapering to 6 inches at top and painted. Galva-
nizing the iron or creosoting the wood may preserve the poles thirty-five years.
They are 30 to 60 feet long, have one-
fifth to one-tenth of their length in the ^-, ^\".T S
ground, according to soil, pole length, ■* " ^ r'''j ! ffi
and number of wires, and stand verti-
cally in as straight a line as possible, E
125 feet apart. Lengths may vary with ^^^
207.
208.
the contour to keep the line more nearly straight. At unavoidable curves
lieavier poles are inclined outward, guyed or double-guyed laterally on the
outside by strands of No. 6 or 8 galvanized iron from beneath the single cross-
arm, or the middle of the lower half of several cross-arms to a guy stub or
anchor, or they are braced on the inside by a half pole, solidly planted and
bolted at SO" angle with the pole.
In raising, two spikes may replace the ladder; the "dead man" holds what-
ever is gained in raising.
(b) Cross-arms of iron are clamped; of clear yellow pine or oak wood are
bolted (fig. 208) into gains cut in the poles, braced with iron and spaced as shown.
The pins are of locust.
154 HANDBOOK FOR ELECTRICIANS.
(c) Giiys of iron strand are put laterally on every tenth pole of a
straight line, on all poles from which service wires lead to either side,
and longitudinally on the two poles of an unusually long span and
the two or three end poles of every line.
(12) Insulators of porcelain or blown glass, subject to not less than
a 6,000-volt, 5-ampere, break-down test, have the two or three petti-
coat form, and are screwed to iron or oak pins which are bolted or ,09
screwed to the cross-arm.
(J) ITEMS :N^0T PREVIOUSI.Y SPECIFIEJDo
(Brackets refer to manufacturer.)
Annunciator, index or gravity drop.
Anti-hum, Clarke.
Arc lamp, inclosed [G. E.].
Babbitt metal, "Best."
Bases, porcelain of all kinds [G. E.].
Bell, single stroke, ' ' Vigilant "or " Covered. "
Bell, vibrating, dust and water tight [ W. E. ] .
Binding post, English [W. E.] or Nos. 1, 3, and connectors [Mn.].
Boards (panel), marine type [W. E.].
Boxes (junction, outlet, switch), iron-armored or marine [W.E.].
Buzzer, Eco or Lungen.
Call box. Firman with Ans. back [B. ] .
Clamp, Klein or ' ' parallel. "
Conduit, iron-armored insulating [W. E.].
Connectors, Mclntire.
Cut-outs, bases, receptacles [G. E.].
Drill, hand, hollow handle [W. E.].
Gong, clock to 60 strokes, marine [W. E.].
Gauge, calculating U. S. Wireman's [Mn.].
Gauge, caliper, Micr. 0.001 to 0.5 inch [Mn.].
Instruments, portable, Weston.
Insulators, glass, 2 or 3 petticoat.
Insulators, porcelain, F. H. screw or G. E. knob.
Junction box, iron-armored or marine.
Lamps, incandescent. Navy [G. E.].
Pliers, Stubs or "Universal" [Mn.].
Push button, plain, bronze, water-tight.
Receptacle, water-tight [G. E.].
Rheostat, Carpenter.
Socket, lamp, marine [G. E.].
Soldering torch, gasoline. Imperial or Wellington.
Soldering furnace, " Combination " or "Universal."
Speed indicator, Starrett.
Switch (in closet or on switch board), knife [G. E., W. E., or Mn.].
Switch (in conduit) snap, D. P., marine.
Switchboard (dynamo or battery) [G. E., W. E. or E. S. B.].
Switchboard, telegraph or telephone [W. E.].
Telegraph instruments [Bunnell] :
Key, steel lever, solid ti'unnion, with or without legs.
Key, cable, on rubber base.
Relay, Western Union.
Relay, box and key combined.
Relay, pocket, nickle-plated [W. E.].
Relay, polarized, armature lever vertical.
Register, ink, self starting and stopping, one or more pens.
Set, polar duplex, W. U
Set, quadruplex, W. U.
Testing set, magneto to ring through 50,000 ohms.
Tool handle, "Cocobolo."
Tool handle, eleven tools [W. E.].
Voltmeter, recording, Bristol's.
Wheatstone bridge [W. E. or Biddle].
SPECIFICATIONS FOR REQUISITIONS, ETC.
155
(K) RUIiES GOATERXING lilNE CONSTRUCTION.
9. ( 1 ) Small conductor resistance, large insnlation resistance, order, perma-
nency and accessibility characterize good wiring. To wire neatly and effec-
tively is an art.
(2) Wires which are separately insulated run at least 1 inch apart, parallel if
in the same direction, straight between the fewest possible insulators, in contact
with insulators only, and in such a way that no two wires can ever touch each
other.
(3) Avoid temporar J' work ; in construction regard all other wares as "live"
and bare.
(4) If a kink or a nick occurs in the condiictor, cut it out. If the insulation
gets damaged, paint and tape the conductor as in jointing.
(5) In cutting a wire, gi"ip it with the cutting jaws of the pliers so moved as
to cut an arc of a circle. Twisting breaks the knife edge. Then grip the wire
with the flat jaws close to the cut and one or two sharp twists will give a square
break.
(6) Avoid "come alongs" or vises when they tear the insulation, but take a
series of half hitches or noose wrap with a small rope.
(7) Jointing electrical conductors is of hou.rly occurrence and requires the
care and sldll acqiiired only by practice.
210, 211.
(a) Joints in copper or aluminum lines are often made with the Mclntire
(fig. 210) connector. The two ends brightened are slipped from the opposite
directions into the close-fitting double sleeve which is then twisted by special
pliers. Solder the ends only to avoid annealing the main line and smooth down
projecting parts which might pierce the insulation.
(b) The lineman's splice (fig. 212) for galvanized iron, sometimes for soft cop-
per, is made by holding the two cleaned ends at an ^ _^^
angle in a hand vise, and twisting with pliers by half u ff^^S^^^SSS S "~^
turns each end in succcession five times closely around - 2
the line and soldering.
(c) All joints of insulated wire, after being cleaned and thoroughly dried, are,
as a rule, alternately painted with a thin, uniform coat of rubber or other solu-
tion, and wound with tape half lapping. Each winding is a little longer than
the one before it and runs oppositely. In stripping insulation to make a joint,
cut as in Avhittling toward the ends into a lead-pencil shape. For special wires
follow the manufacturer's directions in jointing.
(cl) The ends of a strand are separately joined by a twist or a connector, as
above, in i)laces not opposite, to avoid too large a bunch when finished. Then
paint and tape alternately.
(e) The ends of a large solid core are beveled and notched for at least 1 inch,
then soldered together into a round piece of the same diameter as the conductor,
then wrapped closely with fine copper which is also solidly soldered, and the
whole is finally taped. The finished insulated joint is considerably larger in
diameter than the cable.
(/) Insulating joints — Carefiilly cut the ends of the insulation, and clean
with a little benzole. Rub a little rubber solution over, and then carefully
wind spirally over the joint and tapered end of the insulation, pure rubber tape.
Cover this with rubber solution and wind on more until the diameter of joint
is about the same as the rest of insulation. Over this and for about two inches
on each side of the cut ends of the insulation, wind especially prepared braid-
ing. Finally varnish the whole.
ig) Vulcanized rubber joints. — Cover joint with pure rubber strip. Rubin
some special rubber solution, allow to dry, bind with valcanizing rubber tape
three or four layers. Then with prepared rubber tape cover the whole with a
156
HANDBOOK FOR ELECTRICIANS.
piece of strong silicia cut to length of joint and then rolled round it, having a
longitudinal seam. Bind this with strong cotton selvedge tape. Joint is now-
ready for the cure, vv^hich consists in subjecting it for half an hour or more to
the action of molten sulphur, the joint being placed in a specially made box for
the purpose. Molten sulphur is run out, and joint cooled, the outer wrapping
of silicia and cotton removed and, if the vulcanizing is satisfactory, the joint is
finished by braiding and varnishing.
(h) Most large cables and special makes have specially designed mechanical
joint boxes.
(?) Make as few joints as possible. Solder all joints or other stirfaces perma-
nently in contact.
(j) Solder is to prevent rust between the wires of a joint ; acid for cleaning, or
a flux will later cause rust. Therefore use resin.
Use the soldering iron for small
wires and dip the large wires in
molten solder or pour on with
a ladle. In all cases avoid burn-
ing the insiilation.
(k) Work with clean hands in
insulating a joint. If the tape ^*'**
gets burned or dampened or dirtied, cut the piece out and begin again.
(8) A standard tie is made by a short length of tie wire, bare or insulated like
the main, but one or two numlDers smaller. Fig. 213 is for galvanized iron; fig.
214 is for H. D. copper main, which should not be bent.
(9) A lightning rod of No. 6 bare galvanized wire extends from 1 foot above
the top of every tenth pole to a few hand turns of the wire buried at its foot.
k-^
213.
INDEX.
Battebies, Primary 114
Amalgamating zincs 114
Bichromate 117
Care of 114
Cells, how joined 115
Copper oxide llti
Current weakens 114
Directions, general 114-5
Dismounting 116-7
Dry 115
Eagle 116
Gravity 115
Fuller 117
Kinds of 115
LeClanche 115
Local action 114-7
Maintenance 115-(')-7
Management 114
Mounting 115-6-7
Polarization 114
Principles 114
Qualities of good 115
Room 114
Boilers, Steam 7
Banking fires 8
Blow-off 10
Care of 8
Cleaning 13
Cleaning fires 8-9
Corrosion 13
Explosions 14
Feed water 13
Firing 7
Fittings 9
Foaming 8
Gauge glass 10-17
Incrustation 13
Injector 12
Inspection 13
Low water 8
Lying idle . 9
Management of 8
Material - 9
Piping 9,47
Plug, fusible 10
Pressure gauge 10-13
Priming 8
Pump 10
Safety valve 9
Steam gauge 8
Tools 7
Dynamos, D. C 49
Armature 43-4-6, 51-2
Bars 45
Bearings 45, 52
Brush holder 49, 50
(157)
Page. Page.
Dynamos, D. C. — Continued.
Brush setting 50-3
Care of 5.3-5
Coils, armature 44
Commutator 42-5, 50-3
Compounding 49
Core, armature 44
Diseases 52
Drum 43-4
Failure to generate 53
Field, magnetic 42
Field, windings 45
Foundations 47
Fuse firing 46
G. E., D. C. sets 47
Generates alternating 42
Goveinor 48
Heating 52-5
Induction, laws of 42
In parallel 51-4
Inspection 53
Management of 53
Lap winding 43-4-5
Lead 55
Noise 52
Oil rings 45
Packing 49
Piping 47
Pressure 47
Ring winding 43-4
Running 47, 54
Self-exciting 43
Special service 46
Speed 47-8, 53
Spools 49
Starting 51-4
Steam pipes 47
Stopping 55
Telephone call 46
Tested 47, 51-2
Troubles 52
Valves, relief 48
Wave winding 1 43-4
Westinghouse (fig. 74) 72
Windings 45
Engine, Oil, H.-A 29
Air inlet 34-8
Alterations, fundamental 39
Crank po.sition8 35
Critical positions 29
Cycles ^ 29
Cylinder 29,38
Exhaust 34-8
Failure of 36
Fly wheel—- 36
Governor 27, 37
158
INDEX.
Page'.
Engine, Oil, H.-A. — Continued.
Governor bracket 36
Ignition retarded .38,41
Indicator cards 29,41
Instructions for .3.5
Lamp, heating 35
Oiling 36-9
Oil tank 38
Nomenclature 31
Piston 3.5-8
Piston's strokes 29
Port 35
Principles of 29,31
Pump 34-6
Eegulation 34-7-8
Kunning 37
Skew wheel .39
Spray hole 38
Starting 35-6
Starting gear 36
Stopping - 39
Strokes 29
Testing 40
Valve box ., 34-7-8
Valve, horizontal 34-8
Valve, vertical 34
Vaporizer 29,3.5-6-8
Water supply 38
"Works well 39
Engine, Steam 16
Adjustments 17-23
Angle of advance 18,20-22
Bearings 25
Care of 17
Clearance 25
Connecting rod 25
Crank 17
Cross-head 25
Cut-off 19, 22
Dead center 23
Eccentric arm 20-2
E.xhaust 17
Full port 18
Governor 22-7-8,48
Heating 17-8
Inspection 23
Knocking 17
Laps 18
Lead 18
Level 23
Lining up 23
Lubricator 18
Management of '. 17
Oil 17
Operation 16
Packing 17,25,49
Piston, fit of 23
Piston strokes 17,21
Piston valve 27
Pressure 47
Positions, critical 20
Running 16, 51
Slide valve 25
Speed 47-8
Starting 16, 51
Stopping 16
Strokes, piston 17,21
Page.
Engine, Steam — Continued.
Testing 23, 47
Travel, piston's IS
Valve's positions is, 20
Valves, relief 1^
Valve slide j")
Hoist Ammunition 88
Automatic safety stop 88
Connections 89
Instrvctigns, Special 5
Directions, printed 5
Text books 6
Measurements and Tests 141
Apparatus required 141-2-4
Armature resistance 142
Battery resistance 144
Cable's insulation 144
Cai-e of instruments 141
Conduction resistance 141-2
Connections 143
Continuity of circuit 141
Current strength 141
Crosses 144
Difference of potential 141
Dynamos 144
Electromotive force 141
Galvanometer resistance 144
Grounds 143-4
Insulation resistance 142-3-4
Joints 142-3
Magneto 144
Open circuit 143
Resistance, battery 144
Resistance, conduction 141-2
Resistance, insulation 142-3-4
Resistance, small 142-3
Resistance, ordinary 141-2-3
Storage battery, resistance 144
Telephone, use of 144
Wheatstone bridge 141-2
Laws, Examples, Tables 135
Bridge wire, table 137
Capacity 135
Cells, combined 136
Copper wires, table 137
Current, strength 135
Difference of potential 135
Direction of current 135
Divided circuit 136
Electromotive force 135-6
Equivalents 135
Examples 138-140
Feeder, sizes 139
Formula, general 138
Fuses, sizes 138
Gauge, wire 137
Heat 135-6
Kilowatt 135
Metal deposited 137
Ohm's law 135-8
Power 135-7
Quantity 135
Resistance 135-6
Safety fuses 137
Sizes of wires 138-9,140
Table, wiring 137
Taps 138-9
INDEX.
159
Xaws, Examples, Tables — Continued.
Underwriters' table 137
Units 135
Wires, copper 137
Wire, size of 137-S-9
Miscellaneous 109
Anemometer 112
Battery, firing 110
Bells, electric 111
Care of anemometer 113
Connections 110
Detonator 111
Dynamo, firing 110
Failure to fire 110
Firing battery 110
Firing key 109
Fuses 109,110
Mechanism 111-2-3
Mine charge 110
Mine fuse 110
Placing the fuse 110
Precautions in firing 111
Pressure, wind 113
Self-register 112
Stop-clock 112
Velocities of wind 113
Wiring 111
MoTOKS, Electric, D. C 78
Adjusting rheostat 81-3
Back E. M. F 78
Blow-out (figs. 107-8,110) 82-3
Booster 87
Care of 84
Compound 80
Connections 80-3-5
Controller 88
Cores 79
Direction of rotation 78
Dynamotor 86
Electric hoist 88
Efficiency of 78
Heating 85
Hoist, electric 88
Installing 83
Leonard 85
Management of 84
Motor generator, 86-7
Multipolar (fig. 118) 78-9
Overload, C. B 83
Principles 78
Protection to 80
Regulation 80
Reversing 85
Rheostat, S. and S. (figs. 109, 110) 80-1
Rheostats, installing 83
Running 84
Shunt 79, 82-3
Series 79, 81-5
Special forms 85
Special uses 79
Starting 84-5
Starting box 80
Stopping 85
Switch 83
Teazer system 86
Underload, C. B 83
Watt-hour meter 85
Page.
Motors, Electric, D. C. — Continued.
AVestinghouse (fig. 118) 87
Winding 79
Night-Signal Sets 103
Assembling 106
Boughtou set 106
Cable 103-5-6
Connections 103-5-6
Controller, trucklight 107
Keyboard (fig. 137) 103-6
Ladder . 104
Lanterns 104
Mechanism 103
Operation 104-8
Packings 105
Plug 104-5
Receptacle 104-5
Switch, controlling 107
Truck light 106
U. S. form 106
Wiring 103-5-6
Search-Light Projectors 90
Arc 98
Automatic feed 95
Base sheeting 97
Beam 91-2
Cable 98,101
Carbons 90, 91-4-6
Carbon holders 93
Carboning lamp 9.3-5
Care of lamp 94-5-6, 101
Connections 97-8-9,100
Controlled 91
Controller (fig. 123) 97-8
Couplings 102
Covers 102
Crater 95
Current 91
Dead resistance 99
Diagrams 130-1-2
Drum 91
Feeding 91-6
Field (figs. 135-6) 102
Flaming 96
Front door 92
Focusing lamp 94
General Electric Co.'s 90
Hand control (fig. 133) 90
Hissing 96
Illumination 102
Image of arc 94
Installing 92-7-9
Lamp mechanism (figs. 124-7-8) 93
Largest size 102
Location 102
Mechanism (fig. 124) 95-7-8-9
Methods of observing 102
Mirror 101
Motors 97-8
Mushroom 96
Names of parts 92-3-7
Navy 90
Observers 102
Operating 101
Operating lamp 93-4-5-6
Operators 102
Parabolic mirror 90-2
160
INDEX.
Page.
Search-Light Projectors — Continued.
Pilot-houso 91
Placing lamp 93
Probability of injury 102
Rheostat 00
Schukert (fig. 120) 90
Screen shutters 91
Signaling with 102
Small motion 101
Speed of control 92
Sizes 90
Starting magnet 94
Striking the arc 96
Switch controller 98
Training mechanism 98
Transportable 102
Truck 92
U. S. foi-m (fig. 123) 92
Voltage 95-0,101
Wiring 94-6-8-9, 100
Specifications 14.5
Armatures 147,4.3-4—6, .51
Battery room 145,65
Blow-off 146, 16
Boilers 145,7
Cabinets 150
Cables-.' 1 152
Circuit breakers 149,150
Closet system 149
Conduit - 151-2
Construction of lines 154
Cross-arms 1.53
Cro'jshead 145, 25
Cut-outs 149, .57-8
Deadman 153
Duct 152
Dynamo , 146-7, 47
Dynamo room 145, 48
Engine 146-7, 16
Feeders 149
Filament lamp 148
Fuses 149, 109
General rule in specifications 145
Generators 146-7, 47
Governor engine 147, 2-7-8
Guides 146, 23-4
Guys 1.54
Injector, steam 146, 12
Insulating joints 1.55
Insulators 154
Items, miscellaneous 154
Joints 155
Lamps 148
Lightning-arrester 1.53
Lightning rods 156
Lubricator 147, 18
Mandrel 1.52
Miscellaneous items 1.54
Motors 148, 78
Outlets 151
Overhead lines 1.52
Piping 146, 152, 9
Piston rod 146
Poles 153
Power house 145
Projectors 148, 90
Pump 146
Page.
Specifications — Continued.
Rheostat, motor 148
Safety valve 146, 9
Search lights 148, 90
Shaft 146
Sockets, lamp 149
Solder 156
Steam gauge 146, 8
Storage battery 147, 65
Switchboard 147, 56
Switches 1.50-1, 57, 61
Ties 156
Underground lines 151-2
Vulcanizing rubber 155
Wires 150-1-2
Wiring 149,151-2-3
Storage Battery 65
Back, E. M. F 68
Battery room 65
Buckling L 76
Booster connection 75
Care of 67
Charge of 67
Charging, initial 67,76
Connecting up 66,74-5-7
Current 67
Density of solution 67-^
Discharge 6!>
Drop in voltage 69
Electrolyte 66-8-9, 71-2
End cells 62-4-8
Endurance 76
First charge 66
Gassing 68,71
Good condition 66
Inspections 70-1
Instructions 67
Instruments 69, 74r^
Jars 65
Maintenance 70
Management of 67,70
Maximum rate 67
Mi.xing solution 70
Object of 6.5,76
Out of commission 72
Polarity •— 77
Portable 76
Records 71-2-3
Restoration 68
Room 65
Sediment 70-1
Separators 66
Setting up 65
Shipment 66
Specific gravity 67-8-9
Stand 65
Sulphating 76
Switchboards 74-5
Temperature effects 67
Unpacking 65
Voltage 67-8-9
Switchboards 56
Ammeter 56, 60
Apparatus 56, 60
Arrangement 56
Back connections 61
Best for forts 56
INDEX.
161
Switchboards — Continued.
Care of 64
Circuit breakers 57-8
Conditions fulfilled ^ 56
Connections 56
Design 56
End cells 62-4-8
Engineer 57-8-9
Fuses 61
Golden Gate board 63
Key West board 62
Location 56
Management of 64
Overload, C. B 57-8
Operation of 64
Panel 56
Preble board 62
Switches 57,61
Underload, C. B. 57-8
Voltmeter 56-7
Telegraphy 118
Abbreviations 119, 121
Adjustments 119,120
Beginners 120-1
Breaks 122
Care of 120-4-6-7
Code 118-9, 121
Code, artillery 122
Code, calls 121
Code, signal 121
Dash 118
Diagrams 118,120-1
Directions 120
Dot 118
Escapes 123
Faults, line 123
Fog, signals 122
Heliograph 122
Installing 126
Instructions 120-1
Key 118, 120
Lantern 121
Lineman 123
Management 124-6
Message forms 119
Morse 118
Operation 124
Principles telautograph 123
Page.
Telegraphy— Continued.
Receiving 120-1-2
Relay 118, 120
Searchlight 121-2
Sending 120-2
Setting up heliograph 122
Signal flags 121
Sounder 118
Space, signal 118
Sticking 120
Telautograph 123
Torch 121
Transmitter (fig. 167) 123-5
Wigwag 121
Telephony 128
Adjustments 131
Apparatus 128
Battery 131
Bell, polarized 128, 13iVl
Bridge 128
Care of 130-1
Central station 133
Common battery 132
Connections 128-8
Cross-talk 131
Details 128
Drops 133-4
Dynamo 46
Faults 130-1
Handling 130
Holtzer Cabot ' 132
Induction 131
Intercommunicating 131
Jacks 134
Keys 133
Magneto 46,128,131
Management 130
Number on circuit 130
Noises, induction 131
Parallel connections 131
Receivers 128,131
Secondary coil 128
Series connections 128
Transmitter 128,131
Troubles 130
Using 130
Without central 132
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