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American Institute of Electrical Engineers, Transactions of the

Volume 57: 1938

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Displaying Results 1 - 15 of 15
  • Application or Modern Electric Vehicles to Urban Transportation

    Publication Year: 1938 , Page(s): 57 - 60
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  • Electrical Equipment ror Modern Urban Surrace Transit Vehicles

    Publication Year: 1938 , Page(s): 50 - 56
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    This paper reviews modern urban surface transit developments, traces the reasons for the changes, and outlines some of the problems involved and their solution. View full abstract»

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  • A New Correlation of Sphere-Gap Data

    Publication Year: 1938 , Page(s): 45 - 49
    Cited by:  Papers (2)
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    The similarity principle for electrical discharges is used to correlate the most recent AIEE sphere-gap data for both positive and negative impulses. Empirical formulas are developed from which the entire range of data can be calculated to within about 1.5 per cent. Some practical results of this study are: 1. Spark-over curves for each value of spacing to diameter ratio are straight lines when plotted to logarithmic scales, at least to within the certainty of the present data. 2. A spark-over voltage chart covering the entire useful range of sphere sizes, spacings, and air densities can be constructed easily. 3. New air-density correction factors are derived which differ appreciably from those previously published. View full abstract»

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  • Temperature Limits for Short-Time Overloads for Oil-Insulated Neutral Grounding Reactors and Transformers

    Publication Year: 1938 , Page(s): 39 - 44
    Cited by:  Papers (5)
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  • Recent Advances in Resistance Welding

    Publication Year: 1938 , Page(s): 37 - 38
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  • Corona Voltages of Typical Transformer Insulations Under Oil

    Publication Year: 1938 , Page(s): 34 - 36
    Cited by:  Papers (7)
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  • A new single-channel carrier telephone system

    Publication Year: 1938 , Page(s): 25 - 33
    Cited by:  Papers (1)
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    A new single-channel carrier telephone system, known as the type H, has recently been developed and is now being applied. This new system offers improved performance, and also, because of its lower cost, is applicable to providing service over shorter distances than were economical with the earlier system. The type-H system, which is characterized by a number of new features and special developments, is applicable not only to the needs of telephone companies but also to those of railroads, power systems, and oil companies. In the first place it is designed to operate either on ac or on dc plate and filament supply. A repeater is available to extend the range of operation. Through the use of specially designed but simple filters the system can be employed on circuits which are equipped with bridged telephone stations at intermediate points as is frequently the case in railroad operation. A unique feature is the use of opposite sidebands of the same carrier frequency for opposite directions of transmission. The upper sideband is used in one direction and the lower sideband in the other, the carrier being suppressed. For the modulators and demodulators copperoxide "varistors" are employed in place of vacuum tubes. The amplifiers are single stage, employ pentode tubes and are stabilized in performance by feedback. The filters are simplified in construction by the use of coils with a new type of core material and by improved designs of paper condensers. View full abstract»

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  • The thyratron motor at the Logan plant

    Publication Year: 1938 , Page(s): 19 - 24
    Cited by:  Papers (8)
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    The motor is rated 400 hp, 2,300 volts, 3-phase, 60-cycles, 40°C and was designed to drive an induced draft fan having a speed range from 625-350 rpm. It closely resembles a standard synchronous motor with a rotating field, except that it has two independent star-connected stator windings installed in the same slots. Unlike a synchronous motor, however, the field terminals, after being brought out through slip rings, connect to the neutral points of the star windings. The six remaining power leads connect in a special arrangement to a series of 18 type FG-118 thyratron tubes, each having a continuous rating of 12.5A and a maximum rating of 75A. During the year the motor has been in operation at this writing, a comparatively large number of minor difficulties arose. Yet in spite ??of these, the plant operators are very enthusiastic about its performance. Experience has shown them that no drive compares with it for ease of control, for smoothness of draft regulation, for ability to rotate at very low speed, and for almost entire elimination of fan blade maintenance expense. In view of the fact that plant operators are pretty hard-headed and tend to look with suspicion on new "gadgets," this response would seem convincing evidence of its success from a practical standpoint. View full abstract»

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  • Some Engineering Features of Petersen Coils and Their Application

    Publication Year: 1938 , Page(s): 11 - 18
    Cited by:  Papers (9)
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    Service experience with Petersen coils on transmission systems and networks in this country has demonstrated conclusively certain facts concerning these protective devices which may be stated as follows: 1. There is definitely a place for Petersen coils in American system-protective practice. 2. The Petersen coil will prevent the interruptions to service usually associated with transitory flashovers to ground. 3. The Petersen coil may be applied to any system insulated for full neutral displacement. 4. Petersen coils do not lose their effectiveness if used on a system when different sections are switched out of service unless the system capacitance is changed more than 25 to 30 per cent. 5. Surges during switching operations encountered on the first Petersen-coil application have not recurred in later applications. 6. By the use of Petersen coils, it is possible that from 70 to 80 per cent of all faults may be cleared without the opening of a single oil circuit breaker, and without any dip in the phase-to-phase voltage, thus improving system stability and service continuity. View full abstract»

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  • A New High-Speed Distance-Type Carrier-Pilot Relay System

    Publication Year: 1938 , Page(s): 5 - 10
    Cited by:  Papers (16)
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    This paper outlines the reasons for application of pilot relay equipment, particularly of the carrier-current type. A one-cycle carrier-pilot-relay scheme is described which now makes available the desirable high-speed and back-up characteristics of step-type distance protection combined with the 100 per cent simultaneous tripping feature possible with a pilot circuit. Impedance and over current supervised single-phase directional elements are utilized for controlling carrier on phase and ground faults, respectively. View full abstract»

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  • Electrical studies of living tissue - II: Correlation between tissue response and voltage distribution

    Publication Year: 1938 , Page(s): 1 - 4
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    In a previous paper published in Electrical Engineering [pp 768-772, July 1936] the authors demonstrated the effects of tissue capacitance on the shape of the voltage waves across tissue during the passage of current impulses of rectangular wave shape. Using the voltage wave shapes as criteria of circuit constants, this work has been extended here to define the character of the equivalent circuits. We find that for rectangular waves of current 0.001 to 0.0001 second in duration and from 1 to 10 times the rheobase (the rheobase current is the minimum current that will produce a response, that is, it is the current represented by the ordinate of the horizontal asymtote to the intensityduration curve) value in intensity that human and frog tissue behaves electrically as a simple circuit consisting of one condenser and one or more resistors. The magnitude of tissue impedance remains constant throughout the duration of the impulse. The correlation between tissue response and the voltage distribution in the tissue has been determined and is here described on the basis of the voltage distribution in the equivalent circuits. View full abstract»

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  • Erratum

    Publication Year: 1938 , Page(s): nil4
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    Presents revisions to various equations and formulas from selected articles. View full abstract»

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  • Preface [Transactions to contain only finally reviewed papers and approved discussions]

    Publication Year: 1938 , Page(s): nil3
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    Freely Available from IEEE
  • [Breaker page]

    Publication Year: 1938 , Page(s): nil2
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    Freely Available from IEEE
  • Transactions of the American Institute of Electrical Engineers

    Publication Year: 1938 , Page(s): nil1
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    Freely Available from IEEE