AIEE Convention report; mentions new Hewlett insulators

[Trade Journal]

Publication: Western Electrician

Chicago, IL, United States
vol. 41, no. 1, p. 7-8, col. 1-3


AMERICAN INSTITUTE OF ELECTRICAL ENGINEERS.

The twenty-fourth annual convention of the American Institute of Electrical Engineers was held in the Cataract House, Niagara Falls, N. Y., beginning on Tuesday, June 25th, and ending Friday, June 28th.

The meeting was called to order by President Samuel Sheldon of New York city and. after the formal handing over of the keys of the city of Niagara Falls in a brief address by Mayor Douglass, the business and papers, of the convention were taken up.

The registration for the first day's session was rather light, but before the end of the convention nearly 500 had registered, making this one of the largest conventions in the history of the Institute.

ENTERTAINMENTS AND EXCURSIONS.

The local committee is to be praised for its part in making this convention a success, both in the work pertaining to the meetings and in providing excellent entertainment for the visiting engineers.

A large reception committee, consisting of the members living in the vicinity of Niagara Falls, was at the train to meet incoming delegates, and aided greatly in helping them to get acquainted and catch the spirit of the convention.

Many members were accompanied by ladies, and the wives of the members of the local committee did not spare themselves in adding to their comfort and entertainment.

On Tuesday afternoon a trolley ride was taken through the Niagara Gorge. The entire afternoon was set asi.de for this and for such sightseeing as the members were individually inclined. On Wednesday afternoon the factory of the Natural Food Company was visited, and afternoon tea was served by the company. On Thursday morning an automobile trip was arranged for the ladies of the convention, and on the evening of that day the members and their ladies were tendered a reception at the Cataract House, which was largely attended. At the invitation of the local committee the Institute took a "searchlight trip" on Friday evening over the Gorge Route to the Whirlpool Rapids and a considerable number took advantage of this novel feature for their entertainment.

While no excursions to the different electrical generating and transmission plants were planned, yet the local committee made arrangements so that all who desired could visit these plants. Small parties were made up at any time members desired to go, and someone familiar with the installations conducted parties through, the convention badge admitting the wearer to any of these plants, both on the American and Canadian sides. This method of showing the visiting members through the various plants proved to be more satisfactory than any other method could have been.

RELATION OF LOCAL BRANCHES.

On Thursday evening the officers of the Institute and the representatives of the various branches dined at the International Hotel, Mr. Paul Spencer of Philadelphia presiding. Topics concerning the relation of the branches to the Institute were discussed. The constitution recently adopted has served to place the branches on a much better footing than formerly. About half the total membership of the Institute is now connected with some branch, and it is hoped that during the year more branches will be organized, so that a much larger percentage of the membership may enjoy the privileges and benefits of the branch meetings. Mr. Charles F. Scott of Pittsburg remarked that whereas he had hoped that at least 50 per cent. of these branches might be successful, he had been surprised to find that all had so far proved so.

THE NEW CODE OF ETHICS.

Another important step taken by the Institute at this convention was the approval of a "Code of Ethics" which was referred to the board of directors for revision and final action. This code was prepared by a committee appointed a year ago at the Milwaukee convention, consisting of Dr. Schuyler Skaats Wheeler of Ampere, N. J., chairman. Dr. Charles P. Steinmetz of Schenectady and Harold W. Bulk of New York. This is probably the first code of ethics ever approved by an engineering body and will undoubtedly go far toward directing the engineer in his decision for right or wrong in his relationship to his employer, his client, his fellow engineer and the public. While these rules are not all that every engineer had hoped, they will serve as a basis on which to build each year by careful revision. For the young engineer these rules will be particularly important. The Code of Ethics is given in full on a succeeding page.

PROGRAMME OF PAPERS.

The following papers were read and discussed at the meetings:

TUESDAY MORNING.

Address of Welcome.

President's Address, "The Properties of Electrons," by Samuel Sheldon.

"The Heating of Copper Wires by Electric Currents," by A. E. Kennelly and E. R. Shepard.

"Interaction of Synchronous Machines," by Morgan Brooks.

"Power-factor, Alternating-current Inductive Capacity, Chemical, and Other Tests of Rubber-covered Wires of Different Manufacturers," by Henry W. Fisher.

TUESDAY EVENING.

"Protective Apparatus Engineering," by E. E. F. Creighton.

"Practical Testing of Commercial Lighting Arresters," by Percy H. Thomas.

"A Proposed Lightning Arrester Test," by N. J. Neall.

"Inductive Disturbances in Telephone Lines, by Louis Cohen.

WEDNESDAY MORNING.

"Choke Coils Versus Extra Insulation on the End-Windings of Transformers," by S. M. Kintner.

"Protection of the Internal Insulation of a Static Transformer Against High-frequency Strains," by Walter S. Moody.

"Transmission Line Towers and Economical Spans," by D. R. Scholes.

"Lightning Rods and Grounded Cables as a Means of Protecting Transmission Lines Against Lightning," by Norman Rowe.

"Notes on Transformer Testing," by H. W. Tobey.

WEDNESDAY EVENING.

"The Transmission Plant of the Niagara Lockport and Ontario Power Company," by Ralph D. Mershon.

"Location of Broken Insulators and Other Transmission-line Troubles," by L. C. Nicholson.

"A New Type of Insulator for High-tension Transmission Lines," by E. M. Hewlett.

"Some New Methods in High-tension Line Construction." by Harold W. Buck.

"Switchboard Practice for Voltages of 60,000 and Upward," by S. Q. Hayes.

THURSDAY MORNING.

"Deflocculated Graphite," by E. G. Acheson.

"Single-phase versus Three-phase Generation for Single-phase Railways," by A. H. Armstrong.

"The Choice of Frequency for Single-phase Alternating-current Motors," by A. H. Armstrong.

"Twenty-five Cycles versus 15 Cycles for Heavy Railway Service," by N. W. Storer.

THURSDAY AFTERNOON.

"Commutating-pole Direct-current Railway Motors," by E. H. Anderson.

"The Attitude of the Technical Schools Toward the Profession of Electrical Engineering," by H. H. Norris.

"The Concentric Method of Teaching Electrical Engineering," by Vladimir Karapetoff.

Report of the Committee on a Code of Ethics (report adopted).

Standardization Rules. The proposed revision of the Standardization Rules was reported by the Standardization Committee and was adopted.

FRIDAY MORNING.

"Regeneration of Power with Single-phase Electric Railway Motors," by William Cooper.

"Fractional Pitch Windings for Induction Motors and Alternators," by C. A. Adams, W. K. Cabot and G. S. Irvmg, Jr.

"The Vector Diagram of the Compensated Single-phase Alternating-current Motor," by W. I. Slichter.

"Zigzag Leakage of Induction Motors," by R. E. Hellmund.

FRIDAY AFTERNOON.

"Track-Circuit Signaling on Electrified Roads," by L. F. Howard.

"Some Power Transmission Economics," by F. G. Baum.

"One-phase High-tension Power Transmission," by E. J. Young.

LIGHTNING PROTECTION.

The registration on Tuesday was not as heavy as had been expected, and in consequence the papers scheduled for that morning were not as well discussed as those later on in the meeting when more members were present and more interest aroused.

The papers on lightning protection and lightning-arrester testing brought forth many favorable criticisms of the steps in advancement along these lines which this year has brought. Accurate data on the frequency and character of lightning discharges have not yet been obtained, so that design in this direction is as yet more or less speculative. An adequate test on a lightning arrester must be one which shall cause a spark to pass over the arrester with an opportunity for the full power of the machine to follow. This, of course, is impossible unless made at the point of installation, and would then be destructive to the apparatus under test. Much hope is expressed for the electrolytic arrester now under the process of development.

USE OF CHOKE COILS.

The papers on the transmission of power extended over into Wednesday morning, when the question of the use of choke coils and the increase of insulation on the end turns of transformers, as a protection against lightning and high-frequency surges, was brought up. It seemed to be the consensus of opinion of the engineers discussing the papers that, whereas the increased insulation on the end turns of transformers for high potential was necessary, an extra protection could and should also be secured through the proper use of choke coils.

The choke coil should be used to prevent the rush of current to ground from the transformer over the lightning arrester or static discharger, but should not be of a size to produce resonance with the capacity of the wiring of the station at the ordinary frequencies of lightning discharges, and thus set up resonant voltages which will break down the insulation of the apparatus it is designed to protect.

The proper, place for installing the choke coil was not agreed upon. Suggestions ran from placing it inside the transformer case, in order to reduce the capacity of the wiring between the coil and the transformer, to that of placing it outside of the station, in order to reduce fire risks due to arcing over turns on the coil when the line discharges.

The coil should be designed to fit the particular station it is to protect. In some cases it may even be necessary to use two sets of lightning arresters, one on each side of the choke coil. The fact was also brought out that some stations for high voltage are operating at present without the use of choke coils, relying upon the extra insulation on the end turns of the transformers for protection.

A NEW LINK TYPE OF INSULATOR.

The papers creating the most attention Wednesday evening were those by E. M. Hewlett of Schenectady and H. W. Buck of New York upon a new type of high-voltage insulator and its use. The insulator, as shown, consists of units which are each capable of withstanding 20,000 to 30,000 volts. These units may be connected in series by links of cable or loops of wire, so as to form the insulator for the required voltage in the form of a chain with the links insulated from each other. The insulator is then suspended by one end to the cross-arm, and the high-tension wire or cable fastened to the other. Sufficient room is allowed so that in high winds the high-tension wire will not swing against the pole or tower. The principal advantages asserted for this type of insulator are that, if broken, the insulator is easily repaired, a new unit being inserted, thus reducing the cost of repair; also the voltage on a line may be increased and the same posts used by merely inserting the proper number of additional units. A strain insulator is also made up in a similar manner.

ALTERNATING-CURRENT RAILWAY PRACTICE.

The meeting of Thursday morning in which the questions of alternating-current traction and the proper frequency for the same was brought up in the papers by A. H. Armstrong of Schenectady and N. W. Storer of Pittsburg, proved to be the most interesting of the whole convention. The principal discussion, centered around the choice of frequency for the best results.

The single-phase alternating-current motor seems to give the best promise for use in the future electrification of the steam roads. This motor is at present in use as essentially a low-frequency motor. On account of troubles from sparking, this frequency should be lowered below that of 25 cycles, the lowest at present in commercial use. The introduction of a new frequency, and especially one which is too low for most other purposes, is not looked upon with satisfaction by the leading engineers and manufacturers.

As brought out by Dr. Steinmetz in the discussion, each class of alternating-current machines has a critical frequency at which it is most economical to manufacture. For induction motors this frequency is 40; for transformers much higher than we are now using; for synchronous converters, 25 cycles, and for the alternating-current series motor now in use, as low as possible, zero frequency or continuous current being the best. For this reason the type of machine must be changed to reduce the sparking at 25 cycles, or the frequency lowered for this purpose. The development of the series motor should be to lower the current produced in the short-circuited segments, by the introduction of resistance, or an inductance, or to lower the counter-electromotive force produced in the leads between the segments.

The question again resolves itself into the mariner in which the power for operating the roads is to be produced. If each road produces its own power, or if the power for operating these roads be produced independent of power for other purposes, and with no reserve from present companies operating within transmission distance, then a frequency different from those used at present does not affect the problem so largely.

P. Junkersfeld of Chicago brought out the interesting fact from recent estimates for the coming year, on the passenger traffic entering Chicago for a distance of 25 miles, that if these roads be electrified, the total load could be furnished by the present generating companies in the city and be but so to 25 per cent. of their total load. Also for the next five years the proportion would be much less, due to the fact that power requirements for industrial and lighting purposes are increasing so much faster than those for passenger traffic. The power for freight traffic cannot be so easily estimated, owing to the tendency toward the removal of the switch yards out from the center of the city, where more and cheaper land may be secured.

With this and other data at hand, it would not appear such a stupendous undertaking from the point of view of the power producer, to electrify the steam roads.

Again, with the use of alternating-current motors for railway operation, what has 15 cycles to offer which cannot be duplicated by 25 cycles or some other frequency? The present gauge of railroads and the diameter of car wheels limit the size of the motor to be used, and any increase in output for a given size of motor is an important consideration from an engineer's point of view. It is said in Mr. Storer's paper that with the alternating-current series motor as at present designed, the output may be increased from 30 to 40 per cent. for a given weight of motor by decreasing the frequency from 25 to 15 cycles. The next point arises in the questions: Will not a still further decrease in frequency be still more advantageous; and are there not other factors entering which affect this consideration?

The next problem to be met is the generation of power at this lower frequency. Twenty-five cycles offers considerable difficulty to the turbo-generator designer in the number of poles and the high speeds required for good practice in this direction. As two poles is the smallest number which may be used on a generator, the speed of the machines would then be 900 revolutions per minute, which is higher than the practice at present for large-size units. Bipolar design also introduces many difficulties to the generator designer.

Mr. Stillwell said that the problem of electrification of steam railroads is much different from that of the introduction of lighting by electricity, due to the fact that the men at the head of these companies are men trained to look at things broadly. Any new plan which they are to adopt must result in increased traffic and increased profits. As pointed out in the paper recently presented by Messrs. Stillwell and Putnam before the Institute, a saving of about 15 to 25 per cent. could be made in the operation of railroads by the use of the single-phase system today in existence. The large amount of power required for the operation of trunk lines and the long distances to be transmitted make alternating current at a voltage not lower than 6,000 the only feasible plan to be adopted.

Charles F. Scott said that the main question must not be lost sight of in the discussion of the details. The question is an engineering one, which cannot be answered by "yes" or "no," definitely, without having specific conditions stated. As in the past, the design of railway equipment must center around drawbar pull and the locomotive.

Twelve years ago, when the Institute met at Niagara Falls, the first of the 25-cycle generators had just been put into commission. This was the first commercial use of 25 cycles and was looked upon with considerable disfavor by many engineers. Now the greater part of all electricity generated for power use in this country is at this frequency. Are we not at the point of a similar step to another frequency somewhat lower for use on our railways? What will we think 12 years hence when we look back on the deliberations of today? A step of this character should be undertaken only after due deliberation and consideration of all the factors attending, but if the step seem proper, let it be taken.

In regard to generating and f