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Starting-current limiting device for single-phase induction motors used in household electrical equipment

  • US 5,164,651 A
  • Filed: 07/03/1991
  • Issued: 11/17/1992
  • Est. Priority Date: 06/27/1991
  • Status: Expired due to Term
First Claim
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1. An apparatus for use in the suppression of the starting current supplied by a single-phase AC power source supplying an AC voltage with a fundamental frequency, said apparatus comprising:

  • means for generating a timing signal in accordance with the waveform of the AC voltage supplied by the single-phase AC power source;

    means responsive to the timing signal for generating triggering signals with predetermined patterns;

    switching means which connects the single-phase AC power source to the single-phase AC motor, said switching means modifying in response to the triggering signals the waveform of the AC voltage supplied by the single-phase AC power source into a waveform-modified voltage with the ratio V/F thereof maintained at a value substantially equal to the flux density of the single-phase AC motor, where V is the average power of the waveform-modified voltage, and F is the frequency of the waveform-modified voltage;

    said switching means directly connecting the single-phase AC power source to the single-phase AC motor when the current delivering into the single-phase AC motor has reached a predetermined value.

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