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Electrical Engineering

Issue 8 • Date Aug. 1941

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Displaying Results 1 - 25 of 31
  • [Front cover]

    Publication Year: 1941 , Page(s): c1
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  • [Advertisement - Front inside cover]

    Publication Year: 1941 , Page(s): c2
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  • [Advertisements]

    Publication Year: 1941 , Page(s): 1 - 12
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  • Contents

    Publication Year: 1941 , Page(s): 1
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  • Highlights

    Publication Year: 1941 , Page(s): 368
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  • Comfort avery Adams — 1940 Lamme medalist

    Publication Year: 1941 , Page(s): 369 - 370
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    “For his contributions to the theory and design of a-c machinery and his work in the field of electric welding”, the AIEE Lamme Medal for 1940 was presented at the Institute's recent summer convention in Toronto to Doctor Adams who now is consulting engineer for the Edward G. Budd Manufacturing Company of Philadelphia, Pa. Th is was the thirteenth presentation of this medal, which was established by the will of the late Benjamin Garver Lamme for the recognition of “meritorious achievement”. THE purpose of giving any one a medal is to focus public attention on the recipient, so that his achievements may gain greater public appreciation, and young men may be inspired to emulate them. During the quarter of a century I have known Professor Adams, his qualities of mind and attitude toward life have been to me a continual source of inspiration, so it is of them that I wish to speak today. He has first and foremost been a teacher — not merely of his students, but of his associates. There are two ways of learning, of teaching, or of doing — the superficial way and the fundamental way. The first way is the most impressive. I remember well a professor who could answer almost any question immediately. If, however, he were asked a second question, going deeper into the subject, and then a third and a fourth, his answers became slower and less sure, until finally he could give no further information. His knowledge was only about six layers deep. View full abstract»

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  • Facts versus propaganda

    Publication Year: 1941 , Page(s): 371 - 373
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    Whether we have a world of chaos growing out of propaganda and blind thoughtlessness or a world of peace based upon fact and common sense, depends upon the individual, and the type of education to which he has been subjected, as Doctor Adams points out in his response to the presentation of the AIEE Lamme Medal at the summer convention in Toronto. DEEP down in the hearts of most of us is an ideal, towards which we are striving. We sometimes stumble and fall by the wayside, pick ourselves up and carry on. We often refer to this ideal as the spirit of the man, or the divine urge to be something better and finer than shows on the surface. A good portrait painter is the one who is able to bring out this spirit rather than to reproduce merely the superficial appearance. Mr. Alger is a good portrait painter, as he has given you a picture of what I would like to be. In other words, he has emphasized the best. View full abstract»

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  • Lightning phenomena: I — General characteristics

    Publication Year: 1941 , Page(s): 374 - 384
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    Although Franklin conducted his famous lightning experiments about the middle of the 18th century, little more was learned until about a generation ago when lightning outages on expanding electric-power systems made an intensive study of the phenomena imperative. Many investigators in different parts of the world have studied lightning during that period, many special instruments have been devised for recording various characteristics of the phenomena, and from information obtained through the use of these instruments remedial measures have been devised — to the end that in spite of the continuously expanding network of electric-power lines, outages caused by lightning have been greatly reduced. In a series of three articles, the authors have reviewed and described: (I) the general characteristics of lightning, the accumulation of the charge, and the mechanism of the discharge; (II) instruments available for measuring the properties of lightning; and (III) results of field investigations in which the instruments described in part II were used. Part I appears on this and the following pages; parts II and III are scheduled for subsequent issues. THE physical manifestations of lightning have been with us from the remotest times, but only comparatively recently have the phenomena become even partly understood. Franklin in his electrical experiments between 1740 and 1750 succeeded in identifying lightning as the static electricity of his time. Beyond this fact little was learned until within the past 25 years. The real incentive to obtain additional knowledge lay in the necessity of the electrical industry to protect against its effects. As longer transmission lines were built the need for reduction in outages due to lightning became more acute. This placed more stringent requirements upon lightning arresters and other protective devices. Largely through the co-operation of the utilities and manufacturers and through the use of special instruments such as the kl- donograph, cathode-ray oscillograph, surge-crest ammeter, Boys camera, and fulchronograph, information of a very valuable character has been obtained regarding stroke mechanism and the voltages and currents associated with lightning. View full abstract»

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  • Powerful ultraviolet light sources

    Publication Year: 1941 , Page(s): 384 - 388
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    More and more industrial applications are being found for the recently developed high-pressure tubular mercury-vapor lamps which are now available in lengths over five feet and with wattages greater than 4,000; some of these are described by the author, who discusses the advantages of these lamps over previously known sources of ultraviolet radiation. THE ADVENT of the high-pressure vapor lamp with self-lighting activated electrodes1,2 has made possible the development of new types of ultraviolet generators of high power and large size, which have become a very important tool for a number of industrial applications. First introduced in ultraviolet lamps for therapeutic and prophylactic use, the high-pressure quartz mercury-vapor lamp has been developed considerably further in size and power in recent years and is finding new and interesting uses in commercial irradiation processes. This development was facilitated by several important advantages which the self-lighting, high-pressure lamp offered over the previously known types of ultraviolet light sources; namely, mercury-vapor lamps of the pool type and carbon-arc lamps. View full abstract»

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  • If the black-out comes

    Publication Year: 1941 , Page(s): 389 - 392
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    American cities can profit by European experience to plan air-raid precautions that will permit traffic movement without creating undue hazards View full abstract»

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  • Operating results with PCC cars

    Publication Year: 1941 , Page(s): 392 - 395
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    The PCC trolley car, designed several years ago by a committee of street-railway-company executives, has now been in operation long enough to appraise its contribution to the industry. Its quietness, higher speed, improved operating characteristics, and greater passenger convenience and comfort as compared with older cars have attracted new passenger traffic, with the result that the general downward trend of traffic has been reversed on lines where these cars have been substituted for older ones. NOTHING in recent years has so completely changed the outlook of the transit industry as the PCC car. From 1931 to 1934 relatively few city surface cars were purchased. During the last six years almost 2,000 PCC cars have been purchased, as well as similar types which have essentially the same electrical equipment and represent similar improvement over the older vehicles. On May 1, 1941, 1,467 PCC cars were in operation in 14 cities of the United States and Canada. These cars had accumulated a total mileage of more than 146,000,000, or 100,000 miles per car. The 100 cars in Brooklyn, N. Y., had an average mileage of 188,000; the first 201 cars in Pittsburgh, Pa., 206,000; and the 83 cars in Chicago, Ill., 173,500. It is evident that sufficient experience covering a wide variety of conditions is available to form a reliable basis of judgment. View full abstract»

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  • Institute activities

    Publication Year: 1941 , Page(s): 396 - 412
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  • Of current interest

    Publication Year: 1941 , Page(s): 413 - 418
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  • Transactions section: Effect of sapphire-crystal orientation on the wear of watt-hour-meter bearings

    Publication Year: 1941 , Page(s): 811 - 813
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    This paper describes the most recent of a series of studies on the life of watt-hour meter bearing materials. It covers an investigation of the effect of jewel crystalline axis orientation upon jewel wear. Lifetime stability of meter calibration is a function of bearing wear. A study of the wear (after several years' service) of the sapphire jewel cups of meters in relation to crystalline orientation confirms predictions of another investigator; and a corroborative theory, based upon the physics of crystals, is presented. View full abstract»

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  • The dielectric strength of glass — An engineering viewpoint

    Publication Year: 1941 , Page(s): 814 - 818
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    The purpose of this paper is to provide the engineer with co-ordinated information and data regarding the dielectric breakdown of glass which will permit him to apply this insulating material more effectively for high dielectric strength. In the discussion of the subject, particular attention has been paid to “edge effects” and other factors which cause wide variations in breakdown voltages — variations which are responsible for many of the seeming inconsistencies found in published results on the dielectric failure of glass and other materials. The author has concluded that it is possible to make a reasonable approximation of the breakdown voltage of glass, if the conditions of the test or of the application can be sufficiently well determined. The characteristic breakdown curves of this paper do not represent the results of any one series of tests, but are rationalized from data selected from many sources, including unpublished tests. The data curves included refer mainly to Pyrex glass, but corresponding data have also been included on electrical porcelain because of the interesting comparisons shown. View full abstract»

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  • Overvoltages in polyphase induction motors during single-phase operation

    Publication Year: 1941 , Page(s): 819 - 822
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    Introduction IN the course of the starting, reversal, or normal operation of a polyphase wound-rotor induction motor, it occasionally happens that either the stator or the rotor or both may be allowed to operate single phase. In some cases it has been noted that the voltage of the open terminal or terminals under these conditions has a steady-state peak value well above its normal maximum. While scattered references to this effect may be found in the literature, and though the general subject of single-phase operation of polyphase induction motors has been discussed from time to time, apparently the magnitude of these voltages has not been the subject of a thorough and organized investigation. This paper is based on the results of a study, undertaken to determine analytically the maximum theoretical voltages of a three-phase induction motor under single-phase operating conditions, and, so far as possible, to check these calculated figures against actual test results. View full abstract»

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  • Photographic study of A-C arcs in flowing liquids

    Publication Year: 1941 , Page(s): 823 - 828
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    I. Introduction THE importance of fluid flow in aiding arc extinction in circuit interrupters has long been known. Two general types of explanation of the large effect found have been offered. Slepian1,2,3 who seems to have been the first to stress the importance of the motion of the gases liberated by the arc from the surrounding oil or solid insulation in oil breakers and expulsion fuses, sought the explanation in reduced arc section at current zero, and increased diffusion rate of ions and molecules arising from the turbulence. Other investigators have expressed similar views, at least in part.4,5 View full abstract»

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  • Theory of the brush-shifting A-C motor — I

    Publication Year: 1941 , Page(s): 829 - 833
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    This is the first of a series of papers explaining the theory and principles of operation of the brush-shifting a-c motor. Operation of the machine, either as a motor or a generator, is explained on the basis of the superposition of currents. The theory of the primary current loci is developed for both high-speed and low-speed adjustments. A method of determining the primary current loci from no-load measurements is presented. Experimental data have shown the theory to be valid. View full abstract»

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  • Theory of the brush-shifting A-C motor — II

    Publication Year: 1941 , Page(s): 834 - 836
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    In the preceding paper1 of this series, a simple theory underlying the circle diagram of the brush-shifting a-c motor was presented. It is the purpose of this paper to advance this theory, and to show how it can be used to determine such quantities as efficiency, current, torque, and speed for different conditions of operation. The procedures outlined and explained have been checked experimentally, and found to be accurate for both high-speed and low-speed adjustments. View full abstract»

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  • The determination of magnitude and phase angle of electrical quantities

    Publication Year: 1941 , Page(s): 837 - 839
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    Although the three-voltmeter method for measuring the relative magnitude and phase angle of two voltages or currents is well known, the use of vacuum tube voltmeters, which draw negligible amounts of energy from the circuit, permits the use of the method for purposes which previously have not been considered. A further improvement of the scheme by balancing out one component of either voltage or current adds to the accuracy of the results. The method is considered for two purposes, namely: the measurement of the capacitance and power factor of imperfect condensers, and the measurement of the ratio and phase angle of current transformers. View full abstract»

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  • Ampere-squared-second recorder

    Publication Year: 1941 , Page(s): 839 - 842
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    A device is described which records the ampere-squared seconds in an electrical impulse of less than 0.5-second duration. A number of these have been used in resistance-welding applications to monitor the electrical variables and have contributed greatly to the uniformity of welds. The problem of indicating 1/60-second impulses at the rate of 100 a minute with the same device that will correctly integrate a half-second impulse has been solved by the use of a moving element with an infinitely long natural period, combined with a supplementary circuit which returns the element to the starting position in a fraction of a second. View full abstract»

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  • Glass-bulb mercury-arc rectifiers for traction service

    Publication Year: 1941 , Page(s): 843 - 845
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    The paper gives a general survey of the ability of glass bulb mercury-arc rectifiers to satisfactorily meet the stringent requirements of traction service. The subject matter is arranged on the assumption that engineers of the United States and Canada are not familiar with the use of this type of equipment for traction work, and the author has approached the subject from the point of view of an engineer considering the merits of different types of conversion equipment. Major features pertaining directly to glass bulbs are discussed such as plant capacity, maintenance, efficiency, robustness, etc., but no attempt is made to include wider problems common to mercury-arc rectifiers as a class, namely frequency changing, inversion, harmonics, etc. View full abstract»

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  • A new mercury rheostatic element for regulation and control

    Publication Year: 1941 , Page(s): 846 - 849
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    Introduction IN many regulating and control systems, the primary or actuating stimulus is available only at a low power level and must be amplified to obtain sufficient power output for the various control functions. This requirement, along with the increased use of automatic controls during the past few years has resulted in many industrial applications which require a simple, reliable power amplifier. Electronic tubes and special designs of rotating machines have been used for amplification where a continuous type of control is required, but in most applications it is difficult to justify the use of tubes or rotating amplifiers. Summary The principal design features, along with several typical applications, were described for a new form of mercury rheostatic element which has been designated as the “Mercurystat”. The unique features of the Mercurystat are its large number of hermetically sealed mercury contacts and the small force and travel required for their operation. It was shown that relatively large amounts of power can be controlled by the Mercurystat and because of the small input power required for its operation, power amplification in the order of 100,000 can be obtained. The performance of this new device along with its simplicity and absence of wearing moving parts should find many applications for it in automatic control systems. View full abstract»

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  • Modern motors serve city transit systems

    Publication Year: 1941 , Page(s): 850 - 853
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    City transit motors operated today include many new mechanical and electrical features. Modern vehicles differ greatly from those of a decade ago and propulsion motors contributed substantially to the advances achieved. Meeting present-day needs has required designs for 300 and 600 volts involving extensive use of new materials, application to new types of drive, and suitability for dynamic braking. Mechanical design includes unusual developments in frame construction, method of mounting, lead arrangement, ventilation, housings, and bearings. Compactness has led to ingenuity in brushholder arrangement to secure accessibility. Armatures require judicious selection of materials for shafts, cores, and commutators as well as special seasoning and balancing procedure. Electrical design betterments have been introduced in armature slots, armature coils, field coils, and insulation. Provision for quietness and good commutation are also salient points. The new designs have resulted in high electrical and weight efficiency for series motors used on Diesel-electric busses, trolley coaches, and street cars in comparison with old type machines. Excellent commutation has produced outstanding stability at rapid accelerating and dynamic braking rates. Vehicle performance is exceptional with respect to safety, operating efficiency, available selection of accelerating and braking rates, and the broad speed range of the dynamic brake. View full abstract»

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  • Measurements of pre-breakdown currents in dielectrics with a cathode-ray tube

    Publication Year: 1941 , Page(s): 854 - 858
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    A. Introduction IN order to obtain more information regarding the mechanism of electrical breakdown in insulating liquids, a number of experimenters1,2,3 have studied current flow as a function of applied voltage, using high-sensitivity d-c amplifiers with indicating instruments having relatively long-time constants. Such instruments will not follow rapid changes in current where the time intervals are of the order of milliseconds or less. Therefore we decided to investigate the possibility of using a cathode-ray tube as a current detector to follow current changes just preceding breakdown. This paper describes current measurements in liquids with 200-microsecond impulse voltage waves and current measurements in liquids and solids with gradually increasing unidirectional voltage applied to the specimens. View full abstract»

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Aims & Scope

This Periodical ceased publication in 1963. The current retitled publication is IEEE Spectrum.

Full Aims & Scope