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Single-phase induction motor safety controller

  • US 5,670,858 A
  • Filed: 10/07/1996
  • Issued: 09/23/1997
  • Est. Priority Date: 06/03/1991
  • Status: Expired due to Fees
First Claim
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1. An electronic control apparatus for automatically adjusting electrical input to a single phase alternating current (AC) induction motor running at constant RPM comprising:

  • means for sampling voltage input provided by an electrical source to the motor, said means being connected to an input line from the electrical source;

    means for rectifying the sample voltage input taken from the electrical source to yield a rectified output voltage;

    means for creating a fixed pulse indicating zero voltage crossing;

    means for sampling current input being provided by the electrical source to the motor to create a time-variable pulse indicating zero current crossing, said time-variable pulse which triggers a monostable output voltage; and

    means for adjusting voltage supplied to the motor by using the fixed pulse and the monostable output voltage.

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