-©•^ 1734 ^ 537. 05 (?e v.n^s>» Goodwin, Harold fVacVlcal economics in distriba- ion with +heir effect on the commer- cial polica of a central station com- pan^. jReturn this book on or before the /Latest Date stamped below. Theft, mutilation, and underlining of books are reasons for disciplinary action and may result in dismissal from the University. University of Illinois Library APR 1965 1 1 ! i L161— 0-1096 Digitized by the Internet Archive in 2015 https://archive.org/details/practicaleconomiOOgood 'O DOLLARS PER YEAR TWENTY CENTS PER COPY Published Monthly By m. XVII., No. 12 General Electric Company’s Publication Bureau DEC., 1914 Schenectady, New York ON THE CHARLOTTESVILLE fis ALBERMARLE RAILWAY. LIBRARY OF THE UNIVERSITY OF VIRGINIA IN BACKGROUND GENERAL ELECTRIC . REVIEW Single-Phase Electric Railways By EDWIN AUSTIN Member of the Staff of “The Engineer” London CONTENTS Chapter 1 — The Single-Phase System. II — The London, Brighton and South Coast Railway. The Midland Railway. Ill — The Midi Railway. IV — The Blankanese-Hamburg-Ohlsdorf Railway. The Dessau-Bitterfeld Railway. The Murnua-Oberammergau Railway. The Mittelwald Railway. V — The St. Polten-Mariazell Railway. VI — The Martigny-Orsieres Railway. The Valle-Maggia Railway. The Rhaetian Railway. The Lotschberg-Simplon Railway. VII — The Rotterdam-Schevenningen Railway. VIII — The Thams- havn-Lokken Railway. The Rjukan Railway. IX— The Swedish State Rail- ways. X — The Parma Single-Phase Tramways. XI — The New York, New Haven and Hartford Railway. The New York, Westchester and Boston Railway. The Spokane and Inland Empire Railway. The Rock Island and Southern Railway. The Hoosac Tunnel Railway. The St. Clair Tunnel Rail- way. Devoted to exact and careful descriptions of complete rail- ways and portions of main line railways electrified on the single- phase system, of which there are two in England and a great number in Europe and six in the United States. 308 Pagts 8x1 1 346 Illuslrations Cloth, Net $5.00 Electrical Traction and Transmission Engineering By Prof, SannM Sheldon, A.M., Ph.D., D.Sc., and Erich Hausmann,E.E.,M.S. CONTENTS Determination of the Number and Size of Cars for an Urban Road. Tractive Effort Required for Car Propulsion. Types and Per- formance Curves of Motors. Speed Curves. Railway Motor Control. Energy Consump- tion. The Distribution System. Substations. Transmission Lines. Steam and Hydraulic Power Stations. 317 Pages 53^x8 In. 127 Ulus. Net $2.50 Electric Railways Theoretically and Practically Treated By SIDNEY W. ASHE, B.S., E.E. Vol. I - - - Rolling Stock By Sidney W. Ashe and J. D. Keiley Contents — 290 pages Chapter I — Units — Curve Plotting — Intsru- ments. II — Analysis of Train Performance. Ill — Train Recording and Indicating Instru- ments. IV — Direct Current Series Railway Motor. V — Alternating Current Single-Phase Motors. VI — Types of Control and Their Operation. VII — Car Bodies. Vlll — Trucks. IX — Brakes and Braking. X — Electric Loco- motive. XI — Electrical Measurements. Vol. II — Engineering Preliminaries and Direct Current Sub-Stations By Sidney W. Ashe Contents — 288 Pages Chapter 1 — Preliminary Considerations. II — Determination of Required Motor Capacity. Ill — Motor Capacity (continued). IV — Sched- ules and Load Diagrams. V — Power House and Substation Location. VI — Rotary Con- verter Substations. VII — The Rotary Con- verters. VIII — The Transformer. IX — Insulating Oils. X — Auxiliary Substation Apparatus. 5x7 illustrateJ Net $2.50 each Public Utilities Their Cost New and Depreciation, by HAMMOND V, HAYES, Ph.D., Consulting Engineer CONTENTS Property Valuations— General Considerations. Replace- ment Costs of Physical Property. Determination of Replace- ment Cost. Value as Going Concern. Values of Good Will and Franchises. Original Cost. Commercial Value. The Worth of Service to the Consumer. Reserves for Deprecia- tion. Life of Plant. Depreciation. Fair Present Value — Rates. Fair Present Value — Condemnation Sale. General Consideration Relative to the Regulation of Public Utility Undertakings. m Pages 6*9 Cloth Nel%im Engineering Valuation of Public Utilities and Factories By HORATIO A. FOSTER Author of “Foster’s Electrical Engineer’s Pocketbook” CONTENTS Value: Commercial, Earning, Physical, Intangible, etc. Purposes of Valuation. Instructions for Valuation. Forms for Use in Appraisals. Valuation of Various Properties. Cost of Valuing a Property. Value of Good Will, Going Concern. Going Value. Depreciation. Renewals. Amor- tization. Depreciation Funds. Appreciation. Franchise Values. Capitalization. Control of Public Utilities. List of Public Service Commissions. Court Decisions. 350 Pages 6*9 Many Forms Net $3.00 HAVE YOU A COPY OF FOSTER’S HANDBOOK? D. VAN NOSTRAND COMPANY Publishers and Bookseliers X 25 PARK PLACE NEW YORK c. 1< ’ Co - - 1 GENERAL ELECTRIC REVIEW HALL STACKS- I The Edison-Equipped Electric Truck is the ultimate solution of the most important problem now confronting the Warehouse and Storage Business, i.e. : Transportation. Why Edison Storage Batteries? Because Edison Nickel-Iron- Alkaline Storage Batteries have the following advantages in this kind of service: 1. They may be “boosted” at very high rales and charged sufficiently in a short time to meet emergency conditions. 2. They are everlastingly on the job and require no expert attention in the garage or on the road. 3. They may be left idle or worked for months on very small daily mile- age without injury or extra care. 4. They are guaranteed to be capable of developing 100 per cent of rated capacity during four full years, thereby eliminating all risk on the purchaser’s part that the profits of the road will be spent on repairs or renewals. ECONOMY plus RELIABILITY plus PERMANENCE The Warehouse Business is a fertile field for the Central Station and Electric Truck Manufacturer. We have a Co- operative Campaign we would like to discuss with you. Edison Storage Battery Co. 164 Lakeside Ave. Orange, N. J. II GENERAL ELECTRIC REVIEW Motor Driven Auxiliaries In many modern central stations, particularly where economizers are used, the heat balance requires some or all of the auxiliaries to be motor driven. A particularly attractive combination of Thyssen Entrainment Air and Hot Well Pumps with direct connected motor is shown in the illustration; this being suitable for operation in conjunction with surface condenser for high vacuum turbine requirements. A Thyssen Patent Air Pump is here shown with the top cover lifted, and consists of two centrifugal water impellers delivering water through entrainment nozzles and producing vacua closely approximating the theoretical. 99% OF THEORETICAL VACUUM SIMPLE RUGGED RELIABLE Surface, Jet and Barometric Condensers, Water Cooling Towers, Closed Feed Water Heaters. C. H. WHEELER MFC. CO., PHILADELPHIA, PA. BRANCHES: New York Chicago Boston Cleveland Charlotte Pittsburgh Cincinnati San Francisco GENERAL ELECTRIC REVIEW III IV GENERAL ELECTRIC REVIEW o ''We think the chain equipment is one of the best things that has ever been put onto the direct drive individual motor equipped printing press, '' Speaking further regarding the chain drive we had put onto one of his presses, this printer says: “We wish you would have your representative call on the writer within the near future and take up the proposition of equipping all of our machines with these chains. We find that on this one press that is equipped with your chain that we get the same number of impressions per hour with two buttons less on the electric controller and it takes from five to six amperes less of electricity to drive the machine than it did with the old belt equipment.” Speaking of a motor-to-lineshaft drive, another firm writes us: “The chain has given us excellent satisfaction and has paid for it- self many times over, and we intend to install them at various places in the future.” These and many similar letters from our customers show the uni- versal satisfaction given by MORSE Silent Chain Drives. They would surely represent your sentiments also. You simply can’t beat MORSE Silent Chain Drives for use in connection with electric motors, because they are positive, like gearing, and flexible like belting, yet more efficient than either. They save you power, protect the motor from shocks and jars and cost little to maintain, some drives now operating in their twelfth year without repairs of any kind having been made. For a short time we can offer special inducements on any new work you will undertake. Investigate this matter fully at once. Particulars free and no obligation to buy. Ash for Publication No. 12, also. Morse Chain Company, Ithaca, N. Y. Electrical Dept. B-54 GENERAL ELECTRIC REVIEW V -f'A E 3 xi JTJ SxJ 7 xJ 0 jVJ D U 37.£)jN ELErlHJCAL £i'JOJ'j')^SKii i'i j'/Mi'lUfx'iCTiJflEfia fi u t; Ei y, Ej^j 0 lx\jN o . The above Works of The British Thomson-Houston Co., Ltd. cover an area of acres, they have a floor space of 800,000 square feet, they consist of 72 buildings of brick and steel construction, and are equipped with the most modern plant for the manufacture of all kinds of Electrical Apparatus for Traction, Power and Lighting Head Office and Works: Rugby, England. Registered and Export Offices: 83 Cannon Street, London. Branch Works: Coventry and Willesden. Lamps and Wiring Supplies: 77 Upper Thames Street, London. BRANCH OFFICES: Birmingham Cardiff Dublin Glasgow Leeds London Manchester Middlesbrough Newcastle Sheffield Swansea FOREIGN REPRESENTATIVES: ARGENTINE — Buxton Cassini & Co., Buenos Aires. AUSTRALIA — Australian General Electric Co., Melbourne & Sydney. Unbehaun & Johnstone, Adelaide. Engineer- ing Supply Co. Ltd., Brisbane. Chas. Atkins & Co., Ltd., Perth. BRAZIL — Cia General Electric do Brazil, Rio de Janeiro. CHILI AND PERU — W. R. Grace & Co.. Santiago and Lima. CHINA — Andersen, Meyer & Co., Shanghai. COLOMBIA — Wesselhoeft & Wisner, Barranquilla. CUBA — Zaldo & Martinez. Havana. INDIA — The British Thomson-Houston Co., Ltd., Calcutta. Turner Hoare & Co., Bombay. JAPAN — The British Thomson-Houston Co., Ltd., Yoko- hama. Bagnali & Hilles, Yokohama. Mitsui & Co., Tokyo and Osaka. MEXICO — The Mexican General Electric Co., Mexico. NEW ZEALAND — The National Electrical and Engineering Co., Ltd., Auckland, Dunedin. Wellington. Christchurch and Invercargill. SOUTH AFRICA — The South African General Electric Co.. Johannesburg, Durban and Capetown. Johnson & Fletcher. Bulawayo and Salisbury. VI GENERAL ELECTRIC REVIEW Compact Induction Motors Mounting of a Horizontal Induction Motor To reduce the motor length 10 to 20 per cent, use BALL BEARINGS. Save floor space and aisle room. Note in the mounting arrangement shown, the short length taken up by the ball bearings. Note also the liberal lubricant cham- bers — compactness is gain- ed without sacrificing mechanical strength or electrical efficiency. For other mountings and applications send for bulletin No. 16 -G. SKPHALL BEARING CD. 50 CHURCH ST. NEW YORK 90% EFFICIENCY FROM SMITH TURBINES r In ■ Recent tests of a number of Smith l urbines -ft j -f ii| ^ ’'ffl have again proven their superiority over all others. These tests show efficiencies of from 8o% to over 90% at part gate. The engraving represents one of five units each of 17,000 horse power at 514 r.p.m. flV under 600 foot head furnished the Georgia . V ■ ’■ Power Co. ! Turbines furnished for heads from 5 feet to 650 feet. Also Head Gate Hoists, Steel Pipe, Trash Racks, etc. . 'M -X; uotfoiTv^^ SEND FOR BULLETIN G S. Morgan Smith Co., York, Pa. Branch Offices: 644 American Trust Bldg., Chicago, 111 ., and 176 Federal St., Boston. Mass. GENERAL ELECTRIC REVIEW VII You need the new ENGINEER’S EDITION of the TRANSMISSION LINE CALCULATOR Simple as a slide rule Rapid and reliable What is it? A handsome morocco bound volume, 834 inches square, containing two complete charts, each with a revolving transparent disk, together with explicit directions for their use. What will it do? It will calculate in TWO MINUTES both the per cent voltage drop and power loss in ANY circuit up to 70,000 volts, with results guaranteed accurate within one-fifth of one per cent. Who is it for? Designing, operating and consulting engi- neers, managers, superintendents, wiring con- tractors and students. How can it be obtained? Send me your check or money order for ^5.00, and I will forward you by return mail a copy for examination. If it is not com- pletely satisfactory you may return it within five days and I will refund your money. Order your copy today! ROBERT W. ADAMS, E. E. 180 TABER AVENUE PROVIDENCE - - - R. I. Safety LAST Although SAFETY FIRST is the general outcry, we have headed this ad SAFETY LAST, owing to our belie j that SAFETY LAST is bet- ter than SAFETY not at all. Considering that the majority of users of the Holbrook Hide Faced Hammers and Raw Hide Mallets have found in their use SAFETY LAST, because if what they tell us is true, they have used most every de- scription of a hammer or mallet, which they considered practical for electric and copper workers, finally finding that the raw hide is far superior, not only from an economic basis, but also producing an article super- ior to that which they have formerly been able to make. The raw hide surface, although soft enough not to bruise the article on which they are working, is hard enough to get the desired results from the contact of the blow. If these essentials are true, they having tried out various hammers or mallets construct- ed of other materials, and have at last adopted the use of our raw hide goods, which by their continued use proves to us that they have found Safety LAST WE WOULD BE VERY GLAD TO FURNISH DESCJUPTIVE LITERATURE WITH PRICES ON REQUEST. Holbrook Raw Hide Company Manufacturers Providence, R. I. VIII GENERAL ELECTRIC REVIEW 3EJ2 '.'''it mm San Francisco Municipal Building Wired with G-E Wire and Cable About go miles of G-E Wire and Cable will be used in the new San Francisco Municipal Building. When completed, this will be one of the largest and finest municipal buildings in the world. The illustration showing the building during construction, gives some idea of its great size and handsome appearance. G-E Wires and Cables are used in the largest and highest buildings in the world, as well as on the world’s greatest engineering accomplishment, the Panama Canal. General Electric Company Li St of Sales Offices Immediately Following Reading Pages * 5192 GENERAL ELECTRIC REVIEW IX Getting the Utmost Return from Invested Capital Capital and labor conditions make efficiency imperative. Every machine in a factory, every foot of its floor space, every employee must yield a maximum return on the investment. One device or method will save at this point, another at that, but electric power properly applied through a G-E motor will save at many points. In manufacturing processes using electric power, this motor. Industry’s Master Workman, is also a great power economizer. A G-E motor can be applied to drive each of your machines at a maximum productive speed, even though this speed varies for each second of the machine’s operation. A G-E motor on each of your machines allows the best use of floor space, making every machine to which it is applied independent of line-shafting and belts. A G-E motor on each of your machines, when driven by purchased power, stops the power bill whenever a machine is shut down. G-E motors can be connected to a curve-drawing meter which will record when each machine is started or stopped as well as show the amount of power consumed at any moment. This graphic record forms excellent means of discovering efficient employees. Our engineers will be pleased to study local conditions and suggest suitable electric equip- ment. Write our nearest office. General Electric Company List of Sales Offices on Page Immediately Following Reading Pages 5252 X GENERAL ELECTRIC REVIEW G-E Switchboards Made of MONSON SLATE This slate is supplied true to dimen- sions and with a fine finish. It stands a high insulation test, is strong and tough but drills readily and takes a beautiful black oil finish which costs practically nothing. IT NEEDS NO PAINT. Portiand-Monson Slate Company Office, Portland, Maine Quarries, Monson, Maine GENERAL ELECTRIC REVIEW XI 99 % Vacuum with The A WHEELER TURBO-AIR PUMP recently tested showed the ^ ^ following results with hurling water at 70°: 100% vacuum on a closed air suction. 99-7% with 5 cubic feet of free air per minute. 99.4% with 10 cubic feet of free air per minute. And 99% with 20 cubic feet of free air per minute. Consider These Figures The norrrial air leakage of a large turbine and condenser is only 5 to 10 cubic feet of free air per minute, which the pump will handle at vacuums above 99%. This means that you can maintain at the turbine exhaust, vacuums of 283^ to 29 inches in the Summer and 29^^ inches and higher in the Winter, depending upon the amount of circulating water pumped. If interested in Turbo- Air Pumps, ask for our new Bulletin 111; in Surface Condensers, ask for our new Bulletin 106-A; in High Vacuum Jet Condensers, Bulletin 107; in Cooling Towers, Bulletins 104 and 109. WHEELER Condenser and Engineering Co. CARTERET 110 The Pioneer American Condenser Builder NEW JERSEY XII GENERAL ELECTRIC REVIEW THE GRAND CENTRAL TERMINAL HOT WATER HEATING SYSTEM is supplied by these four 14-inch sin- gle stage motor-driven turbine type ALBERGER CENTRIFUGAL PUMPS Alberger pumps are used in connection with many other forced circulating systems including the Senate Office Building, Wash- ington, D. C., Biltmore Hotel, New York, Crouse-Hinds Company, Syracuse, and the National Museum, Washington, D. C. WRITE FOR CATALOGUE E. ALBERGER PUMP & CONDENSER COMPANY 140 CEDAR STREET, NEW YORK Chicago Pittsburgh St. Louis Boston Atlanta New Orleans San Francisco General Electric Review A MONTHLY MAGAZINE FOR ENGINEERS Manager, M. P, RICE Editor, JOHN R, HEWETT Associate Editor. B. M. EOFF Assistant Editor, E. C, SANDERS Subscription Rates: United States and Mexico, $2.00 per year; Canada, $2.25 per year; Foreign, $2.50 per year: paybble in advance. Remit by post-office or express money orders, bank checks or drafts, made payable to the General Electric Review, Schenectady, N. Y Entered as second-class matter, March 26: 1912, at the post-office at Schenectbdy, N. Y., under the Act of March, 1879. VOL. XVII. , No. 12 Copyright 1914 by General Electric Company December, 1914 CONTENTS Frontispiece Editorial: The Paths of Progress Workmen’s Compensation By James O. Carr Practical Economies in Distribution with Their Effect on the Commercial Policy of a Central Station Company By Harold Goodwin, Jr. Page 1150 1151 1152 1159 The Successful Operation of a Telephone System Paralleling High Tension Power Lines . 1175 By Charles E. Bennett The Ventilation of Allegheny Summit Tunnel, Virginian Railway 1182 By F. F. Harrington Electric Fields 1186 By F. W. Peek Some Notes on Bus and Switch Compartments for Power Stations 1188 By Emil Bern Practical Experience in the Operation of Electrical Machinery 1193 Transformer Leads Reversed; Importance of Equalizer; Sparking by Load Changes; Reversed Field Coils; Ridging of Commutator; Lamps Flickering By E. C. Parham Recent Views on Matter and Energy 1197 The Atomic Theory of Matter, Part IV By Dr. Saul Dushman The Electrification of Cane-Sugar Factories 1204 By a. I. M. WiNETRAUB Notes on the Use cf Thermo-Electric Apparatus in High Frequency Systems, Part II By August Hund Application of Power Apparatus to Railway Signaling, Part III . . . 7 By H. M. Jacobs From the Consulting Engineering Department of the General Electric Company Question and Answer Section 1210 1214 1229 1230 Illustrating the Article in this Issue on the Application of Power Apparatus to Railway Signaling, by Mr. H. M. Jacobs THE PATHS OF PROGRESS In this issue we conclude a series of articles by Dr. Saul Dushman entitled “Recent Views on Matter and Energy.’’ All of our readers who have read these contributions must have been struck by the boldness of many of the speculative theories that have recently been propounded, as well as by the fact that we seem to be on the verge of great developments in the realm of scientific thought. The ultimate constitution of matter has been the plaything of profound thinkers for generations and the origin of energy has been no less a subject for speculative theorizing, but it has been left to the scientific minds of this generation to attempt to propound a monistic theory to account for all natural phenomena. The atomic theory originally propounded to account for the mysteries of the structure of matter was developed into an electron theory to explain electrical phe- nomena, and now, as a product of modern scientific thought, we have the quantum theory which is an atomic theory of energy. Thus it seems likely that we shall ultimately not only fully develop, but we may prove by patient research and experimental work, a common theory for both energy and matter which may be broad enough to include all natural phenomena. Should this be accom- plished it is highly probable that all natural phenomena will be found to be governed by a few simple laws, and that the complexity of many of our scientific theories in the past has been caused by a lack of knowledge of the simple laws that govern the movements and “habits” of the ultimate “something” of which both energy and matter are born. Such a simplification of theories would undoubtedly lead to great progress in scien- tific discovery and ultimately to enormous industrial developments in a multitude of different directions, and it is for this reason that all engineers and professional men in general should try to follow the trend of modern scientific thought. The series of articles referred to were written with the idea of giving a general understanding, in simple language, of some modern scientific speculations that may ultimately have a far-reaching industrial influence. We believe that there is too generally a tendency to consider all higher scientific reasoning to be beyond so simple an interpretation that the ordinary lay mind can derive any benefit following it. In reality this is very far from the truth. While it is true that it takes a great mind to translate scientific thought into simple terms, it is also true that many men have devoted much time to this task. Scientific developments and discoveries have been almost entirely derived in the first place from speculative imaginations. All theories must be imagined before they can be propounded, tested, and proved or disproved; indeed, speculative imagination can almost be said to be the root of all progress. Those who take no trouble to familiarize themselves with the speculative imaginings of modern scientific minds are, we believe losing much that would lead to valuable inspirations that might be applied to their own work, no matter what its nature. In these days of specialists there is too marked a tendency to think a general under- standing of the activities of others as of little value. Imagination is the seed of all originality and in these days of competition there is more and more need of original thought in all industrial activities. The type of reason- ing displayed in developing scientific" theories^ by such men as Kelvin, Planck, etc., might well be imitated in many walks of engineer- ing and business life. The imagination should be given full range and any theory arrived at should be tested till some are found that will bear the fruit desired. We believe that a careful study of the work accomplished by those great minds engaged in scientific research might give great inspiration and lead to an added efficiency in the reasoning powers of all men. 1152 GENERAL ELECTRIC REVIEW WORKMEN’S COMPENSATION By James O. Carr Law Department, General Electric Company Workmen’s compensation laws are one of the products of modern conditions, and the laws throughout the union are many and varied, no less than twenty-four states having adopted laws compensating workmen for industrial accidents. No one claims that these laws are perfect and it is likely that many modifications, based on experience gained from their working, will be adopted from time to time. The author deals in a very interesting manner with many phases of the different laws already in force and discusses the pros and cons of their practical working. — Editor. One of the most remarkable reform move- ments in the industrial world of the United States in recent years is that which has had for its object the enactment of laws requiring the payment of compensation to workmen who are injured in the course of their employment. The theory upon which this movement has proceeded is that the workman should be compensated for disabilities resulting from industrial accidents regardless of the question of fault, and that the financial burdens of such accidents should be borne by the industry in general rather than by the workers alone. While this principle has been in force in some of the European countries for many years yet it is only within the past five years that the matter has been taken up actively in the United States. A law was enacted in the State of Massa- chusetts in 1907 permitting employer and employee to agree on a plan of compensation and the State of Montana passed a compensa- tion act relating to the coal industry in 1909, yet neither seemed to accomplish the desired result and little or no progress was made thereunder. It really received its initial impetus in 1909 when a commission was appointed by the Legislature of the State of New York to investigate the whole subject. During the year 1910, two compensation laws were passed in the State of New York, one elective and one compulsory, but early in the year 1911 the compulsory law was declared unconstitutional by the Court of Appeals of the State of New York, upon the ground that it took the property of employers without due process of law. During the year 1911, compensation laws were passed in the States of California, Illinois, Kansas, Massa- chusetts, Nevada, New Hampshire, New Jersey, Ohio, Washington and Wisconsin, some of which were compulsory and some elective. Since that time, compensation laws have been passed by other states so that the prin- ciple is now in force or soon will be in twenty- four different states. One of the last states to enact a workmen’s compensation law was the great State of New York, where the law was passed in the month of December, 1913. That law is in many respects the most liberal to the workman and the most burdensome to the employer of any compensation law passed by the various states. It was passed more or less hurriedly with the idea that the practice of compensating workmen for injuries sus- tained through industrial accidents should be commenced at once and that an actual trial of the law would show wherein it ought to be amended so as to improve it for the benefit of all concerned. It has been in actual opera- tion since July 1, 1914, and it is already evident that many changes are necessary to make the law more workable. Many of the most prominent labor leaders in the country have said that the present workmen’s compensation law of the State of New York is the best compensation law ever passed in this country. That this is so from the standpoint of the workman is undoubtedly true. Many of the employers feel that the law ought to be less burdensome to them than it is. However, this will undoubtedly be worked out satisfactorily in time. In most of the states the law is elective, that is, the employer and the employee may elect to accept the ptovisions of the law or not just as they choose. In the case of the employer who elects not to comply with the provisions of the law, however, all his defenses are taken away in case the workman sues him for damages for personal injuries, so that the employer is almost compelled to accept the provisions of the law rather than to attempt to defend negligence actions and be subjected to the large verdicts which would certainly be rendered against him. If the employee elects not to accept the provisions of the law, he is relegated to the same rights which he had at the time the new law went into effect. In the opinion of many who are conversant with these compensation laws, the workman should only have the rights which existed at common law if he refuses to accept the provisions of the WORKMEN’S COMPENSATION 1153 compensation law, the idea being to compel both parties to abide by the principle of com- pulsory compensation. In some states the eompensation law is compulsory, that is, both employer and employee must abide by the requirements of the law and the employer must pay the com- pensation therein provided. The elective laws were passed by many of the states in order to avoid, if possible, any question as to the constitutionality of the law such as was raised at the time the first com- pulsory law was passed by the State of New York. The new law in many of the states provides that all workmen shall come under its provisions except farm and domestic labor. In other states, the laws are so framed as to cover only those workmen who are engaged in so-called hazardous employments. Where this has been done, however, some means have been found to include nearly all work- men. This very feature is one of the objec- tions to the New York law because it is uncer- tain what workmen are eovered by the law and what ones it does not cover. How much better it is for a workman to be under the protection of the compensation laws can readily be seen. As soon as he is injured, he is, in many of the states, entitled to medi- cal attendance for a period of from two weeks to three months, at the expense of the em- ployer. This also covers hospital treatment, medicine and other requisites. All of this is to be provided by the employer. If the injury causes temporary disability of more than one week, in some states, and more than two weeks in others, which is called the waiting period, the workman is paid a certain percentage of his average weekly wages, ranging from 50 per cent in some states to 66% per cent in others, so long as the dis- ability continues, subject to certain limitations as to length of disability and amount paid. In some states, in the event that an accident eauses total permanent disability to the work- man, he is paid the weekly percentage of his earnings for periods of time ranging from six years to the remainder of his natural life. If the workman sustains a permanent partial disability, such as the loss of a finger, eye, hand, arm or foot, he is then paid a certain stipulated amount per week for a certain period to compensate him for the loss sustained. In some states he is also paid weekly eompensation during the time of disability caused by the permanent injury ; but the most satisfactory way seems to be to pay a certain fixed amount which is considered suffi- cient to compensate for the loss, and this is provided for in the laws of most of the states. In some states, the workman is compen- sated for the loss of earning power due to injury. This is likely to prove quite trouble- some as time goes on and will lead to compli- cations, as some of the Workmen’s Compen- sation Commissions of the various states seem inclined to hold that if a workman goes back to work and takes a different job which pays less money than he earned at time of injury, he is therefore entitled to compensation for loss of earning power. If an injury proves fatal, then the widow, children or other dependents are paid a certain percentage of the weekly wages of the deceased workm;an. In some cases this com- pensation is paid for the life of the widow if she does not re-marry, and in others, for a certain number of years and not to exceed a certain amount. The compensation to be paid to children usually ceases when they reach the age of eighteen. In addition, many of the states require the employer to pay a certain amount for funeral expenses. The compensation is paid to the workman in various ways. In New York, for instance, the employer pays the money to the Work- men’s Compensation Commission and it in turn pays the injured workman or his depen- dents. This plan is unwieldy and cumber- some and is not nearly as expeditious as the practice in many other states where the employer makes arrangements to pay the workman direct the amount provided by law pursuant to an agreement made between the parties which is subject to the approval of the Commission. In some states where the prin- ciple of state insurance has been put into effeet, the compensation is paid direct to the workman from the premiums paid in by the employers. In some states, the compensation must be secured to the workmen either through the medium of insurance in stock or mutual companies, through the medium of a state fund or, if the employer can give satis- factory proof of his financial ability to pay com- pensation to his employees, he may be per- mitted to carry his own insurance upon giving a satisfactory bond or depositing sufficient security to guarantee the payment of the com- pensation. Most employers carry insurance in either stoek or mutual companies. Only the employers having a large number of employees can afford to carry their own insurance. Various methods are adopted for handling disputes between the interested parties so that 1154 GENERAL ELECTRIC REVIEW the workman may receive the compensation to which he is entitled as soon as possible after an accident. As time goes on, many developments will take place in connection with the practical working out of these laws and we shall have a far better knowledge of them and their beneficial effects or otherwise five years hence. That the general plan is sound and will work out to the interest of all concerned is probably conceded by all who have given the matter thoughtful consideration. The necessity for such legislation has been more or less forced upon us by the course of human events and by the many changes and develop- ments in the method of carrying on modern industry. Prior to 1880, the handling of business on a large scale and through the medium of great corporations was practically unknown, except perhaps with respect to railroads and the manufacturing interests in New England. Subsequent to that time, however, by reason of the great improvements in machinery, it became possible to have done by machinery the work which had formerly been done by the individual workman, and in many instances the workman was displaced by machinery. The result of this has been that in every industry the production has been marvelous- ly increased and this feature has been largely instrumental in developing the great manu- facturing industries in the United States. While enormous strides were being made in the manufacturing field, there was also a great increase in the number of industrial accidents due to the greater use of machinery and the hazard incident thereto. As a con- sequence, the burden on society was greatly increased because of the fact that the work- man was seldom compensated for disabilities due to accidents occurring in the course of his employment. In former years, when manufacturing was carried on in a small way by the individual employer, he usually knew most of his employees and took more or less of a personal interest in them and in their welfare. This resulted in a friendly feeling between the employer and the employee and there then existed a bond of human sympathy between them. It is also a fact that in those days the labor union was almost unknown and had little or no influence upon manufacturing operations. With the development of the industry through the medium of machinery there came another development, that of the labor union> which today has almost a predominating influence in all parts of the country where large bodies of workmen are employed. With these developments and the creation and growth of the large corporations the human element was lost sight of in many ways. The workman was looked upon more and more as a machine rather than an individual. This, of course, was not true in every case, but it is true and must of necessity be so where thous- ands of workmen are employed in one industry since those in charge of the industry are absolutely unable to be in personal touch with all of the employees. This is also true where the labor unions predominate, because the members of the labor organizations seem to prefer to deal with their employers through the medium of their organizations and this has a tendency to eliminate the personal element. In the days of small industries, when a workman was in trouble or was incapacitated through injury, he was, in many instances, looked after in some way by his employer who attempted to relieve him and his family from the loss which he was bound to sustain. It is not to be understood that this was so in every instance but it was in many cases. At the same time the employer who was engrossed in accumulating wealth undoubtedly very often overlooked the misfortune of his employee and was inclined to rely upon his legal rights in the event that any claim was made upon him for compensation. The common law governing the relations of employers and employees in connection with injuries sustained during the course of employ- ment was such that the employer was seldom held legally responsible for injuries which happened to the workman in the day’s work. The only way in which the workman could recover money damages from his employer was by proving that the employer was negli- gent and that he did not fulfill the duty which he owed the employee. It can well be realized how difficult it was for the employee to sus- tain this burden when he was obliged to prove that he himself was in no way negligent and that his actions did not contribute to the accident; that he did not understand the risk and did not assume it and that the accident was not due to the neligence of some other employee engaged on the work. Prior to the enactment of the Employers Liability Laws, in many states even the superintendent in charge of the work was held in many instances to be a co-employee, so that if for any reason WORKMEN’S COMPENSATION 1155 the accident happened through his negligence the employee could not recover. The law in these respects being so harsh upon the employee and the burden on society caused by industrial accidents having increased so rapidly, it became more and more apparent that there must be some enlargement made of the rights of the employee to recover for accidents sustained in the course of his employment. As a result many of the states have from time to time passed so-called employers liability laws, placing a much greater burden upon the employer and reliev- ing the employee in many ways. Up to the year 1912 these laws had become so drastic so far as the employer was concerned that it was more and more difficult for him to escape the payment of damages to injured work- men regardless of how the accident might have happened. This situation came about in many respects through the work of unscrupu- lous lawyers who became so skilled in negli- gence litigation that they could almost always find some means of making the case a question of fact which the Courts have held required the submission of the case to a jury. Within the past ten years the submission of such a case to a jury almost invariably result- ed in a verdict for the plaintiff against the defendant. If the defendant was a corpora- tion it was almost a foregone conclusion that the verdict would be a substantial one and that it would eventually be sustained by the Appellate Courts. Juries in the past five years have seemed to lose their reason and judgment when called upon to render ver- dicts in cases of this character. The amounts awarded by them have been astounding and unreasonable beyond any question. Passion and prejudice have undoubtedly prevailed in a great many cases of this character and have tended to influence the verdict. The defendant, however, has found it almost impossible to demonstrate that such was the case. The slogan has been: “The corpora- tion is rich; it can stand it. Let’s give the poor fellow a good substantial verdict.’’ By reason of this situation the employer who has been looking into the future has tried to establish for his own welfare as well as that of his employees, a system of com- pensation which would to some extent relieve the employees from the burden of industrial accident and that the employers have suc- ceeded admirably in many cases is a well- known fact. That this should be done from a social standpoint need not be demonstrated. That it should be done from a business stand- point also requires no demonstration. The employee himself was made to realize that it was for his interest to co-operate with his em- ployer along these lines when it became more and more apparent that the lawyers who handle negligence litigation were in almost every instance merely exploiting the injured work- man for the purpose of getting the substantial fee which they would obtain in the event of the litigation being successful. The speculative feature of this class of litigation had a tendency to make the plaintiff as well as his lawyers disregard the truth in many instances, the sole object being to endeavor to obtain a verdict against the employer. Many employers have for years been carrying on their own systems of compensa- tion for injured and killed workmen and their dependents, and have been successful in their efforts in this direction and have succeeded in reducing the annoyance and expense incident to negligence litigation to a minimum and have thereby been able to increase the com- pensation and relief to the injured employee. Particularly is this true in respect to the employer who has handled his own insurance rather than by having insurance companies protect him through the medium of casualty insurance. Undoubtedly one of the greatest incentives to the enactment of workmen’s compensation laws in the various states has been the methods adopted by casualty companies in conducting their business and in adjusting claims made by employees for injuries sus- tained by them. The attitude of the insur- ance companies until very recent years has been that they would not pay anything to the injured workman if it was possible to avoid it, preferring to rely upon their legal defenses in case the workman saw fit to bring a suit. Whenever an accident happened the insurance company intervened between the employer and the employee and the employee was obliged to conduct his negotiations, if any, with the insurance company. Naturally the ordinary workman is not versed in matters of this character and he was at a tremendous disadvantage when attempting to do business with the representatives of the insurance companies. As a result he was imposed upon; he was unable to clearly understand his legal rights, and was made to understand that before he could hope to recover anything he would be obliged to go through a protracted litigation which might extend over a period of years and in the end it was possible and per- haps probable that he would be unsuccessful. 1156 GENERAL ELECTRIC REVIEW in which event he would recover nothing. During all the time that this litigation might continue he would have the worry and annoy- ance of it and nothing to compensate him for his injury, which in many instances was serious ; so that the insurance companies by use of such arguments were in most instances able to effect a settlement for a small amount and get the case disposed of. It is significant that the records show that prior to the time when compensation laws were first enacted in this country the amount disbursed by insurance companies in the way of payment of com- pensation to injured employees was about 30 per cent of the total premiums, the balance being used by the insurance companies for the payment of their expenses and dividends to their stockholders. Of the 30 per cent prob- ably a large amount was paid over by employ- ees to lawyers and others for assistance rendered by them. It can readily be seen that the real purpose for which insurance was taken out was not to insure the payment of compensa- tion to the injured workmen when the accident was due to the fault of the employer, but rather to relieve the emoloyer from making any pay- ment whatsoever and as a result the workman received a small percentage of the amount to which he was really entitled and in addition considerable feeling was engendered between him and the employer. It was apparent to the manufacturers who where able to look ahead that this state of affairs, coupled with the expense and annoyance incident to the harass- ing negligence litigation, could not continue much longer and that some remedy should be found which would make both of these things entirely unnecessary, and in addition enable both employer and his employee to work more in harmony with each other, and afford the man who was injured at his work a partial recompensation for the loss which he should sustain. The workmen were also beginning to think along the same lines. While the employers and employees may both claim the credit for workmen’s compen- sation legislation, yet regardless of the question as to whom the credit belongs it may safely be said that it is one of the greatest steps in promoting social welfare that has occurred in modern times. It may well be termed: “The movement to conserve human life and health through the medium of legis- lative enactment.’’ As times goes on both the employer and the employee will wonder why the great waste of human life and health which we have endured up to very recent years was permitted to go on unchecked when it was possible to remedy the difficulty so readily. It will also be found after these laws have been enforced for a short time that neither the employer nor the employee would be willing to go back to the old condition of things under any consideration. That it may be classed as paternal legislation is in one sense true, but on the other hand it is agreed that paternal legislation that brings desired results to all parties interested alike is the best kind of legislation that can be enacted. There can be no ground for arguing that such a law is unjust and inequitable, so far as the principle is concerned. In the years gone by the machine in the shop when out of order was shut down and promptly repaired so that it might be again put in use for the purpose for which it was designed and thereby enable the employer to make use of it In turning out his product. In the same way the horse that was used for hauling the freight and other material around the plant when taken sick was prompt- ly attended to by the veterinary. He was fed and cared for, and every effort made to put him in good condition so that he could again resume his work. To be sure no wages were paid to the horse but yet as compensation for the food and care which he received he per- formed a certain amount of work for the employer. That this condition of affairs should have been overlooked for so many years and these principles not applied to the human machine seems almost startling in the light of present day developments. Why is it that the human machine did not receive equally as good care and treatment as the others? Was it because of selfishness or neglect or failure to consider the true merits of the situation? The answer undoubtedly is that when the human machine became out of order for any reason it could promptly be replaced by another without any trouble or apparent expense, and for that reason the man who was injured in employment was displaced, for the time being in any event, by another workman who was prepared to take up his work, and if the former employee had been so disabled as to be unable to resume his employ- ment then the new one could remain on permanently. In the case of the horse it would cost a substantial sum of money to replace him even temporarily, whereas with the human being it cost nothing, so that the action taken may properly be said to have depended entirely upon the question of cost. Nowadays the employer is finding out that it is money well invested to keep the human machine in proper working order and con- WORKMEN’S COMPENvSATION 1157 dition. The benefits derived from his efforts in this direction are manifold. It is seen not only in the workman himself but the benefit redounds to his wife and children and to the public in general which is relieved from any apparent burden so far as he is concerned. If a man is in good physical condition he can naturally do more work and do it better than the man who is ailing and unfit for the employ- ment in which he is engaged. The more and the better production the manufacturer is able to put out the more business he does, the larger his income, and presumably the greater his profits. The saving to the community in general, by reason of the enactment of laws regarding compensation of workmen who are injured in the course of their employment, will more than compensate for any additional ex- pense to which the state may be put in admin- istering such laws. Heretofore a large portion of the time of our courts has been devoted almost exclusively to the conduct of neg- ligence litigation arising out of accidents to employees. In fact the calendars in some of the courts in the larger cities have been almost entirely filled with these negligence actions. Without question the work of the courts in such a state as New York will be so materially decreased by the disappearance of this class of litigation that many of the judges will have time on their hands and some of them could be dispensed with. When the enormous expense that is attendant upon the operation of the courts is realized it will be seen at a glance that a great saving is to be effected. In addition to that, the workman who is seriously injured is not going to be a burden upon himself and his family , and upon society in general. He is not going to be made to feel that he is dependent on charity : for his existence. He is still going to be able to hold his head up among other men, knowing that so long as he is deprived of his ability to work by reason of the injury sustained in the course of his employment he is going to receive compensation to assist him to a I considerable extent in caring for his family during the time of his disability. This feeling I of self respect which the workman will have is in itself worth a good deal and will tend to make him in most instances a better citizen. I The burden of compensating employees will be borne by the industry and when it is of sufficient amount to be at all appreciable it will be added to the cost of the production, and the consumer, which is the public, will pay for it. In this way society in general pays the expense as it really does in everything else ultimately. The workman who is compen- sated while injured will, by being able to receive enough to keep his family from want, also be able to keep his children in school and thereby confer an untold benefit upon them. They will not of necessity be obliged to start in work when the wage earner of the family is disabled, whereas they might be obliged to do so much before the intended time if there were not other means of support. Of course it is impossible to have legislation of this character which is not without some drawbacks and subject to much criticism. In many of the states the claim is made that the compensation is too liberal and too far- reaching in that it will be an incentive where the compensation is too high for the injured workman to remain out of employment as long as he possibly can. Of course there may be something in this, particularly if the work- man carries his own insurance either through insurance companies or some fraternal organi- zation, for by taking such insurance benefits in conjunction with the compensation paid by the employer he may derive more than the sum which he would receive when working steadily. This, however, is a condition which must be met. In some states the list of dependents is carried to extremes, persons being entitled to compensation as far remote from the injured person as grandparents and grandchildren and nephews and nieces. It is undoubtedly true that the schedule of compensation for partial permanent dis- ability seems in many instances high but time alone will tell how burdensome this may be in the states where such compensation seems to be unduly high. Fortunately this only per- tains to a class of accidents which are fewest in number. That an untold amount of good is going to be accomplished by these laws must be admitted without controversy. It is going to have a tendency to cause employers to investigate more carefully their working conditions in order that they may ascertain wherein they may reduce the number of accidents in their factories. Every accident prevented means, theoretically, so many dollars earned, because by reducing the number of accidents the expense incidental thereto will also be diminished. An employer will be warranted in expending money for the purpose of reducing the number of acci- dents because it will be found to be an excellent investment. The amount of stimu- lation that has occurred since the beginning of the agitation for workmen’s compensation legislation is surprising. Many large manu- GENERAL ELECTRIC REVIEW 1158 facturers have b66n and. now are spending thousands of dollars in safeguarding machinery and doing other things to decrease the hazard of the employment and make it safe for the life, limb and health of the employee. Natur- ally these things have a tendency to iniprove the efficiency of the workman and his sur- roundings. One of the great elements which have been found to have a very important bearing upon industrial accidents is the question of lighting and it has been shown that many accidents which could well be prevented have been caused by failure to properly light the place where the employee was performing his work. It has been found a simple proposition in many ways to place these safeguards around the employee and thereby reduce the possibility of accidents and it is undoubtedly due to the fact that it has been so simple and easy to do these things that they have been left undone for so long a period of time. In another respect, outside of compensation for industrial accidents, the employee is bound to derive a substantial benefit. The burden which the employers have had placed upon them has led them to take a much greater interest in the welfare of their employees and has put them in touch with many conditions which were unknown before. Until recent years no special effort has ever been made to fit the work to the man but it has usually been a case of fit the man to the work. The requirements of the compen- sation laws have given the employer a new incentive and that is to try to see that he has workmen physically able to perform the work for which they are engaged. To this end many of the employers of labor throughout the | country have adopted the policy of medical \ examination which is believed will prove to be | of untold benefit to employer and employee ; alike. It does not mean that the man who is not physically perfect will be shut out or pre- vented from obtaining employment, but it does mean that more care will be used in the emplovment of labor and that an effort will be made to place the man at the kind of work which he is physically able to do rather than to place him at the kind of work which he thinks he wants to do but for which he does not know he is physically unfit. Such pro- cedure is bound to be beneficial to both parties . because it will tend to improve the efficiency of the employee, thereby benefitting the manufacturer; it will tend to conserve the life and health of the employee, thereby enabling him to perform his duty to society , and by lengthening out his life it will extend the period of his usefulness to his family and the community. Society has much to be thankful for when we consider the amount of suffering and distress that is going to be saved by reason of the enactment into law of the principle of compensating workmen who are injured in the performance of the work_ incident to their employment and in the , years to come the employers and employees will wonder why such a blessing to mankind | was not brought into existence many years ^ before. PRACTICAL ECONOMIES IN DISTRIBUTION WITH THEIR EFFECT ON THE COMMERCIAL POLICY OF A CENTRAL STATION COMPANY DOHERTY MEDAL PAPER— 1914 By Harold Goodwin, Jr.* Assistant Superintendent Distribution, The Philadelphia Electric Company The content of this article is of great practical value to all those concerned in any way with the distribution - of electrical energy through overhead lines (the,.«e&ditions existing in underground lines are conformable to ” the same treatment as is used herein for overhead lines). This article is meritorious chiefly because, unlike others, its author has studiously avoided falling into the error of delivering either with an exposition based only on theory or a treatise founded ^lely on practice. A comparison of the merits of the radial and the tree systems is made; load capacity data/(5f the secondary distributing lines are given in tabular form; and cost data of line materials and their erectioij are presented, also in tabular form. A careful explanation of the local factors which have to be considered in distribution problems and well-balanced helpful advice supplement the value that can be derived from the tables. Through the courtesy of Current News we have been able to publish this excellent article. — Editor. INTRODUCTION The technical press is at present filled with notes on the cost of central station service showing at one end of the system the present low generating costs and at the other the almost fixed charges per customer’s service. ’Twixt these there is a great gulf fixed and labeled “Distribution Costs.’’ The central station man goes into competition with the isolated plant and finds his main generating costs much lower, but then he has to add “Distribution Costs’’ that seem to wither his chances for the business. Mr. P. Junkersfeld, in his report on “Distribution” to the last (1914) midwinter convention of the A.I.E.E., states; “The great importance of the subject of distribution of electrical energy is further indicated by the fact that, in the average central station system in a large city, the fixed', charges and operating expense of the distribution system are nearly three times the fixed charges and operating expense of the power house.” Most central stations meter the output of their generating or substations and also sum up the total of customers’ meter registra- tions and compare the two. There is a dis- crepancy of from 10 to 50 per cent. This is put down as distribution loss; a little is accounted for as transformer core loss and the remainder just entered mentally to the discredit of the distribution engineers. Yet what is being done to reduce these costs and losses ? Eminent engineers are working to increase turbine and generator efficiencies if only by half of one per cent. Practically all transmission systems are in the hands of competent engineers. Others of equal standing in their profession are continually devising means, by combining loads of different characteristics, by which the efficiency of the substations may be raised. These same men lay out, more or less definitely, distribution systems with rules as to voltage and phase of motors, grouping loads on transformers, maximum voltage drop from feeder end to last transformer, etc. Then what? The operation of the generating stations, transmission systems, and substations is put in the hands of engineers; complete meter and instrument readings are continually taken and the results are checked up against those previously calculated and an efficient condition is thus maintained. But what is done for the efficiency of the system beyond the substation ? The general rules on voltage, phase, etc., are given to a “practical man” who knows from experience the “one- hundred-and-one ” mechanical details that enter his problem and he proceeds to build primary lines, hang transformers, run second- aries, and supply the current to meters registering with almost absolute accuracy to the fraction of a per cent. General voltage tests are made and the job is said to be a good one. A complaint may come in and the voltage being found a little low a new trans- former is hung, or new secondaries are run in a manner which has caused no complaint to the “practical man” at another location and is therefore to him the proper thing. Some “practical men” have gone further and have investigated their transformers to see that they are properly loaded and have ^ * The writer desires ,to take occasion to express his apprecia- tion of the excellent distribution work done by the Aerial Line Department of The Philadelphia Electric Company, which has inspired this paper, though it has been done without the confi- dence of these figures. He also wishes publicly to extend his thanks to Mr. William Foster for his willingness in supplying the assumed figures on costs and to Mr. N. E. Funk and Mr. Clarence W. Fisher for,.their>ssistance in the preparation of the article. 1160 GENERAL ELECTRIC REVIEW thus shown a considerable saving. This showing, with the ability which guided their work, has qualified them for higher positions which they have assumed. They have then written articles showing mostf beautifull}^ the advantages of grouping load on transformers and the advantages of diversity factor and so forth; they have proceeded to the study of transmission lines and given us no end of valuable information and short cuts on the calculation of these problems. But what have they done to help the man who is still struggling to determine whether he should put a transformer in every block with small secondary wires, or only one in every four blocks with heavy secondary wires? At this point the young technical graduate has advanced his theories and figured out a superb ( !) system with conductors tapered down toward the end of the secondary, giving what he claims to be the ideal system of distribution. Suddenly a large load is to be added at a point where his conductors have been neatly tapered down; it is necessary to renew them and he comes to believe the “practical man” is correct in building with the same size conductor throughout, so he throws his theory to the winds and is lead by the “practical man.” Occasionally special cases force themselves upon him and he may figure out what is the economical arrange- ment. But as yet no practical man who has acquired the theory, or theoretical man who has learned the practice, has given to his fellow practical workers throughout this country even the most simple and funda- mental tables of capacity and economical use of wires, except the N.E. Code rules on the ampere capacity of various sized con- ductors. The “Lamp Committees” are now dis- cussing the question of adopting one standard voltage lamp for a given system. Yet who knows for alternating current systems in general whether the range in voltage on the lamps is to be arbitrarily fixed by the com- mittee at a maximum which they consider will still give good service, or whether the actual losses of energy in the distribution system supplying the lamps will not definitely limit the range of voltage at the different services ? It is with this vast and complicated unknown of DISTRIBUTION that this paper will deal. First will be submitted a few comments on primary systems and a pre- liminary set of tables for guidance of the practical man. Then a study of the funda- mentals of the economic side of the situation will be made, pointing out the need for research and testing along certain lines. Attention will be confined entirely to over- head lines and detailed discussion will only be given the transformer and secondary lines. The methods used in comparing fixed with operating charges are familiar and of course apply equally well to primary and secondary, though the almost infinite complication of the secondary problem is increased seven-fold when the primaries are considered in con- junction with it. There are, however, certain practical limitations, explained later, which enter to exclude the primary from considera- tion and the solutions are therefore more general than would appear at first sight. All methods also apply to underground construction and to comparison of overhead and underground structures, though to cover completely only the subject in hand would require such a large volume that consideration of these last two subjects has been omitted entirely. All figures on costs are altogether approxi- mate and are not supposed to represent the experience of any one company, and are ’ introduced simply to make the results more tangible. It would, of course, be possible to work out the whole problem with algebraic , symbols leaving it to anyone interested to substitute true values and solve for the result. It would also have been possible to take these figures from “Data” or other handbooks. ■ But they are simply assumed and are there- fore not open for discussion unless their accuracy materially affects the conclusion?? ■ The figures on maximum carrying capacity of wires are derived from Table B, para- graph 18 of the “N.E. Code,” 1913 edition. All figures connected with power and voltage loss are based on the familiar formulae: DXWXC \ PXE^ V = PXB where A — area of conductor in circular mils. D = distance one way from source to receiver. W = load in watts. C = 2400 for 95 per cent power-factor, single-phase. = 3380 for 80 per cent power-factor, single-phase. P = per cent power loss of delivered power. E = receiver volts. PRACTICAL ECONOMIES IN DISTRIBUTION V = per cent voltage loss. B = constant given in following table for 60 cycles: No. 'of Wire B.&S. Gauge Conductor Area Circular Mils VALU 95 Per Cent P-F. E OF B 80 Per Cent P-F. 6 26,200 1.05 1.00 4 41,600 1.11 1.10 2 66,600 1.18 1.26 0 106,000 1.31 1.49 00 133,000 1.34 1.66 000 168,000 1.49 1.95 0000 212,000 1.62 2.09 PRIMARY DISTRIBUTION SYSTEMS There are two generally accepted alternat- ing current distribution systems which can be considered regardless of the cycles, phase, or voltage so long as the latter is not above the generally accepted standard of 2400 volts. These two systems are the"‘-‘Iree ” or “main and branch’’ system, and the “radial’’ or “center of distributioin ’ ’ system. Fig. 1 shows the “center of distribution’’ f*system as submitted by Mr. H. B. Gear in Appendix II, to the report of the Distri- bution Committee to the last (1914) mid- winter convention of the A.I.E.E. For this Fig. 1. Radial System of Distribution system very good voltage regulation is claimed on account of the radial feeds from the centers A, B, and C. The same writer shows in another diagram that emergency connections between the three circuits must be provided at points where they come close together. In his concluding paragraph he states : “The feeder system must be reinforced as may be necessary from time to time to Fig. 2. Main and Branch System of Distribution Ti'cc. * carry the added load. This involves re- arrangement of connections of primary main and many complicated ‘ cut-overs ’ which add to the expense very materially.’’ We do not doubt this writer’s statement. Now contrast this first method with the “tree’’ or “main and branch’’ system shown in Fig. 2, for covering the same section. A rough comparison will show that the wire lengths from the feeding points to the most distant points are not materially different from those in Fig. 1, and therefore the regu- lation must be almost the same. In fact, it is difficult to see where Fig. 1 has any advantage, so long as there are no diagonal streets. A comparison can also be drawn on the basis of continuous service which is one, if not the most rigid, requirement at the present time. Suppose trouble occurs and a man goes out to locate and repair it. In the “radial” system he has to go around many corners and look in many places. On the “tree” system he has one straight main to travel and after clearing that, if necessary, he can travel out any branch he finds in trouble, moving quickly to the point in question. Suppose the main feed “B” is in trouble in either system. See how simple it is to 1162 GENERAL ELECTRIC REVIEW “cut-over” the load to “A” or “C” on the main street in Fig. 2, while in Fig. 1 it would apparently be done in an out-of-the-way comer. Mr. Gear’s opinion has been quoted on the work necessary to introduce a new feeder in Fig. 1. Notice how simple it is in Fig. 2. The breaks may be closed and the main cut into four sections and the new feeder mn at a minimum expense. In Fig. 2 there would probably be another main running directly by the substation. This would have branches on the same streets as A, B, and C. These would be mn to meet each ’other on the same street parallel to the rriciin. A, B, C, 3.nd in C3,s6 of trouble on B, and C the whole load could temporarily be transferred to the mains nearer the sub- station. _ Consider also the simplicity of the pole line constmetion in Fig. 2, as compared to the main of 112/224 volts which allows for a slight loss in the service wires and house wiring, insuring 110 volts at the lamp socket. The power loss and voltage _ loss are both assumed at 1 per cent. If it is decided that this is the proper loss to allow for any system the values of loads in the tables are correct; if a different loss is to be allowed the values can easily be multiplied by that per cent. An attempt will be made later to determine ; what that value is and it should be noted , particularly that there is no reason why it should work out to an even per cent, indeed when the tables have once been multiplied it makes little difference in their use how ^ irregular the per cent voltage or power loss may have been. ' Tables have been used throughout rather than curves, because there are so few standard | sizes of wire on any system that it is believed , to be a more simple matter to pick the | - K. — — - w — g A < O Fig. 3. Electric Circuit with Uniformly Distributed Load the many irregular dead ends and corners to be turned in Fig. 1. _ . But it is not intended to discuss the primary systems in this paper, so probably enough has been said to allow the assumption later in the calculations that, for all normal loads, the primary should always be present. The cost of its erection can, therefore, in general be neglected. ^ LOAD CAPACITY OF SECONDARY ^ distribution lines As stated in the introduction, it is proposed to present a set of tables of the capacity o secondary distribution systems for the use of the practical man. These alone will not show whether a given system is economical or not, but they will show the losses in any system and anyone using them may depend on his own judgment for determining the allowable losses until such time as the calculations shown in the latter part of this article have been made. ,,n/oon u The three-wire nominal llU/22U^oit single-phase secondary system has been assumed with an actual delivery voltage from values from the tables for a few^ sizes, rather than from a curve covering all sizes. The distribution of loads covered in the'i tables are typical; First: Load concentrated at one end ot secondary with transformer at opposite end. Second: Uniformly distributed load witff transformer at one end. ' Third: Uniformly distributed load with;j transformer in center. * Any other loadings can be figured from a combination of these. All loads are giy^n kilowatts. The uniformly distnbuted load tables have been carried down to the lower hundreds of feet merely to show how enor- mously the capacity increases under these conditions though it is an impractical condi- tion on a pole line since services can only be tapped from the mains at poles, which are in the vicinity of 100 feet apart. -r . It is interesting here to note that it the lamps of various customers are proper!} rated for the average voltage of the secondaip supplying them, it makes no difference in th( central station revenue how great the voltag* drop, within a long range, since the cun^e o if i PRACTICAL ECONOMIES IN DISTRIBUTION IKD watts to volts is a straight line for a consider- able distance both sides of normal rating. It does make a very considerable difference, however, in the amount of light received and current consumed by the first and last customers, since the lamps of the former will be burning above rating and those of the latter below rating. The length to be used in calculating both voltage and power loss with a uniformly distributed load is a point of interest. It is generally known that to find the maximum voltage loss, half the greatest distance and the total load are used in the formula. However, it is probably not so well known that to find the total power loss only one-third of the total length is used. It may therefore be worth while to derive the equations for voltage drop and watts loss in the uniformly loaded circuit represented by Fig. 3. 5r = an electric circuit of uniform resist- ance. S = source, and load is distributed uni- formly towards “ T.” I = current at “ 5. ” Current at “ T ” = 0. E = potential difference between “S” and“r.” W = total power loss in circuit. Let f = current at any point “A” at a distance “x” from “T.” Then . J t~L X. = volts loss in a section “dx.” Let Then r = resistance of circuit per unit length. de = irdx. r r 7 rxdx = ^ T Jo J J c xdx. But 7rL2 ^ L -Lr = R. Similarly = watts loss in a section “dx.” Then dw — i^rdx. U 3 PrL 3 ■ In order to show the method of a])])lying the formula (page 11 GO of “Introduction”) to the following tables, calculation is here made of the capacity of 500 feet of No. 00 wire at 224 volts delivered with a power loss of one per cent, a power factor of 80 per cent, and with the load concentrated at the opposite end from the transformer. The formula as given previously reads: nxwxc PXE^' • Since “W” is the unknown the formula is transposed for use : AXPXP DXC ■ A = 133,000 circular mils. P=1 per cent. E = 224 volts. D = 500 feet. C = .3380. Then W = 133,000X1 X (224)2 500X3380 = 3.9 kilowatts. This value will be found in Table II. A similar calculation for 1 per cent maxi- mum voltage loss may be made. This involves the use of the formula : V = PXB. Since “P” is the unknown this may be transposed : But U= 1 per cent. P=1.6G (page 1161). P = rh = 0.602. 1.66 _ 133,000 X 0.602 X (224)2 500X3380 = 2.4 kilowatts. This value may be found in Table I. As noted in the first paragraph these tables are useful for determining the loss under any given conditions. Suppose a 500-foot, No. 00 secondary, similar to that used in the preceding calculations is carrying a load of 12 kw. and it is desired to know the voltage drop. Table I or the foregoing calculations show a load of 2.4 kw. will produce a drop of 1 per cent. Therefore 12 kw. will produce a drop of 12 divided by 2.4, or 5 per cent. The actual voltage drop is then 5 per cent of 224 or 11.2 volts. The values of “P” as used in the foregoing formula are shown in the second column of GENERAL ELECTRIC REVIEW 1164 Tables I to VI. In the third column is shown the maximum load the circuit will carry without overheating, based on the rating of wires with other than rubber insulation m Table B, paragraph 18 of the “N.E. Code, 1913 edition. COST DATA ON DISTRIBUTION LINES The following figures given in Tables I to VI are dependent on the fundamental electrical properties of wires and are entirely independent of how or when the wires are erected or the cost of erecting them. It is now proposed to consider the costs of erecting wires and their supports with a view to ascer- taining the factors which need particular attention. As stated in the introduction, the figures have only the most general foundation in practice and are merely assumed tabulated in order to show the data which W- W Table I KILOWATT CAPACITY OF SECONDARY MAINS Load Concentrated at Opposite End of Main from Transformer Single-Phase; 1 Per Cent Maximum Volts Loss; 224 Volts Delivered Wire Size B.&S. 00 000 0000 0.95 1.00 0.90 0.91 0.85 0.79 0.76 0.67 0.74 0.60 0.67 0.51 0.62 0.48 Maximum 12.5 ! 19.1 16.1 26.6 22.4 42.6 35.9 : 48.0 40.3 58.6 49.3 69.2 59.3 UPPER FIGURES KILOWATT CAPACITY— 95 PER CENT P-F. LOWER FIGURES KILOWATT CAPACITY— 80 PER CENT P-F. (MOTORS; 100 j 200 300 1 400 j 500 h je > 1 5.2 2.6 1.7 ] 1.3 i 1.0 3.9 1.9 1.3 1.0 0.8 7.8 3.9 2.6 2.0 1.6 5.6 2.7 1.9 1.4 1.1 11.8 5.9- 3.9 2.9 2.4 7.8 3.9 2.6 1.9 1.6 ia.8 8.4'' 5.6 4.2 3.4 10.5 5.2 3.5 2.6 2.1 20.5 10.3 6.8 5.1 4.1 1 11.8 5.9 3.9 2.9 2 A 23.4 11.7 7.8 5.9 4.7 1 12.7 6.3 4.2 3.2 1 2.5 27.4 13.7 9.1 6.9 1 5.5 15.0 7.5 5.0 3.8 3.0 Distance in Feet 600 0.9 0.7 1.3 0.9 2.0 1.1 2.8 1.7 3.4 2.0 3.9 2.1 4.6 2.5 700 0.7 0.6 1.1 0.8 1.7 1.1 2.4 1.5 2.9 1.7 3.3 1.8 3.9 2.1 800 0.6 0.5 1.0 0.7 1.5 1.0 2.1 1.3 2.6 1.5 2.9 1.6 3.4 1.9 900 0.6 0.4 0.9 0.6 1.3 0.9 1.9 1.2 2.3 1.3 2.6 1.4 3.0 1.7 1000 0.5 0.4 0.8 0.6 1.2 0.8 1.7 1.1 2.0 ■ 1.2 2.3 1.3 2.7 1.5 Wire Size B.&S. 6 4 2 0 00 000 0000 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 Table II KILOWATT CAPACITY OF SECONDARY MAINS Load Concentrated at Opposite End of Main from Transformer Single-Phase; 1 Per Cent Power Loss; 224 Volts Delivered Maximum 14.9 12.5 19.1 16.1 26.6 22.4 42.6 35.9 48.0 40.3 58.6 49.3 69.2 59.3 l"o"w"e"r f^'SuL^^ ^;i‘:Xt\^ c^^^ac^ItVIo P^gR c^nt^ p-I: Distance in Feet 100 5.5 3.9 8.7 6.1 13.9 9.9 22.0 15.7 27.7 19.7 35.0 24.8 44.2 31.4 200 2.7 1.9 4.3- 3.1 6.9 4.9 11.0 7.8 13.8 9.8 17.5 12.4 22.1 15.7 300 1.8 1.3 2.9 2.0 4.6 3.3 7.3 5.2 9.2 6.6 11.7 8.3 14.7 10.5 40Q 1.4 1.0 2.2 1.5 3.5 2.5 5.5 3.9 6.9 4.9 8.8 6.2 11.0 7.8 500 600 1 700 800 900 1.1 0.9 ! 0.8 0.7 i 0.6 0.8 0.7 ; 0.6 0.5 0.4 1.7 1.4 1.2 1.1 1.0 1.2 1.0 0.9 0.8 0.7 2.8 2.3 2.0 1.7 1.5 2.0 1.6 1.4 1.2 1.1 4.4 3.7 3.1 2.8 2.4 3.1 2.6 2.2 1.9 1.7 5.5 4.6 4.0 3.5 3.1 3.9 3.3 2.8 2.5 2.2 7.6 5.8 5.0 4.4 3.9 5.0 4.1 3.5 3.1 2.8 8.8 7.4 6.3 5.5 4.9 6.3 5.2 4.5 3.9 3.5 ' _ . - .. 1000 I 0.5 0.4 0.9 0.6 1.4 1.0 2.2 1.6 2.8 2.0 3.5 2.5 4.4 3.1 PRACTICAL ECONOMIES IN DISTRIBUTION 1165 anyone studying this subject should prepare and also to give a basis for the sample calcu- lations made later. Table VII shows approximate costs of erected poles when erected singly or in lots up to ten in the same vicinity. It is very evident that, particularly in the smaller sizes which are used largely in local distribution, it is very advantageous to erect a large number at one time. In fact if, in a given section, the load gradually grew so as to call for two 40-ft. poles at a time, erected through- out the year, till seven were standing, it would have been just as cheap to have erected ten in the first place. This means that ten poles could be erected ready for new business Table III ’ KILOWATT CAPACITY OF SECONDARY MAINS Uniformly Distributed Load, Transformer at One End Single-Phase; 1 Per Cent Maximum Volts Loss; 224 Volts Delivered Wire UPPER FIGURES KILOWATT CAPACITY — 95 PER LOWER FIGURES KILOWATT CAPACITY 80 PER CENT P-F. CENT P-F. (lights) (motors) Size B &S Distance in Feet p Maximum 100 200 300 400 oOO 600 700 800 900 1000 6 j 0.95 14.9 10.4 5.2 1 3.4 . 2.6 2.0 1.7 1.6 1.3V 1.2 1.0 ^ 1 1.00 12.5 7.8 3.9 1 2.6 1.9 1.6 1.3 1.2 1.0 0.8 0.8 4 1 0.90 19.1 15.6 7.8 ; 5.2 3.9 3.2 2.6 2.2 2.0 1.8 1.6 1 0.91 16.1 11.2 5.6 ' 3.8 2.7 2.2 1.9 1.6 1.4 1.2 1.1 2 / 0.85 26.6 23.6 11.8 1 7.8 5.9 4.8 3.9 3.4- 2.9 2.6 2.4 0.79 22.4 15.6 7.8 ' 5.2 3.9 3.2 2.6 2.2 1.9 1.8 1.6 0 ( 0.76 42.6 33.6 16.8 i 11.2 8.5. 6.8 5.6 4.8 4.2 3.8 3.4 ^ 1 0.67 35.9 21.0 10.5 ; 7.0 5.2 4.2 3.5 3.0 2.6 2.4 2.1 00 j 0.74 48.0 41.0 20.5 13.6 10.3 8.2 6.8 5.1 4.6 4.1 > 0.60 40.3 23.6 11.8 j 7.8 5.9 4.8 3.9 3.4 2.9 2.6 2.4 000 ] 0.67 58.6 46.8 23.4 I 15.6 11.7 9.4 7.8 6.8 5.9 5.2 4.7 0.51 49.3 25.4 12.7 1 8.4 6.3 5.0 4.2 3.6 3.2 2.8 2.5 0000 I 0.62 69.2 54.8 27.4 18.2 13.7 11.0 9.1 7.8 6.9 6.0 5.5 0.48 59.3 30.0 15.0 1 10.0 7.5 6.0 5.0 4.2 3.8 3.4 3.0 Table IV KILOWATT CAPACITY OF SECONDARY MAINS Uniformly Distributed Load, Tr,ansformer at One End Single-Phase; 1 Per Cent Power Loss; 224 Volts Delivered Wire UPPER FIGURES KILOWATT CAPACITY 95 PER CENT P-F. (LIGHTS) LOWER FIGURES KILOWATT CAPACITY 80 PER CENT P-F. (MOTORS) Size B.&S. p Maximum Distance in Feet — 100 200 300 400 500 600 700 800 900 1000 6 { 1.00 14.9 14.9 * 8.2 5.4 4.0 3.3 2.7 2.4 2.1 1.8 1.6 1.00 12.5 12.1 5.8 3.9 2.8 2.4 1.9 1.8 1.5 1.2 1.2 4 { 1.00 ib.l 19.1 * 13.1 8.7 6.4 5.2 4.3 3.7 3.3 2.8 2.6 1.00 16.1 1 16.1 * 9.1 6.0 4.6 3.6 3.0 2.7 2.2 2.1 1.8 2 j 1.00 26.6 1 26.6 * 20.8 13.8 10.3 8.3 6.9 6.0 5.2 4.5 4.2 1 0 i 1.00 22.4 22.4 * 14.8 9.9 7.3 6.0 4.9 4.2 3.7 3.3 3.0 1.00 42.6 42.6 * 33.0 22.2 16.0 13.4 11.1 9.6 8.2 7.5 6.6 1 00 1 000 / 1.00 35.9 35.9 * 23.6 15.6 11.7 9.3 7.8 6.6 5.8 5.1 4.6 1.00 48.0 48.0 * 40.8 27.6 20.7 16.5 13.8 12.0 10.3 9.3 8.2 1.00 40.3 40.3 * 29.5 19.8 14.7 11.7 9.9 8.4 7.3 6.6 5.8 1.00 58.6 58.6 * 52.5 35.0 26.3 21.0 17.5 15.0 13.2 11.7 10.5 ) 1.00 49 .d 49.3 * 37.2 24.9' 18.6 15.0 12.4 10.5 9.3 8.4 7.5 0000 1 1.00 69.2 69.2 * 66.5 44.0 33.2 26.4 22.0 18.9 16.7 14.7 13.2 1:00 59.3 59.3 * 48.0 31.5 23.6 18.9 , 15.8 13.5 11.7 10.5 9.4 * Maximum allowable load; less than 1 per cent power loss. 1166 GENERAL ELECTRIC REVIEW with a chance that three might never be used and still it would cost no more than the other “piece meal’’ method. Similar and indeed more striking lessons could be drawn from Table VIII, showing the cost of erected secondary wires. For instance, if the initial financial burden were not too great, and if streets were open so that it would be possible to erect secondaries in a residential section in runs of 1000 ft. at a time instead of 200 ft. at a time. No. 2 wire could be used instead of No. 6 without additional cost. This would mean a tremen- dous difference in the capacity of the system as can be seen by referring to these two sizes in Table VI for 1000 ft., which shows that Table V KILOWATT CAPACITY OF SECONDARY MAINS Uniformly Distributed Load, Transformer in Center Single-Phase; 1 Per Cent Maximum Volts Loss; 224 Volts Delivered Wire UPPER FIGURES KILOWATT CAPACITY — 95 PER CENT P-F. (LIGHTS) LOWER FIGURES KILOWATT CAPACITY — 80 PER CENT P-F. (MOTORS) Size B.&S. Maximum Distance in Feet 100 * 200 300 400 500 600 700 800 900 1000 0.95 29.8 29.8 > 3-2 20.8 13.9 6.. 10.4 8.0 ' ■/ 6.9 5.9 5.2 4.6 vb 4.2 ® 1 1.00 25.0 25.0 15.6 10.4 7.8 6.2 5.2 4.5 3.9 3.5 3.1 4^ 0.90 38.2 38.2 31.2 20.8 15.6 12.5 10.4 8.9 7.8 6.9 6.2 ^ 1 0.91 32.2 32.2 22.4 14.9 11.4 8.9 7.5 6.4 5.6 5.0 4.5 0.85 53.2 53.2 47.2 31.4 23.6 18.9 15.7 13.5 11.8 10.5 9.4 0.79 44.8 44.8 31.2 20.8 15.6 12.5 10.4 8.9 7.8 6.9 6.2 0.76 85.2 85.2 67.2 44.8 33.6 26.8 22.4 19.2 16.8 14.9 13.4 0.67 71.8 71.8 42.0 28.0 21.0 16.8 14.0 12.0 10.5 9.3 8.4 00 1 0.74 96.0 96.0 82.0 54.6 41.0 32.8 27.3 23.4 20.5 18.2 16.4 0.60 80.6 80.6 47.2 31.5 23.6 18.9 15.8 13.5 11.8 10.5 9.4 000 1 0.67 117.2 117.2 93.6 62.4 46.8 87.4 31.2 26.8 23.4 20.8 18.7 0.51 98.6 98.6 50.8 33.9 25.4 20.3 17.0 14.5 12.7 11.3 10.2 0000 1 0.62 138.4 138.4 109.6 73.0 54.8 43.9 36.5 31.3 27.4 24.4 21.9 0.48 118.6 118.6 60.0 40.0 30.0 24.0 20.0 17.1 15.0 13.3 12.0 * Maximum allowable load; less than 1 per cent volts loss. Table VI KILOWATT CAPACITY OF SECONDARY MAINS Uniformly Distributed Load, Transformer in Center Single-Phase; 1 Per Cent Power Loss; 224 Volts Delivered UPPER FIGURES KILOWATT CAPACITY — 95 PER CENT P-F. (LIGHTS) LOWER FIGURES KILOWATT CAPACITY — 80 PER CENT P-F. (MOTOR) Size B.&S. Maximum Distance in Feet p 100 * 200 300 400 500 600 700 800 900 1000 1.00 29.8 29.8 29.8 * 21.8 16.5 13.1 11.0 9.3 8.2 7.3 6.6 1.00 25.0 25.0 23.2 16.8 11.7 9.3 7.8 6.7 5.8 5.2 4.6 1.00 38.2 38.2 38.2 * 34.8 26.1 20.8 17.4 14.9 . 3.1 11.5 10.5 1.00 32.2 32.2 32.2 * 24.5 18.3 14.6 12.2 10.4 9.1 8.1 7.3 9 / 1.00 53.2 53.2 53.2 * 53.2 * 41.5 33.1 28.6 23.7 20.8 18.5 16.6 1.00 44.8 44.8 44.8 * 39.3 29.9 23.7 19.8 16.9 14.9 13.4 11.8 n / 1.00 85.2 85.2 85.2 * 85.2 * 66.0 53.0 44.0 37.6 33.0 29.4 26.4 1.00 71.8 71.8 71.8 * 63.0 47.0 37.7 31.4 26.9 23.6 21.0 ■ 18.9 1.00 96.0 96.0 96.0 * 96.0 * 83.0 63.2 55.2 47.3 41.5 36.8 33.2 00 1 1.00 80.8 80.6 80.6 * 78.5 59.1 47.2 39.4 33.9 29.6 26.2 23.6 ( 1.00 117.2 117.2 117.2 * 117.2 * 104.6 83.9 70.0 59.9 52.5 46.6 42.0 000 { 1.00 98.6 98.6 98.6 * 98.6 * 74.2 59.4 49.5 42.5 37.2 33.0 29.9 0000 1 1.00 138.4 138.4 138.4 * 138.4 * 132.0 106.0 88.3 75.9 66.4 58.9 53.0 1.00 118.6 118.6 118.6 * 118.6 * 94.0 75.5 62.7 54.0 47.0 41.9 37.8 * Maximum allowable load; less than 1 per cent power loss. PRACTICAL ECONOMIES IN DISTRIBUTION 1167 Table VII COST IN DOLLARS OF ONE ERECTED WOOD POLE Length of | number of poles erected at one time Pole in Feet 1 2 3 4 5 6 7 8 9 10 35 $16.00 $14.00 $12.00 $11.00 $10.50 $10.00 $9.60 $9.40 $9.20 $9.00 40 18.25 16.25 14.25 13.25 12.75 12.25 11.85 11.65 11.45 11.25 45 20.50 18.50 16.50 15.50 15.00 14.50 14.10 13.90 13.70 13.50 50 23.25 21.25 19.25 18.25 17.75 17.25 16.85 16.65 16.45 16 25 55 27.25 25.25 23.25 22.00 21.25 20.75 20.10 19.75 19.45 19.25 60 35.50 33.50 31.50 30.25 29.75 29.00 28.35 28.00 27.70 27.50 65 37.50 35.50 33.50 32.25 31.75 31.00 30.35 30.00 29.70 29.50 70 39.50 37.50 35.50 34.25 33.75 33.00 32.35 32.00 31.70 31.50 Table VIII COST IN DOLLARS PER 100 FEET FOR THREE ERECTED SECONDARY WIRES ON POLES ALREADY ERECTED BUT NOT ARMED OR GUYED. 1 SPAN = 100 FEET Wire Size B.&S. DISTANCE 100 200 300 400 500 600 700 800 900 1000 6 $8.50 $6.90 $6.10 $5.55 $5.15 $4.85 $4.60 $4,45 $4.30 $4.15 4 9.55 7.95 7.15 6.60 6.20 5.95 5.70 5.55 5.40 5,25 2 11.20 9.60 8.80 8.25 7.85 7.60 7.35 7.20 7.10 6.95 0 13.65 12.05 11.25 10.70 10.35 10.10 9.85 9.70 9.60 9.45 00 15.30 13.60 12.95 12.40 12.05 11.80 11.55 11.40 11.30 11 15 000 17.70 16.10 15.35 14.80 14.45 14.10 13.90 13.70 13.55 13 35 0000 19.30 17.70 16.95 16.40 16.05 15.75 15.40 15.15 14.95 14.75 j Table IX 1 CREDIT IN DOLLARS PER 100 FEET FOR WIRE REMOVED WHEN SAME IS REPLACED BY OTHER WIRE AND REMOVED WIRE HAS NOT PASSED USEFUL LIFE Wire Size B.&S. LENGTH IN FEET OF RE.MOVED WIRE 100 200 300 400 500 600 '700 800 900 1000 6 i $0.35 $0.35 $0.35 $0.45 $0.55 $0.70 1 $0.80 ! $0.90 $0.90 $0.90 4 1 .55 .55 .55 .75 .80 1.05 1.15 I 1.35 1.35 i 1.35 2 1.05 1.05 1.05 1.20 1.50 1.75 2.00 2.20 1 2.20 2.20 0 1.75 1. /5 1.75 2.10 2.45 2.85 1 3.20 1 3.55 1 3.55 3.55 00 2.20 2.20 2.20 2.60 3.05 3.50 ' 3.95 4.40 1 4.40 4 40 000 2.85 2.85 2.85 3.40 3.95 4.50 1 5.15 i 5.70 5.70 5 70 0000 8. bo 3.50 3.50 4.20 4.90 5.60 ; 6.35 7.05 : 7.05 ' 7.05 Table X COST IN DOLLARS OF ERECTION OF A TRANSFORMER ON AN ERECTED POLE WITH PRIMARY AND SECONDARY LINES ALREADY ON POLE; ALSO COST OF CHANGING TO ANOTHER SIZE Group Transformer Size Kv-a. Original Installation Changing to Group A Changing to Group B Changing to Group C A B C 1 to 10 15 to 25 30 to 50 $5.50 6.50 7.00 $4.00 3.50 5.00 $5.00 5.00 5.00 $6.00 6.00 6.00 \ 1168 GENERAL ELECTRIC REVIEW through the 1000 ft. with the transformer in the center the No. 6 wire would carry 6.6 kw. while the No. 2 wire would carry 16.6 kw. This is an increase to 2^ times the capacity without additional expense if one can just look ahead far enough. On account of the increase in load in any section it may be necessary at any time to replace small wire with a conductor of larger size. It is therefore interesting in this con- nection to determine how much return can be had for removing the wire which is so expensive to erect. This return is here termed “credit” and is the scrap value of the wire minus the cost of removing it. These credits are shown in Table IX for wire which may still be used over again. The credits mn higher for the greater lengths because they might be returned to second-hand stock while the shorter lengths would just be cut down and scrapped. A comparison of this table with Table VIII shows strikingly the results ot not building lines large enough at first to carry all load which may arise during the useful lite of the wire. . , Now that the poles and primary and secondary lines of a distribution system have been considered, it is time to consider the transformer which ties together the pnmary and the secondary mains. This has properties similar to those of poles and wires m that it costs money as is clearly shown m Table XL It also shares with the wires m absorlung some of the energy which it transmits. But it goes further than that, absorbing enerp’ whether it is transmitting any or not. this constant drain of energy is c^led the core loss, and is shown in Table XI for trans- formers from 1 to 50 kv-a., both m watts and in cost in dollars per annum at cent per ^'Vhere has been some discussion about the rate at which the core loss should be charged. Some would say that it must take share of the generating substation and distribution costs while some would merely charge its coal ’cost. This latter would appear to be more nearly correct since the core loss totals less than 1 per cent of the peak load and therefore has a negligible effect on the generating capacity. Its effect on the remain- der of the system is so distributed over the whole that its effect is absolutely negligible^ fudging it by the standards for commercial loads, it has a 100 per cent load factor on the 24-hr basis and is so distributed that it r nuires no additional apparatus and it is there- fore entitled to the absolute minimum rate. Table XI also shows the cost of the various sizes of transformers and the cost of erection. From these figures with interest at 6 per cent and depreciation 10 per cent, on the basis of a life of 10 years, the cost of keeping a transformer on the line for a year has been worked out and is shown. Some would like to claim longer life than 10 years, thoug general experience would not seem to warrant it for the average size pole type transfomen Of course, these figures should be modified by the latest data on each system m making the caleulations. . , The core loss has been materially reduced in recent years. It probably makes rnore expensive construction to reduce the loss, and by letting it run higher the transformer should be cheaper. It is therefore the business of the manufacturing companies to obtain a true balance between these factors. No allowance has been made for mmn- tenance charges against the transformer since many companies have done practically no maintenance work on them and no definite figures as to the amount necessary or how it will improve the life of the transformer or its capacity, are readily available Howeve^ just a superficial study of the table will show that if 10 years is the true life of a oO-kv-a. ^ transformer, without any maintenance^ wor , work that would improve the life to lo years ,, could cost as much as $10.00 per year. This ( is easily enough to pay for most complete ! lightning protection, purification ot ttie on, and complete cleaning when out of service and still leave a very wide margin of protit. Many people familiar with transformers can scarcely tell the difference between a 40 and a 50-kv-a. transformer when they see| it on the pole. Yet the last column shows the < difference is $8.10 a year. A practical man m choosing whether to put up a 40 or a ^u-, kv-a. transformer will very likely decide to use the 50, saying: “It will be needed in a couple of years anyway. _ However it will cost $16.20 more in that time and it wou cost only $6.00 (Table X) to change |t. This last column (Table XI) shows that if tl^ average size of transfonners on any system could be reduced say from 15 kv-a. to 10 kv-a it would warrant the expenditure o approximately $6.00 per transformer^ annum. This is easily enough to pay ve^ complete tests and records of ever\ trans- In this connection it is not out of place tc consider briefly what tests and records axi necessary. On small systems with one or twc PRACTICAL ECONOMIES IN DISTRIBUTION 1169 men handling all records it is very generally possible to have one set of records for all. But on larger systems it becomes necessary to have records of customers’ loads in the contract department, meter department, and distribution department. Experience has shown the great difficulty of keeping these records up to date, particularly with medium size business places, where different sizes of lamps are kept on hand and used on different- evenings according to the season of year and business expected. So it is an open question in the distribution department, with which 2 cents per kw-hr. since it is a peak load. This is discussed more fully in considering rate for energy losses in the secondary (page 1172). The transformer has been treated in a manner slightly different from that in which the pole and wire costs were treated; that is, its cost per annum has been determined as well as the initial cost. It is now proposed to do the same for secondary wires but, since the previous tables show plainly that it is uneconomical to erect wires in short sections, figures for 1000-ft. sections only have been made up. These are shown in Table XIII. Table XI INITIAL COST OF, AND ANNUAL CHARGES AGAINST POLE TYPE TRANSFORMERS Life, 10 Years; Depreciation, 10 Per Cent; Interest, 6 Per Cent; Total Capital Charges, 16 Per Cent; Energy to Supply Core Loss, Cent per Kw-Hr. Kv-a. COST IN DOLLARS CORE LOSS Total Annual Charges Original Erection Total Annual Watts Cost per Year 1.0 $20.00 $5.50 $25.50 $4.10 25 $1.10' $5.20 2.0 30.00 5.50 35.50 5.70 '35 1.50 7.20 3.0 40.00 5.50 45.50 7.30 45 1.95 9.25 4.0 50.00 5.50 55.50 8.90 50 2.20 11.10 5.0 55.00 5.50 60.50 9.70 55 2.40 12.10 7.5 75.00 5.50 ?0.50 11.30 75 3.30 14.60 10.0 90.00 5.50 95.50 15.30- 90 3.90 19.20 15.0 120.00 6.50 126.50 20.20 120 5.25 25.45 20.0 150.00 6.50 156.50 25.00 - 145 6.35 31.35 25.0 180.00 6.50 186.50 29.80 170 7.45 37.25 30.0 200.00 7.00 207.00 33.00 -- 190 8.30 41.30 40.0 240.00 7.00 247.00 39.50 225 9.80 49.30 50.0 ■ 280.00 7.00 287.00 46.00 260 11.40 57.40 only we are now concerned, whether it is necessary to keep any record of load except for the larger customers — that is, for the customers whose loads are say one-fourth or one-half of the transformer capacity supplying themr But it is evident from Table XI that it is most necessary to keep records of actual tests, showing that the transformers are working at least up to their rating, and, if they will stand it, above their ratings during the peak. The two factors that determine whether they will stand it or not are the temperature and the regulation. This is a great subject in itself and there is not space here to say more than that one central station has just started some practical in-service tests on this basis and there may be some very interesting results to report in the future. As a matter of interest and for subsequent use, the copper loss and regulation of trans- formers are shown: in Table XII. The cost cl energy for copper loss has been assumed at PRACTICAL COMBINATION OF DATA FOR ECOMON ICAL RESULTS In the preceding sections of this article the losses in various apparatus and the cost of maintaining it in service have been shown. It is now proposed to combine these to show what is the truly economical design for a secondary distribution system. This would appear a very complicated problem, and indeed it is. But it is here that the “practical man’’ comes in to simplify matters. For instance, in considering the question of service to a row of houses by wires run along the rear on brackets from one end, the “practical man’’ says it is useless to consider running the primary lines in to a transformer placed in the center of the row, no matter how cheap a job it will make, on account of the same objections which have been advanced against the “radial system,’’ and also on account of the life hazard of { 1170 GENERAL ELECTRIC REVIEW Table XII TRANSFORMER REGULATION AND COPPER LOSS AND COST PER YEAR AT 2 CENTS PER KW-HR. FOR FULL LOAD OPERATION 1 HOUR PER DAY Size Kv-a. Regulation 95 Per Cent P-F. COPPER LOSS Size Kv-a. Regulation 95 Per Cent P-F. COPPER LOSS Watts Cost Watts Cost 1.0 2.5 30 S 0.22 15.0 1.5 220 . 11.60 2.0 2.5 50 .36 20.0 1.4 295 2.16 3.0 2.3 70 .51 25.0 1.4 355 2.59 4.0 2.1 85 .62 30.0 1.4 430 3.14 5.0 1.9 95 .69 40.0 1.3 485 3.54 7.5 1.7 120 .88 50.0 1.2 600 4.38 10.0 1.6 160 1.17 Table XIII DATA ON ANNUAL CHARGES AGAINST 1000 FEET OF THREE-WIRE SECONDARY, EXCLUSIVE OF COST OF POLES "Wire Size B.&S. Initial Cost from Table VIII Average Life Years Depreciation Interest Total Capital Charges Maintenance Total Annual Charges Per Cent Per Cent Per Cent 6 S 41.50 25 4.0 6.0 10.0 ‘ ■ S 4.10 $ 3.00 $ 7.10 4 52.50 25 4.0 6.0 10.0 5.20 3.00 8.20 2 69.50 25 4.0 6.0 10.0 7.00 3.00 10.00 0 94.50 30 3.3 6.0 9.3 8.80 3.00 11.80 00 111.50 30 3.3 6.0 9.3 10.40 3.00 13.40 000 133.50 35 3.0 6.0 9.0 12.00 3.00 15.00 0000 147.50 40 2.5 6.0 8.5 12.50 3.00 15.50 Table XIV ANNUAL CHARGES AGAINST A THREE-WIRE SECONDARY SYSTEM, 1000 FEET LONG, SUPPLIED BY A 30-KILOWATT TRANSFORMER IN THE CENTER, WITH A , .* UNIFORMLY DISTRIBUTED LOAD OF 30 KILOWATTS, OF 95 PER CENT * POWER-FACTOR 224 Volts Delivered; Rate, 2 Cents per Kw-Hr. ; Showing Most Economical Size of Wire 1 II Wire Size B.&S. POWER LOSS ANNUAL FIXED CHARGES TOTAL FIXED AND OPERATING ANNUAL CHARGES FOR DIFFERENT DAILY PERIODS OF OPERATION Max. Volts Loss Per Cent Secon (From Table VII) Per Cent dary In Kw. Trans- former Copper in Kw. Total Kw. Annual Cost with Load on 1 Hour per Day Trans - former Lines Total 1 Hour 2 Hours 3 Hours 5 Hours 8 Hours 10 Hours 6 4.5 1.34 0.43 1.77 $12.90 $41.30 $ 7.10 $48.40 $61.30 $74.20 $87.10 $112.90 $151.60 $177.40 7.1 4 2.8 0.84 0.43 1.27 9.30 41.30 8.20 49.50 58.80 68.10 77.40 96.00 123.90 142.50 4.6 2 1.8 0.43 0.43 0.96 7.00 41.30 10.00 51.30 58.30 65.30 72.30 86.30 107.30 121.30 3.2 0 1.13 C).34 0.-13 0.77 5.60 4.130 11.80 53.10 58.70 64.30 69.90 81.10 97.90 109.10 2.2 00 0.90 0.27 0.43 0.70 5.10 41.30 13.40 54.70 59.80 64.90 70.00 80.20 95.50 105.70 1.8 000 0.71 0.21 0.43 0.64 4.70 41.30 15.00 56.30 61.00 65.70 70.40 79.80 93.90 103.30 1.6 0000 0.56 0.17 0.43 0.60 4.40 41.30 15.50 56.80 61.20 65.60 70.00 78.80 92.00 101.20 1.4 \ PRACTICAL ECONOMIES IN DISTRIBUTION 1171 running, primary wires open on a row of residences. This is, of course, an extreme case, but it is brother to the case of a moderate size load on a side street ; that is, a street that has not been chosen for a primary branch, as in Fig. 2. The practical man says: “Let it cost more, but if any reasonable arrangement can be made, keep the transformers on the main street.” Further, the junction pole at a comer would appear to be the ideal place to feed economically in both directions ; but objection is rightly made that a junction pole is complicated enough without the trans- formers; it is already the most difficult to maintain and renew, and it usually of necessity has a street lamp. This limits the transformer poles to those in the center of the block. There may also be some alleys requiring lines and therefore junction poles, so in a block 500 ft. long there may be only two or three poles available for transformers. Con- sidering that there may be separate light and power transformers required, apparently only one pole per block will be available for a light- ing transformer, unless sufficient economy by using more can be shown to warrant the shortening of the spans and the erection of an additional pole. Then, the practical man goes further — he says: “Transformers, like all other apparatus on a line, are points of trouble,” and he wants as few of them as •possible, in order to maintain continuous service, so that one transformer for every two blocks would be much better. Conclud- ing, he thinks that a secondary system, such as shown in Fig. 4, considering the primary lines running on the “main streets” would be ideal, except that the transformers would have to be moved to the pole next to the corner. So the problem would on the whole appear to be much simplified by the apparent complications of practical conditions. The most economical condition is, of course, when the sum of the fixed capital and main- tenance charges, and the operating charges or cost of the power loss are a minimum. The ; question of increased or decreased consump- tion of current by the lamps might at first be thought to influence this problem, but it has ji no connection. If lamps are supplied rated j at exactly the service voltage of each individ- I ual customer, it then makes no difference what is the range in voltage from the nearest to the most distant service. If lamps are supplied to all alike of the average voltage on the secondary, then the increase in consumption of some will offset the decrease by others, so far as the central station is concerned. The results of the calculations in Table XIV amply justify this assumption and preclude the necessity of further discuss- ing the ethics of the matter. •d Cross <8 fUey # Tro/ys/orrrer — 3y//reS&cor?£/or^ St. Cross t k . St. Cross St. \ Crass A . St \ 1 \ •C: Fig. 4. Ideal Secondary Distribution It is not proposed here to work out econom- ical conditions for all cases but to give an example of the procedure. The case taken will be that which the forenamed practical considerations would point to as normal. Suppose there is an actual combined running load of 30 kw. in two blocks, each 500 ft. long, making a total length of secondary of 1000 ft. (This is very near the condition on the main business street of a small town or an outlying business street of a large city.) The 30 kw. can just be carried by No. 6 wire without over-heating. The question is, what size wire shall be used to supply the load. The charges for the 30 kv-a. transformer will be fixed. The charges for the wire will be fixed for each size regardless of the length of time the load is in use. The operating costs or power loss in the secondary will vary with the length of time the load is in use, and the copper loss of the transformer is included with it, since it varies in exactly the same manner. It is therefore evident that the answer, i.e., the size of wire, will vary with the length of time the load is in use. Since the load does I 1172 GENERAL ELECTRIC REVIEW not come on or go off suddenly or stay at any fixed value, and since it, as well as the time in use, varies throughout the year, a rnore general answer can be obtained by finding the most economical sizes for each period of use from 1 to 10 hours. The charge per kw-hr. for energy losses, like the charge for core loss of a transformer, is open for discussion. It is in reality the total cost of supplying current to the class of customers supplied by the secondary line in question, minus the customer or^ service line and meter charges. The practical way to obtain this, until the whole subject of distri- bution has been given muqh more detailed attention than it has received to the preset time, is to take the average rate per kw-hr. paid by the customers on a secondary main and subtract the average charges per kw-hr. delivered for service and meter costs, the figure of 2 cents per kw-hr. has been used m Table XIV, but is obviously very low for lighting customers. Any increase in this value would tend to increase the economical size of wire. Table XIV needs study, rather than comment. It sums up all that has gone before and shows most conclusively that there ^s an economical size of wire to be used for every condition and that this size is not far different from what the practical man is accustomed to use, but is right in the range of commercial practice. In the particular case in hand it is probably not out of the way to assume that the load would be “ on ” two or three hours per day as the average. The table shows that for this use the best size of secondary is No. U. No. 00 is so close to the same econorny and with better economy if the load should run for four hours, that it is a question indeed it it should not be used. . But while the fact that the most economical size of wire can be exactly determined is ot great interest, the final column is of even greater. It shows that if central stations could afford to abandon their present distri- bution systems and build new ones in accord- ance with these principles of design the question of different lamp voltages for differ- ent customers would be settled. With the most economical size of wire the range o voltage in the hypothetical case considered is only 2.2 per cent or 1.1 per cent from the average. This is such a small amount that it is negligible, as can be seen by reference to any of the standard candle-power curves published by lamp manufacturers. buch curves show a change of only 3.5 per cent in candle-power for a 1 per cent change in voltage. (A very complete discussion of this subject is given in the report of the Lamp Committee to the Pennsylvania Electrie Association, 1913.) . In other words, the central station with lines designed without regard for initial cost and with regard for total economical opera- tion will supply service of which there can be absolutely no complaint. This does not consider the primary losses which might cause different voltages on the different transformers. Similar ealculations can, however, be made for them ^^d it is probable that the results would be similar to those for the secondary and warrant large enough wire to offset the losses. At any rat^ a practical remedy is to get a great enough load density so that the primary lengths from the first to the last transformer on a circuit are short, and it is then found with the “tree” system that there is almost no difference of voltage on the different trans- In Table XIV the load is fixed at 30 kw. It is interesting as another general problem to determine at what load the advantage turns— say from No. 6 to No. 4 wire, when the loads are in use three hours per day. ims is determined in Table XV, which is similar to Table XIV, except that only two sizes of wire are eonsidered, and the tme is • constant at three hours per day, while the load is varied from 1 to 30 kw. Table XV shows plainly that with a loaa of 7)4 kw. or less the No. 6 wire is the rnore economical, while if the load is increased to 10 kw. or above, the No. 4 wire is n^ore iU KW. U1 dUvJVC, ^ ^ j +. economical. It is also interesting to find that . 1 • r*o I economical, lu lo aiou -- . the voltage loss for this maximum economical load is only 1.8 per cent or a variation ol no more than 0.9 per cent from the mean vame | This table should be extended to cover all ■ sizes of wire for aetual use, but the principle is the same and extension here is not con- sidered necessary. _ • j Next, it is interesting to consider the practical matter of replacing small wire with larger when the load has increased enough to require it. This will be done by means of the tables on the original cost of wire and credit for removal of wire when replaced by larger. (Tables VIII and IX.) The case taken for a sample calculation will be that of the erection of No. 6 wire to carry its full capacity of 7)4 kw. and later changing it to No. ^ when the load requires. The question is to find how much time PRACTICAL ECONOMIES IN DISTRIBUTION 1173 must elapse between the original installation and the date of increase, in order to make it economical to erect the No. G wire and later change it to No. 0. The No. 6 wire carrying 73^ kv-a. for three hours per day (Table XV) costs $26.20 per year. A similar secondary of No. 0 wire carrying lYl kv-a. with a 73^-kv-a. transformer costs $27.45 per year, made up as follows: Fixed charges for transformer $14.60 Fixed charges for secondary lines. ... 1 1.80 Transformer copper loss 0.120 kw. Secondary power loss (0.2S4 per cent) 0.0213 kw. Total 0.1413 kw. Cost of 0.1413 kw. 3 hours per day. . 1.05 Total $27.45 Table XV ANNUAL CHARGES AGAINST A THREE-WIRE SECONDARY SYSTEM, 1000 FT. LONG AND CONSISTING OF NO. 6 OR NO. 4 WIRE, SHOWING LOAD POINT AT WHICH ECONOMY TURNS FROM ONE TO THE OTHER. LOAD IN USE 3 HOURS PER DAY AND DISTRIBUTED UNIFORMLY OVER LENGTH OF LINE. 95 PER CENT POWER-FACTOR 224 Volts Delivered; Rate, 2 Cents per Kw-Hr. Trans- former Size Kv-a. 1 Annual Cost Trans- former NO. 6 WIRE NO. 4 WIRE Fixed Charge Total Fixed Charges Operating Cost Total Fixed Charge Total Fixed Charges Operating Cost Total 1.0 $5.20 $7.10 $12.30 $0.75 $13.05 $8.20 $13.40 .$0.60 $14.00 2.0 7.20 1 7.10 14.30 1.20 15.50 8.20 15.40 1.20 16.60 3.0 9.25 7.10 16.35 1.80 18.15 8.20 17.45 1.65 19.10 4.0 11.10 7.10 18.20 2.40 20.60 8.20 19.30 2.25 21.55 5.0 12.10 7.10 19.20 3.00 22.20 8.20 20.30 2.85 23.15 7.5 14.60 7.10 21.70 4.50 26.20 8.20 22.80 3.75 26.55 10.0 19.20 7.10 26.30 6.90 33.20 8.20 27.40 5.55 32.95 15.0 25.45 7.10 32.55 14.40 46.95 8.20 33.65 9.45 43.10 20.0 31.25 7.10 38.35 19.80 58.15 8.20 39.45 14.70 54.15 25.0 37.25 7.10 44.35 29.70 74.05 8.20 45.45 21.00 66.45 30.0 41.30 7.10 48.40 39.30 87.70, 8.20 49.50 24.00 73.50 Table XVI SHOWING DERIVATION OF OPERATING COSTS IN TABLE XV, GIVING OPERATING COST FOR TRANSFORMER AND SECONDARY FOR 1 YEAR WITH USE OF 1 HOUR PER DAY. RATE, 2 CENTS PER KW-HR. TRANSFORMER NO. 6 WIRE POWER LOSS NO. 4 WIRE POWER LOSS Size Kv-a. Copper Loss in Kw. Per Cent Kw. Total Kw. Cost Per Cent Kw. Total Kw. Cost 1.0 0.030 0.15 0.0015 0.0315 $0.25 0.095 0.0010 0.031 $0.20 2.0 0.050 0.30 0.0060 0.056 0.40 0.19 0.0038 0.054 0.40 3.0 0.070 0.45 0.0135 0.083 0.60 0.29 0.0087 0.079 0.55 4.0 0.085 0.61 0.0244 0.109 0.80 0.38 0.0152 0.100 0.75 5.0 0.095 0.76 0.0380 0.133 1.00 0.48 0.0240 0.129 0.95 7.5 0.120 1.14 0.0854 0.205 1.50 0.71 0.0542 0.174 1.25 10.0 0.160 1.52 0.152 0.312 2.30 0.95 0.095 0.2.55 1.85 15.0 0.220 2.28 0.342 0.662 4.80 1.43 0.214 0.434 3.15 20.0 . 0.295 3.03 0.607 0.903 6.60 1.90 0.380 0.675 4.90 25.0 0.355 3.80 0.950 1.355 9.90 2.48 0.620 0.975 7.00 30.0 0.430 4.55* 1.37 1.80 13.10 2.86 0.860 1.090 8.00 1174 GENERAL ELECTRIC REVIEW Therefore the No. 0 wire costs but $1.25 more per year than the No. 6 wire. To change from No. 6 to No. 4 wire and from a 734 kv-a. to a 30 kv-a. transformer involves charges against the expense account (Tables VIII, IX and X) of, Changing wire Changing transformer Total $38.50 To change from a 734 kv-a. to a 30 kv-a. transformer in connection with the No. 0 wire costs $6.00. The difference of these charges to expense is $32.50. This figure is to be compared to the difference of $1.25 in operating costs for the period previous to the change. If $32.50 is divided by $1.25 it is found that unless the smaller load is in use over 26 years before the increase comes, it would have been more economical to erect the No. 0 wire originally. These figures are most startling. Yet they are only extreme in the fact that if any other combination is chosen the period will be longer instead of shorter. They do point out very clearly the necessity of working up tables similar to these, using absolutely the most reliable information at hand, and the extension of all these calculations to cover concentrated and other distributions of mad^ as well as the case of uniformly distributed loads here used. There is another saving that could be made by using several sections of the No. 0 wire together till the load increased to an extent to require separate transformers. This would be equivalent to “closing through_ the secondaries on one of the main streets m rig. 4 and omitting one of the transformers on this street. It could then be sectionalized, in the light of greater information on the load, at a future date. In this connection it is interesting to note that if an extreme load came on at any point the transformer could be placed directly at that point and the load would not affect the general capacity of the secondary in the slightest degree. EFFECT OF ECONOMIES ON COMMERCIAL POLICY The economies that can be practised if the future load is known, as has been shown in the previous sections, are so obvious that the commercial policy that they dictate fol- lows without argument. The engineer can build lines very economically if he is allowed to do it in large sections at a time, and if the curve of the predicted growth of load is known. Therefore, the first step is to take a large section or even one street for three or blocks and determine the growth of load and lay out an economical distribution to cover this; then, send the contract agent to secure the first contract. As soon as this has been done build the whole distribution system and leave it to the contract agent to come up to the mark set for him. He will have no excuses of high service costs or length of time to run service, and will simply have to hustle. Incidentally, he will be reduced from his pres- ent high place as the man who brings the new life blood into the Company and will become simply a hard-working part of the machine. , It would be possible to write at length on ^ the methods for determining the growth of load curve and the sections of a property first to be treated, but that is a detail that can easily be worked out if the general plan is adopted. ! CONCLUSION . , In conclusion, particular attention is drawn ( to the fact that this is but the beginning ■ of the solution of the great problem of aerial distribution. The problem of underground lines needs treatment in a similar manner, only ^ perhaps more urgently, since the investment is ' much greater. The comparison of overhead and underground lines is exactly similar, | only probably even more startling in some of i its results. I Let all concerned in any way in distribution! bear these few facts in mind and make all ^ their work and records conform, so that in ^ the near future the rational solution of this i ever-present problem of the central station^ may be reached. 1175 THE SUCCESSFUL OPERATION OF A TELEPHONE SYSTEM PARALLELING HIGH TENSION POWER LINES By Charles E. Bennett Electrical Engineer, Georgia Railway & Power Company The author describes the successful installation of a telephone line on the towers of the Georgia Railway & Power Company’s Tallulah Falls 110,000-volt transmission line. The fine degree of potential balance between the two wires of the telephone line, necessary for satisfactory communication, was obtained by transposing the wires at every tower and by thorough insulation. Drainage coils are connected between the wires and to ground to relieve the line of low frequency high potential stresses, while high frequency surges are discharged through vacuum type lightning arresters, supplemented by horn gaps. A large number of tests were conducted on this line to determine the effects produced by different arrangements of apparatus, and the results are given in the text and in the accompanying oscillograms. — Editor. The problem of locating private telephone lines on the steel towers of high voltage power lines instead of carrying them on a separate pole line is one that has been under discussion for some time, and many of the larger com- panies have abandoned the use of a telephone line carried on the towers on account of the many troubles occasioned by this arrange- ment. When telephone lines parallel high tension transmission lines they are subjected to influences which may under certain conditions interfere with the proper transmission of speech. This interfering influence is, in all cases, due to the static induction from the high tension transmission line. Under normal operating conditions, i.e., with fairly well balanced three-phase circuits, this influence will be slight; but with abnormal operating conditions on the transmission line, the effect created on a telephone line may increase to such an extent as to become destructive. In addition to these influences the telephone line is subjected to disturbances occasioned by lightning discharges, which, however, are very similar in character .to the effects created by abnormal conditions on the transmission line, such as those occasioned by switching with unbalanced phases, arcing grounds, etc. Under normal operating conditions the effect of the static induction upon the two wires of the telephone line is practically the same, with the result that the two wires will assume a definite potential with regard to earth. With a well insulated and properly transposed metallic line, the potentials of each wire against ground will be nearly alike, and hence there will be no difference of potential between the two wires themselves. .In telephone work, however, even the smallest difference of potential between the wires will create a flow of current through the telephone receiver. This current, being alternating, produces a noise in the receiver which may be loud enough to render talking impossible. The higher the voltage of a transmission line and the closer the telephone line to the trans- mission line, the more prominent will be the noise in the telephone, with a slightly un- balanced telephone line. As this disturbing current is due to a difference of potential. Fig. 1. Photograph of a Standard Line Tower of the Georgia Railway 85 Power Co., Showing the Power Wires and the Telephone Wires and Their Transposition it is obvious that the noise in the receiver is in a measure independent of the absolute value of the voltage of each line to ground, and that it cannot be eliminated unless the voltage on both wires be made exactly alike. This condition, which is termed “balanced,” is realized by properly insulating and trans- 1176 GENERAL ELECTRIC REVIEW posing the telephone wires. The larger the number of transpositions per mile, the more nearly will the potential on the wires be equalized ; and the better the insulation of the lines, the less will there be a chance for a Fig. 2. Dimensioned Drawing Showing the Location of the Power and Telephone Wires on Tower “leak” (to ground), causing a drop of po- tential on that particular wire, with the sub- sequent result of unbalancing the line and rendering it noisy. From the above it will be seen that so tar as the noise of the line is concerned it can be kept within any limit, provided the telephone line is properly transposed and well insulated. On the other hand, it will be seen that the existing potential between telephone wires and ground, by reaching high potential values, may not necessarily impair the transmission of speech, but will seriously strain the insulation of the instruments and make their use dangerous. *The transmission system of the Georgia Railway & Power Company consists of a double 4/0 circuit from Tallulah Falls to Atlanta, a distance of 90 miles, with double 2/0 circuits extending northward to Lindale -and southward to Newnan from Atlanta. The line from Atlanta to Lindale is about 75 miles in length, while the line to Newnan is about 40 miles. All of these lines are operated at from 110,000 volts to 120,000 volts at 60 cycles. This system is paralleled by a single two- wire telephone circuit located about 10 feet (diagonally) below the bottom^ power con- ductor and carried on the horizontal angle iron which forms a part of the tower. The original layout was made with pm insulators of 11,000-volt design, but the many induced surges or steep front waves punc- tured them with such remarkable rapidity that is was decided more insulation or punc- ture-proof quality — was necessary. From a construction standpoint it was found most Fig. 3. Telephone Booth Connected, Showing Discon- necting Switch and Horn Gaps convenient to re-insulate the line with sus- pension disks. It has been found that one suspension unit will withstand most of the *A full description of Tallulah development of tte Georgia Railway & Power Company will be found m the June and July, 1914, issues of the Review. ( I i THE SUCCESSFUL OPERATION OF A TELEPHONE SYSTEM 1177 electrical stresses, but in order to secure perfect continuity, two were used. The telephone wires are spaced at three-foot centers, the wire itself being No. 4 copper clad, of 30 per cent conductivity, drawn from 400 lb. ingots in lengths of about half a mile to minimize the number of joints. All joints are made with special “figure eight” splicing- sleeves about nine inches long. The reason for using wire of this size was that it might be strung parallel to the power conductors and still be able to withstand a loading of about three-quarters of an inch of ice without exceeding the elastic limit. Transpositions are made on all towers, which average about nine or ten to the mile. The wires are supported by suspension insu- lators on each side of the tower, two insulators being used at each point of support, and transpositions made with long and short loops between the insulators located on Fig. 4. Front View of the Telephone and Its Protective Equipment as Installed opposite sides of the tower. The transposi- tions are all made with the same clockwise twist, so as to make a running transposition. At intervals of four miles, telephone booths are located. They are simply frame buildings of the knockdown type, about four feet square. with a 22,000-volt switch of special con- struction on the roof. This switch is made with horn gaps to ground, set at approxi- mately three-eights of an inch, and the two poles are operated simultaneously by means of a hand lever inside the booth. An insulated Fig. 5. Side View of the Apparatus shown in Fig. 4 platform is provided in the booth on which the operator may stand while throwing the switch that cuts the station in multiple with the line. This switch is opened as soon as the operator finishes his conversation. In otherwords, the telephones in the booths are only connected to the line during the time they are in actual use, and the equipment is therefore not endangered by surges or light- ning along the line, nor is the talking impaired by having a number of stations in multiple. At numerous places, convenient to working crews, the telephone line is sectionalized to facilitate the location of trouble, and at the intermediate substations 22,000-volt double- pole switches are used for this purpose. Specially designed receiving and sending equipment is located at the power house and substations, which is standard for all stations. It comprises a horn gap to ground mounted on a bracket at the entrance to the building, and a 50-turn air choke coil; the line then 1178 GENERAL ELECTRIC REVIEW passing through 20, 000- volt entrance bushings to the interior, where a specially designed double-pole fused switch is inserted. From this switch the line is connected through a horn gap and vacuum arrester to a one to one Fig. 6. Connection Diagram of a Telephone Located at a Station Type Y-109-B insulating transformer, which in turn is connected to the telephone instru- ment. The usual way to relieve telephone lines of high potential is to bridge a so-called bleeding or drainage coil across the line. Considerable experimenting was done with drainage coils on this line, and it was found that the ordinary type was not of sufficient carrying capacity. Sizes of 1 kw., 3.5 kw., and 5 kw. were soon destroyed and then a 15 kw. 2200-1100/- 220-110 Type H lighting transformer was installed, which has given very good results. The telephone line is connected to the terminals of the 2200-volt winding and the middle point of this winding connected to ground. The secondaries are then left open circuited. This arrangement will offer a high inductive resistance to the talking currents, but a very low ohmic and negligible inductive resistance to the flow of current from the two wires to ground, owing to the fact that the simultaneous discharge from the wires through the coils to ground will neutralize the mag- netic effects. This bleeding coil becomes an effective outlet for all low frequency currents indueed from the transmission line. Sudden changes in the transmission line, like switching, arcing grounds, lightning discharges, etc., have all the same effect upon a balanced telephone line, namely, to charge the two wires suddenly to a very high potential. Owing to the rapidity, or in other words, the high frequency with which these charges are induced on a telephone line, the small inductance of the bleeding coil, no matter how accurately balanced, is not sufficient to prevent these charges from flowing to ground, and therefore another , apparatus is required which will act as an ' outlet for these particular disturbances, j It has been found that the vacuum type ! arrester is best suited for this service. This arrester consists of two electrodes enclosed in a partially exhausted metal tube and connected across the line. This arrester is very sensitive to charges of high fre- quency and will begin to discharge freely Fig. Line Wires vvwwww One to One AMVWWVA, Transformer 7. Connection Diagram of a Telephone Located in a Booth as soon as the voltage on the lines reaches about 300 volts. The peeffiiar advantages of these arresters lie in the fact that the dis- charge occurs gradually instead of dis- ruptively, and these discharges have no ill THE SUCCESSFUL OPERATION OF A TELEPHONE SYSTEM 1179 effect upon the electrodes, leaving the line perfectly clean and balanced. It is advis- able to place fuses in circuit to protect this arrester from destruction should the dis- charges, for some reason or other, exceed the safe value for which it is built. The large gaps or horns, being set at three-eighths of an inch, form a sort of rough protection to all the equipment, should it be subjected to very high momentary potentials. The station equipment of this system was tested by impressing 60,000 volts on it, which resulted only in the blowing of a fuse. Calculations were made to determine the potential of the line against ground by use of the following formula, which is offered for those interested in figuring out new lines: Let A, B and C represent the three con- ductors of a three-phase power circuit, and 5 and T the conductors of the telephone circuit. Let Eo be the voltage between each wire of the power circuit and ground. Let r = radius of power conductor in inches. a = distance in inches between A and ground. (Av.) b = distance in inches between B and ground. (Av.) c = distance in inches between C and ground. (Av.) 5 = distance in inches between 5 and ground. (Av.) t = distance in inches between T and ground. (Av.) Then , 2a — r for s in the above formulae. (From Ferguson’s “Elements of Electrical Transmission.’’) By the use of this formula a theoretical induced potential of 5700 volts for the above line was obtained. Tests have subsequently been made to ascertain the actual value of this induced potential. With one power line energized (the power conductors being on nine-foot centers in a vertical plane), an induced potential reading of 5600 volts from line to ground was ob- tained. As the high-voltage system has its neutral grounding at the power house, the voltage between each power line and ground was, of course, 63,500 volts. The current in the drainage coil neutral was 4.47 amperes at the time the above readings were obtained. In order to ascertain the maximum poten- tials that could be induced on this line, the following tests were made and results ob- tained as indicated: With the top wire of one power circuit charged, an induced potential reading of 5100 volts was obtained between telephone line and ground. With the middle wire of one power circuit charged, the induced potential reading was found to be 7200 volts. With the bottom wire of one power circuit charged, the induced potential reading was found to be 10,000 volts. With the top wire of each power circuit charged, the induced potential reading was found to be 9300 volts. With the middle wire of each power circuit charged, the induced potential reading was found to be 13,100 volts. With the bottom wire of each power circuit charged, the induced potential reading was found to be 18,200 volts. Eq ec = Eo log log log log 5-f-5 b — s 2b — s r C + 5 c — s 2c — r and ^s = Vea^+eb‘‘+eJ‘— (eaeb+eaec+ebec) where e is equal to potential of wire 5 against ground . Potential of wire 7 against ground may be found by a similar process, substituting t All of the above readings were taken with a 100 to 1 potential transformer and indi- cating voltmeter, the drainage coil being disconnected. Tests were then made with the drainage coils connected across the line at Gainesville and Atlanta and three wires of north circuit excited. Figures give current in ground connection of drainage coils. Line voltage 110,000 50,000 Current in ground connection of drainage coil at Atlanta, Ga. 1.0 amp. 0.6 amp. Current in ground connection of drainage coil at Gainesville, Ga 2.6 amp. 1.15 amp. Current in ground connection of drainage coil at Gainesville with drainage coil at Atlanta disconnected from line 3.55 amp. 1.50 amp. 1180 GENERAL ELECTRIC REVIEW Fig. 8. Upper Curve: Line Potential Phase 1. Lower Curve: Current in Ground Connection of Drainage Coil Fig. 9. Upper Curve: Line Potential Phase 3. Lower Curve: Current in Ground Connection of Drainage Coil Fig. 10. Upper Curve: Current in One Wire of Telephone Line 0.8 amp. Middle Curve: Current in Other Wire of Telephone Line 0.8 amp. Lower Curve: Cur- rent in Ground Connection of Drainage Coil 1.6 amp. Record taken while Lightning Arresters were being charged X f' V / i ‘ : ^ / Fig. 11. Upper Curve: Line Potential Phase 2. Lower Curve: Current in Ground Connection of Drainage Coil f / '' ■A J / \ 1 / -t . ■' * f • A-/ A ./ A\ / V' ■ U '/ \ ,/ ■ Fig. 12. Upper Curve: Line Potential Phase 3 to Ground 63,500 volts. Lower Curve: Induced Potential on Telephone Line 3500 volts \ ...A^ ^ \\ \ ■ V * A i : -9 ^ A . A / A / V; / ■ V -T. A. J Fig. 13. Upper Curve: Voltage on Phase 3 of Power Line, while Arresters were being charged. Lower Curve: Current in Groimd Connection of Drainage Coil on Telephone Line OSCILLOGRAPH RECORDS OF INDUCED WAVES THE SUCCESSFUL OPERATION OF A TELEPHONE SYSTEM 1 181 Fig. 14. Upper Curve: Potential of Phase 3 Power Line to Ground. Lower Curve: Induced Potential on Telephone Circuit 5600 volts The voltage from teleph^e line to ground with three wires of the north circuit excited to the line voltage shown, and with drainage coils connected at both Atlanta and Gaines- ville, was as follows: Line voltage 110,000 volts 50,000 volts At Atlanta 0.0 volts 0.0 volts At Gainesville 31.0 volts 18.0 volts At Tallulah 234.0 volts 100.0 volts The following figures give the voltage from telephone line to ground with three wires of the north circuit excited to the line voltage shown, and drainage coil connected at Gainesville but disconnected at Atlanta: Line voltage • 110,000 volts 50,000 volts At Atlanta 158.0 volts 70.0 volts At Gainesville 41.0 volts 20.0 volts At Tallulah 240.0 volts 105.0 volts Three drainage coils are now installed on the Atlanta-Tallulah line, one each at Gaines- ville, Tallulah and Atlanta, and the talking over the line is excellent. If the following principles are adhered to in the construction of a telephone line, paralleling a high tension line, successful operation should follow: 1 . The telephone line should be thoroughly insulated from ground, allowing a liberal factor of safety, as insulation is paramount. Fig. 15. North Circuit Charged. Voltage Curve: Voltage between Telephone Line and Ground 5100 volts Fig. 16.* Potential Wave on Telephone Line with One Circuit of Power Line Charged. Voltage between Tele- phone and Ground 4500 volts 2. The line should be constructed with as few joints as possible. 3. The ohmic resistance of the line should be as low as possible, so as not to decrease the intensity of the talking waves. 4. A perfect potential balance should be obtained between wires. 5. Transposition should be made at every tower, so as to maintain equal potential between the two telephone wires and ground. * From this oscillograph record, which was taken on a tele- phone line strung parallel to 110,000-volt power line for a distance of fifty miles but carried on a separate pole line, it can be seen that the number of harmonics is considerably greater than when telephone line is strung on towers carrying power lines. 1182 GENERAL ELECTRIC REVIEW THE VENTILATION OF ALLEGHENY SUMMIT TUNNEL, VIRGINIAN RAILWAY By F. F. Harrington Engineer of Structures, The Virginian Railway Company The ventilating equipment for the Allegheny Summit tunnel is located at the eastern portal, and was installed for the purpose of driving the smoke and gases emitted by engines on the upgrade or westbound trip ahead of the train, thus relieving the train crew from the disagreeable and unhealthful effects. Trains in the opposite direction coast on the downgrade, with the locomotive fires banked, and therefore no provision has been made for ventilating the tunnel during the passage of these trains. The plant will ultimately be automatic in operation, and the control apparatus has been built accordingly, although the track circuits have not yet been installed. — Editor. Allegheny Summit Tunnel is located on the Virginian Railtvay, 277.6 miles from Norfolk, Va., between Yellow Sulphur and Merri- mac. Princeton, W. Va., 340 miles from Norfolk, Va., is the assembling yard for coal mined at points west and north along the main line and on branch lines. At this point long trains are made up and sent through to tidewater. The maximum eastbound grade from Prince- ton to Sewalls Point, with two exceptions, is 0.2 per cent compensated for curvature, and the maximum westbound grade between the same two points, with two exceptions, is 0.6 per cent compensated. The exceptions are at Onley Gap and Allegheny Summit, located respectively 3 and 62 miles east of Princeton. A single engine hauls 80 loaded cars of 100,000 pounds capacity from Princeton yard to tidewater without assistance, and the same engine hauls an equal number of empty cars against westbound grades, except at the summits mentioned above. At Allegheny Summit a single pusher engine is used between Whitethorne and Fagg, hauling 80 loaded coal cars eastbound on a maximum 0.6 per cent compensated grade from Whitethorne to the summit, a distance of ten miles, and 80 empty coal cars westbound on a maximum 1.5 per cent compensated grade from Fagg to the summit, a distance of seven miles. A typical cross section of Allegheny Tunnel is shown in Fig. 3. The alignment is tangent except for about 200 feet at the east end, which is on a two-degree curve, and the grade is 1.22 per cent except for about 1000 feet at the west end, which is on a vertical curve. The total length between portals is 5176 feet and the cross sectional area is 375 square feet. It was lined with timber throughout when constructed in 1908, and afterwards concrete footings were constructed and two sections 50 ft. and 248 ft. long were lined with concrete. The remainder of the tunnel was lined with concrete last year, and as this lining contracted the sec- tional area and increased the heat consider- ably, the ventilation of the tunnel was author- ized by the management to improve the operating conditions. A brief description of the ventilating plant follows: The method employed for the ventilation of the tunnel is covered by patents held by Chas. S. Churchill and Chas. C. Wentworth, of Roanoke, Va., who furnished the general plans and specifications for the nozzle and the necessary data for obtaining bids from the fan manufacturers. The plant is illustrated by the accompanying photographs and plans. Figs. 1, 2, and 3, and is located at and con- nected to the east end of the tunnel. It con- sists briefly of two large fans operated by : electric motors, one set being located on each side of the track. These fans force air through sheet iron ducts between the fans and the , nozzle, and then through the nozzle, the reduced opening of which gives a high veloeity to the air through the tunnel. The smoke and gases from the westbound engines on the i ascending grade are therefore driven ahead, thus cleaning the tunnel and making it cool and comfortable for the trainmen. The east- bound engines, drifting on the descending j grade, emit little smoke and gases, and it is j not necessary to operate the fans; although j this is occasionally done to clear the tunnel after their passage. The ventilating plant was designed to deliver a volume of 590,000 cu. ft. of air per minute through the nozzle, whieh has an j outlet area of 74 sq. ft.; this corresponding to a veloeity of air in the tunnel of about 1600 j ft. per minute. A thorough investigation I was made of the relative economy of operation ll by steam and by electricity, and of the con- I struction of a power plant and the purchase of I power; it was finally decided to use electric | current and purchase power from the Appala- chian Power Company, which operates in that locality. VENTILATION OF ALLEGHENY SUMMIT TUNNEL 1183 The Appalachian Power Company was organized in 1911 for the purpose of develop- ing the water power of New River and dis- tributing it electrically throughout southwest Virginia and southern West Virginia. It furnishes electric power for the operation of coal mines and other industrial plants in those districts. The high tension transmission lines operate at 88,000 volts and feed sub- stations at various points, where the voltage is lowered for distribution through secondary lines to the various power consumers. A special high tension transmission line was were manufactured by the B. F. Sturtevant Company, Hyde Park, Mass. They are con- structed of in. steel, IIG^^ in. in diameter, 8034 width, and deliver through the nozzle 295,000 cu. ft. of air per minute when operating at 195 r.p.m. The induction motors are of the slip-ring type, rated 300 h.p., three-phase, 60-cycle, 2200-volt, 514-r.p.m., and drive the fans by means of Morse silent chains, spaced 5 ft. 6 in. on centers. The switchboard is arranged with auto- matic starters for operating the motors from track circuits, but the track circuits have not View Showing Position of Ventilating Equipment and Tunnel Portal built from Radford, Va., to the east portal of the Allegheny Summit Tunnel, where a sub- station was constructed which lowers the voltage to 2300 volts for the operation of the ventilating plant. The contract for electric power provides for a primary charge per kilo- watt of maximum demand, and a secondary charge for current consumed based on a slid- ing scale. The maximum demand and the current consumed are determined by suitable meters, and a minimum annual charge is made regardless of the power consumption. The fans are of the multivane type, with single inlet and top horizontal discharge, and been installed. The object of the automatic control is to make the plant more reliable and to reduce the cost of operation. The switchboard consists of one main line control panel and two automatic motor starting panels mounted on pipe supports. The main line control panel consists of two three-pole single-throw oil switches with auto- matic overload and no-voltage release trip- ping coils. The incoming line feeds these switches and each controls the current to one of the motor starting panels. On this panel is also mounted an indicating voltmeter and ammeter, which shows the total input to both 1184 GENERAL ELECTRIC REVIEW motors. The motor starting panels each com- prise two current limit relays, one main line double-pole oil emersed contractor, and five double-pole contractors which cut out the resistance in the secondary of the motors in balanced steps and thus give equal fluctua- tions of current in each step. All of the con- trol apparatus is located in the motor house on the north side of the track, and the two three-wire lead-sheathed cables to the motors on south side of track are installed under- ground in 6-in. conduit. The motors are protected from lightning by choke coils and multigap type lightning arresters. sq. ft. measured on the projection at right angles to the axis of tunnel. The front of the nozzle is provided with openings to which the air ducts from the fan housings are connected. The nozzle is thoroughly braced and is air tight. It was manufactured and erected by the Roanoke Bridge Company, Roanoke, Va. The air ducts between the fan housing and the nozzle are made of 3^-in. sheet steel and braced with angle irons. Particular attention was given to the construction of these ducts and the fan housing in order to prevent exces- sive vibration from the operation of the fans. Side View of Ventilating Equipment The blowing nozzle is constructed of steel, with the exception of the inner lining which is of heart long leaf yellow pine, tongued and grooved and bolted to steel girts. It is made to conform to the dimensions of the tunnel where it connects to the portal, and is 50 ft. long outside the tunnel. The inner lining is also of the same form and dimensions as the tunnel; but the outer lining, made of j/g-in. steel plates, is enlarged in the form of a coni- cal surface with cross sections parallel to the inner lining from a point 5 feet from the portal to the face of the nozzle. The minimum distance between the inner and outer linings at a point 10 ft. from the portal is 1134 in.; and the area of the contracted opening is 74 The foundations for the ventilating plant are of concrete and the motor houses are of reinforced concrete and brick. In order to save expense the floors of the motor houses were placed about 8 ft. above the top of the rail, and concrete stairways and lookout platforms are provided for the convenience of the operator. The motor house on the north side of the track is larger than that on the south side, in order to provide room for the switchboard for both motors. The foundations and motor houses were con- structed in accordance with plans furnished by the Railway Company. The ventilating plant was put in operation April 1, 1914. Anemometer tests were VENTILATION OF ALLEGHENY SUMMIT TUNNEL 1185 made, which showed an average air velocity in excess of the contract requirements and an actual power consumption of about 600 h.p. Train tests indicated that a speed of from 14 to 15 miles per hour could be attained, with the smoke driven ahead of the engines, thus giving good ventilation in the tunnel under ordinary operating conditions. A bulletin has therefore been issued to limit the speed of westbound trains to 14 miles per hour, and at this rate the regular freight trains will not be required to slow down in going through the tunnel. The fans operate only for westbound trains, and the time of running is ordinarily less than ten minutes. A train dispatcher’s telephone is installed in the motor house to enable the operator to keep in touch with the train movements in both directions and to communicate with the Appalachian Power Company at Bluefield, through the dis- patcher’s office at Princeton, in case of cur- rent failure or for any other reason. The total cost of the ventilating plant was about $30,000. Sectional Views of Nozzle and its Relation to Tunnel GENERAL ELECTRIC REVIEW THE ELECTRIC FIELD By F. W. Peek, Jr. Consulting Engineer, General Electric Company All electrical design is dependent the'amS tSrfndVctivt'fff ects r?he""eKostaB^ e.ec.c «e.a.-E..oK. In order that electrical energy may flow along a conductor, energy must be stored in the space surrounding the conductor. This energy must be stored in two forms; electro- magnetic and electrostatic. _ The electromagnetic energy is evinced by the action of the resulting stresses; for instance, the repulsion between two parallel wires carrying current, the attraction o suspended piece of iron when brought near the^ wires, or, better yet, if the wires are brought up through a plane of insulating material, _ and this plane is dusted with iron filings, and gently tapped, the filings will form in eccentric circles about the conductors. These circles picture the direction of the magnetic lines of force of the magnetic field. This only exists when current is flow- ing in the conductor. Fig. 1 is an experimental plot of such a field made by placing a sheet of blueprint paper on the plane and exposing to sunlight after the filings had arranged thein- selves. Such plots of magnetic fields are quite familiar to most of us. In designing the magnetic circuits in apparatus, it is gen- erally of importance to lay them out in such a way that the magnetic flux is uniformly dis- tributed. If the lines are over- crowded in one place it may mean local loss and heating. If high voltage is placed be- tween two conductors there will be an attraction between them. A suspended piece of dielectric, as a glass fiber, will tend to turn in definite directions at different points around the conducts. If the conductors are brought up through an insulating plane, as before, and the plane is dusted with a dielectric, such as mica filings, and tapped, the filings will fom in arcs of circles beginning on one condimtor and ending on the other conductor. Such an experimental plot is shown in Fig. . ® dielectric field is thus made as tangible as the magnetie field. Insulation breaks down at any point when the dielectric flux density at that point exceeds a given definite value. In high-voltage apparatus it is theretore Fig 1. A Photograph of an Iron-Filing Map of the Magnetic Lines of Force about Two Cylinders * Fig. 2 was made at 10,000 volts. The conductors were 3 cm. in diameter and were at a spacing of 9 cm. between centers. Fig. 2. A Photograph of a Mica-Filing Map of the Dielectric Lines of Force between Two Cylinders THE ELECTRIC FIELD 1187 important to so design the dielectric circuit that the flux density is uniform or in propor- tion to the breakdown density of the insu- lations at the different parts of the circuit. In Fig. 2, the density is greatest at the conductor surface and break-down will occur there first. The dielectric flux density at any point is proportional to the volts per cm. (or voltage gradient) at that point. The strength of insulation is generally expressed in terms of the voltage gradient. Fig. 3 is the superposition of Figs. 1 and 2. It represents graphically the magnetic and dielectric fields in the space surrounding two conductors which are carrying energy. The power is a function of the product of these fields and the angle between them. Fig. 4 is the mathematical or exact plot corresponding to Fig. 3. In comparing Figs. 3 and 4 only the general direction and relative density of the fields at different Fig. 3. A Photographic Superposition of Figs. 1 and 2 Representing the Magnetic and Dielectric Fields in the Space Surrounding two Conductors which are Carrying Energy Fig. 4. A Mathematical Plot of Fields shown in Fig. 3 points can be considered. The actual number of lines in Fig. 3 have no definite meaning. The dielectric lines of force in Fig. 4 are drawn so that one twenty-fourth of the total flux is included between any two adjacent lines. Due to the dielectric field, points in space surrounding the conductors have defi- nite potentials. If points of a given potential are connected together, a cylindrical surface is formed about the conductor; this surface is called an equipotential surface. Thus, in Fig. 4, the circles represent equipotential surfaces. As a matter of fact, the intersection of an equipotential surface by a plane at right angles to a conductor coincides with a magnetic line of force. The circles of Fig. 4, then, are the plot of the equipotential sur- faces and also of the magnetic lines of force. The equipotential surfaces are drawn so that one-twentieth of the voltage is between any two surfaces. For example: If 10,000 volts is placed between the two con- ductors, one conductor is at + 5000 volts, the other at — 5000 volts. The circle ( oo radius) mid- way between is at 0. The poten- tials in space on the different equipotential surfaces, starting at the positive conductor, are + 5000, +4500, +4000, +3500, + 3000, +2500, +2000, +1500, + 1000, +500, 0, -500, -1000, -1500, -2000, -2500, -3000, -3500, -4000, -4500 and — 5000. A very thin insulated metal cylinder may be placed around an equipotential surface without disturbing the field. If this conducting sheet is con- nected to a source of potential equal to the potential of the sur- face which it surrounds, the field is still undisturbed. The original conductor may now be removed without disturbing the outer field.. The dielectric lines of force and the equipotential sur- faces are at right angles at the points of intersection. The di- electric lines always leave the conductor surfaces at right angles. The equipotential cir- cles have their centers on the line passing through the con- ductor centers; the dielectric force circles have their centers on the neutral line. 118S The dielectric and magnetic fields may be treated in a very similar way. For instance, to establish a magnetic field a mapeto- motive force is necessary; to establish a dielectric field an electromotive force is necessary. If in a magnetic circuit the same flux passes through varying cross sections, the magnetomotive force will not divide up equally between equal lengths in the circum Where the lines are crowded magnetomotive force per unit length of the magnetic circuit will be greater than where the lines are not crowded toother. i he magnetomotive force per unit length of the magnetic circuit is called the magnetizing force. Likewise, for the dielectric circuit where the dielectric flux density is high a greater part of the electromotive force per unit length of circuit is required than at parts GENERAL ELECTRIC REVIEW where the flux density is low. Electromotive force or voltage per unit length of dielectric circuit is called electrifying force, or voltage gradient. If iron or material of high pemiea- bility is placed in a magnetic circuit the flux is increased for a given magnetomotive force. If there is an air gap in the circuit the magnet- izing force is much greater in the air than m the iron. If a material of high specific capacity or permittivity, as glass, is placed in the dielectric circuit, the dielectric flux is in- creased. If there is a gap of low permittivity, as air, in the circuit, the voltage gradient is much greater in the air than in the gl^s. The dielectric circuit must always be con- sidered in the proper design of high-voltage apparatus. The fields conductors may be plotted with mica filing in the same way. SOME NOTES ON BUS AND SWITCH COMPARTMENTS FOR POWER STATIONS By Emil Bern SW.TCBBOAKD ENC.NBEK.NC DEPARTMENT, GENERAL EL.CIE.C COMPANV The bus and switch compartments of a study*^ q^s^artmle incorporates a description ; system- and therefore their design Serves the niost fundamental rules ^ of certain important advances that tiave^^e^ce^tly fire-proof^bus and switch compartments; and it also , dLJfies™he'dfffSent“^^^^^^^ designs and discusses their relative merits.-EDiTOR. Large capacity power stations have out- grown the switchboard having switches con- Lctions and buses supported on the board proper as the electrically operated switches of large capacity are usually installed in the posi- tion which is most convenient with respect to high potential buses and heavy connections. The buses and all parts of the switching _sy stern must be most carefully protected to avoid short circuits; and at the same time they should be designed to withstand the abnormal conditions caused by short circuits or overloads, hor heavy currents at medium high voltages, the objects just named seem to be best accom- plished by installing the buses, connections and switches in masonry compartments._ The purpose of this article is to discuss briefly certain typical designs of fire-proof compartments for switching apparatus, based on the familiar type of oil switch illustrated in Fig. 1 and Fig. 2. The construction of the two types of switches is the same, except or the arrangement of the oil vessels and their contacts. In both constructions the walls of the cells are built of bnck or concrete and the top and bottom of soapstone slabs. W hiie not shown in the illustrations, there are flame-proof doors in front of the cells. These < are hung from steel work at the top so_ as to . swing open easily in case of an explosion in the cell. ^'^Concrete has gained in favor over bnck - for masonry work and therefore the mapnty of today’s bus and switch compartments are built of concrete. In some cases complete < forms are made, usually of wood, and the ^ whole compartment poured. This procedure | gives the most substantial construction, it is more often the case, however, that concrete slabs are used set in cement. When this scheme of construction is used the compart- ment is so designed that w^^^ a small number of different size slabs. Fairly accurate work can be obtained by this method, and the cost of forms is reduced wTere^the design of the compartment is not too complicated, and where the desired dimensions agree with the size of bncks available, brick construction is usually the most convenient for smaller compartments This is especially true in cities where concre work cannot be handled conveniently on 1189 BUS AND SWITCH COMPARTMENTS FOR POWER STATIONS ig. 1. Bottom-Connected Oil Switch. Parallel Arranged Contact; ■apacities and conditions. From the values iven in the table any bus compartment can Fig. 2. Bottom-Connected Oil Switch. Tandem Arranged Contacts clamps for attaching the connections to the buses; and also to take into account mechan- ical clearance and convenience in installing the material. The compartment shelves are usually made about two inches thick; but sometimes are thicker when made of con- crete for large compartments. The thickness of the barriers between phases is determined by the mechanical strength of the structure; this also applies to the thickness of compart- ment walls. In brick compartments there is very little choice, for the dimensions of the brick usually predetermine them. In con- crete structures the thickness of the walls and barriers is generally from three to four inches. Disconnecting Switches Several different types of disconnecting switches are used. For voltages up to 3300 they are generally mounted on marble bases without insulators. When provided with insulators they are usually mounted on slate or steel bases. The steel base has the advan- tage of occupying small space, it preserves the adjustment of the switch, and is less liable ^ to injury during shipment and con- struction work. Fig. 3 shows several methods of mounting disconnecting switches in com- partments. account of lack of space. The shelves or partitions are then usually made of soapstone or slate, but sometimes of concrete. Often- times bricks vary considerably in size, which makes accurate work very expensive since close adherence to certain dimensions often ' necessitates cutting the bricks or making abnormal bonds. For this reason it is usually more satisfactory to cut and drill the buses and connections when installing them than to make them up beforehand from the com- partment drawings. The design of fire-proof bus compartments is usually such as to enclose or to separate the i different phases of the buses and connections by masonry. The masonry portions of the ; compartments must be considered as being at ■ ground potential; therefore, the general dimensions of the compartments are deter- ; mined primarily by the minimum allowable ■ distance between live parts and ground for ' the voltages used. This rule has already I determined the most important dimensions of bus supports and the switching apparatus. Fig. 3 shows sections of typical bus com- partments with their fundamental dimensions , for different voltages based on average easily be designed. It is, of course, necessary to first determine the dimensions of switches, busbar supports, buses, connections and the 1190 GENERAL ELECTRIC REVIEW Volts A Ground Dist. B C Volts A Ground Dist. B C 2.500 6,600 15.000 22.000 35,000 2" 3" ZV 6" 10" 9" lor 12" 20" 25" 12" 14" 15" 20" 25" 45.000 70.000 90.000 110,000 14" 21" 27" 33" 34" 45" 56" 72" 34" 45" 56" 72" to the bus, the busbars are usually arranged horizontally, i.e. laid on side. _ The available space for the switching equipment determines to a great extent the design of the compartments. Sometimes the buses are located on the floor below the oil switches, which construction is very desirable when using bottom-connected switches, pro- vided the disconnecting switches between the oil switches and the bus are located so that a person operating them can see whether the oil switch is open or closed. To meet this condition, and thus eliminate the danger of operating the wrong disconnecting switch, they may be installed in a sub-compartment in the oil-switch cell just above the floor. A door for this sub-compartment, of the same width as the oil switch, helps to determine without question which disconnecting switch- es belongs to a certain oil switch. Fig. 3. Dimensioned Sectional Views of Typical Bus Compartments for Various Voltages Disconnecting switches are occasionally used for isolating horizontal sections of the bus, andin this case are located in the compart- ments in a straight line with the bus, with the insulators secured either to the shelf or to the back wall of the compart- ment. If the bus is heavy enough and is securely anchored, it can serve as the hinge and clip for the switch, thus simplifying the construction somewhat. Whatever type of switch is used, care must be taken to see that Pfoper clearance to ground is obtained with the blade in any position. To withstand, mechanically, stresses incidental to momentary short circuit and heavy overloads, it is necessary that the buses and connections be securely anchored, while at the same time pro- vision must be made for the expansion and the contraction of long buses due to temperature changes. 1 he bus supports may be secured either to the shelves or to the back wall of the compart- ment, but must be located near openings so as to be accessible for cleaning and inspec- tion. For convenience in joining connections Buses in the Floor Fig. 4 shows a simple arrangement of oil switches with sub-compartments, discon- necting switches and the buses installed in the floor. The buses are supported and are accessible from below. Earners of asbestos lumber or similar matenal may be provided between the connections of different phases, if considered necessary. If disconnecting switches are required on one side of the oil switch only, the parallel arranged oil switch ‘ may be used and installed against the wall, ^ as shown in section A, Fig. 4. With discon- Sus Section Oi/Stvitcn L- 1 ' 1; 1 ' ■> 1 1 i| !i ,1 1 i' I* Li ! ' li 1' 1 i 'll <1 1 1 'T'^ ft iCH n * )Rr| flUi Ir d n ro Generator Thonsformer Feeder D/sconnectinf Siv/Cch • Gases - Fig. 4. Two Arrangements for Oil Switches wi^ DisconnecUng Switch Sub-Compartments and with Buses in the Floor necting switches on both sides of oi switch, it is possible to arrange all of them n the sub-compartments by providing spact back of the oil switch for operating them, o by using the tandem arranged switch as showi BUS AND SWITCH COMPARTMENTS FOR POWER STATIONS 1191 in section B, Fig. 4. With the first arrange- ment, a bus-section oil switch may be installed directly over the buses; while with the tandem arranged switches, the construction can be materially improved and made more compact by locating the bus-section oil switch in line with the other switches. elements cannot be made under the floor. A very compact construction of this kind is shown in Fig. 6, which provides for bus-tie, transformer, and generator switches connected Buses in Compartments Below Oil Switch Floor Fig. 5 shows different features of a construction with bus com- partments on the floor below the oil switches, and with disconnecting switches arranged in sub-com- partments. A represents a bus- section switch; and B, a bus-tie, generator, or transformer switch connected according to the dia- gram. C shows the application of the tandem arranged oil switch to the same conditions as A and B. If the room containing the bus compartments is used for other purposes also, it is advisable to provide doors between the barriers to guard against accidental contact with the connections. Bus and Switch Compartments on Same Floor Fig. 5. Standard Arrangements for OU Switches with Disconnecting Switch Sub- Compartments and with Bus Compartments beneath the floor It is often necessary to install the bus and switch compartments on the same floor, and in some cases this floor is immedi- ately above the transformer compartments, so that the connections between the different the same as in Fig. 5. This construction requires, however, a set of disconnecting switches arranged horizontally in the buses. Passages through the compartments can easily B C Fig. 6. Arrangements wherein the Switch and Bus Equipments are located on the floor. Electrically these connections are identical to those of Fig. 5 1192 GENERAL ELECTRIC REVIEW 1 ' flBSSoge Oi/ Smtc/) Bassege — : » : ~ 9 \ . T : 1 y 1 i 1 1 1 nJ:\i -i-'- _ 4.L n --4 , be provided under the main bus, as indicated in the Figure. Another construc- tion providing the same electrical con- nections is shown in Fig. 7. Here false floors must be pro- vided over the con- nections, unless these can be carried through and under the floor. This false floor over the con- nections between the oil switches and the compartments consists of remov- able slate slabs resting on vertical brick or concrete barriers between the connections. With this construction it is necessary to pro- vide doors for the compartments as well as for the oil switches. Section A shows the construction of a bus-tie con- nection, section B a generator or transformer connection, and the plan view C a com- bination of the above for connecting a gen- erator to its transformer or to the main bus the same manner as indicated in the C/rcu/t Connect ea to Main Bus. Fig. 7. Arrangements wherein the Switch and Bus Equipments are located on the Floor. A different but equivalent scheme to that shown in Fig. 6 diagram of Fig. 6. Section D shows how a feeder circuit may be connected to the main bus, and how the instrument transformers may be installed in line with the auxiliary bus compartment if desired. Disconnecting switches may also be accommodated in this compartment for isolating the instrument transformers from the line when energized from the other end. A bus-section oil switch with disconnect- ing switches may be installed as illustrated at E, but it must, however, be placed at right angles to the main compartment. PRACTICAL EXPERIENCE IN THE OPERATION OF ELECTRICAL MACHINERY Part III (Nos. 13 to 18 inc.) By E. C. Parham Construction Department, General Electric Company (13) TRANSFORMER LEADS REVERSED Fig. 1 is a diagrammatic sketch of the connections for two direct-current generators connected to supply lights and power by three- wire distribution. Between the middle or neutral wire and either outside, the voltage of one dynamo is available (110 volts); between the two outside wires, the voltage available is that of A and B in series (220 volts). Lamps are connected to adjacent wires and 220-volt motors to the outside wires. Wherever three wires are run, the neutral should be the middle one, because, as indi- cated in Fig. 1 (b), should the neutral and uov. Fig. 1 one of the outside wires become accidently interchanged some of the lamps are likely to be blown up and 220-volt motors connected (to the outside wires will not speed to their rated r.p.m. In Fig. 1 (c) the distributing wires are arranged correctly but the two generators are indicated as having been connected so that their voltages are in opposition instead of in addition. In this case it is still possible to get 110 volts between the middle wire and each outside wire, but the middle wire is no longer a neutral wire; it has become the return wire for the outside wires and has to carry the sum of their currents instead of the difference. Further- more, the voltage across the outside wires is zero. - — HOOV. NAAAAAAAAAAAAA/ HOOV NAAAAAAAAAAMAAA/V Fig. 2 These sketches are suggested to explain to an operator why he might not be able to start a motor from the outside lines of a recently connected three-wire service when supplied from a single-phase transformer, even though the lamps are operating normally across both 110-volt legs. Fig. 2 (a) indicates the normal connections of the single primary and double secondary of a single-phase transformer when connected for three-wire secondary supply. It will be noted that the arbitrarily selected current directions are the same, indicating that the e.m.f. of each secondary coil boosts the e.m.f. of the other secondary coil so that the e.m.f. of the outer terminals is the sum of the individual e.m.f’s, just as in the case of the d-c. generators of Fig. 1 (a). Fig. 2 (b) indicates the wrong connections to which one operator’s trouble was due. One of the secondary leads had been interchanged in bringing it through the bushing. This connection gave the same conditions of voltage distribution as in Fig. 1 (c) . It is important that careful attention should be given when making connections, as in this case, for example, the error might be dis- 1194 GENERAL ELECTRIC REVIEW covered only after an attempt was made to start a motor between the outside wires or after undue heating of the middle (on account of having to carry the sum of the outside currents instead of the difference) was noted. (14) importance of equalizer Fig. 3 shows the connections of two generators of which Ai and Az are armatures, Fi and F 2 are series fields, Ki and K 2 are individual line switches, and E\ and Et are equalizer switches. If Ex and F 2 are closed while either machine is carrying the load, part of the current of the loaded machine will pass through the equalizer to and through the series field of the idle machine, the circuit effect of the equalizer being to place the series fields of the two machines in parallel. The closing of ^^e equalizer switches adds to the no-load excitation of the incoming machine and there- by enables this machine to take its share of the load, assuming the correct no-load adjustments to have been made. Within certain limits, the equalizer will prevent one machine from driving the other as a motor in case they should be thrown together when the voltage of the one is considerably below that of the other, since the current through the equalizer and series field of the low- voltage machine increases its excitation. As stated, there is a limit to this automatic regulation because the equalizer possesses resistance and because the excitation due to the equaliz- ing current is only a part of the total excita- tion of the machine. While the automatic division of the load upon the two machines will be impaired seriously by an unnecessary high-resistance equalizing connection, it is improbable that such an equalizer would cause sudden trouble in the operation of the generators. If the resistance of the connection, however, is infinite (caused by the equalizing switches being open), it is a practical certainty that arc-overs or other like troubles will soon occur. Operators, therefore, should be sure that all equalizing switches are closed between the machines that they are about to parallel. (15) SPARKING CAUSED BY LOAD CHANGES The series field shunts for generators of low and moderate current capacity are made of German silver ribbon; those for heavy 1 current machines are made of cast-iron grids. In either case, the shunts are constructed non-inductively. The scheme of connections employed is indicated in Fig. 4. A shunt is arranged to have such a resist- ance that the portion of the arrnature which passes through the senes field (the portion not “by-passed” or shunted) will be correct to give the desired degree of com- pounding. The size of the shunt which will be required is determined experirnentally since this method of procedure is simple and is satisfactory in most cases. Among a group of motors which receives its electric energy from one generating source there will occasionally be one or more large motors that are frequently started and stopped, thereby causing sudden larp changes in the output of the generator. Under such ; conditions a generator will require a different^ type of series field shunt, viz., an inductive shunt. If an non-inductive shunt is used, the self -inductance of the series _ field winding, will force more than a proportionate amount of current through the shunt during a peno of sudden increase in load current, and, con-^ versely, it will cause the series field winding^ to retain more than a proportionate share | of the load current during a period of sudden? decrease in load current. This unequal rate of j change of current in the shunt and series field : winding will cause a distortion of the field j magnetism. Such a displacement of the fiux, will probably result in more or less serious; sparking at the brushes. A shunt which is- non-inductive will not maintain a constant ^ proportional division of the current between, it and the series field winding (i.e., will not maintain the series field current proportional to the load) during the period of a rapid change of load. Therefore, the condition of widelv varving load may prevent a non- inductive shunt from performing its function properly. When the conditions of the load are sufficiently severe as to make it necessary to overcome this variable division of the load current between the shunt and the series field winding, because of the bad commutation produced thereby, satisfactory operation can be secured by including an inductive element OPERATION OF ELECTRICAL MACHINERY 1195 ' in the shunt. This arrangement is indicated in Fig. 5, in which F is the series field, NS the non-inductive part of the shunt, and IS the inductive portion. This latter consists of copper wire wound on an iron core having an y- -Shunf YJ>^er/^s ^Shunt . Qr/etd ^ rie/d flrmalurei • Rheostat Fig. 4 air gap that can be varied to give the desired amount of self-induction. The total ohmic resistance of the inductive and non-inductive I parts in series must be such as to give the I required degree of compounding for steady I currents; the resistance of the inductive part must be adjusted by trial to give I sparkless commutation when the load is I suddenly varied. Since the inductive part I necessarily has some ohmic resistance, a t change of taps in this part in order to change its self induction will also change its ohmic resistance and hence the total ohmic resistance of the shunt. Frequently, the whole inductive change can be made by means of the air-gap, which, of course, will not change the ohmic resistance. Final adjustment will require a trial of several combinations of inductive and non-inductive shunt. As a practical illustration of the operation of shunts, reference may be made to an instance where momentary sparking of gener- ators and their tendency to flash over was caused by the starting and the stopping of heavy direct-current motors in a cement mill. An inductive shunt was later obtained and connected in series with the non-inductive shunt, and then the resistance of the latter was decreased until the combined resistance of the two elements, inductive and non- inductive, was the same as the resistance of the original non-inductive shunt alone. In this particular case it was unnecessary to make any adjustments of self-induction in the inductive shunt because by coincidence the amount happened to be correct. (16) REVERSED FIELD COILS If one or more field coils are reversed on a generator of any type, one result is to lower the voltage obtainable from the armature. In the case of a direct current generator, sparking at the commutator will also suggest the possibility of reversed field coils; in the case of an alternator, however, as there is no commutator, the sparking symptom will be absent. In any case, the magnitude of the effect will depend somewhat on the relation between the number of reversed poles and the total number of poles in the machine. A large alternator, which was excited from a multi-polar generator, was packed so full of mud and wood as the result of being submerged during a flood that it had to be dismantled for cleaning. The exciter also had been through the same experience. After reassembling, it was impossible to generate normal voltage. Everyone attributed the trouble to dampness and the two machines were baked “almost to death ” in a determined effort to dry them. Finally, it was noticed that both machines were about dry and that further drying was not improving the condi- tions materially. Further, it was observed that there was more sparking at the exciter commutator than formerly. An investigation disclosed a field spool of reversed polarity. This error of assembly was corrected and it was supposed that all trouble had been eliminated. On starting, however, it was found to be impossible to get the alternator voltage much higher than it was before. (The effect upon the exciter voltage could not be observed because there was no direct current voltmeter available.) Then it was suggested that some of the poles of the alternator might be reversed, as in the case of the exciter. This proved to be the case: Out of a total of 32 poles, five poles of reversed polarity were found distributed around the revolving field. The correcting of this fault enabled normal voltage condition to be restored. (17) RIDGING OF COMMUTATOR By ridges on a commutator are meant those alternate high surfaces which remain when 119G GENERAL ELECTRIC REVIEW intervening grooves are cut in the commu- tator by the brushes. This may be due to sparking (visible or invisible) , to lack of end-play in the armature, to tracking of the brushes (that is, placing the brushes along circumferential lines on the commutator so that certain zones of the surface are not subjected to brush wear), or to excessive brush tension. Sparking which may be so slight that it cannot be seen in a well-lighted room becomes evident in a dark roorn. kind of sparking may be due to using the wrong quality of brush. Even with staggered brushes end-play is essential to good perma- nent commutator operation. The movement can generally be obtained by insuring that the machine is actually^ level, but if amount of play is insufficient it should be secured in some way even if it is necessary to turn off the inside end of one of the armature bearings. The brush tension should be no greater than is required, the proper amount being obtained by trial and observation. When the brushes are not properly staggered, even if the commutation is of the best, the unwiped part of the commutator in course of time will stand above the wiped part, unless this tendency is overcome by well-applied sanding of the ridges. If both lubricating and standard brushes are used on a machine, they should be distributed as far as possible so that each kind is correctly staggered in regard to that and the other kind. Notwithstanding the fact that all ordinary precaution had been taken, the skilled operators of a certain station seeming y found that a ridge on one commutator cou d not be prevented. It was finally noticed that all the positive brushes were staggered with regard to each other, as were also the tives ; the positive tracked positive, and the negative tracked negative, and the positives were cutting grooves. On re-arranging the brushes correctly on the holders all grooving and ridging stopped. LAMPS FLICKERING The full lines of the diagram in Fig. 6, represent the connections of a two-poffi, direct-current armature mounted upon the same shaft with a circular, iron-cored react- , ance, the two members constituting the mam i feature of a so-called three-wire generator. The end connections of the reactance are tapped to diametrically opposite points of the armature winding and it is very essential that these points be diametrically opposite. From the center of the reactance is run a wire called the neutral; this neutral, in conjunction with the two outside wires from the generator, constitutes the three-wire distributing line. The reactance is simply a device by rneans of which the internal neutral, or half -voltage point of the armature, may be reached. Half of the series field winding of the gener- ator is placed in one main, or outside and the remaining half in the other to help balance the voltage when the load becomes j unbalanced. . , ; With balanced load, the current in each ^ main is the same and the current in the , neutral is zero. The turning off of lamps on one side and not on the other tends to raise the voltage of the more lightly loaded side; ■ this tendency is partly neutralized by the weakened series field on that side acting to lower the voltage. The reactance carries ' alternating exciting current all the time, and it carries direct current only when the load ; is unbalanced. In this latter case there is a : neutral current and it is equal to the difference ' between the current in the two mains. A case of severe flickering of the lamps furnished with energy by a certain three-wire generator was traced to the tap of the neutral wire on the reactance coil center, as shown by the dotted line in Fig. b. 1197 RECENT VIEWS ON MATTER AND ENERGY Part IV By Dr. Saul Dushman Research Laboratory, General Electric Company In this issue, the last of the series, the author indicates the manner in which the atomic theory of mat- ter has been affected, by the atomistic theories of electricity and energy. The result of all the recent investi- gations and speculations has been to strengthen more firmly the position held by the older theory of the atomic and molecular structure of matter. The greatest interest now centers in the question as to the structure of the atom itself, and in this connection the views of Rutherford and Bohr seem to be in best accord with actual observations. ATOMIC THEORY OF MATTER It is evident from what has been stated so far that the tendency of modem physics is to adopt atomistic views in the explanation of all phenomena. We have an atomic theory of electricity, an atomic theory of energy and we have been familiar for over a century with an atomic theory of matter. The theory in which Dalton found such a simple explanation of the fundamental laws of chemical combination has, as is well known, been regarded as unnecessary by one school of chemists, while a number of others have adopted the faith of their colleagues, the physicists, and prefer to speak of atoms and molecules rather than of international and reacting weights. It is not our intention in this paper to enter into any polemical arguments as to which attitude is the more correct. We are here concerned mainly with a recital of experimental facts and a presentation of the theories which have been put forward in explanation. Applications of Kinetic Theory of Gases The first great impetus to the adoption of the atomic and molecular theories of the structure of matter was undoubtedly given by the speculations of Maxwell, Boltzmann and Clausius. The kinetic theory of gases indicated simple relations between the vis- cosity, heat conductivity and diffusion coeffi- cients of gases; the validity of these relations has been confirmed experimentally. Similar considerations were extended to the case of solids and liquids, and we have observed that in this manner Boltzmann was able to calculate atomic heats and to account for the law of Dulong and Petit. More recently, the study of the motions of ultra-microscopic particles, such as are present in colloidal solutions has led to results that are in splendid accord with the deductions from the kinetic theory of gases. The number of molecules per gram-mol of any substance has been determined in half a dozen different ways, and it is quite justifiable to state that “today we are counting the number of atoms in a given mass of matter with as much certainty and precision as we can attain in counting the inhabitants in a city. No census is correct to more tjian one or two parts in a thousand,’’ and there is little probability that the number of mole- cules in a cubic centimeter of a gas under standard conditions differs by more than that amount from 27.09 XIO^^* Observations in Support of Atomic and Molecular Theories The study of radio-active phenomena has given powerful support to these atomic and kinetic conceptions; we see the disintegration of atoms going on under our own eyes, as it were. The spinthariscope is tangible evidence of atoms in motions, and very recently C. T. R. WilsoM has succeeded in photo- graphing the tracks of alpha and beta particles as they shoot out spontaneously with immense velocities. ^ The investigations of J. J. Thomson on positive ions which ought to be mentioned in this connection, have enabled us to measure, independently of other methods, the masses of the positively charged molecules that are repelled from the anode of an ordi- nary X-ray discharge tube. The method used is practically the same as that used for the REviEw^i^lgralit”"'’ 'Proc. Roy. Soc. 87 , 277 (1912). 2See pl^tographs of the tracks of alpha particles in General Electric Review, July 1913 1198 GENERAL ELECTRIC REVIEW determination of ejm for the cathode rays.® Not only has J. J. Thomson determined in this manner the nature of the different constituents of a gas mixture, but he has also shown that this method of chemical analysis is infinitely more refined than any other method hitherto used. Similarly S. C. Lind^ has shown that in the case of chemical reactions produced by alpha particles, the weight of evidence is in favor of the theory that each alpha particle pro- duces one ion by bombardment of molecules and that subsequently these ions react to form neutral molecules. Arrangement of Atoms in Crystals Experimental evidence of the atomic struc- ture of matter has been obtained recently by still another method. It has already been mentioned that considerations based on the quantum theory led to the conclusion that X-rays are merely electromagnetic waves of extremely short wave-length (10“® to cm). To measure these wave-lengths in the usual manner by means of a ruled diffraction grating was therefore out of question. It occurred to Laue that in the regular arrange- ments of atoms in a crystal we have gratings whose lines are naturally “ruled” so closely that their distances are of the same order of magnitude as the wave-lengths of X-rays. On passing the X-rays though a crystal diffraction patterns were obtained, and from the photographs of these it was found that the observed wave-lengths were of the same magnitude as those calculated. But within the past year still more interest- ing results have been obtained by Bragg and Bragg,® who have used this method to determine the structure of crystals. We can now see, as it were, the manner in which the atoms in a crystal of rock salt or zinc blende are arranged, and we can even tell whether these atoms are at rest or vibrating about some position of equilibrium. Thus, we find that in a crystal of NaCl, the sodium and chlorine atoms are arranged in the form of a cubical lattice-work with chlorine and sodium atoms situated in alternate corners, so that for example ' " the sodium atom has six neighboring chlorine atoms equally close 3The beam of positive rays is passed through magnetic and electrostatic fields acting at right angles to each other and to the path of the rays. From the photograph obtained when the deflected beam strikes a sensitive plate, it is possible to calculate e/m; consequently, if there is more than one kind ot ion, its presence is revealed by a separate streak on the plate. See Proc. Roy. Soc. 89, pp..l-20, 1913, for full details, also a recent monograph on "Positive Ions by J. J. Thomson. ^Trans. Am. Electrochem. Soc. 24. 339 (1913). with which it might pair off to form a molecule of Nad” In the case of the diamond the results obtained are equally striking. Every carbon atom is found to be united to four neighbors in a perfectly symmetrical way, while six carbon atoms are linked into a ring similar to that used to represent the benzene molecule. These results are among the most interesting that have been obtained in recent years.® In view of these observations, the stereo- chemical models of the organic chemist are endowed with an even greater degree of approximate reality than was hitherto dreamed of. _ . We are getting a glimpse, as it were, into the innermost structure of the molecules, and are learning daily more and more about the manner in which their constituent atoms are bound together. Structure of the Atom. Theories of J. J. Thomson and Stark But not only do we know something about the structure of the molecule, we are also in a fair way to knowing something about the structure of the atom, the unit out of which molecules are built up. We have learned already that the atoms must contain elec- trons. The obvious conclusion is that besides electrons the atom contains also a positively charged residue or nucleus. In what manner are these electrons and nucleus related to each other, and to the properties of the resulting atom? Here we touch upon the most funda- mental problem of physics as well as chemis- try. Of the many attempts that have been made in recent years to formulate a theory as to the structure of the atom, those of J. J. Thomson and of Stark are among the most important. Here we can only mention these theories very briefly.^ According to Thomson the atom consists of a positively charged outer sphere with the electrons arranged uniformly on one or more spherical shells inside. By means of this theory it is possible to account for the fact that the properties of the elements are periodic functions of the atomic weight; also, for the existence of certain valency relations. Stark’s theory lays most emphasis on the existence of so-called valency electrons. He ^W. L. Bragg, Proc. Roy. Soc. 89, 248—277 (1913). W. H- Bragg, Proc. Roy. Soc. 89, 277—291 (1913). ®See also still more recent papers by W. L. Bragg and W. H. Bragg in Proc. Roy. Soc. 7An excellent discussion is given in Campbell's Modern Theory, second edition. Chapter XIII. RECENT VIEWS ON MATTER AND ENERGY 1199 imagines that a chemical combination between i; two atoms “represents not a direct attraction ' of one atom for the other, but a simultaneous attraction of both atoms for the same electron ' which thus forms a bond between the atoms.” , On this theory, “the energy of chemical . combination represents the change in the ; potential energy of the valency electrons connecting the atoms which takes place when they transfer some of their lines of force from the electro-positive to the electro-negative atom. It will be the greater the less the attraction of the former atom for an electron, and the greater the attraction of the latter.” By far the most important contribution i that has yet been made to this subject is, however, contained in a series of papers by i N. Bohr* that appeared during the latter half of the past year. Interpenetration of Atoms To understand the arguments advanced ii by this writer, it is necessary to refer to a number of experiments that were carried out in Rutherford’s laboratory and which led him ; to a new conception of the structure of the ; atom. Rutherford and Geiger found that when the_ alpha particles from radium or other radio-active substance met a thin gold leaf, most of these passed though the metal with only slight deflection, but now and then one of these particles was completely deflected around so that it returned towards the side of the source. This phenomenon, known as the scattering of alpha particles, was found to obey the same laws as the repulsion of one electric charge in motion by another charge of similar sign at rest. The moving alpha particle carries a positive charge which is twice as great as that of the electron. It is in fact the same as the helium atom with two positive charges. From the amount of scattering suffered by some of these particles, the conclusion was drawn that at some point in their paths these particles pass through the very intense electrostatic field caused by a positive charge whose magnitude _ is approximately equal to one-half the atomic weight of the metal through which the scattering occurs. Furthermore, the conclusion was drawn that the alpha particle must approach the repelling positive charge (or nucleus) within a distance which is infin- itesimal as compared with the radius of the atom. While the radius of an atom is about *Phil. Mag. 26, 1-25; 476-502; 857-875 (1913). cm., the experiments on the scattering of alpha particles by hydrogen showed that the former must have approached the hydro- gen nucleus so closely that their centers were only 1.7X10-1* cm. apart. In other words, it was necessary to 'conclude that the alpha particle penetrated within the atom of the other metal. Rutherford’s Atom Model These results led Rutherford to assume a structure of the atom which is quite different from that of J. J. Thomson. According to the former “the atom must be assumed to consist of a positively charged nucleus surrounded by a system of electrons which are kept together by attractive forces from the nucleus. This nucleus is assumed to be the seat of the essential part of the mass of the atom, and to have linear dimensions exceedingly small compared with the linear dimensions of the whole atom." Furthermore, as the magnitude of the positive charge in this nucleus corresponds to half the atomic weight, it is necessary to assume that the number of electrons rotating about, the nucleus is equal to one-half the atomic weight. The difference between the atom models of Rutherford and Thomson may be illus- trated by means of the diagrams shown in Fig. 1. + Fig. 1 In this connection it is worth noting that as a result of experiments on the scattering of X-rays, Barkla was led some years earlier to conclude that the number of electrons in the atom _ must be equal to one-half the atomic weight. Bohr’s Theory of the Structure of Atoms and Mole- cules While the experimental results thus pointed towards a nuclear structure of the atom, it was found that there are apparently good theoretical reasons for assuming that such an atom would be quite unstable. According to the classical electro-dynamics an electron rotating about a positive charge would very quickly radiate its energy in the form of 1200 GENERAL ELECTRIC REVIEW electromagnetic waves, its orbit would grow smaller and smaller, with increasing speed, until finally the electron struck the positive nucleus. No such objections could, however, be raised against the model of Thomson. But according to Bohr the difficulties in the way of assuming Rutherford’s atom model disappear when account is taken of the fact that the classical electro-dynamics has been found inadequate in describing the behavior of systems of atomic size. “By the introduction of Planck’s constant h, the question of the stable configurations of the electrons in the atoms is essentially changed, and it is on the basis of Planck’s theory of energy that Bohr builds up a theory of the structure of atoms and molecules. The principal assumptions made by him are as follows ; (1) That the electrons revolve in circular orbits about the positive nucleus, with an angular momentum which is the same for all the eleetrons in the atom. That is, for each electron, mvr = hj2 tt, where m denotes the mass, V the velocity, and r the radius; or the angular momentum is equal to Planck’s constant divided by 2 tt. (2) That in the stationary state the dynamical equilibrium of such a systern can be discussed by the help of the ordinary mechanics. In other words, the relation between the frequency of rotation {v), the average kinetic energy of the electron, and the radius of the orbit (r) can_ be calculated by the laws of ordinary dynamics. (3) That in the stationary orbit no energy is radiated. This is contrary to the classical electro-dynamics. When, however, in conse- quence of emission or absorption of energy, the frequency changes, the problem is no longer one that can be dealt with by ordinary dynamics. During the latter process there is an emission or absorption of a homogeneous radiation, whose frequency (v) is the average of the frequencies of rotation before and after the energy change. The amount of energy radiated or absorbed is then equal to some integral multiple oih v. From these assumptions Bohr deduces a number of interesting results. Assuming, as known, the values of the elementary charge e, the mass of the electron m, and Planck s constant h, he calculates the radius of the electronic orbit to be equal to that of the atom and the frequency of the energy radiat- ed to be about the same magnitude as the frequency of ordinary visible radiation. Furthermore, he calculates the ionization voltage, that is, the work required to expel an electron from an atom, and obtains a result that is in agreement with observed values. Bohr also shows that his theory enables him to account for the well-known laws of B aimer and Rydberg connecting the fre- quencies of the lines in the line-spectra of the ordinary elements. He finds V - 2 7T^ me^^ /I 1_\ where a and b are integers and the other letters have the usual significance. The quantity before the bracket should be equal to the Rydberg constant of which the observed value is 3.29Xl0ih Bohr’s calculated value is 3.26X10^h Nuclear Charge. Atomic Number On the basis of the above assumptions, Bohr also shows that the configuration of any system of electrons, i.e., the frequency and linear dimensions of the rings, is completely determined when the nuclear charge and the number of electrons in the different rings are given. Corresponding, however, to different ^ distributions of electrons in the rings, there will, in general, be more than one configura- ‘ tion satisfying the conditions of angular j momentum and stability. The physical and i chemical properties thus depend upon the ^ munber of electrons, or nuclear charge, and the ^ mode of arrangement of these electrons. , The experimental evidence supports the hypothesis that the nuclear charge of _ the atom of any element corresponds to the position • of the element in the series of increasing atomic j weights. Thus, the oxygen atom being eighth | in the series, should have a nuclear charge j of eight unit charges and eight electrons. \ The periodic table of the elements thus | assumes a new significance. The order of the j elements in this table corresponds to the number of unit positive eharges of the nucleus. According to Bohr’s theory, the physical and chemical properties of the atom depend upon the magnitude of this nuclear number; since, however, any given number of electrons may often assume different configurations it is possible for two or more elements to exist having the same nuclear charge, that is, the same place in the periodic table, but possess- ing different atomic weights. This is quite in accord with the conclusions reached by Soddy and Fajans independently, from a consideration of the transformations that occur in the radio-active elements. The RECENT VIEWS ON MATTER AND ENERGY 1201 discussion of these deductions is, however, reserved for a subsequent paragraph. Again, according to Bohr’s theory the emission of characteristic X-rays is accounted for as being due to the removal of an electron from an inner ring. On the other hand, the radio-active changes depend upon trans- formations occurring within the nucleus itself. The formation of a helium atom from an alpha particle is a case of the actual formation of an atom from a positive nucleus and two electrons. Bohr’s Theory of the Method of Formation of a Hydrogen Molecule Bohr gives a very interesting picture of the manner in which two hydrogen atoms form a molecule. The hydrogen atom has the simplest imaginable structure; it consists of a nucleus of unit positive charge and one electron revolving round it. “The nuclei of two such atoms repel each other. The revolv- ing electrons of two atoms close together, if rotating in the same direction, constitute two parallel currents of electricity, and these attract one another and arrive in the same plane.’’ The molecule thus consists of the electrons that revolve like the governor-balls of an engine about an axis formed by the two nuclei. Bohr calculates the energy that would be liberated in the process of combina- tion of the atoms and obtains a result in substantial agreement with the value pre- viously calculated by I. Langmuir.® If the value of a theory is to be measured by the number of observations it correlates and by its suggestiveness then Bohr’s theory of the structure of atoms and molecules is one of the most important contributions to scientific literature that has been made in recent years. Other Theories of Atomic Structure J. J. Thomson^® and, more recently, Peddie“ have suggested other atom models. According to the former, the intra-atomic forces need not necessarily obey the observed electrostatic laws, and he assumes that the forces acting upon an electron in the atom are, firstly, a radial repulsive force, varying inversely as the cube of the distance from the center and diffused uniformly throughout the whole of the atom, and secondly, a radial attractive force, varying inversely as the 9J. Amer. Chem. Soc. SJf, 860 (1912), also Phil. Mag., Jan., 1914. ‘“Phil. Mag. 26, 792-799, (1913). “Phil. Mag. 27, 257-268, (1914). square of the distance from the center and confined to a limited number of radial tubes in the atom. On the basis of this theory Thomson is able to account for the relation between velocity of emission of electrons and frequency of incident radiation as demanded by the quantum theory; and he is also able to account for Balmer’s law. Professor Peddie would also explain the variation in properties of atoms and molecules in a similar manner as due to structural conditions within the atom rather than to the failure of the ordinary dynamical equations in the case of such systems, and along with Thomson he postulates regions of attractive force alternating with regions of repulsive force. Bohr’s theory has, however, proven so far to be the most stimulating conception of atomic and molecular structures and while there are, no doubt, a good many difficulties in the way of accepting it as it stands there are very many reasons for believing it to be a much closer approximation to the truth than any other theory. High Frequency Spectra of the Elements Within the present year Moseley, working at Manchester University, has followed up these speculations of Bohr by actually determining the magnitude of the nuclear charge of the atoms of most of the elements. When the atoms of any element are bom- barded by electrons traveling at high velocity, they emit characteristic X-rays. Bohr showed that there is a definite relation between the charge on the nucleus of these atoms and the frequency of the characteristic X-rays emitted. Moseley, therefore, made the different ele- ments anti-cathodes in an X-ray tube, thus bombarding them in succession with cathode rays, and then measured the wave-length of the X-rays emitted. For this purpose he made use of Bragg’s method of reflecting the rays from a rock-salt crystal and photo- graphing the resulting diffraction pattern. Knowing the distances between the atoms of the rock-salt cyrstal and the angle at which the X-rays are reflected from the surface of the crystal, it is possible to calculate their frequencies. In this manner Moseley found that the relation between p, the frequency of the X-rays emitted by the bombarded element and N, the charge on the nucleus, is given by the formula: v = A{N-BY GENERAL ELECTRIC REVIEW 1202 where A and B are constants for each set of characteristic rays. He has determined in this manner the atomic numbers of all the elements from aluminum, 13, to gold, 79. There appear to be only three elements in this range which have not been discovered by the chemist. The atomic weight thus appears to have vastly less importance than the atomic number. In fact, as stated above, there may exist two or more elements having different atomic weights but exactly the same atomic number. Isotopic Elements By examining the very high frequency radia- tion (gamma rays) emitted by radium B and by bombarding lead with beta rays from radium B, Rutherford has found that both these elements give the same characteristic rays, indicating that they have the same atomic number, 82. Now so far as their chemical and physical properties are concerned, the two elements behave identically the same; yet^ the atomic weight of lead is 208, while that oj Ra B is about 214-5- Lead and radium B are not the only examples of elements that differing in atomic weight yet occupy the same place in the periodic table. Soddy has found a number of similar cases among the other radio-active elements, and he has designated them isotopes (occupying the same place). These elements are absolutely inseparable by all chemical methods derived so far; yet they differ in that respect which has hitherto been taken to be the most important charac- teristic of an element — its atomic weight. It that is true, then the atomic weight of a so-called element is really the average value of the atomic weights of the isotopes of which it is constituted, and ought to depend upon the particular proportion in which the isotopes happen to be present. In agreement with this conclusion it has recently been shown by Richards and Lem- bert^'^ that lead from radio-active sources has an atomic weight of 206.6, whde ordinary lead has an atomic weight (determined by the same method in parallel analyses) of 207.15. The difference is much greater than any possible experimental error. It must further- more be observed that both specimens of lead are identical in all other respects. Thus, both give the same ultra-violet spectrum. Is Mass Entirely Electromagnetic in Origin ? And now we must mention briefly one more conclusion which is probably more far reach- >2Jour. .A.m. Chem. Soc.. 36 , 1329 (July, 1914). ing than any yet deduced. According to Rutherford and Bohr, the nucleus of an atom is infinitesimally small compared with the dimensions of the atom, yet practically the whole mass of the atom is concentrated m this nucleus. Now let us quote Rutherford himself. “It is well known from the expenments of Sir J. J. Thomson and others, that no posi- tively charged carrier has been observed of mass less than the hydrogen atom. The exceedingly small dimensions found for the hydrogen nucleus add weight to the suggesticpn that the hydrogen nucleus is the positive electron, and that its mass is entirely electro- magnetic in origin. According to the electro- magnetic theory, the electrical mass of a charged body, supposed spherical, is g ^ ’ where ^ is the charge and a the radius. The hydrogen nucleus consequently must have a radius about 1/1830 of the electron if its mass is to be explained in this way. There is no experimental evidence at present contrary , to such an assumption. ' For some time we have been familiar with the idea that the mass of the negative electron , is electromagnetic in origin ; if the same holds ^ true for the positive electron or hydrogen ; nucleus, then we are forced to conclude that • all matter is really a manifestation of elec- ' trical charges in motion. , In the above remarks an attempt has been f made to present to the reader in a general and confessedly superficial manner sorne of those j concepts which have been evolved in physical j science during the past decade. We have seen : that in analogy with the ordinary atomic | theory of the structure of matter there has j been developed not only an atomic theory j of electricity but also one of energy. These theories are, however, not to be regarded as opposed to views previously held, but rather as an attempt to obtain a deeper comprehension of the innermost mechanism of natural phenomena. In a word, while the physics of the past century dealt with nature microscopically, and emphasized the idea of i continuity , the physics of the present regards nature microscopically and finds that under- neath the apparent continuity there exist distinct discontinuities. For the chemist as well as physicist a knowledge of the investigations which have '3phil. Mag., March, p. 494 (1914). 1203 RECENT VIEWS ON MATTER AND ENERGY led to these new speculations are of extreme importance. Objection may of course be raised to these speculations because of their obviously hypothetical nature. The argument may be advanced that since the theory of today is apt to be cast aside in favor of the theory of tomorrow, what then is the use of any theory at all ? As Royce states If certain general theories are mere conceptual constructions, which today are, and tomorrow are cast into the oven, why dignify them by the name of philosophy? Has science any place for such theories? * * * Why not say, plainly: Such and such phenom- ena, thus and thus described, have been observed; such and such experiences are to be expected, since the hypotheses, by the terms of which we are required to expect them, have been verified too often to let us regard the agreement with experience as due to merely chance; so much then with reasonable assurance we know; all else is silence— or else is some matter to be tested by another experiment? Why not limit our philosophy of science strictly to such counsel of resigna- tion? Why not substitute, for the old scientif- ic orthodoxy, simply a confession of ignorance and a resolution to devote ourselves to the business of enlarging the bounds of actual empirical knowledge? * * * “Why not ‘take ^^Introduction to the translation of Poincare’s “Foundations oi bcience. the C3.sh 8,nd let the credit Why pursue the elusive theoretical unification any further, when what we daily get from our sciences is an increasing wealth of detailed information and of practical guidance? As a fact, however, the known answer of our own age to these very obvious com- ments is a constant multiplication of new efforts towards large and unifying theories.” The scientific investigator overwhelmed with numerous observations and results of experiments in different fields finds an actual need for some unifying conception that will make it easier to understand the manner in which all these varied phenomena are corre- lated. The scientific imagination, that uncontrol- lable product of the human intellect, can no more be stifled by a rule of logic than freedom of thought could be repressed by any theo- logical dogmas. And surely it is worth while to make an error occasionally if the net result be an increased enthusiasm and inspiration to increase further the sum of human knowl- edge. ^ In^ conclusion, the writer wishes to express his sincere appreciation of the kindly interest taken in this paper by both Dr. W. R. Whitney and Dr. I. Langmuir, without whose encouragement and inspiration it would not have been attempted. 1204 GENERAL ELECTRIC REVIEW THE ELECTRIFICATION OF CANE-SUGAR FACTORIES By a. I. M. WiNETRAUB Engineer, Zaldo & Martinez, Havana The author here discusses the “steam balance” of a sugar factory, as well as the points of superiority of electric motor drive over steam-engine drive. By “steam balance” is meant that condition obtaining when no more steam is generated than needed for high-pressure cooking and for mechanical power, the exhaust from the latter being sufficient for all the low-pressure cooking purposes. In the economical operation of a cane-sugar factory, the important factor is rather to maintain a “steam balance” than simply to create it. This can be done only by the use of apparatus which provides a means of regulating a portion of the steam flow to suit momentary conditions. It is shown that the only apparatus possessing this function in a satisfactory degree is a steam turbine of the extraction type coupled to an electric generator. The author also compares steam drive with electric drive for factory power and shows the great saving in favor of the latter method, as well as the reasons for its greater reliability, thus further confirming his conclusions that only by electrification can cane-sugar factories obtain the utmost in reliable operation and financial economy. — Editor. Another very satisfactory season of electri- cally operated cane-sugar factories has just been completed in Cuba; and while the pre- vious seasons left very little doubt that proper electrification meant an unqualified success, the present season, beside upholding the past record, strengthens the conviction that the adoption of electric drive practically imposes itself upon cane-sugar factory operation. Cuba has the distinction of being the pioneer in applying the alternating-current system on a large scale to sugar factories, and the results obtained have been so gratify- ing and convincing that foreign countries have followed the lead. To-day this system is being introduced in Australia, Hawaii, and other cane growing countries. There is hardly an owner of a sugar factory in Cuba who has not seen at least one of the electrified sugar mills. Of the replies to a circular letter sent to sugar mill owners, 80 per cent were unconditionally in favor of electrification. This statement, made by the interested com- panies, is in itself a fair proof of the satisfac- tory features visibly apparent in an elec- trified factory, but the engineer can obtain more than a superficial proof by a careful analysis of the conditions. The advantages obtained by the electrifica- tion of a cane-sugar factory are, of course, not limited to fuel economy only, although this lat- ter has been proved to be in itself a very con- siderable item. As will be shown herewith, there are other gains equally important and far reaching in insuring uninterrupted efficient operation at a reduced cost of production. No matter whether an electrical equip- ment is being selected for a new sugar house or whether the problem involves the electri- fication of an already existing steam-driven factory, the first and foremost consideration should be that of creating and maintaining a steam balance. The steam balance in a sugar factory may be defined as the condition under which live steam will be generated to an extent only sufficient to furnish the required mechan- ical drive and that ordinarily necessary for the high-pressure cooking apparatus, the exhaust from which after deducting condensation losses will be just enough for the ultimate evaporation and concentration of the entire dilute. In an already existing steam-driven factory, with probably an upset steam balance, there is another very important consideration, viz., that of designing an equipment which will produce and maintain the steam balance with such an expenditure of money that the combined interest and depreciation of the new and superseded plant will be more than covered by the total economy thus secured. ' There still are a few makers of sugar factory ; machinery who, although admitting that in an : existing steam-driven factory electrification ■ can show a great decrease in the cost of pro- duction, are skeptical about the application J of electricity to newly designed factories. , The main argument they advance is that a steam balance can be created in a new steam- driven factory when properly designed. While it may be true that a steam balance ; can so be created, it will be shown in the i following that an electrical equipment having properly designed turbine-generators is the ■ only one which will maintain the balance. ) Furthermore, such advantages as reliability, j ease of control, cleanliness, low cost of installed equipment, economy of lubrication, flexibility of installation, reduced operating expenses, reduced repair expenses, main- tenance of cooking apparatus in an efficient state, and others can only be obtained by the use of an adequate electrical equipment. In an ordinary sugar factory, the initial steam pressure at the engine is about 75 lb. gauge per square inch and the exhaust about 8 lb. gauge per square inch. In expanding one pound of steam from this initial to exhaust pressure, the engines will use up therefore 918,000 — ■ 835,000 or 83,000 ft-lb., leaving theoretically available in the exhaust THE ELECTRIFICATION OF CANE-SUGAR FACTORIES 1205 (assuming no condensation) 835,000 ft-lb., which is over ten times the energy used for mechanical drive. Usually the available heat in the exhaust steam of a sugar factory is at least seven and a half times that used by the steam engine to do the mechanical work, and with ample heat protective cover- ing may be even eight times that amount. This fact therefore must not be lost sight of, viz., that by far the greatest portion of the heat energy contained in the live steam appears in the exhaust and is" not used for mechanical drive. After a steam balance design has been arranged to give, with a certain steam consumption of engines, the required heat for evaporation in the form of exhaust steam, every additional heat unit used in excess for mechanical drive in the cylinders of the steam engines necessitates the release of eight heat units into the exhaust. These of course will be wasted if the balance of the steam requirements has been reached before. With a lack of steam balance it is sometimes necessary to employ live steam for cooking and, at others, to waste exhaust steam. This means taking no advantage of the heat units in the steam for mechanical drive in the former case and wasting heat units in the exhaust in the latter case. It would be a comparatively easy matter to obtain a steam balance for any sugar house if the milling and evaporating con- ditions were uniform and constant. This, unfortunately, is not found to be so in practice for both the mechanical drive, with the cor- responding exhaust steam production, and the requirements of evaporation vary due to field, yard, and factory circumstances; and, what is worse, the variations are independent of each other and may not occur at the same time. Let us assume that, at a certain period “B,” the crushing and milling engines in a steam- driven factory are operating at full load and are producing an exhaust which is just suffi- cient for the evaporation of the juice extracted and diluted some time before, say at period “A,” which is now being evaporated at period “B.” If, for any reason, at period “C, ” the milling capacity in tons per hour is reduced, the quantity of exhaust steam is also reduced due to the lessened mechanical load, and is therefore insufficient for the dilute obtained at period “B.” In this case live steam would have to be employed for evaporation. On the other hand if, at period “C”, the load increased there would be an excess of exhaust steam for evaporating the dilute from the cane crushed at period “B,” which would result in a consequent waste of exhaust steam. A still better illustration of this condition is available in a cane-sugar factory where several tandem grinding rolls are operating. The change-over from operating one or two of these sets at a time may mean an excess or a lack of exhaust steam for evaporating the dilute accumulated before the change-over, and the steam balance, if such existed pre- viously, is thereby upset. It has been suggested that low-pressure turbine-generators be installed to utilize the exhaust steam from milling engines and to have electric motors drive the pumps and other mechanical appliances about the fac- tory. While this arrangement appears to be satisfactory to a certain extent, it implies the use of large condensers in connection with the turbine-generators and involves the feature of evaporating the dilute by means of live steam; for with such an arrangement there would be no exhaust steam available for cooking. This would call for a complete revolution in the manufacture and operation of cooking apparatus. The suggestion of utilizing the exhaust steam in low-pressure turbines has been originated mainly because of the desire for creating and maintaining a steam balance. There have also been other suggestions to eliminate the difficulties attending an excess of exhaust steam, most of which apparently disregard the fact that instead of attempting to utilize in one way or another the heat con- tained in an excess of exhaust it is naturally more logical not to produce this excess of exhaust steam. The problem of obtaining maximum fuel economy can unquestionably be solved with such an equipment as will give: (1) Sufficient exhaust steam for cooking at all times. (2) A variable supply of exhaust steam. (3) A control of exhaust steam production to give only the needed exhaust. (4) An automatic governing device to make the exhaust production directly pro- portional to the cooking requirements. It requires no special effort to see that a sugar house which is equipped to fulfill these conditions will take care of all requirements and will at the same time secure a steam balance with its consequent ideal fuel economy. Extraction-type steam turbines have been used quite extensively in electric power plants for furnishing electric light and power 1206 GENERAL ELECTRIC REVIEW and, at the same time, supplying exhaust steam for general heating purposes. The conditions in a sugar factory are not material- ly different from those just mentioned and there is absolutely no reason why such an arrangement when suitably adapted to a sugar house should not give ideal results. Fig. 1 is a diagram illustrating the principle involved in accomplishing the desired end. The letters A illustrate extraction-type steam turbine-generators which have their exhaust lines connected to a common condenser. An extraction connection is shown from the first stage of each turbine leading into a common exhaust receiver. The crushers and mills are in this case steam-driven and their exhaust is also led to the common exhaust receiver. Between the first stages of the turbines and the common exhaust receiver there are installed automatically operated valves B, which are interlocked with the valves C. Valves B and C are set in such a manner that when the pressure in the exhaust receiver is maintained at 6 to 8 lb. per square inch or higher, valve B is shut and C is wide open. With such an arrangement, let us assume that the crushing and milling engines are Fig. 1. A Diagram showing an Ideal Arrangement for the Utilization of Steam in an Electrified Cane-Sugar Factory furnishing sufficient exhaust for the assumed cooking requirements, and that the turbines are operating fully condensing which gives high fuel economy. When the demand for exhaust steam in the cooking apparatus is greater than can be supplied by the crushing and milling engines, the pressure in the exhaust main drops and automatically opens valve B and closes valve C until the pressure in the main exhaust pipe is again 6 to 8 lb. At this time, valve B again closes and the turbine again operates condensing. Valves B and C can be designed in such a manner as to afford a partially opened B valve with a correspondingly partially closed C valve. Then, the turbine will operate non-condensing only to the extent of that portion of the steam which passes through the first stage and is then extract- ed for cooking, while the remainder of the steam taken by the turbine passes through to the condenser and effects a correspondingly economical consumption. Since the exhaust steam from operating the crusher and grinding rolls is never sufficient for the entire evaporation of the dilute, it is advisable, in a sugar factory where the crushers and rolls proper are to be electrically operated, to have one non-extraction turbine- generator exclusively for the mills and crushers and to have another one or two turbine-generators of the extraction type to compensate for the lack or excess of exhaust steam as described. The non-extraction tur- bine-generator should have a capacity equal to about 50 per cent of the total mechanical drive in the factory and should operate non- condensing, its exhaust steam being carried into the exhaust receiver just as in the case of the steam-driven crushers and mills. The turbines operate normally non-con- densing, feeding their exhaust steam into the exhaust pipe line for evaporation of the dilute. When the quantity of exhaust steam exceeds the requirements, the pressure in the exhaust line rises and operates a valve which diverts the excess exhaust steam into the condenser. If the quantity of exhaust steam from the turbine is insufficient for the cooking requirements, the pressure in the exhaust pipe line drops and the valve is operated automatically in such a manner that more exhaust steam is fed into the exhaust line and less is diverted into the condenser. When all the steam exhausted from the turbine is required in the exhaust pipe line, the valve opens wide, the condenser connection is automatically shut, and the turbine operates non-condensing . Fortunately, when operating entirely non- condensing, with as low a steam pressure as the 80 lb. per square inch that is available in most sugar mills, and exhausting at about 6 to 8 lb., the steam turbine consumes over twice as much steam as when exhausting into a 26-in. vacuum. This is decidedly a favorable feature in the operation of a sugar factory. THE ELECTRIFICATION OF CANE-SUGAR FACTORIES 1207 for the arrangement described can furnish the factory with enough exhaust steam to fulfill its maximum requirements and, when not as much is required, the portion of steam that is not needed is condensed and effects the operating efficiency corresponding to the vacuum in the condenser. The proper control of the electrically- driven air and injection pumps, that serve the auxiliary condenser which operates in con- nection with the extraction turbines, can be obtained by automatic starting and stopping devices that are governed by the valves B and C. Similar arrangements can be made in case the exhaust from the turbines should be carried to the central condenser, or man- ually by means of signals operated by the valves B and C. In the suggested layout the feature which will undoubtedly arrest the engineers’ atten- tion is the one pertaining to the operation of the extraction turbine at times under a vacuum with the consequent necessitated use of a condenser and additional cooling water. If it is remembered, however, that the vacuum may be as low as 25-in. and still give decided advantages and, above all, that the turbine condenser is an emergency equip- ment which is to operate only when the steam balance is endangered, and, if it is further remembered, that the condenser is to take care of only a part of the steam input to the turbine, it will be readily appreciated that the size of the condenser, the water it requires, and the attention to its auxiliaries are of very little importance compared with the enormous advantages to be derived. It must always be kept in mind that when steam is extracted in the manner suggested, from the first stage of a turbine, it has been used efficiently in the first stage for producing power, and the steam which passes through the remaining stages has been used on the regular condensing basis of efficiency and therefore the arrangement when taken as a whole is very efficient. Knowing that the condenser’s duty is mostly to condense the excess of exhaust steam and this on the basis of vacuum effi- ciency, it will at once appear that the quantity of steam to be taken care of and therefore the condenser required are not of alarming proportions. In most cases, it will probably be possible to connect the vacuum end of the extraction turbine to the main condenser of the sugar factory so that the additional requirements would be reduced to pumping only a little more cooling water and operating the air pump a little faster. To correct for a steam balance in a 1000-bag per day sugar factory which consumed about 80,000 lb. of live steam per hour and which was unbalanced to the extent of wasting as much as 18,000 lb. of exhaust per hour, it has been found that with the installation of only a 300-kw. extraction turbine the otherwise wasted exhaust steam could be made available to evaporate, in the effects and vacuum pans, some 30,000 lb. of maceration water* which in the case under consideration meant over 20 per cent maceration on cane.f In this case some 350 horse power of steam engines could be replaced by electric motors which would eliminate that amount of unnecessary exhaust, there being an excess of exhaust steam in the factory ; and a steam balance could be obtain- ed with an extraction of almost 5,000 lb. of steam from the turbine. With this turbine, requiring about 12,000 lb. of steam at the throttle (80 lb. initial, 6 lb. back pressure) and operating with 5,000 lb. extraction, the size of the condenser for 26 in. vacuum need therefore be of a capacity to take care of only 7,000 lb. of steam per hour, which is indeed not of a size to give any serious concern. It is to be noted in the diagram of the sug- gested arrangement of steam-driven crush- ing and milling engines. Fig. 1, that the boilers operating the extraction turbine-gen- erators (and which are intended for all mechanical drive excepting the mill drivers proper) are shown to be separate from the boilers intended for the milling engines proper. This of course does not mean that new boilers are required in an already existing steam-driven factory that is to be electrified, or that additional boilers than would other- wise be required are needed for a new plant to be installed along the lines suggested. * To best explain the expression "maceration water" it is deemed advisable to quote the following from authorities on the subject: "When water is poured on the bagasse the residual juice in the bagasse is diluted, and after recrushing the bagasse to its former content of juice, it will contain the same amount of dilute, but therefore less saccharine, causing less loss of sugar, so that maceration considerably improves the juice extraction. (H. C. Prinsen Geerligs, 1909, "Cane-Sugar and its Manufac- ture.")" "At the present time two schemes are employed in washing out sugar from the bagasse; in the one which is sometimes dis- tinguished as imbibition, water preferably hot is sprayed on the bagasse as it leaves one mill; in the other known as maceration the partly exhausted bagasse is drawn through a bath kept with diluted juice which has already been_extracted. (Noel Deerr, 1905, "Sugar and the Sugar Cane.")" t The degree of extraction is often conveyed by speaking of the percentage of maceration water as compared to the total weight of cane ground. In this case "20 per cent maceration on cane" means that the weight of water added was 20 per cent of the total weight of the cane ground. 1208 GENERAL ELECTRIC REVIEW Generally speaking of the total boiler capacity of a cane-sugar factory, 50 per cent furnishes steam for the mills proper and 50 per cent for the other drivers about the plant ; and it is possible to divide the total intended capacity of the boilers into batteries so that each may take care of their apportioned duties. The most likely reason causing a drop in boiler pressure is the variable load on the crushing and milling engines and if the boilers feeding them are separate from the other drivers, the load on which is practically constant, there will be the consequent advan- tage of constant steam pressure to the turbine- generator that is to operate the electric motors, a feature which is by all means desirable. It is of course appreciated that with a variable load on the mills proper the quantity of bagasse and its quality are variable and therefore this has a bearing on the pressure of the boilers assigned to the electric drive, but it is practicable indeed to arrange for the bagasse supply in such a manner that con- stant pressure may be maintained on the “electric” boilers with a constant fuel supply. It has been claimed in this paper that the steam balance can be maintained only with a properly designed turbine-generator equip- ment. In no sugar factory will conditions remain absolutely invariable from crop to crop as regards steam consumption, and a steam balance once created in such a factory has a tendency to be upset by the addition or deduction of machinery. If, instead of using turbine-generators of the extraction type, we should attempt to use compound or triple expansion units with the intermediate or low-pressure cylinders acting as “stages” in the same manner as the stages of an extraction turbine, it would perhaps be possible to make arrangements in such a manner that, in accordance with demanded requirements, the intermediate and low pres- sure cylinders may be by-passed and steam thereby be exhausted at a higher or lower pressure for cooking or even below atmosphere to the condenser. This, however, would mean driving the pistons of the corresponding cylinders “dry, ” or without steam at times, a feature which is by no means advisable. As can be seen, the variable quantity of low-pressure steam is not obtainable there- fore with a piston-type steam driver and the steam balance which has as a basis just this condition is only obtainable from a stage- type rotary steam unit with an extraction arrangement such as the Curtis extraction- type turbine. The manager of an important factory in Cuba which has an output of about 150,000 bags of sugar per season calculated that inter- ruptions in his mill represent $6.00 per minute, or over $8000 per actual milling day. This should amply indicate the impor- tance of uninterrupted operation in a sugar factory and it only remains to show that the electric motor affords protection against such interruptions. Excluding the mill drivers proper, crystal- izers, and centrifugals, the most important drive in a sugar factory is practically that required for pumping only. All pumping, with the exception of that for masse-cuite and molasses, can and should be done by centrifugal pumps due to their lack of valves and reciprocating motion. Pump inter- ruptions are due mainly to the sticking or breaking of valves and to the failing of the cylinder lubricating system. The centrifugal pump eliminates these difficulties entirely because it has no valves and does not require internal lubrication. The advantages to be derived from using high-speed pumps of this type are therefore obvious. The benefits of simplicity and reliability which are obtained by the use of centrifugal pumps are easily augmented by the adoption of electric motor drive. Furthermore, an electric motor would be the logical selection for driving a centri- | fugal pump, since both are naturally high- speed machines and can be coupled together directly. As to the application of electric motors to : the pumping of masse-cuite and molasses, j steam troubles are avoided inasmuch as no i complicated oiling system or close attention | is required with electric motors; and this of j course also holds true for the other drives | about the factory, such as crystalizers, centrifugals, blowers, conveyors, air pumps, etc. With the advent of the new rotary air I pump, the application of the electric motor becomes still more universal; and there is really no drive where the electric motor could not show superior operating character- istics, a decreased measure of attention required, and a greater degree of continuity of operation. From a very carefully controlled sugar factory in Cuba producing 1100 bags of sugar of 325 lb. each per day of 23 hours, a careful analysis of the results furnished the following data. THE ELECTRIFICATION OF CANE SUGAR FACTORIES 1209 The total cost of the extra fuel purchased during the crop season of 160 days was $ 20 , 000 . The live and exhaust steam piping for the small engines and pump connections only was found to have over 7500 square feet of radiating surface and the value of fuel being taken at 25 cents per million B.t.u. or about $7.00 per ton of coal equivalent, it was cal- culated that over $4,000 was lost in radiation and condensation per crop, which represents 20 per cent of the amount spent for extra fuel. The piping mentioned takes care of approxi- mately 1500 h.p. in engines and assuming, when electrified, a wiring loss of 2}/2 per cent, which is indeed reasonable when considering a properly distributed alternating-current installation, we have a loss of 37.5 h.p. With a consumption of 25 lb. of steam per horse power hour lost, the steam loss per season of 160 days of 23 hours each would be 3,450,000 lb. of steam. Assuming that with $7.00 worth of fuel we can produce 19,000 lb. steam ($7.00 per ton of coal) , the cost of the lost power would be 3,450,000X7 19000 = $1270 Considered against the $4000 this shows a difference of $2730 which represents a saving of over 13)/^ per cent of the purchase of extra fuel. On the basis of conditions as found in the sugar factory referred to, further comparison has been made relative to the labor and inci- dental material expense. Steam Electric Labor expense during crop, per day .... $65.19 $26.55 Labor exp. lay-by, endof crop, per day Labor expense pump- 2.79 0.28 ing station 3.33 0.00 $71.31 $26.83 Or, atotalfor IbOdays $11,409.60 $4292.80 Labor balance in favor of electric drive . . . $7116.80 The lay-by labor expenses at the end of the crop are due to dismounting the machinery and coating it with non-rusting material to protect it while standing idle for 200 days. The labor expense of the pumping station is due to the fact that, in the case of this steam sugar factory, it is necessary to have a small pumping station at a distance of one mile from the factory, a condition which applies to practically all sugar mills in Cuba. The time lost in starting the engines when stopped on dead center, in slow acceleration, and in other general features which would cause complete shut down of the mills proper can be assumed to be four minutes daily at $6.00 per minute, or a total of $3,840 for a Steam Electric Material for repair- ing pipe coverings per crop day. . . . $1.25 $0.06 Material for piston packing, lubrica- tors, spares, etc., per crop day .... 19.87 1.10 Paint, painting tools and labor per crop day 1.20 0.12 Oil and grease per crop day 13.83 2.50 Cotton waste per crop day 1.87 0.60 Repairs and oil at pumping station per crop day. . . . 0.25 0.10 Or,atotalforl60days $38.27 $6,123.20 .$4.48 $716.80 Material balance in favor of electric drive . $5,406.40 crop of 160 days. This item is not chargeable to the “electric” column. To resume, we have in favor of electrified sugar factories the following items: (A) Saving in transmission losses $ 2,730.00 (B) Saving in labor (C) Saving in incidental 7,116.80 material 5,406.40 (D) Saving, interruptions 3,840.00 Total .... $19,093.20 per crop. The values given in the “steam” column are amounts actually spent in the sugar factory under consideration, while the ones in the “electric” column are computed values from carefully analyzed obtainable conditions during a crop of 160 days with an assumed electrical layout and quite liberal help. It should be noted that the comparison is made on the basis of all drives other than for mills proper, which latter have in this case been assumed to be steam driven. Remembering now that the factory makes 1100 bags of sugar per day or about 175,000 bags per season, the saving just mentioned, which it must be recalled is exclusive of fuel economy, represents almost 11 cents per bag of sugar or over 2 per cent of the average 1210 GENERAL ELECTRIC REVIEW value at which a bag of sugar was sold in Cuba during the last crop. The fact must not be lost sight of that these data as obtained apply to an exception- ally well managed factory and that the advantages of an electric drive over the average steam drive will be decidedly greater than the ones just shown. The exhaust steam from a turbine-generator contains no oil, as is the case with the recip- rocating engine; and, if turbine-generators are used in a cane-sugar factory, the heating coils and the calandria of the evaporating apparatus will receive no heat-insulating oil coatings. It is well known that the efficiency of the cooking apparatus in cane-sugar factories is greatly impaired by such scales, the transfer of heat from the exhaust steam to the liquor being greatly diminshed. Any arrangement which will avoid the forming of such scales and which will maintain the heating surfaces in a maximum heat trans- mitting condition must be productive of economy not only in time and fuel but also in maintenance cost of the heating apparatus. With a properly designed, well constructed and installed turbine-generator equipment, it is undoubtedly possible to obtain at least an additional 34 per cent yield due to the possibility of increased maceration ; and in the mill under consideration an 1134 per cent yield could be obtained instead of an 11 per cent. This represents an increased revenue of 234 per cent which, translated into dollars and cents on the basis of last crop’s average prices (3^ reales per arroba; i.e., approxi- mately 2 cents per lb.), means an extra income of $19,775. Outside of the saving in fuel it may be expected therefore that a proper electrification of this mill should produce a saving of about $40,000, which in itself is indeed a respectable sum to pay for interest and depreciation on an electrified mill to cover the new and superseded machinery. NOTES ON THE USE OF THERMO-ELECTRIC APPARATUS IN HIGH FREQUENCY SYSTEMS* Part II By August Hund Research Laboratory, General Electric Company This article is a continuation of one which appeared under the same title in the October, 1914, issue of the Review. The present installment deals with different combinations of thermo-elements, such as the thermo-cross and the three-thermo-cross methods, which provide sensitive means of determining the reaso- nance curve and the logarithmic decrement of a circuit.- — Editor. The actual dissipation of energy in A , Fig. 9, is W=V.l2 (31) If only the thermo-couples I and III are used, the deflection of the galvanometer will be a = K . I,. I (32) = K^ |^V./2+(Ei./2+|(V+ri)^J This shows that the indicated energy is larger by the quantity 2 K i Since V 1 . I2 F+ Li ’) C = R we obtain the expression for the deflection of the wattmeter as follows: « = I FI2+ |^Fi./2+-2“] I ( 33 ) The correction factor, j^Ei.l2+— “ must be separately determined for each value ^ of the energy to be measured. This can be done automatically by the addition of the two thermo-couples, II and IV, as shown in Fig. 9. The thermo-couples I and III would measure the energy according to equation (33). The thermo-couple IV measures the energy \\ L; and the thermo-couple II, if made half as sensitive as the other thermo- R.Iv‘' couples, will measure the energy • Then * ERRATUM. — The title for Fig. 6 which occurred in Part I of this article. General Electric Review, October, page 986 should have read as follows: “Fig. 6. The Thermo-couple system shown in Fig. 2 shunted to measure heavy currents. When a proper value of self-inductance is used in the two branches, the system will give accurate readings at any frequency.” THERMO-ELECTRIC APPARATUS IN HIGH FREQUENCY SYSTEMS 1211 by properly connecting these thermo-couples, as shown in Fig. 9, the actual energy can be measured directly. The following is a description of a recent application of the thermo-cross bridge to the measurement of resonance and to the determi- nation of the logarithmic decrement. This determination has usually been carried out by the method of Bjerkness, in which either the self-induction or the capacity of the circuit is varied until the current becomes a maximum at resonance. Such a Bjerkness curve is represented by the expression 00 dt = function (X) (34) 0 where X is the wave length and i^ the instan- taneous value of the current in the resonator circuit. It is essential that the energy of the oscillator circuit (Fig. 10) be kept absolutely constant since any variation in it affects the current indicator in the resonator circuit. In order to overcome this objectionable feature, L. Mandelstam, N. Papalexi and others* worked out an improvement by caus- ing both the oscillator and the resonator currents to act on the indicator. Their resonance curve is represented by CO ii.i^ dt = function (X) (35) 0 Fig. 9. A Scheme of Connections which is an Improvement over that shown in Fig. 8 where A and A are the instantaneous values of the current in the oscillator and resonator circuits, respectively. These are defined by the equations ii = Io\€ ^ sin (2 tt ft-\-'^i) A = /026 ^ sin (2 7T ft + '^i). In the theory, as worked out by Mandelstam and Papalexi, it is shown that resonance takes place when f- . I i\_A2dt = (), c Fig. 10. A Scheme of Connections for Applying the Thermo- Cross Bridge to Determine the Resonance Curve of Circuit 1 and to Measure the Logarithmic Decrements of Circuits 1 and 2 at which time the currents A and A have a phase displacement of about 4^1 — 4^2 = 90 degrees with respect to each other. The reso- nance curve reaches its maximum for a definite amount of tuning, which is dependent on the decrement of the resonator and oscillator circuit. Since this is a zero-method, it is inherently independent of the energy varia- tions in the oscillator circuit, and is obviously therefore preferable to the previously de- scribed Bjerkness method. In place of the short-circuit-ring-dynamometer, which is used for the current indicator in the Mandelstam and Papalexi method, a thermo-cross bridge may be substituted, thus procuring a con- siderably higher sensibility in range, accuracy and ease in manipulation. In order to illustrate this method the dia- gram of connections is given in Fig. 10. The currents if and A^ have practically the same phase difference as A and A of the oscillator and resonator circuits (if the coupling induct- *L. Mandelstam and N. Papalexi, Ann. d. Phys., 33, 1910, M. Dieckman, Diss. Strassburg, 1907. H. Rohmann, Diss. Strassburg, 1911, L. Kann, Phys. Z., 12, 1911, L. Isakow, Phys. Z., 12, 1911. 1212 GENERAL ELECTRIC REVIEW ances are small). The galvanometer deflection a becomes 00 dt 0 00 dt 0 (36) Fig. 11. A Resonance Curve taken with the Method Shown in Fig. 10 Since ^ CO ^ CO ^ CD A representative resonance curve as obtained by this method is given in Fig. 11. The deflections of the galvanometer are plotted against 100 C-Cr Cr ' where Cr is the value of the capacity at resonance and C is the value of the capacity when the resonator circuit is not in tune with the oscillator. It will be noted that the curve is very slanting at the point of resonance. It is evident, therefore, that this method is very sensitive since a very small change in the capacity C corresponds to a considerable variation in the integral value J. dt. Another combination of thermo-elements which can be used for measuring the values of two oscillating circuits is due to M. Dieckmanf, who arranged three thermo- crosses as shown in Fig. 12. In this method the thermo-elements J, II and III are connected in series with a galvanometer, and the connections are so made that the effects of J and II are additive and III is subtractive. The electromotive force of each thermo- element is as follows: I is directly proportional to II is directly proportional to III is directly proportional to (Mifi+W 2 f 2 )^. The values of ni and «2 depend upon the ratio of the coupling turns in the oscillator and resonator circuits, respectively. With these connections one is able to obtain galvanometer deflections which are proportional to f CO dtj 0 OsciHotor /Resonator Fig. 12. A Scheme of Connections using a Combination of Three Thermo-Couples to Determine the Resonance Curve of Circuit 1 and to Measure the Lrogarithmic Decrements of Circuits 1 and 2 since where a. is the galvanometer deflection and ^ is a constant. fM. Dieckman, 1. c. THERMO-ELECTRIC APPARATUS IN HIGH-FREQUENCY SYSTEMS 1213 The curve marked OO A-^2 dt 0 in Fig. 13 is plotted from the results obtained by this method. The abscissae are degrees on the scale of the condenser which is inserted in the resonator circuit and the ordinates are deflections of the galvanometer. The Bjerk- ness curve, OO dt, D is also shown in Fig. 13 in order to facilitate comparison between the two methods. This latter resonance curve is the plot of data as secured by means of an ordinary thermo- couple, such as is shown in Fig. 2. The couple was inserted in a separate circuit which was loosely coupled to the resonator. It is well to note that the maximum point of the Bjerkness curve comes at exactly the same abscissa as the zero point of the 00 . t 2 dt curve. 0 In this section a short discussion on the measurement of the logarithmic decrement will be given in order to point out the wide field of application of the thermo-cross bridge and the three-thermo-couple method. The sum of the logarithmic decrements may be computed from an ordinary resonance curve, such as the 00 dt curve of Fig. 13, from the formula Al“h A2 — 7 T. = 7T.- Cr-C C Cr-C C a !' I « \ar — a 2_ r 2 (38) In this formula Ai and A 2 are the logarithmic decrements of the circuits 1 and 2 respectively of Fig. 12, a is the deflection of the galva- nometer which is proportional to 00 dt and corresponds to the value C of the capacity which is in circuit 2, and a.r corresponds to Cr at which value the circuit 2 is in resonance with circuit 1. If the corresponding wave lengths X and be introduced, equation (38) would become Ai+A 2 = 2 (38a) ing to the Method shown in Fig. 12, is shown compared with Curve J tV dt. which is plotted from data obtained by the Ordinary Bjerkness Method If the logarithmic decrements are to be determined from the J 00 . 22 dt 0 curve in Fig. 13 for the two maximum integral values, the following formulae may be used Ai+ A 2 — 7T . = 7T Cl — Cr Cr — C 2 ■“c^ = 27T. = 27T. Xi — Xr Xi X,- — X2 X2 (39) In this case Xr and Cr are the values of circuit 2 at resonance, for which condition J 00 i\ . ii dt = 0, 0 Xi and Cl are the values of wave length and capacity respectively at maximum positive deflection of the galvanometer, while X 2 and C 2 are the corresponding values at maximum 1214 GENERAL ELECTRIC REVIEW negative deflection of the galvanometer (see Fig. 11). If the extreme parts of the 00 i \ . Z2 dt 0 curve are too flat and the corresponding wave lengths and capacities can only be approximately determined, the following for- mulae may be used where (7* and Cy are the values for the capacity and X* and \y are the values for the wave length. All these values correspond to the intersection of the 00 ii . Z2 dt 0 curve with any line parallel to the abscissa, such as is shown in Fig. 11. In this case it is convenient to plot the galvanometer deflec- tions against the capacity or the wave length of the resonator circuit. APPLICATION OF POWER APPARATUS TO RAILWAY SIGNALING Part III By H. M. Jacobs Signal Accessories Department, General Electric Company This article is the last of a series of three on the subject of railway signal power apparatus. The first, or introductory article, described in a general way the underlying principles of the various systems in common use, and the second dealt only with electrically controlled signals for both automatic block work along the right-of-way, and for interlockings at stations, terminals, crossovers, etc. The present article describes a few installations on some of the leading roads of the East and Central West, dealing particularly with the equipment at certain interlocking towers that has been put in service within the past three years. — Editor. It may be said with a degree of certainty that the sole thought in the mind of the average traveler relative to movements of trains is the desire to reach his destination safelv and on schedule time ; but to a technical man, or one interested in railroading, some knowledge about the great organization of trained workmen who devote their energies to the accomplishment of these ends, and of the vast amount of equipment involved, adds interest to the journey. The demand for a reduction in train schedules and better service has increased tremendously the responsibilities of the signal department of the various railroads, and railway signaling may now be rightly con- sidered a science in itself. It is manifestly to the advantage of any road to establish certain standards, as this will minimize the amount of supplies to be carried in its store- houses, and reduce the first cost because of the ability to purchase in large quantities and to duplicate orders. Each road, in solving its own problems, has thus evolved its own standards, until we now have almost as many standards as there are railroads. The Railway Signal Associa- tion, composed of men in the employ of signal departments of railroads and represent- atives of manufacturers interested, was formed to bring about a crystalization in standardization, to obtain an economical and satisfactory product, and to establish a certain excellence in manufacture to meet the exacting requirements. There are, however, certain standards to which the various roads hold tenaciously ; and it should be so, for each is dependent on its particular traffic requirements, the system of signaling installed, the available power for power-operated systems, and other elements too numerous to mention here. It is beyond the scope of this article to deal with signal requirements and standards; only the power equipment accessory to the operation of the signal system will be considered. A few of the more recent installations of the past three years are described here, and in addition the equipment for some installations not yet placed in service and others installed to handle a problem not encountered in ordinary power service. NEW YORK CENTRAL 86 HUDSON RIVER RAILROAD CO. The automatic signals and track circuits on the New York Central are operated from storage batteries arranged in duplicate groups APPLICATION OF POWER APPARATUS TO RAILWAY SIGNALING 1215 at each location and so connected to a charging switch (previously described) that while one group is supplying power to the signals the other may be connected to a series charging line, in series with similar groups at other locations. Power stations, located at points where com- mercial power is available, supply these lines at a volt- age of from 350 to 600, as conditions require, and maintain a constant cur- rent of 5 amperes. A single-panel switchboard controls the generator and the two feeders, but the current in each line is main- tained at the proper charging value by means of series plate-type rheostats. These rheostats are mounted in some instances on the wall and in others on the back of a separate panel which also provides starting and control apparatus for the motor. The station is protected by choke coils and Type ME lightning arresters on each line, and the same kind of arresters are attached to the return wire at mile intervals. At the electric interlockings there are re- quired three distinct batteries, one floating on the charging circuit and two in duplicate ; the main or machine battery to deliver 110 to 142 volts for operating the signal and switch motors, the lock and indicator batteries 12 volts, and separate track batteries 2 volts for supplying power to each track circuit within the limits of the interlocking. These batteries are charged in series, or separately in various combinations, from specially designed mer- cury arc rectifiers having a high and low voltage tube. The low voltage batteries alone may be charged from the high voltage tube in series with a variable resistance. The New York Central uses the type of switchboard recently standardized by the Railway Signal Association for charging under the conditions just described, as well as the line charging panel and the motor and line control panel. The rectifier is a slight modifi- cation of the standard panel arranged to obtain the double voltage range. The most recent installation, shown in Fig. 1, is the interlocking near Rome, N. Y. Directly back of the motor-generator set is the two-way line charging panel for the signals on either side of the interlocking limits. The single feeder panel is for future signaling over the Rome, Watertown & Ogdensburg Railroad. The rectifier panel stands at the left of the four-panel board adjacent to the motor and line control panel. The two interlocking control panels are at the right. Short interruptions of the power supply or minor breakdown of part of the charging equipment at one of the 600-volt line charging stations causes little or no concern, but continued failure or destruction of the station would be a serious matter. To pro- vide against this emergency the railroad has fitted up a baggage car as a portable substa- tion. It contains a single cylinder 6-kw., 600-volt gasolene-engine-generator set, a 600- volt d-c. to 110-volt d-c. motor-generator set, a three-panel switchboard, and complete substation equipment. The car may be run on a siding and the charging line temporarily tied in. BOSTON 86 ALBANY RAILROAD A little over a year and one-half ago, the Bostoti & Albany put in service an instal- lation of d-c. automatic signals and inter- locking at Worcester, Mass. The top floor of the signal tower contains the interlocking Fig. 1. Power Station, Electric Interlocking, near Rome, N. Y. New York Central 1216 GENERAL ELECTRIC REVIEW machine, the ground floor the five-panel switchboard, power units and relay rack, and the basement the storage batteries. Three- Fig. 2. Railway Signal Battery Charging Apparatus Installed in Baggage Car for Emergency Use. New York Central fie Hudson River Railroad phase, 60-cycle, 440-volt power from a com- mercial source is delivered to the switchboard for the induction motors of the two sets and for a 10- kw., 440/220-volt single- phase step-down transformer that is connected to a mercury arc rectifier for charging the main 65-cell lead-type storage battery for the interlocking machine. The rectifier equipment is unique in that it is mounted on a 90-inch three-section panel containing instruments and switching equipment to match the rest of the switch- board. The interlocking battery is not furnished in duplicate and must there- fore be charged during operation. A fixed resist- ance may be cut into circuit to draw from the rectifier sufficient current to main- tain the arc on low fluctua- tions of load when circumstances require that the interlocking machine be operated directly from the rectifier. As it is not advisable to raise the voltage on the interlocking machine to the high value necessary to complete the battery charge, an end cell switch has been installed. One panel contains station lighting switches and 10 battery charging switches for the track circuits within the limits of the inter- locking. The local track batteries are charged from the rectifier, and the track and motor batteries on either side of the interlocking are charged in series, similarly to the method of the New York Central & Hudson River Railroad previously described, from a 550- volt d-c. railway source controlled from a switchboard at Jamesville, a few miles away. The charging line is carried through the d-p. d-t. lever switches on the right-hand panel, simply looping through the station. In case of failure of this source these switches may be thrown down onto an emergency generator circuit, the charging being controlled on this panel by the generator and two rheostats, one in each line feeder extending in opposite directions from the station. This generator is one unit of a three-unit emergency set, the other two units being an induction motor and a 110/175-volt d-c. generator to supplant the rectifier. One panel controls the charging of the dup- licate lock and indicator batteries from a small two-unit motor-generator set not shown in Fig. 3. Fig. 3. Power Equipment for Direct Current Signaling Installation on the Boston 8b Albany Railroad, Worcester, Mass. The commercial supply is practically im- mune from a prolonged failure, and as the provision for emergency is so complete and APPLICATION OP POWER APPARATUS TO RAILWAY SIGNALING 1217 the switching arrangement so flexible, the possibility of a total failure is most remote. LAKE SHORE & MICHIGAN SOUTHERN RAILWAY The Lake Shore & Michigan Southern Railway recently placed in service a battery charging equipment for the automatic inter- locking plant at Toledo, Ohio, the switchboard of which is rather unique. Two mercury arc rectifier equipments are provided, the panels of which match and line up with the switching panel, and the switching arrangement is such either separately or in scries with cither the main battery or the portable batteries; or it is possible to charge alone either the track batteries, the lock and indicator batteries, or a small number of ];ortable batteries from the low voltage tube on one of the rectifiers. This condition so seldom arises that it was deemed unnecessary to provide two tubes on both rectifiers. A six-pole throw-over switch is provided to interchange connections from the high voltage to the low voltage tube on the rectifier to meet this special condition. Fig. 4. Single-Phase Mercury Arc Rectifier and Battery Feeder Switchboard for Charging Signal Batteries, Lake Shore & Michigan Southern Railroad, Toledo, Ohio that the batteries may be charged in every conceivable combination. The battery equipment consists of one main 55-cell interlocking battery, two duplicate 6-cell group track batteries, two duplicate 10-cell group lock and indicator batteries, and a variable (20 to 90 cells) Edison portable battery. Under normal conditions the port- able batteries will be charged from one recti- fier and the main battery from the other. The track batteries and lock and indicator batteries are connected to d-p. d-t. battery transfer switches in such a way that the discharge circuits can never be broken. The batteries connected in the charging sides of these switches may be charged simultaneously The switchboard also provides four 220-volt single-phase a-c. lighting circuits, each supply- ing a number of transformers having secon- dary taps to provide 10, 11, 12, 13, 14 or 15 volts for lighting the signals. PENNSYLVANIA RAILROAD COMPANY The Pennsylvania Railroad has recently completed an installation of automatic block signals on the main line between New York and Pittsburgh, and between Philadelphia and Washington. This comprises a total of 895 track miles equipped with alternating- current automatic block signals, and 91.2 track miles changed from direct-current to alternating- current automatic signals. Over this distance 1218 GENERAL ELECTRIC REVIEW the signals are fed from a transmission line supplied at intervals from the company’s power plants, the spacing between plants being determined approximately by the load Fig. 5. Switchboard for Controlling Two 240-volt Single-Phase Generators and Two 3300-volt Single-Phase Feeders for Alternating Current Signaling System, Penn- sylvania Railroad of the intervening sections of the line. Each station has sufficient capacity to feed in both directions to adjacent stations. Under normal conditions each station may be operated at half-load feeding in one direction, or only alternate stations may supply power in both directions, the other stations being for emergency service. The line is further sectionalized at each signal location in such a way that should a short circuit occur the faulty section may be cut out and power fed to the remainder from the two adjacent stations, thus making all signals operative. It is important to note a high degree of standardization throughout the whole system. In 18 stations the steam-engine-driven units are all 35-kv-a., 220-volt, single-phase, 60- cycle generators. The feeder panels with one exception are all arranged to feed in two directions. Fourteen stations have two generating units each with individual gener- ator control panels, four stations have one unit and generator panel, and one station has a 25 kv-a. gasolene-engine-driven unit with generator panel and one-way feeder panel, the equipment of all panels for similar duty being identical. Fig. 5 illustrates a two- generator, two-way feeder switchboard, and Fig. 6 the installation at the station operated by the gasolene engine-driven unit. In order to minimize the responsibility of the operator each exciter has its own voltage regulator, so that synchronizing is simplified as much as possible. The power generated at 220 volts is stepped up to 3300 volts before going to the switchboard. Power circuits are made and broken on oil switches, and plug type dis- connecting switches are mounted on the panels. All parts customarily exposed, whether low tension or high tension, are either completely covered by asbestos lumber cases or bushings securely clamped, so that it is impossible for the operator to come in contact with any live part, at either front or back of board. When the movements of the semaphore blades are retarded by weight of sleet or snow, and it is advisable to hasten the movements, the line voltage is boosted 10 per cent without readjustment of the voltage regulators by opening a small lever Fig. 6. Railway Signal Power Station Installation, Pennsylvania Railroad switch at the side of the regulator base. Aluminum cell static dischargers are con- nected to the lines where they leave the sta- tion. APPLICATIONS OF POWER APPARATUS TO RAILWAY SIGNALING 1219 The transmission lines consist of two No. 4 or No. 0 B.&S. gauge copper wires heavily insulated and embedded in asphaltum pitch in wooden trunking approximately two feet under ground. The sectionalizing outfit at each signal location consists of an iron mechanism case enclosing a d-p. d-t. non- automatic oil switch, a short-circuit indicating relay, a 3300/110-volt, 600-watt or 1000-watt transformer, and two primary plug cutouts. The transformer is connected to the middle terminals of the oil switch, the two throws of which are independent, so that when both sides are closed the transformer is connected across the line feeding through; or the trans- former may be fed from either side with the other side open, or cut off entirely by opening both sides. The short-circuit indicating relay is connected in series with the line of the normal power supply side, and when actuated by heavy overload or short circuit the arma- ture plunger will latch up and give a per- manent indication until restored to normal by an attendant. When a short circuit occurs in any section, the relays in every sectionaliz- ing outfit between the generating station and the faulty section will be actuated by the abnormal current and indicate by the position of the plunger that trouble is beyond. An attendant will then open the outgoing side of the oil switch in the last sectionalizing case to the remainder of the line from power stations on the two ends. It is thus evident how in a very short time a faulty section may be cut free with minimum interruption Fig. 8. Turbine-Driven Self-Excited Alternator, Pennsylvania Railroad to the system. The relays in the outfits adjacent to an interlocking tower have their auxiliary contacts connected to an indicating lamp in the tower, to assist in locating the trouble. At Monmouth Junction, N. J., the Pennsylvania Railroad has installed two small steam turbine-driven alternating-current generators, 5- kv-a., 110-volts, single-phase self- excited. A duplicate set is installed at the North Philadelphia station, and a fourth, similar in every way, except for operation on compressed air, is in seWice at Rahway, N. J. These units are only 6 ft. 3 in. long, 28^ in. wide and 36j^ in. high. CENTRAL RAILROAD OF NEW JERSEY Fig. 7. Gasolene Engine Set in Power Hous^, Pennsylvania Railroad giving the indication, and the incoming side of the oil switch in the next adjacent sectional- izing case, in order to cut free the faulty section, after which power may be supplied The accompanying illustration (Fig. 9) is typical of ten installa- tions on the Central Railroad of New Jersey made during the past two years by the Union Switch & Signal Company, and indicates the standard for battery charging serv- ice for the particular kind of signaling installed. The motor-generator sets (in duplicate) are arranged for d-c. — a-c. or a-c. — d-c. con- version, depending on the particular kind of 1220 GENERAL ELECTRIC REVIEW commercial power available. The generators are 45-ampere, 20/50-volt shunt wound machines, for charging Edison A-0 225- ampere-hour storage batteries. The inter- and discharge currents of both sets of bat- teries without conflict. The more recent installation in the Jersey City Terminal yards provides a-c. track circuits and lighting in towers “A” and “B,” while direct current for charging the interlocking batteries is supplied from a mercury arc rectifier. Alternating current is supplied normally from a 575-volt source through either one of two duplicate 575/110- volt transformers and distributed to the various lighting and track circuits. Emerg- ency a-c. supply is available at 2200 volts. This is stepped down to 575 volts, and a transfer equipment consisting of two double- pole contactors and a control relay provides ^or automatically supplying power therefrom without noticeable interruption upon failure of the normal source, and automatic resump- tion upon its return. All this control equip- ment is mounted on a panel 76 in. high and 32 in. wide. The arrangement in tower “C” is somewhat different. The accompanying illustration. Fig. 11, shows only an a-c. feeder panel with transfer equipment similar to that in towers “A” and “B.” CHICAGO, MILWAUKEE & ST. PAUL RAILWAY The Chicago, Milwaukee & St. Paul Railway has recently put in service the last Fig. 10. Signal Tower, Central Railroad of New Jersey 40 miles of a 458-mile alternating-current automatic block signal installation, on which construction work was begun in 1912. This comprises five separate divisions, all double Fig. 9. Battery Charging Equipment, Central Railroad of New Jersey locking battery consists of two duplicate groups of 16 cells each, and the track batteries of two duplicate groups of 12 cells each. Each track battery is subdivided into six groups of two cells each, discharged in multiple and charged in series. The twelve groups of track batteries (six on charge and six on dis- charge) are so connected to the 13-blade charging switch that the multiple-series dis- charging groups are con- nected in series to the charging circuit and the series charging group in multiple-series to the track circuit on each throw of the switch without interrupting the track circuit supply. The four-pole double-throw transfer switch likewise interchanges the interlock- ing batteries without inter- ruption. The interlocking battery may be charged separately or in series with the charging group of track batteries, and the latter may be charged separately through small fixed resistance by a very simple switching equipment. By means of turn button type ammeter switches one ammeter serves to indicate both the charge APPLICATION OF POWER APPARATUS TO RAILWAY SIGNALING 1221 track, with ten substations, viz.. Savanna to Elgin, 111., having three substations; Lake to Rondout, one substation; Milwaukee to North La Crosse, three substations; Bridge Switch to Hastings, two substations; and Minneapolis to Hopkins, one station. From these stations 543 automatic signals and 96 semi-automatic signals are supplied. All stations receive their power from 60- cycle commercial source, and with one exception all stations on any one division are supplied from the same system so that the load between stations may be picked up by either station without interrup- tion or danger of interference between two unsynchronized power systems. Magnetic locks are provided on the oil switch at the Savanna station and on the oil switch feeding to Savanna in the Forreston two-cir- cuit station, to make connection between these two stations impossible, as the supply sources here are two independent systems. The panels are all 90 in. high and of natural black slate, with the exception of the station at Sparta, which is blue Vermont marble to match and line up with an existing board. Power is metered and controlled at the voltage received. The panel equipment consists of a single-phase watthour meter, an automatic oil switch with time-limit overload trip for each feeder, and a voltmeter for the bus. Transformers are located in the outgoing feeder circuits to step-up from the receiving voltage to 4400 volts for transmission. A spare transformer, equal in capacity to that of the heaviest feeder, is installed in each station, together with primary and secondary switching equipment. The stations on the ends of the section are single feeder, and the intermediate stations double feeder, and of such capacity that the total load may be carried by alternate stations if desired. Emergency operation is thus provided under all conditions, in a manner similar to that on the Pennsylvania Railroad already described. With the exception of the Portage station, the eommercial power supply seldom, if ever, fails. In order to guard against rather frequent interruption at the Portage plant, an auxiliary equipment has been furnished, which consists of a two-unit motor-generator set, the motor being of the synchronous type driving an a-c. generator to charge a 90-cell Edison storage battery. The switchboard and set are furnished with such automatic control equipment that upon failure of the a-c. power supply, the set will run from th6 storage battery, supplying the signal line from the a-c. machine at normal voltage and frequency without interruption. A synchro- nizing equipment is provided so that upon resumption of the commercial supply the a-c. machine may be synchronized and operation resumed as before. This equipment has been in satisfactory operation for over nine months. The Chicago, Milwaukee & St. Paul Rail- way is particularly fortunate in having ample and satisfactory commercial power available and has carried out the idea of standardizing power apparatus to a very high degree. NEW YORK, NEW HAVEN 8e HARTFORD RAILROAD Directly across the tracks from the Boston & Albany installation described is the inter- locking tower and power plant controlling the alternating-current signals and inter- locking on the New York, New Haven & Hartford Railroad. The tower is of pleasing architectural design, is of concrete construc- tion and three stories high. The upper story contains the interlocking machine, the ground floor the switchboard duplicate power units and relay racks, and the basement the storage batteries and transformers for the incoming line. The switchboard consists of two induction motor panels, two d-c. panels, a storage bat- tery panel, two a-c. generator panels, and the synchronizing and speed regulator equipment. The three units comprising the duplicate motor-generator sets are a three-phase, 60- cycle, 440-volt induction motor, a 7^-kv-a., single-phase, 60-cycle, 440-volt self-excited alternating-current generator, and a 10-h.p., 90/160-volt shunt wound d-c. machine. Only one set is in operation at a time, the other being held in reserve. Under normal conditions the motor sup- plied from the commercial power source drives the set, the signal circuits being supplied from the a-c. generator, while the d-c. machine either charges or floats on the storage battery. Upon failure of the com- mercial power supply the d-c. machine auto- matically acts as the motor of the set, operating from the storage battery. Speed is held constant by an automatic speed regu- lator. The battery has capacity sufficient to thus operate the system one-hour. Upon resumption of power, it is unnecessary to synchronize the motor, as it is of the induction type. 1222 GENERAL ELECTRIC REVIEW DELAWARE, LACKAWANNA 8t WESTERN RAILROAD A little less than two years ago, the Dela- ware, Lackawanna & Western Railroad put in service an electro-pneumatic interlocking plant at Montclair, N. J. The power plant of main battery are so connected that, when interchanging them from charge to discharge and vice versa, the discharge circuit is never interrupted. The track batteries are so con- nected to a five-pole double-throw switch that the two component groups of the charging set Fig. 11. ‘‘The Yankee** passing Signal Tower at Worcester, Mass. N. Y., N. H., fls H. R.R. shown in the illustration is located in the basement of the signal tower and consists of two duplicate induction motor-driven air compressors, duplicate sets of Edison A- 10 batteries for the interlocking and for track circuits, three motor-gener- ator sets for battery charging, and a switchboard to control all. The air compressors are each of 100 cu. ft. per minute capacity and of the four- cylinder two-stage type, and are driven through double- herringbone gears by three- phase, 60-cycle, ISOO-r.p.m. induction motors starting on external resistance in the rotor circuit and controlled from the switchboard. The motor-generator sets are of unit frame construc- tion. The motors are three- phase 60-cycle, 220-volt machines, and the shunt wound generators are rated for 75 amperes, 15 volts. The main batteries for the interlocking are arranged in two duplicate sets of 16 cells each, and the track batteries in duplicate sets of two groups, four cells per group, or a total of eight cells per set. The two duplicate sets are in series and those of the discharging set in multiple ; and by reversing the position of the switch the duty of the two sets of batteries, as well as the connections, are interchanged without disturbance to the discharge line. Fig. 12. Power Equipment for Alternating Current Signaling Installation on New York, New Haven & Hartford Railroad, Worcester, Mass. The switchboard is so arranged that, by running all three motor-generator sets at the same time, the track batteries may be charged from any one, and the main battery APPLICATION OF POWER APPARATUS TO RAILWAY SIGNALING 1 223 from the other two connected in series; but should any one set be disabled the main battery may be charged from the remaining two, and when the charge is coni]3lete the track batteries may be charged from either one of these. Thus by alternating the times of charge the two sets of batteries may be charged one at a time from the two motor- generator sets, so that the disability of the other set will not cripple the system. With the exception of the air compressor governor, which is located on the wall, the automatic starting equipment is all mounted on the switchboard. The air governor is set for operation between SO and 90 pounds per square inch. A six-pole double-throw lever switch connects one or the other of the compressors to the operating circuits. LONG ISLAND RAILROAD The recent electro-pneumatic a-c. signal installation on the Long Island Railroad at Jamaica, N. Y., requires four separate interlocking towers, all of which receive a-c. power at 2200 volts, 25 cycles, which is transformed to 220 volts for delivery to the switchboard. The compressed air for operat- ing the switches and signals is obtained from the company’s car shops at Morris Park, near tower “ R.” Both steam and electric trains pass through the interlocking, but by far the greater number are electric, as the lines to New York and Brooklyn are electrified. 500-volt d-c. propulsion current is supplied from the insulated third rail. In each of the two small towers, “R” and “MP,” the motor-generator set for charging the duplicate 7-cell lead type interlocking battery consists of a 220-volt, single-phase, 25-cycle induction motor and a 25-volt, 25-ampere shunt wound d-c. generator. The switchboard distributes at 220 volts single- phase to the induction motor and to the track circuits, and from the latter further trans- formation is made at each track section to a lower voltage. It also supplies one of two duplicate transformers for the signal lighting circuits through the upper contacts of a relay held in by energy from the a-c. circuit. Upon failure of the a-c. supply this relay connects the lighting circuits to the d-c. storage battery. At each of the two larger towers “J” and “JE” the switchboard distributes at 220 volts single-phase to the motor, track circuits and lights. On account of the more extensive distribution of the lighting feeders, it is not feasible to supply them at low voltage as from the two smaller towers. To provide the feature of having emergency power available for the lighting circuits when desired, the motor of the set is made of the synchronous type, excited from the d-c. machine, and upon failure of the a-c. supply the d-c. machine will run as a motor from the storage bat- tery and the a-c. machine as a single-phase generator, supplying only the lighting circuits. To govern this emergency action a master relay energized from the a-c. source having upper and lower contacts, an auto- matic starting equipment and two field rheostats for the d-c. machine, are re- quired. The connections to the two rheostats, are inter- changed by the master relay, one rheostat being in circuit when the machine is gener- ating and the other — for governing the speed of the set — when motoring. The control circuits are so connected through the relay contacts ^and a third blade of the lighting switches that should the a-c. power fail in the daytime, when the two light- ing switches are open, the set will come Fig. 12a Power Station in Electro-Pneumatic Interlocking Tower, Delaware, Lackawanna 6a Western Railroad 1224 GENERAL ELECTRIC REVIEW to a standstill if charging the batteries, or remain at a standstill if in this condition. When the lighting switches are closed, the set, if charging the battery, will continue to run Fig. 13. “JE” Tower, Long Island R.R., Jamaica, N. Y. from the battery; but, if the set is at a standstill, the automatic starting equipment will immediately become active and start the set, throwing power on the lighting cir- cuits from the a-c. machine within a very few seconds. The automatic equipment is arranged so that upon reversal of the set the lighting circuits are cut free from the 220-volt bus, otherwise the set would become overloaded and pump back on the supply line. A switch is provided in the starting control circuit so that the set may be started at any time desired. The switchboards and sets in the two larger towers are exactly the same in design and arrangement, the only difference being in capacity of equipment, to provide in one a normal charging rate of 40 amperes and in the other 60 amperes. SOUTHERN RAILWAY The General Railway Signal Company have now under construction four signal instal- lations on the Southern Railway which require seven substations and two power stations. Four of the substations ; Lynchburg, Va., Morristown, Tenn., Howell and Gaines- ville, Ga., are exact duplicates, receiving the power from commercial sources at 2200 volts, three-phase, 60-cycle and delivering 30 kv-a. at 4400 volts, three-phase. The substation at Coster, Tenn., receives power at 220 volts and delivers 30-kv-a. at 4400 volts, three- phase, 60-cycle. The two remaining sub- stations are “outdoor type,” that is, a steel switch house is located at the foot of a pole structure supporting the transmission line and houses the switchboard, instruments, meters and instrument transformers. The power transformers, disconnecting switches, choke coils and lightning arresters are sup- ported on the pole structure. The power houses at Monroe and Whittles, Va., are exact duplicates except in capacity. In these nine stations standardization has been strenuously adhered to. One power station has a capacity of 50 kv-a., three-phase, and the other power station and six sub- stations 30-kv-a., three-phase; the remaining substation, connected temporarily single- phase, will ultimately be the same. All stations bear a similarity in layout and arrangement of apparatus. Disconnecting switches are provided at the low tension side of power transformers and at the line side of the high tension apparatus. The automatic oil switch, ground detector, current and potential transformers for the meter instru- ments, inverse time-limit overload relay, choke coils and lightning arresters are connected in the 4400-volt circuit in the order given. One potential transformer is between the power transformer and the oil switch to indicate whether power is available from the supply. The switchboards of the four duplicate substations consist of two panels 90 in. high, each of two sections of natural black slate mounted on pipe supports and surmounted by the ground detector. Two incandescent lamps in goose neck brackets afford ample illumination for the horizontal edgewise instruments directly beneath. Current may be read in any phase on the one ammeter by a three-way ammeter switch, and a short- circuiting switch is provided to protect the instrument against the heavy starting load. Switches are provided for station lighting. The watthour meter is mounted on the sub- base. The two power house switchboards each consist of three panels similar in height of sections, material and mounting to the four substation switchboards. The high tension feeder equipment and its comparative arrange- ment in the circuit is identical with that in the substation feeders. As the generator voltage is 220, the triple-pole fused main switch acts as a disconnecting switch for the low tension side of the power transformer. A voltage regulator and the customary equip- APPLICATION OF POWER APPARATUS TO RAILWAY SIGNALING 1225 ment for controlling the generator and its exciter are provided. The substation switchboard at the Coster power house consists of two panels 90 in. high, each of three sections of blue Vermont marble mounted on angle iron supports to match and line up with the existing power switchboard. The equipment is identical with the two power-house switchboards, except for the omission of the regulator and panel, rheostat handwheel, exciter switch and exciter instruments, with the consequent reduction in width of the low tension panel. Fig. 14. Front View of Outdoor Substation, Three-Phase, 4400-Volt Railway Signal Line, Southern Railway key socket provides ample light for reading instruments. SIGNALING ON INTERURBAN LINES Hand-controlled lamp signals for turnouts and sidings and stretches of single track have been in use for some time, as well as the automatic permissive signals so common on single track portions of the city lines which permit movement of any number of cars in only one direction until the section is clear before allowing a movement in the opposite Fig. 15. Back View of Outdoor Substation shown in Fig. 14 Figs. 14 and 15 show front and rear views of the first outdoor type substation of this par- ticular class for railway signal purposes. Two of these stations are to be installed, one at Inman, S. C., and the other at Austell, Ga. They are duplicates except that the latter is temporarily connected single-phase, although the full three-phase equipment is furnished so that it may be made three-phase in a few moments by slight changes in the instrument transformer secondary circuits. The equip- ment is the same as that for the other sub- stations, except that no provision is made for reading current. The instrument trans- formers and high tension connections are clearly shown in the back view. A lamp with direction. These, however, place no restriction on the spacing between cars and give no indication as to the condition of the track ahead. Interurban service is akin to railroad service in that it requires heavier rolling stock, increased speed and a definite time sehedule to be maintained under all condi- tions of weather. Such rapid strides have been made in the development of inter- urban equipment in the past few years that automatic block signaling has become not only a refinement, but a necessity. The latter half of the year 1913, saw a great many extensive signal installations on inter- urban roads, notably the lines in Ohio, 1226 GENERAL ELECTRIC REVIEW Indiana and Illinois, on the Scranton & Binghamton line in Pennsylvania, and on the New York State Railways near Rochester and Syracuse. In nearly every instance the switchboards, power transformers and switching equipment are installed in the same substation with the rotary converters that supply the motive power. Power is taken from the mains supplying the rotary converters (usually 370 volts, 25 cycles) and stepped up through duplicate transformers to 2200 volts for distribution to the 2200/110-volt trans- formers supplying the block sections. In some instances the transmission voltage is 4400. In most cases the switchboards are 90 in. high and of two or three sections, slate or marble, to match the existing switchboard. Where unnecessary to line up with existing boards, 48 in. panels on 76 in. supports are usually furnished. The controlling equipment for a two-circuit-feeder panel usually consists of two fused lever switches supplying the step-up transformers, two oil switches with inverse time-limit overload relays and alarm bell attachment, two current transformers and ammeters with an illuminating lamp, and an alarm bell to give notice of an open oil switch. Boards installed at the end of the signaled territory are only single-circuit, but in those cases where the signaling will be extended at some future time the boards in many instances have been made of ample size to contain the equipment for two circuits, although equip- ment for only one circuit is furnished. On many switchboards that have the ammeter connected in the supply side of the step-up transformer, it has been necessary to furnish a switch to short circuit the ammeter on energizing the line because of the heavy momentary rush which sometimes occurs when connecting the transformer — particularly a low frequency transformer — to the supply line under load. To eliminate this trouble and get away from an oil switch which has a rupturing capacity far in excess of what is required on such low capacity circuits a switchboard has been developed and built for the Union Switch & Signal Company, for an installation on the Scranton & Bing- hamton road. The double-pole circuit breaker in the low tension side furnishes ample overload protection, and ordinary outdoor type plug cutouts guard against possible trouble from the outside. The low tension sides of the duplicate transformers are connected to the d-p. d-t. lever switch and the high tension sides to the plug switches and only one pair of plugs furnished, so that the inactive transformer will be dead. For two circuits either duplicate panels or a panel with double this equipment would be furnished. NEW YORK, WESTCHESTER fis BOSTON RAILWAY The New York, Westchester & Boston Railway, connecting White Plains and New Rochelle with New York City, is the only strictly suburban electric railroad built from the ground up without an old road bed as a basis. It consists of a four-track section approximately seven miles in length con- necting with the four main tracks of the Harlem River branch of the New York, New Haven & Hartford Railroad system near 174th Street, New York City, and extending northward to Columbus Avenue, Mount Vernon, where it separates into two double- track lines, one continuing northward to White Plains, 9.4 miles, and the other eastward to New Rochelle, 2 miles, where it again connects with the New Haven system. Transportation systems in New York City are universally direct-current furnished by substations ; this road, however, from its connections with the New Haven system and the successful operation of the installation there existing, naturally installed the same system. Power is purchased from the New Haven power house at Cos Cob, Conn., the connection being made at the end of the New Rochelle branch sixteen miles distant. The transmission is three-phase, 11,000 volts, the conductors being carried on the extended posts of the steel compound catenary struc- tures. Though only one phase is used for propulsion, the three-phase circuit is carried from the point of supply to the machine shops, elevator motors, pumps, and substation for the signal system. On steam roads either direct- or alternating- current signal circuits may be selected; on roads having direct-current for propulsion using both rails for both propulsion and signal current, the latter must be alternating; but on roads using alternating-current for bdth propulsion and signaling, employing both rails for both circuits, the frequency of the latter must not be a low harmonic of the former. This is necessary because of the fact that the signal relays must be selective as to frequency. Suppose the propulsion current to be 25-cycle and the signal current APPLICATION OF POWER APPARATUS TO RAILWAY SIGNALING 1227 60-cycle, each supplied from a different source. Now if the former should rise to 30 cycles, or the latter drop to 50 cycles, the frequency of the signal circuits would be just twice that of the propulsion circuit and serious trouble result from false signal indi- eations. To obviate such difficulties and maintain a certain fixed ratio between the frequencies of the two circuits, a motor-generator set supplied from the same source is necessary. Ordinary fiber-insulated rail joints at the ends of the blocks serve to isolate the track circuits in each block; but to permit the con- tinuous flow of the return propulsion current imped- ance bonds are installed in pairs at eaeh block end across the two rails, one on each side of the insulated joints. These are coils wound on an iron core, with the middle taps of the coils of each pair connected together. They are enelosed in an iron case mounted between the rails with the top practically flush with the surface of the ballast. An installation is shown in Fig. 8 of the first article of this series Fig. 16. Exterior of New York, Westchester 6c Boston Rwy. Signal Substation, Columbus Ave., Mt. Vernon, N. Y. (December, 1913). The propulsion current passes into both ends of one bond, through the common wire, and into the two rails of the other block through the two ends of the other bond ; and thus, by setting up neutraliz- ing magnetic fields in each bond, passes across the block section with a negligible energy loss. As the signal current flows in opposite direc- Interior View of Signal Substation shown in Fig. 16 tions in the two rails, it flows through the bond from end to end, and as the bond is highly inductive, a choking effect is introduced which permits only a negligible portion to pass through, shunting practically all the track circuit current through the track relays. The signal substation at Columbus Avenue, Mount Vernon, is a brick structure of one story, with a high tension gallery at one end for the entrance of the two three-phase, 11,000-volt duplicate lines. Only four wires are brought into the building, as the completing wire for each set of lines eomes from the grounded tracks. The gallery contains the high tension multigap lightning arresters, disconnecting switches, choke coils, a d-p. d-t. disconnecting switch for selecting operation between the two pair of lines, high tension series inverse time-limit, overload relays for tripping the two main oil switches downstairs, and high tension instrument transformers, all insulated to stand a surge potential of 30,000 volts. Surges are frequently set up by disturbances on the propulsion circuit and the phases are badly unbalanced because the voltage regu- lators on the Cos Cob generators regulate on the “propulsion” phase, which necessarily fluctuates greatly. The ground floor of the substation is divided into three parts, viz., the high voltage section directly under the gallery containing 1228 GENERAL ELECTRIC REVIEW the two line switches and duplicate banks of step-down transformers, the operating room, containing the switchboard and duplicate motor-generator sets, and the battery room. From the disconnecting switch in the gallery selecting between the two incoming lines, all the apparatus is in duplicate. One complete equipment consists of a small panel for a d-p. s-t. oil switch (double-pole because one leg of the three-phase circuit is grounded) ; three delta-connected transformers stepping down from 11,000 to 440 volts; a four-unit motor-generator set consisting of 75-h.p., Form K induction motor, a 10-pole, 37-kv-a., 2200-volt, 60-cycle single-phase alternating- current generator with 3-kw., 125-volt exci- ter, and a direct current machine to operate between 110 and 160 volts as a generator to charge the storage battery, and 110 to 90 volts as a 75-h.p. motor; and controlling equip- ment for each machine on the switchboard. One set is of sufficient capacity to take care of the probable ultimate requirements of the road, so that the other may be always kept as a spare. Under normal conditions the d-c. machine is either charging or floating on the battery. Upon failure of the power supply, the low voltage trip attachment opens the main line oil switch, cutting off the induction motor, whereupon the d-c. machine acts as the motor of the set. The speed regulator on the d-c. machine and the voltage regulator on the a-c. machine are so nicely adjusted that a failure and subsequent resumption of supply power produces no noticeable effect on the signal supply. Upon resumption of power the operator closes the main line switch (it being unnecessary to synchronize as the motor is of the induction type), and the operation is resumed, the d-c. machine charging at a greater rate because of the depleted condition of the battery. The switchboard consists of d-c. generator- motor panel, induction motor panel, and a-c. generator panel, each in duplicate, and the three twin-circuit feeder panels. The d-c. panels each have a starting switch for starting the set from the storage battery, although it is usually started from half voltage taps on the transformers through double-pole, double-throw lever switch on the motor panel. The d-c. panels also have circuit breaker, double reading ammeter, line switch and rheostat handwheel for regulating the charging. On the back of each panel is another rheostat that is cut into circuit by the speed regulator when the d-c. machine is motoring, but this is set to maintain proper speed under full load. The battery is of sufficient capacity to drive the set under full load for 25 minutes, begin- ning with a full charge, before the voltage falls to 90. When it reaches this value a circuit breaker located on the back of the board and calibrated to trip out at 90 volts, or under, will open the circuit in order to save the battery from destruction. This pre- caution is hardly necessary, for failures have been at most only of few minutes’ duration. The generator panels also provide exciter control, and the speed regulator relays and contactor equipment are mounted on the subbases. The three feeder panels feed in all three directions from the junction point, each supplying twin single-phase lines through a d-p. d-t. oil switch having a common trip coil. The duplicate signal mains carried on the extended posts of the catenary bridges supply step-down transformers for the signals and track circuits. The lines are run in pairs so that should one become grounded or defective, or require repairs at any point, that portion between the two adjacent sectionalizing outfits may be cut out and operation con- tinued through the other. The seven interlocking plants are all built along similar lines. Direct current for operating the switches and interlocking func- tions is furnished from a 110-volt storage battery. The switchboard. Fig. 17, taking power at 110 volts, 60-cycle, single-phase from duplicate transformers supplied from the signal transmission line for furnishing power to the track circuits and lights on either side of the tower controls the small motor-generator set for charging the battery by continuous floating. FROM THE CONSULTING ENGINEERING DEPARTMENT OF THE GENERAL ELECTRIC COMPANY 1229 FAULTY-FEEDER LOCALIZER This panel carries on its front the indicating lights and also the switches necessary for retaining the balanced condition of the relays under different operating conditions. This balancing operation is very simple. If a feeder is in service its corresponding relay switch is placed in the upper position. If the feeder is out of service the relay switch is thrown down. In the operation of a high-tension electrical system, it frequently happens that a single wire arcs to ground. This arc may be caused by lightning, weak insulation, or some remote disturbance on the system. Unless this arc is extinguished it will very quickly cause considerable damage such as burning off the wire, breaking an insulator, or arcing to the other phase wires, thus causing a short circuit (a non- grounded neutral system is here as- sumed). It is the function of the arcing-ground suppressor to promptly extinguish this arc be- fore damage results. Suppose the fault to be of per- manent nature. If there are a num- ber of feeders connected to the bus there is no way of telling on which one the arc has occurred. The faulty-feeder localizer is designed to select the faulty feeder and light the corresponding indicating lamp, thus giving this important infor- mation to the station operator. With this knowledge the operator can substitute a good feeder for the faulty one, cut off the defective feeder, open the switch of the arc- ing-ground suppressor and the sys- tem has been returned to its nor- mal operation without even a mo- mentary delay to any substation. (This assumes that the insulation of the system is high enough to stand oper- ation with one-phase wire grounded for a short time.) It should be noted that while the faulty-feeder localizer and arcing ground suppressor form an ideal combination either device may be operated independently. The localizer consists of a set of inter- connected relays (one relay for each feeder). These relays have two coils each, the pulls of each coil of the pair are balanced against each other, and the only relay which operates is the one in which an unbalancing occurs. By properly connecting up the relays, they are made independent of all load current, no matter how unbalanced. A time-limit device is added to the relay to make it independent of momentary surges. These two parts form i a unit and there is one unit for each feeder. The relays are mounted on the back of a panel. Faulty-Feeder Localizer The relays are operated from the feeder current transformers. It is necessary to have a current transformer in every high-tension wire of every cable on which it is desired to operate the localizers. The transformers in a single feeder have to be of the same type and ratio; however, it is not necessary for transformers on different lines to be similar. It is possible to use either the meter trans- formers or the overload relay transformers (provided a complete set is installed on each feeder) without interfering with either of these devices. An alternate arrangement is to install separate current transformers for the localizer. The localizer is not intended to prevent a fault developing and consequently, will not do so. It only indicates the defective line after the fault has developed. A. H. D. 1230 GENERAL ELECTRIC REVIEW QUESTION AND ANSWER SECTION The purpose of this department of the Review is two-fold. First, it enables all subscribers to avail themselves of the consulting service of a highly specialized corps of engineering experts, or of such other authority as the problem may require. This service provides for answers by mail with as little delay as possible of such questions as come within the scope of the Review. Second, it publishes for the benefit of all Review readers questions and answers of general interest and of educational value. When the original question deals with only one phase of an interesting subject, the editor may feel warranted in discussing allied questions so as to provide a more complete treatment of the whole subject. To avoid the possibility of an incorrect or incomplete answer, the querist should be particularly careful to include sufficient data to permit of an intelligent understanding of the situation. Address letters of inquiry to the Editor, Question and Answer Section, General Electric Review, Schenectady, New York. Announcement In the 1914 Annual Index of the General Electric Review, included in this issue, there appears a complete classified index of the Question and Answer material for this year. It is recom- mended that this index be kept at hand in order that the greatest service to be derived from the solutions of past problems may be conveniently available. — Editor. TRANSFORMER: EXPLOSION (122) What is the initial cause that later results in an oil-cooled transformer blowing-up or exploding? What is the action following the primary cause that actually produces the explosive effect? What attention is given in the construction of standard transformers to the prevention of explosions? The condition which renders favorable the possi- bility of an explosion within the tank of an oil-cooled transformer is that of an accumulation of hydro- carbon gases and hydrogen mixed with air between the surface of the oil and the transformer cover. Providedno ventis supplied whereby the inflammable gases may escape from the case, an accumulation of them may result from an electric arc or succession of arcs beneath the oil surface. Although confined, no inflammable mixture of gases and air will explode unless raised to its flash temperature by a flame, spark, etc. Where explo- sions have occurred, the ignition may be attributed to an arc, or to corona on the conductors or leads, above the oil surface. Since it is far preferable to avoid the possibility of having an explosion occur and since it has been found impracticable to design a tank to resist a severe explosion should it take place, standard transformers are equipped with “breathers” or gas vents which, besides minimizing the con- densation of moisture, permit the escape of the generated gases fast enough to prevent the pro- duction of a highly-explosive mixture. R. K. W. CATENARY TROLLEY CONSTRUCTION: STRESS FORMULAE (123) Will you please publish or furnish references to a set of formulae from which the stress occur- ring in the messenger cable and in the trolley wire, as used in catenary construction, may be obtained. It is desired that they apply to a line having hangers about 10 ft. apart and spans varying from 90 to 150 ft., and that they take into account variations of temperature from — 20 deg. to -|-120 deg. F. and at least an 8-lb. wind and a inch ice load, also combinations of these conditions. As far as we know, no set of formulae has been arranged that will give exact results when applied to catenary trolley construction. Since the mes- senger cable has approximately uniform loading only at normal temperature, ordinary transmission line formulae are not strictly correct. They are, however, often used where actual test measure- ments are not at hand. Useful formulae have been published at various times of which consideration may be given to the following: Proceedings A.S.C.E., June, 1908 — Mr. R. D. Combs. Elect. Rwy. Journal, October, 1908 — Mr. R. L. Allen. Overhead Electric Power Transmission, Mr. Alfred Still. Handbook on Overhead Line Construction — N.E. L.A. C.J.H. TURBINES: RELIEF VALVES LOW-PRESSURE END (124) What is the reason for not installing relief valves on the low-pressure end of Curtis turbines? Any small valve which could be provided on the shell of a large turbine to allow for a discharge into the station could only be considered as a signal or alarm, for it would not be practicable to place in such a position on the machine a valve that would be sufficiently large to be of any material benefit in preventing excessive pressure in the shell. In fact, any small relief valve placed on a large turbine is more liable to prove to be a source of danger than to be one of benefit, for the reason that the station operators might consider this valve would prove to some extent a safeguard in operation which, of course, it could not. The larger the turbine the greater the degree to which this statement holds true. Operating engi- neers, realizing this, arrange to install an atmos- pheric relief valve on the condenser or on a con- nection between the turbine and the condenser. This valve is made to have sufficient capacity to prevent an excessive pressure being built up in the shell should the condenser fail at any time. In the case of small turbines it would be practi- cable, of course, to place a relief valve of ample dimensions on the machine. However, it has been commonly experienced that in practically every case the operator prefers an atmospheric relief valve that can be piped up to discharge out of doors; and, consequently, since it seems best, the uniform practice of not installing low-pressure relief valves on all size Curtis turbines has been adopted. E.D.D. GENERAL ELECTRIC REVIEW XIII Sales Offices of the General Electric Company This page is prepared for the ready reference of the readers of the General Elec- tric Review. To insure correspondence against avoidable delay, all communica- tions to the Company should be addressed to the sales office nearest the writer. Atlanta, Ga., Third National Bank Building Baltimore, Md., Munsey Building Birmingham, Ala,, Brown-Marx Building Boston, Mass,, 84 State Street Buffalo, N, Y,, Electric Building Butte, Montana, Electric Building Charleston, W, Va,, Charleston National Bank Building Charlotte, N. C,, Commercial National Bank Building Chattanooga, Tenn,, James Building Chicago, III,, Monadnock Building Cincinnati, Ohio, Provident Bank Building Cleveland, Ohio, Illuminating Building Columbus, Ohio, Columbus Savings & Trust Building Dayton, Ohio, Schwind Building Denver, Colo., First National Bank Building Des Moines, Iowa, Hippee Building Detroit, Mich., Dime Savings Bank Bldg. (Office of Agent) Duluth, Minn., Fidelity Building Elmira, N. Y.. Hulett Building Erie, Pa., Marine National Bank Building Fort Wayne, Ind., Fort Wayne Electric Works Indianapolis, Ind., Traction Terminal Building Jacksonville, Fla., Heard National Bank Building Joplin, Mo., Miners’ Bank Building Kansas City, Mo., Dwight Building Knoxville, Tenn., Bank & Trust Building Los Angeles, Cal., 124 West Fourth Street Louisville, Ky., Starks Building Memphis, Tenn., Randolph Building Milwaukee, Wis., Public Service Building Minneapolis, Minn., 410 Third Ave., North Nashville, Tenn., Stahlman Building New Haven, Conn., Second National Bank Building New Orleans, La., Maison-Blanche Building New York, N. Y., Hudson Terminal Building Niagara Falls, N. Y., Gluck Building Omaha, Neb., Union Pacific Building Philadelphia, Pa., Witherspoon Building Pittsburg, Pa., Oliver Building Portland, Ore., Electric Building Providence, R. I., 1012 Turks Head Building Richmond, Va., Virginia Railway and Power Building Rochester, N. Y., Granite Building Salt Lake City, Utah, Newhouse Building San Francisco, C.\l., Rialto Building Schenectady, N. Y., G-E Works Seattle, Wash., Colman Building Spokane, Wash., Paulsen Building Springfield, Mass., Massachusetts Mutual Building St. Louis, Mo., Pierce Building Syracuse, N. Y., Onondaga County Savings Bank Bldg. Toledo, Ohio, Spitzer Building Washington, D. C., Evans Building Youngstown, Ohio, Wick Building For Texas, Oklahoma and Arizona business refer to South- west General Electric Company (formerly Hobson Electric Co.) Dallas, Texas, 1701 No. Market Street Houston, Texas, Third and Washington Streets El Paso, Texas, 500 San Francisco Street Oklahoma City, Okla., Insurance Building For Hawaiian business address Catton Neill & Company, Ltd., Honolulu For all Canadian business refer to Canadian General Electric Company, Ltd., Toronto. Ont. For business in Great Britain refer to British Tiiomson-Houston Company, Ltd., Rugby, England FOREIGN OFFICES OR REPRESENTATIVES: Argentina: Cia. General Electric Sudamericana, Inc., Buenos Aires; Australia: Australian General Electric Co., Sydney and Melbourne; Brazil: Companhia General Electric do Brazil, Rio de Janeiro; Central America: G. Amsinck & Co., New York, U. S. A.; Chile: International Machinery Co., Santiago, and Nitrate Agencies, Ltd., Iquique; China: Andersen, Meyer & Co., Shanghai; Colombia: Wesselhoeft & Wisner, Barranquilla; Cuba: Zaldo & Martinez, Havana; England: General Electric Co. (of New York), London; India: General Electric Co. (of New York), Calcutta; Japan and Korea: General Electric Co. and Bagnall & Hilles, Yokohama; Mitsui Bussan Kaisha, Ltd., Tokyo and Seoul; Mexico: Mexican General Electric Co., Mexico City; New Zealand: The National Electrical & Engineering Co., Ltd., Wellington, Christchurch, Dune- din and Auckland; Peru: W. R. Grace & Co., Lima; Philippine Islands: Frank L. Strong Machinery Co.. Manila; South Africa: South African General Electric Co., Johannesburg, Capetown and Durban. General Electric Company General Office: Schenectady, N. Y. Member of the Society for Electrical Development, Inc. “DO IT ELECTRICALLY” XIV GENERAL ELECTRIC REVIEW T i ■V k i r ^ 1 u Preserve Your Copies of GENERAL ELECTRIC REVIEW Let us do your binding, BINDING I Black Half Morocco Leather. $2.00 Maroon Heavy Buckram $ 1.00 BOUND VOLUMES (1913, 1914) Black Half Morocco Leather.,... $ 4.00 Prices include carrier's charges one way. Forward your copies by mail or express (prepaid) and remit by money order or check. GENERAL ELECTRIC REVIEW SCHENECTADY, N. Y. GENERAL ELECTRIC REVIEW XV w All Silent Chains Look Alike But there is none possessing the Liner Type Joint of Link-Belt Silent Chain * 't ’HE SUCCESS of the Link-Belt Silent Chain is due almost entirely to ^ the superiority of its joint construction. The segmental liners or bush- ings, which are removable, extend across the entire width of the chain, thus doubling the bearing surface and halving the bearing pressure on the joint. The bushings (or liners) are case hardened, and bear upon the case-hardened pin. The latter is free to, and does, rotate with reference to the bushings and presents every particle of its surface for wear. As a result it wears uniformly, keeps round, and the chain maintains to the end its high initial efficiency, (98.2% on actual test). Write for Link-Belt Silent Chain Data Book No. 125. LINK-BELT COMPANY PHILADELPHIA CHICAGO INDIANAPOLIS New York 299 Broadway Boston 49 Federal Street Pittsburgh 1501-3 Park Bldg. St. Louis Central Nat’l Bank Bldg. Buffalo 698 Ellicott Square Detroit 911 Dime Bank Bldg. Cleveland Rockefeller Building Montreal, Can John Millen & Sons. Ltd. Seattle 512i First Avenue S. Denver Lindrooth, Shubart & Co. San Francisco Meese & Gottfried Co. New Orleans Whitney Supply Co. Birmingham General Machinery Co. Los Angeles 204 N. Los Angeles St. Minneapolis Link-Belt Supply Co. o, o 'o. Average Hours per day The time to sell High Efficiency EDISON MAZDAS T^ECEMBER, the darkest month, is also the busiest month of the year for re- tail stores. For the Holiday trade, stores require a great abundance of light. To attract attention to window displays and to invite people inside, the store fronts at this season are always brilliantly lighted. Here, then, is a profitable field for thousands of the big, powerful, high-elfi- ciency, gas-filled, EDISON MAZDA Lamps, not only for exterior lighting but also for use inside the store. Send out your salesmen now with samples to call at all the stores in town. Advertise! Circularize! But be sure that your own store front and windows are evidence that you practice as you preach. Be sure that the name EDISON appears on the lamps you sell — or buy — their wonderful efficiency and unrivalled reputation make them quick sellers. Remember too that factories, theatres, armories, churches, dance halls, motion picture houses, hotels and many other places offer countless opportunities for “high-efficiency” installations. LAMP WORKS ^Jhis owiAm m all OF GENERAL ELECTRIC COMPANY General Sales OflSce. Hairison.N. J. gges Agencies Eve^rwhere GENERAL ELECTRIC REVIEW XVII EDISON DAY RESULTS p ARLY returns from the “front” are unanimous in report- ing remarkable success for the Edison Day campaign. It is by far too early even to estimate on the total results. But this we know — that the progressive lighting companies and agents in nearly all of the more important cities and towns of the United States have co-operated with us in a way sure to make Edison Day an anniversary to be remem- bered. That this country-wide campaign has greatly stimu- lated the sale of Edison MAZDA Lamps is now evident. That the results will be beneficial is clear. Just how long this campaign will be felt in any locality depends largely on how aggressively it is followed up in that locality. All those who ran local Edison Day cam- paigns showed their wisdom— and a word to the wise is sufficient. ^This symbol on oU EdisonMtudoQiitKif EDISON LAMP WORKS OF GENERAL ELECTRIC COMPANY General Sales Office. Harrison.N. J. Agencies Eveiywhere c/DnUend ^tCbodsEiedriar XVIII GENERAL ELECTRIC REVIEW The Babcock & Wilcox Company 85 Liberty Street, New York Water Tube Steam Boilers Steam Superheaters Mechanical Stokers Works: Barberton, Ohio; Bayonne, N. J. Built like a Battleship! The foundation and “hull” of a Wabash steel car are built of solid steel-bolt-riveted steel plates. Ease of mind, as well as ease of body, is provided by trains via WABASH between St. Louis and Kansas City eight fast trains daily between these cities, via Wabash. |^"FOm)WTHEnAG J. D. McNamara, General Pas.enger Agent St. Loui., Mo. TOOLS FOR ELECTRICAL CONSTRUCTION WORK We make a specialty of tools used in electrical construc- tion and maintenance work. Communicate with us for any requirements for linemen, construction gangs, signal men, electricians and kindred artisans. Fifty years’ association with the manufacture of tools has made us familiar with the special requirements. We manufacture the “Klein Line” of tools and sell such other lines as we have found reliable which will mesh in with the products of our own manufacture to make a complete layout of linemen’s, electricians’ and construction tools. We manufacture in our own factories; Splicing Clamps, Climbers, Wire Grips, Lag Screw Wrenches, Wire Twisters, Pocket Tool Sets, Tree Trimmers, Tackle Blocks, Trolley Wire Grips, The “Haven’s” Wire Grip, “Chicago” Wire Grip, Reel Jacks, Wire Reels, Pike Poles, Pole Jinnies, Steel Digging and Tamping Bars, Post Hole Augers, Cant Hooks, Carrying Hooks, Pliers, etc., and we have a large stock of miscellaneous tools always on hand. Catalogs sent on request. MATHIAS KLEIN & SONS CANAL STATION 71 - - - - CHICAGO INDIA MICA & SPLITTINGS D. JAROSLAW 19 TOWER HILL LONDON ENGLAND Silk For Electrical Purposes Silk for Insulat- ing Finest Wire raiding Silk .yle & Co. NEW YORK CITY All Kinds B William R 225 Fourth Ave., Cor. 18th St. GENERAL ELECTRICtREVIEW XIX We Finance Extensions and Improvements to Electric Light, Power and Street Railway properties which have established earnings. If prevented from improving or extending your plant because no more bonds can be issued or sold, or for any other reason, correspond with us. Electric Bond and Share Company Paid-up Capital and Surplus, $12,500,000 71 Broadway, New York Dealers in Proven Electric Light, Power and Street Railway Bonds and Stocks BRASS, BRONZE, COPPER AND The American EXTRUDED METAL GERMAN SILVER Sheets, Rolls, Plates, Wire and Rods,Seam- less and Brazed Brass Company Rods, Special Shapes and Pressed Metal Parts. Tubing. Mouldings, Angles and Channels, Circles, Blanks and Shells. Manufacturers of Brass, Bronze, Copper BARE AND INSU- LATED COPPER WIRE AND CABLE “K.K.” Weather- TOBIN BRONZE— PHOSPHOR BRONZE and German Silver Proof and Slow-Burn- ing Wire. Round and Flat Magnet Wire, Office Plates, Wire, Rods and Seamless Tubes. Mills and Factories and Annunciator Wire. Ansonia Brass and Copper Branch, BENEDICT Ansonia, Conn. DRAWN COPPER NICKEL WHITE Benedict and Burnham Branch, FOR ELECTRICAL METAL Waterbury, Conn. PURPOSES Seamless Tubing, Coe Brass Branch, Torrington, Conn. Rectangular Bars and Sheets, Wire, Rods Coe Brass Branch, Ansonia, Conn. Strips, Commutator and Ingots. Kenosha Branch, Kenosha, Wls. Waterbury Brass Branch, Waterbury, Conn. Copper. XX GENERAL ELECTRIC REVIEW Pipe and Boiler Coverings ASBESTOS MATERIALS of all kinds SOLD AND APPLIED Production ' is possible if the mechanic is equipped with Packings ASBESTOS, RUBBER, FLAX, STEAM, WATER, AMMONIA OIL Starrett Tools These tools are designed to serve a variety of purposes and are made so that they stand years of service. Is your factory taking advantage of every method that will increase its production? Stnd for Catalog No. 20, and see if there is not something in it which you should have. Robert A. Keasbey Co. 100 No. Moore Street New York EXPERT ADVICE ON APPLICATION We manufacture Fine Mechanical Tools Bevels, Calipers and Dividers, Center Te8ters,Clamps, Drill Blocks, Gauges, Hack Saws and Frames, Levels, Micrometers, Rules, Scribers, Speed Indicators, Squares, Test Indicators, Etc. The L. S. Starrett Co. WORLD’S GREATEST TOOL MAKERS Athol, Mass. 42-161 The Gamewell Fire Alarm Telegraph Company General Offices and Works: NEWTON UPPER FALLS, MASS. Fire Alarm and Police Telegraphs for Municipal and Private Plants. Over 1700 plants in actual service. AGENCIES: ' 5708 Grand Central Terminal, New York City. 448 John Hancock Building, Boston, Mass. 1216 Lytton Building, Chicago, 111. 335 Wabash Bldg., Pittsburg, Pa. 915 Postal Bldg., San Francisco, Cal. 304 Central Bldg., Seattle, Wash. Utica Fire Alarm Tel. Co., Utica, N. Y. The Northern Electric & Mfg. Co., Ltd., Montreal, Canada. General Fire Appliances Co., Ltd., Johannesburg, South Africa. Colonial Trading Co., Ancon, Canal Zone, Panama. F. P. Danforth, 1060 Calle Rioja, Rosario de Santa Fe, Argentina Republic. Trajano de Medeiros & Co., Rio de Janeiro, Brazil. C. Lorenz, Berlin, Germany. TAPES and WEBBINGS FOR ELECTRICAL WORK All grades and qualities required in the build- ing and repair of Dynamos, Motors and other electrical apparatus. Every detail of manufac- ture (quality of stock, uniformity of width and thickness, etc.) has been carefully worked out under the advice of the best electrical engineers, and special machinery constructed to produce material as nearly perfect as possible. W Ttie for samples and prices. HOPE WEBBING CO. PROVIDENCE, R. I. GENERAL ELECTRIC REVIEW XXI Technical Books WITH SUBSCRIPTIONS TO General Electric Review Every engineer should own a carefully selected, even if small, shelf of up-to-date books pertaining to the work in which he is engaged. Through an arrangement with the book pub- lishers, we are enabled to offer a year’s subscription to the Review with any one of the follow- ing books at a material reduction over the regular price for the two. This list consists almost entirely of the more recent technical publications; full description of the older works will be found in the catalogues of the publishers. If you do not find what you want here, write us about it. (Amounts in parentheses are publisher’s strictly net prices.) combination PRICE Electric Arcs, by C. D. Child. Ph. D. ($2.00) $3.60 Electric Arc Phenomena, by E. Rasch ($2.00) 3.60 Transmission Line Formulas, by H. B. Dwight ($2.00) ............ 3.60 Single-Phase Commutator Motors, by F. Greedy ($2.00) ........... 3.60 Factory Lighting, by Clarence E. Clewell ($2.50) ............. 3.95 High Efficiency Electrical Illuminants and Illuminations, by W. R. Hutchinson ($2.50) .... 3.95 Induction Motors, by Benjamin F. Bailey ($2.50) 3.95 Electric Traction and Transmission Engineering, by Prof. Sheldon and E. Hausmann ($2.50) 3.95 The Mathematics of Applied Electricity, by Ernst H. Koch, Jr. ($3.00) 4.35 Engineering Mathematics, by Dr. C. P. Steinmetz ($3.00) ........... 4.35 Transmission Line Construction, by R. A. Lundquist ($3.00) 4.35 Overhead Electric Power Transmission, by Alfred Still ($3.00) 4.35 Thermodynamics of the Steam Turbine, by C. H. Peabody ($3.00) 4.35 Electric Central Station Distribution Systems, by H. B. Gear and P. F. Williams ($3.00) .... 4.35 Synchronous Motors and Converters, by Andrae E. Blondel ($3.00) 4.35 Electric Railway Engineering, by Francis Harding ($3.00) 4.35 Electro-Thermal Methods of Iron and Steel Production, by J. B. C. Kershaw ($3.00) ... 4.35 High and Low Tension Switch Gear, by A. C. Collis ($3.50) 4.75 Electrical Machine Design, by Prof. Alexander Gray ($4.00) 5.20 Electrical Engineering, by Prof. Clarence B. Christie ($4.00) 5-20 Theoretical Elements of Electrical Engineering, by Dr. C. P. Steinmetz ($4.00) ...... 5.20 Steam Power Plant Engineering, by G. F. Gebhardt ($4.00) .......... 5.20 Alternating Current Phenomena, by Dr. C. P. Steinmetz ($5.00) 6.00 Transient Electric Phenomena and Oscillations, by Dr. C. P. Steinmetz ($5.00) ...... 6.00 Electric Power Plant Engineering, by J. Weingreen ($5.00) 6.00 Steam Electric Power Plants, by Frank Koester ($5.00) ............ 6.00 Electric Traction for Railway Trains, by Edward P. Burch ($5.00) ........ 6.00 American Electricians’ Handbook, by Terrell Croft ($3.00) .......... 4.35 Electrical Engineers’ Pocketbook, by H. A. Foster ($5.00) ........... 6.00 American Handbook for Electrical Engineers ($5.00) 6.25 GENERAL ELECTRIC REVIEW, Schenectady, N. Y. 191.... Enclosed find $ for , > subscription to the General Electric Review, to i renewal begin with the current number, and the following book: Name Address Subscription rates: United States, $2.00; Canada, $2.25; Foreign, $2.50. XXII B: GENERAL ELECTRIC REVIEW m The Intrinsic lvalue of the printed matter you buy is not represented by its cost in dollars and cents but by the profits it will earn and the prestige it will bring to your enterprise. Buying printing is one thing — printing service another. Any printer can supply you with printing — very few can supply you with sales producing literature that commands recognition and brings results. Q Might as well have the satisfaction of burning your money yourself as to spend it for advertising literature that has not sufficient character to save it from the waste basket. QOur proposition combines distinctive printing and service to an extent that speculation is eliminated. Its purpose is fulfilled by reason of its character, merit and intrinsic value — qualities that hold the intelligent reader’s attention. The Maqua Company PRINTERS AND PUBLICITY PROMOTERS Schenectady - - New York m A CHRISTMAS GIFT AMERICAN HANDBOOK FOR ELECTRICAL ENGINEERS HAROLD PENDER EDITOR-IN-CHIEF The numerous articles in this new Handbook are characterized by their thorough adapt- ability to practical engineering and for the careful statement of their scientific foundation. The following are worthy of note: 1. Separation of Theory from Practice. Being prepared primarily for the practicing engineer, all theoretical discussions are segregated into separate articles. 2. Method of Treatment. The same plan of treatment has been consistently followed in all the articles. 3. Editing. Characterized by very thorough editing, which has re- sulted in the greatest practicable uniformity in the treat- ment of different subjects. 4. Arrangement. To render the contents most accessible and to save need- less repetition, the articles have been arranged in alpha- betical order. 5. Inclusion of Allied Engineering Subjects. Considerable space is devoted to those mechanical and civil engineering subjects which are closely related to electrical engineering practice. 6. Mathematical Tables and Formulas. Include all those that an electrical engineer needs in his work. 7. Bibliographies. Each article has a bibliography giving, not only the leading books on the subject, but also the most important contributions to the engineering societies and technical journals. 8. Completeness. Each article has been made sufficiently complete to render the information contained therein of greatest practical value. 9. Cost Data. The cost data given in the various articles should prove of great value to, first, the engineer for making preliminary estimates, and second, the student and recent technical graduates who are usually sadly lacking in even the rough- est idea of the cost of apparatus and structures. s 2023 pages, 4^4 by 7. Thoroughly illustrated. Morocco, S5.00 net, postpaid. FREE EXAMINATION. NO CASH IN ADVANCE. If you are a member of any National or State Engineering Society, this book will be sent to you for ten days free examination, without cash in advance. A reference will also give you this privilege. SPECIAL OFFER Free of all cost, we will stamp in gold on the cover of any of our books, the name of the purchaser or the recipient. This offer is good until January 1, 1915. Order your copy now, JOHN WILEY & SONS, Inc. 432 Fourth Avenue, New York City London: CHAPMAN & HALL, Limited. Montreal, Can.: RENOUF PUBLISHING CO. This book can be secured from y ERIC A. EOF, Power & Mining Engineering Dept., General Electric Company, Schenectady, N. Y. The New Standard Handbook will be ready in January, 1915 This is the fourth edition — re- written and entirely remanufac- tured. Over 50% of the text is absolutely new. Sixty-one of the leading specialists in all branches of electrical engineering have contributed the material of this new edition. Frank F. Fowle, Editor-in-Chief, has had the counsel and assistance of about the strongest staff that could be selected in this country — yet it is essen- tially a staff of engineers. This fourth edition will even more than before justify the title STANDARD. At the same time the men who have built this book have had the needs of the practicing electrical engineer in mind. It is not written for a few spe- cialists, but as a useful tool in the broad field of electrical engineering. FREE EXAMINATION COUPON I I I I I a Ss o 2 u Z < 3 = g u X m w ^ J < T3 M O U o u o a. Vi McGraw-Hill Book Co.« Inc.y 239 W. 39th Street, New York You may send me on day oTpublication, for Jree examination, a copy of the New Standard Handbook — Fourth Edition. Within ten days of receipt I will either return this book postpaid, or A — Remit $5.00 in full settlement. B — Remit $3.00 and return my copy of the former edition in part payment. This offer is open only to retail customers residing in the United States. Signed Business Address EXCHANGE OFFER The price of the new STANDARD will be $5.00 net, postpaid. Owners of copies of any of the earlier editions can purchase the fourth edition for $3.00 and their copy of the old book. Do not send money or books now. Merely enter your order on the coupon herewith, and decide the value of the new book for yourself when i1 appears. McGraw-Hill Book Co. Incorporatad 239 West 39th St., New York GE12 ,'■> ■>,'/* f.y rt'-ai: I ^ o . ■ .' ' Wl ■4 f:.x* • ^ *, ~ fjrh:, >':^i"v . >^80^ ; "''5^ < .' ■* > * 1 ^ &T’ . - -• rtfrtf • I ■. .. ■- T r. ■ 4 . 11 . L*n.w>'v»y-»-v<\ 1 ' » *r'-_ ■ h- "■■ ’•''A: ''■'»r‘^'-rj^?''’'Xl^P ; . y '<* •»:%'f M3 I f • . .-A iv-.v ::V.o •7 ^';' V :„■,•■■ - -v lasfsite#' ’W^-‘ 0 "' 5=1 :1p a 'A.'. *^' 4' . ' 1 *|i-a n .4< ■'iSLi—-. _r> #.*;' ^^ah^'Jfcu, ■' 1:; * ;• '•I '^» •'• V. /pH.« :-';^t 4-iffS' / ■ / ''/'J j£„ ' ^ ‘ ' r«.« AjAKiiA*'*'" -■•I'.'tH '^' .£,.•■■• V'jIRE. . ^ 't'- ' ■ ■■■' i‘‘'"’ ‘ 1