Showing papers in "Transactions of The American Institute of Electrical Engineers in 1936"
TL;DR: It has been found that electric shock may derange heart action causing ventricular fibrillation without damage to heart tissue, but resulting in death within a few minutes, which establishes the maximum current that may be withstood safely for short durations.
Abstract: A joint investigation of the effects of electric shock on the heart, extending over a period of several years, has yielded many significant results. It has been found that electric shock may derange heart action causing ventricular fibrillation without damage to heart tissue, but resulting in death within a few minutes. This heart effect establishes the maximum current that may be withstood safely for short durations. Threshold fibrillating currents were determined for different conditions of pathway, frequency, and duration using numerous anesthetized animals of different species, comparable in size with man. The discovery was made that the heart is susceptible for only about 20 per cent of its cycle. Successful recoveries from ventricular fibrillation were obtained with large animals of several species by high intensity shocks of short duration.
168 citations
Journal Article•
168 citations
TL;DR: In this article, the resistances from grounding conductors of variou forms to the earth are calculated for practical use in the calculation of the resistance from ground conductors to the ground.
Abstract: Formulas for practical use in the calculation of the resistances from grounding conductors of variou forms to the earth are given in this paper and their use illustrated by examples. The accuracy of the formulas varies considerably, as discussed in the paper, but is sufficiently good that the methods should be helpful to those whose work involves problems of grounding.
135 citations
TL;DR: The shaded pole motor is considered the most popular type of single phase induction motor in the small fractional horsepower range as discussed by the authors, and is widely used for driving fans, and the equations for this type of motor are derived and the performance characteristics are discussed.
Abstract: The shaded pole motor is considered the most popular type of single phase induction motor in the small fractional horsepower range, and is widely used for driving fans The general forms of construction are outlined in this paper, in which the equations for this type of motor are derived and the performance characteristics are discussed
36 citations
TL;DR: In this paper, the effect of the width of resistance rings on the secondary resistance of a squirrel cage induction motors has been analyzed, and it was shown that half of that value is sufficient.
Abstract: The effect which the width of resistance rings has on the secondary resistance of squirrel cage induction motors has been subjected to a mathematical analysis. It is found that the width, in a radial direction, of these rings which connect the conductors of a squirrel cage rotor, need never exceed the pole pitch, and probably half of that value is sufficient. Methods for determining the current distribution in the resistance ring, and for determining the the effective width and resistance are demonstrated.
35 citations
TL;DR: In this paper, the method of symmetrical components, which is so useful in the analysis of symmetrically wound polyphase a-c machines, can be extended readily to analysis of unsymmetrical 2 phase induction machines, such as the capacitor or split phase motor in which the windings are not in space quadrature.
Abstract: By making use of suitably chosen components of current and voltage, the method of symmetrical components, which is so useful in the analysis of symmetrically wound polyphase a-c machines, can be extended readily to the analysis of unsymmetrical 2 phase induction machines, such as the capacitor or split phase motor in which the windings are not in space quadrature. Such extensions to this method, illustrated by a typical numerical example, are presented in this paper.
31 citations
24 citations
TL;DR: In this article, the authors present a general method of impedance calculation equally applicable to all transformer circuits and all construction types, and show how the ''circuit method'' can be used and prove some of the circuit properties and relations.
Abstract: The purpose of this paper is to present a general method of impedance calculation equally applicable to all transformer circuits and all construction types. An effort is made to show how the ``circuit method'' can be used and to prove some of the circuit properties and relations that are pertinent to the problems involved.
17 citations
TL;DR: In this paper, the characteristics of polyphase induction motors are analyzed by the method of symmetrical components in a manner different from other recently published articles, and curves of motor characteristics obtained by tests under unbalanced conditions agree closely with curves obtained by calculation.
Abstract: Characteristics of polyphase induction motors are analyzed in this paper by the method of symmetrical components in a manner different from other recently published articles. The analysis is neither tedious nor highly involved and curves of motor characteristics obtained by tests under unbalanced conditions agree closely with curves obtained by calculation.
15 citations
TL;DR: In this article, a general solution of the problem of determining temperature and heat distribution in conductors, and the development of the theory of the electrothermic ammeter of the thermocouple type, together with its compensation features are presented.
Abstract: Temperature distribution and heat flow in electrical conductors have been subjected to a mathematical analysis, which brings out a number of interesting thermal characteristics of conductors. The material presented in this paper is divided into 2 principal parts, the first being a general solution of the problem of determining temperature and heat distribution in conductors, and the second containing the development of the theory of the electrothermic ammeter of the thermocouple type, together with its compensation features. Practical applications of the theory are presented.
15 citations
TL;DR: In this paper, a circuit arrangement that supplies a large current to a circuit breaker under test and then subjects the open terminals to a high recovery voltage has been used in testing the 2,500,000-kva 287.5-kv impulse oil circuit breakers built for the Boulder Dam-Los Angeles transmission line.
Abstract: A novel circuit arrangement that supplies a large current to a circuit breaker under test and then subjects the open terminals to a high recovery voltage has been used in testing the 2,500,000-kva 287.5-kv impulse oil circuit breakers built for the Boulder Dam-Los Angeles transmission line. A description of this arrangement, which makes available several times the apparent power of the testing apparatus, is given in this paper, together with oscillograms which show details of the arc extinction process not previously known, and the results of a study of voltage distribution.
TL;DR: In this paper, current propagation and earth potentials for earth return conductors with application to electric railway systems are discussed and general formulas are derived from which solutions may be obtained for problemes such as propagation of track currents and voltages.
Abstract: Current propagation and earth potentials for earth-return conductors with application to electric railway systems are discussed in this paper. General formulas are derived from which solutions may be obtained for problemes such as propagation of track currents and voltages, and earth potentials imposed on neighboring conductors.
TL;DR: An analysis of the vibration of cables and dampers, representing the results of several years of research and laboratory and field testing, is presented in this paper, where applications of the formulas to specific cases are given.
Abstract: An analysis of the vibration of cables and dampers, representing the results of several years of research and laboratory and Field testing, is presented in this paper. In Part I, presented herewith, an explanation of the causes and nature of free harmonic vibration of the cable is offered followd by an of the cable is offered, followed by an analysis of the resulting stresses. In Part II, which is scheduled for publication in a subsequent issue, various ways or reducing the maximum stresses and means of controlling the vibration are discussed, including an analysis of the action of Stockbridge dampers. Applications of the formulas to specific cases are given, and comparisons are made with experimental data from laboratory and field.
TL;DR: In this paper, a new carrier pilot system, designed in accordance with these findings, is described, and the results of the investigation are presented in this paper, and a new CARP system is described.
Abstract: Carrier pilot relaying has been regarded by many as the nearest approach to a perfect protective relay system; however, it has not been adopted generally because of its high cost. With the intention of making still further improvements and reducing the cost of carrier pilot systems, a careful investigation has been made. The results of the investigation are presented in this paper, and a new carrier pilot system, designed in accordance with these findings, is described.
TL;DR: In this paper, a comprehensive series of tests on over-all protective schemes has been made, and definite conclusions are drawn regarding the proper lightning protection for machines connected directly to overhead lines or connected through transformers, giving consideration to the type of transformer connection.
Abstract: Supplementing theoretical studies on the protection of a-c rotating machines against impulse waves and previous tests on individual protective devices, a comprehensive series of tests on over-all protective schemes has been made. As a result, definite conclusions are drawn regarding the proper lightning protection for machines connected directly to overhead lines or connected through transformers, giving consideration to the type of transformer connection. Considerable information also is obtained on the propagation of surges through windings, and on the surge impedances of machine windings.
TL;DR: In this article, the results of a sereies of experiments made to determine the heart reaction to currents of different frequencies were presented, showing that the heart response to electric shocks varied with the frequency of the current.
Abstract: Supplementing earlier research progress reports1 concerning the physiological effects of electric shock, the authors here present the results of a sereies of experiments made to determine the heart reaction to currents of different frequencies
TL;DR: In this paper, it was shown that the electrical characteristics of the ordinary sliding contact, such as that between a carbon or graphite brush and a copper slip ring, are dependent upon the oxide film on the surface of the ring.
Abstract: Experiments with oxidized and oxide-Free materials indicate that the electrical characteristics of the ordinary sliding contact, such as that between a carbon or graphite brush and a copper slip ring, are dependent upon the oxide film on the surface of the ring. Results of these experiments are presented in this paper, together with an explanation of the breakdown of this oxide film by the increase of current through the contact, based upon these results. Tests to determine the effects of liquid films on the contact voltage drop, and the variation of thermal voltage in a sliding contact also are reported.
TL;DR: In this article, the results of wind tunnel studies of the vibration in specimen lengths of five types of transmission line conductors are presented in order to measure the frequency and amplitude of vibration for various wind velocities, power required to vibrate the conductor in still air, and amount of energy taken from the wind by the vibrating conductor.
Abstract: The results of wind tunnel studies of the vibration in specimen lengths of 5 types of transmission line conductors are presented in this paper. Measurements of the frequency and amplitude of vibration for various wind velocities, power required to vibrate the conductor in still air, and amount of energy taken from the wind by the vibrating conductor are reported for various conditions.
TL;DR: In this article, tensor analysis is applied to the performance analysis of salient pole synchronous motors to determine the subsynchronous performance characteristics of the salient pole synchronization motors with respect to a tensor tensor model.
Abstract: An extension of the development and application of methods of tensor analysis is given here, applied to the predetermination of the subsynchronous performance characteristics of salient pole synchronous motors.
TL;DR: In this article, the characteristics of a single phase parallel inverter supplying an inductive load were investigated for the case in which the direct current flows in pulses and no attempt was made to derive expressions for pulses in the case of direct current flow in pulses.
Abstract: Calculation of the characteristics of a single phase parallel inverter supplying an inductive load is treated in this paper, which supplements a previous paper on the parallel inverter supplying a pure resistance load. The treatment is confined to the case in which the direct current is constant, no attempt being made to derive expressions for the case in which the direct current flows in pulses.
TL;DR: In this paper, the effect of switching surges on the turn insulation of highvoltage line-starting a-c motors is discussed. But the authors focus on the physical and mathematical interpretation of the phenomena, and the importance of the external circuit as well as machine characteristics is illustrated.
Abstract: The manner in which the turn insulation of high-voltage line-starting a-c motors may be stressed severely by switching surges is described in this paper in such manner as to give both a physical and mathematical interpretation of the phenomena. The importance of the external circuit as well as the machine characteristics is illustrated. Methods are presented for estimating the severity of the stress and the advisable protection. Considerable test data are shown. The test arrangements are described in detail, because new methods had to be devised to obtain the needed data.
TL;DR: In this paper, a general equation for the output of an induction motor operating under unbalanced conditions of applied voltage and primary and secondary impedance, is deduced in terms of frequency of the applied voltage, slip, and rotor copper losses.
Abstract: A general equation (17) for the output of an induction motor operating under unbalanced conditions of applied voltage and primary and secondary impedance, is deduced in terms of frequency of applied voltage, slip, and rotor copper losses, General equations for the currents flowing in the windings are given in appendix I, from which the secondary copper losses, and hence the output and torque, may be calculated. Special conditions of partial unbalance also are considered.
TL;DR: In this article, it is pointed out that scientific progress is not a great leap of imagination, but a steady process, like the advance of a great army; at times strategic positions are captured, as when the positive electron (positron) was discovered, at times there is a steady “mopping up” process all along the line.
Abstract: IT IS AN ALL TOO COMMON practice of scientific publicists and prognosticators to give free vent to their imaginations in a most unscientific way by picturing our descendants as flying through interplanetary space, after the manner of Buck Rogers or operating a navy with a thimbleful of transmuting atoms or banishing old age by administration of glandular extracts. No doubt many of the past triumphs of science were, relatively to the times, as spectacular and even more unexpected than these would be. However, scientific progress is not a great leap of imagination, but a steady process, like the advance of a great army; at times strategic positions are captured, as when the positive electron (positron) was discovered;at times there is a steady “mopping up” process all along the line, as when the systematic search for chemical isotopes followed the first discovery; at times there is retreat, as when a theory is proved untenable; at times a new powerful engine of this scientific war is invented, like the radio tube amplifier. While the scientific campaign is generally well planned in advance and directed toward certain main objectives, it also, on occasion, is opportunistic in that its center of activity may quickly be shifted by some new discovery or idea which discloses new territories to be conquered.