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A.I.E.E., Journal of the

Issue 4 • Date April 1925

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Displaying Results 1 - 25 of 71
  • Keep at it everlastingly

    Page(s): 337 - 338
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    For several years the officers of the four Founder Societies have been endeavoring to bring to the attention of the public the usefulness of the combined training and experience of the engineering profession. View full abstract»

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  • A two-speed salient-pole synchronous motor

    Page(s): 339 - 346
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    The design features and performance characteristics of salient-pole synchronous motors are well known and have been thoroughly covered in the technical press. The synchronous motor has been handicapped in the past because it is inherently a single-speed machine, and a change in speed could be obtained only by a change in the frequency of the power supply. Changing the frequency, however, is not practical in most applications. The special pole described in this paper which allows two-speed operation of a synchronous motor to be obtained at high efficiency is a new feature2. The same principle applied to a generator enables two frequencies to be obtained at the same speed or the same frequency at two different speeds. All that is necessary to change the speed (or frequency) is a pole-changing switch for the stator winding and a reversing switch for the rotor winding. A 5000/2500-h. p., 600/300-rev. per min., two-speed synchronous motor was built without having first constructed a model of any kind. This motor proved to be entirely satisfactory and its characteristics obtained by test agreed very closely with the calculated characteristics. At either speed the two-speed synchronous motor functions exactly as the ordinary synchronous motor. There is nothing special or complicated about its construction, it does not require any more attention than the ordinary synchronous motor, and its expense of maintenance is just the same. The first cost of such a motor is only slightly more than that of the ordinary synchronous motor whose rating is equal to the low-speed rating of the two-speed motor. Therefore, the two-speed synchronous motor is a practical machine and it should open a new field for synchronous motor application. View full abstract»

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  • The single, straight conductor as a new fundamental

    Page(s): 346
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    The Journal Franklin Institute for February contains an article by Carl Hering in which he shows how the single, straight conductor can be used as a fundamental, and how simple and well defined its properties are. View full abstract»

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  • Applications of motors to mine locomotives

    Page(s): 347 - 349
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    This paper discusses the rule of thumb method of applying motors to mine locomotives. It shows why speed of locomotive should be considered in selecting motor horse power. It indicates a rational method of selecting motors for locomotives for general application. View full abstract»

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  • Thermal expansion of aluminum and various important aluminum alloys

    Page(s): 349
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    Scientific Paper of the Bureau of Standards, No. 497, gives data on the linear thermal expansion of 4 samples of aluminum and 51 samples of important aluminum alloys. The preparation, chemical composition, heat treatment, etc., are included. Most of the specimens were examined from room temperature to about 500 deg. cent. Typical expansion curves of the various groups of samples are shown and discussed. View full abstract»

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  • Synchronous motor drive for rubber mills: With special reference to dynamic braking control for safety stopping

    Page(s): 350 - 353
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    Since wound-rotor induction motors with clutch brakes have been very commonly used for this application, a review of the operating conditions and safety requirements is given, in order to show why synchronous motors without clutches may be used for the same application. View full abstract»

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  • Theory and performance of rectifiers

    Page(s): 353
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    The Bureau of Standards recently completed a study of the performance of rectifiers of the type used for charging storage batteries, and the results are now available in Technologic Paper, No. 265, copies of which may be obtained from the Superintendent of Documents at Washington, D. C. View full abstract»

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  • Niagara Falls to be permanently lighted

    Page(s): 353
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    According to a recent announcement permanent illumination is to be provided for Niagara Falls from a battery of twenty-four powerful search lamps which will cast 1,320,000,000 candle power. May 24th is the date set for the completion of the installation and a celebration is being planned by the Niagara Falls Chamber of Commerce for this occasion when this powerful battery of search lamps will be turned on for the first time. View full abstract»

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  • Use of frequency changers for interconnection of power systems

    Page(s): 354 - 356
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    FOLLOWING an extensive study into the cost of power as delivered to the customer, the Brooklyn Edison Company adopted the policy of supplying all the increase in business at 60-cycle alternating-current and curtailing the direct-current load within the capacity of the existing substations. With the 25-cycle generation confined primarily to the supply of power to the direct-current system all new prime movers are being installed with 60-cycle generators. The 25-cycle system is therefore left in a position of barely holding its own. View full abstract»

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  • A new alternating-current general-purpose motor

    Page(s): 356 - 363
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    The desirability of motors possessing the good characistics of induction motors and being capable of operating with leading power factor is pointed out. A new machine is described which operates as self-excited synchronous motor under normal operating conditions. During the starting period and excess overloads, it has the characteristics of an induction motor with wound secondary. The machine has excellent starting and synchronizing torque with a small current draw. The electrical and mechanical phenomena, during the starting and synchronizing periods, are discussed. The size of the machine is nearly equal to that of a slip-ring induction motor of equal rating, and the full-load efficiency is approximately equal to that of a corresponding induction motor. It is shown that the overall efficiency of a plant, consisting of squirrel-cage motors and this new type of motor, is usually higher than that of an equivalent plant using induction motors only, correcting the power factor by idle running correcting devices. View full abstract»

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  • Electrical measurement of physical values: The determination by electrical and magnetic means of quantities not in themselves of an electrical nature

    Page(s): 363 - 365
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    THIS paper was prepared under instructions from the Committee on Instruments and Measurements, with a view to forming a basis for the Committee's work in connection with electrical measurements as applied outside of the strictly electrical field. The system of classification used is in accordance with the nature of the quantity under measurement, rather than with the principle involved; and the subject is treated under nine headings. View full abstract»

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  • Mechanical stresses in busbar supports during short circuits

    Page(s): 365 - 372
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    THE design of busbar layouts calls for the determination of the stresses occurring in the bus supports during short circuits, because the stresses in question may become sufficiently large to weaken, or even rupture, the supports. Moreover, an understanding of the factors affecting the stresses will often permit the designer to modify the layout so as to reduce the stresses, and thus save material or prevent failure. Hence investigations have been directed towards the calculation of support stresses due to electromagnetic forces caused by short-circuit currents in busbar structures. View full abstract»

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  • Development and characteristics of a 1,000,000-volt cascade transformer at california institute of technology

    Page(s): 373 - 378
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    This paper is presented to describe the cascade connection for transformers, and show the standard characteristics of such equipment, but it does not give building-plans for the 1,000,000-volt laboratory, as they have been presented in other publications. View full abstract»

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  • Metallic polar-duplex telegraph system for long small-gage gables

    Page(s): 378 - 386
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    In connection with carrying out the toll-cable program of the Bell System, a metallic-circuit polar-duplex telegraph system was developed. The metallic-return type of circuit lends itself readily to the cable conditions, its freedom from interference allowing the use of low potentials and currents so that the telegraph may be superposed on telephone circuits. The new system represents an unusual refinement in d-c. telegraph circuits, the operating current being of the same order of magnitude as that of the telephone circuits on which the telegraph is superposed. The metallic system is suitable for providing circuits up to 1000 miles or more in length, the grade of service being better than that usually obtained from ground-return circuits on open-wire lines for such distances. About 55,000 miles of this type of telegraph circuit are in service at present. View full abstract»

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  • Discussion at annual convention: A new type of single-phase motor

    Page(s): 386 - 389
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    V. Karapetoff: An impression may be gathered from the paper that the power factor of the motor is improved because the squirrel-cage winding is highly inductive. It seems to me that the squirrel-cage winding necessarily has to be highly inductive so as not to interfere with the series characteristics of the motor at the start. If it were not for an additional mechanical complication (Fig. 2), it would be better to make this winding less inductive at and near synchronism. A transformer diagram at constant current will readily show that the common flux is lagging behind the primary current at a non-inductive load more than at an inductive load. Therefore, the less inductive the squirrel-cage winding, the more the flux φf is lagged behind I (Fig. 4). But the flux in T must be in time quadrature with φf in order that the total e.m.f. between the brushes be equal to zero. Therefore, lagging φf also causes φt and Et to lag more behind I; in other words, it causes the vector of the current to come nearer that of the total voltage E. Thus, the power factor is improved even though the squirrel-cage winding has a high inductance, and the power factor would be improved more, if it were advisable to reduce the inductance of this winding in normal operation. View full abstract»

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  • Sensitive radio-frequency relay

    Page(s): 389 - 390
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    J. Slepian: The device described by Mr. Lewis has several distinct elementary parts performing rather distinct functions; there are the filament and grid, giving the usual detector action, there is a thermally responsive element and there is a contact which opens and closes. View full abstract»

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  • High-voltage impregnated paper cables

    Page(s): 390 - 392
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    D. W. Roper: A point which should be more prominently set forth is that as the operating voltage of a cable increases, the quality must improve. What is needed at the present time is some method of measuring the quality of the insulation and determining the maximum operating voltage for which a given quality of cable is suited, and to which it should be limited. There are also needed some other tests to be applied to cable at the factory in order to determine whether it will be satisfactory for the service for which it is intended. Apparently some further research as well as co-operation between the manufacturing and operating companies is needed in order to develop the proper tests for this purpose. View full abstract»

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  • Discussion at pacific coast convention: The corona as lightning arrester

    Page(s): 393 - 394
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    F. W. Peek, Jr.: In a paper that I presented at Swampscott last year I described some tests in which the variation of the steepness of the wave front and the voltage of a wave were measured as it traveled along a line on which there was considerable corona loss. View full abstract»

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  • Corona losses between wires at extra high voltage

    Page(s): 394 - 397
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    F. W. Peek, Jr.: Prof. Harding has given us some curves up to 500,000 volts on conductors good for operation at 220 kv. or less. His loss measurements under some conditions show a close agreement with the quadratic law over a reasonable range of voltage for the conductors. The difference on several of the conductors is, I believe, due to the fact that sphere gaps were used for voltage measurement. Regarding the divergence at the upper part of the curve where the arc-over voltage is approached, we have sometimes noticed a somewhat similar tendency on measurements that we have made up to one million volts. This has occurred on large conductors at spacing relatively small compared to diameter. It seems to be due to the distortion in the dielectric field that takes place because of the great amount of corona. The ratio of spacing to effective radius becomes small. The flexible corona conductor is distorted and no longer a cylinder. At the voltage when the divergence starts the corona begins to separate into huge cart wheels. These have a shielding effect preventing or lowering the loss between wheels. This does not mean that the quadratic law would not apply for calculation of the loss for million-volt conductors. Larger conductors and greater spacing would be used and the law would hold in the usual way. The tendency to diverge thus seems to apply only to extreme conditions or when spark-over is approached and distortion results. View full abstract»

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  • Interconnection of power systems in the Southeastern states

    Page(s): 397
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    P. H. Thomas: Mr. Mitchell's paper is particularly timely since it indicates not only the most advanced point to which widespread interconnection of large systems has progressed in actual practice, but points out the probable solution of some of the problems now being faced in the further extension of interchange. View full abstract»

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  • Large steam turbine generators

    Page(s): 397 - 398
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    A. M. Rossman: The built-up rotor construction which Mr. Foster describes is interesting to us because of an experience which we have had within the last two or three months with a solid forged rotor. View full abstract»

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  • Heating of large steel-cored aluminum conductors

    Page(s): 398 - 399
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    A. M. Rossman: I was shown recently some results of a heating test of a cable passing through a clamp. The cable was 300,000 cir. mil copper cable and the clamp was a drop forging. In that case the current was raised to such a value as to give an appreciable heating of the conductor. The clamp showed a temperature several degrees higher than the conductor. This is contrary to the results which Mr. Wood obtained. View full abstract»

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  • The possibilities of flash-overs

    Page(s): 399 - 403
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    F. W. Peek, Jr.: If I understood Mr. Austin correctly, it is his belief that insulators on transmission lines may arc-over at very much reduced voltages due to some localized high-frequency phenomena starting at a corona brush. View full abstract»

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  • Lightning and other transients on transmission lines lightning

    Page(s): 403 - 407
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    F. W. Peek, Jr.: In some respects Mr. Creighton's conclusions are not as far from my own as might appear at first glance. The effect on transmission lines is determined wholly by the gradient. The fact that he has very high energy values is due to the high voltages or high cloud heights that he has assumed. View full abstract»

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  • Electric power application in pacific Northwest fir mills

    Page(s): 407 - 409
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    G. B. Rosenblatt: I have recently interested myself in the electrification of the lumber industry, and looking at it as an outsider who is coming in, I have seen some things, possibly, that those who have grown up with the industry don't recognize. View full abstract»

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Aims & Scope

The Journal of the American Institute of Electrical Engineers (AIEE) contains articles published between 1924 and 1930. Contents are devoted to the advancement of theory and practice of electrical engineering and the allied arts and sciences.

This Journal ceased publication in 1930. The current retitled publication is IEEE Spectrum.

Full Aims & Scope