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American Institute of Electrical Engineers, Transactions of the

Volume 59: 1940

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Displaying Results 1 - 7 of 7
  • Dead Points in Squirrel-Cage Motors

    Publication Year: 1940, Page(s):637 - 642
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1390 KB)

    Certain squirrel-cage motors are known to have a wide variation in starting torque depending on the angular position of the rotpor. In extreme cases the torque may be actually negative at certain positions making the motor entirely useless. Various names such as ``dead points,'' ``cogging,'' and ``locking'' torque have been used to describe this condition but no detailed study of its mechanism app... View full abstract»

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  • Effect of Load Factor on Operation of Power Transformers by Temperature

    Publication Year: 1940, Page(s):632 - 636
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1058 KB)

    The practice of loading transformers by temperature is growing among operators who desire to take advantage of the additional capacity offered by this method of loading. The standards now recognize continuous overloads in cool ambients and short-time overloads under recurrent and emergency conditions. The paper discusses the effects of different shapes of system load factors on the aging of the in... View full abstract»

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  • Rapid-Recording A-C Bridge

    Publication Year: 1940, Page(s):628 - 631
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (3337 KB)

    A power-factor and capacitance bridge capable of unattended recording has been described. Changes in the specimen may be fully recorded within one second of their occurrence. The bridge may be used in connection with life tests, during treating processes, and for recording tests on large numbers of nominally identical structures, in the process of production. The automatic control circuits describ... View full abstract»

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  • Low-Voltage D-C Measurements on Electrical Insulating Oils

    Publication Year: 1940, Page(s):625 - 628
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (884 KB)

    1. Apparatus has been developed which is suitable for the measurement at low voltages of the d-c conductances of electrical insulating oils. 2. The change of d-c conductance with time of a highly refined oil has been found to substantiate the theory. that low-voltage methods do measure the true d-c conductance of electrical insulating oils. 3. The change in the conductance of this oil is shown to ... View full abstract»

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  • Frequency Modulation

    Publication Year: 1940, Page(s):613 - 625
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (3085 KB)

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  • A High-Speed Differential Relay for Generator Protection

    Publication Year: 1940, Page(s):608 - 612
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (4099 KB)

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  • Transient Starting Torques in Induction Motors

    Publication Year: 1940, Page(s):603 - 607
    Cited by:  Papers (22)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2056 KB)

    A transient fundamental-frequency torque is shown to occur in the starting of all induction motors. For full-voltage starting on a general-purpose squirrel-cage motor, this torque may be as high as two or three times the pull-out torque. A consideration of such torques is particularly advisable for cases where induction motors are started and stopped frequently or continuously, since under such co... View full abstract»

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