Rotary dynamoelectric machine having high-resistance rotor

  • US 4,158,225 A
  • Filed: 02/28/1977
  • Issued: 06/12/1979
  • Est. Priority Date: 08/21/1975
  • Status: Expired due to Term
First Claim
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1. A rotary dynamoelectric machine comprising:

  • a generally annular polyphase stator having a predetermined number of wound poles adapted to be interconnected to an a.c. power source; and

    an induction rotor including a cylindrical laminated ferromagnetic core positioned within said stator for rotation about a longitudinal central axis thereof when said stator is energized by the power source, said rotor having a plurality of electrically conductive bars each extending the length of the core adjacent the cylindrical surface thereof, and conductive end rings at the ends of said rotor electrically connected to the ends of said bars at the respective ends of the core, at least one of said end rings having a plurality of radial slots therethrough thereby forming a plurality of spaced arcuate ring segments whereby the resistance of said rotor is substantially increased, the number of said radial slots being an odd number which is other than a multiple or submultiple of the predetermined number of stator poles thereby to avoid dead-spot positions at which the rotor may stop and from which it is difficult to restart.

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