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Motor control system

  • US 4,465,961 A
  • Filed: 06/15/1981
  • Issued: 08/14/1984
  • Est. Priority Date: 06/15/1981
  • Status: Expired due to Fees
First Claim
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1. In a control system for an alternating current motor having a switching means for switching connections of a DC supply to the windings of the motor at a rate which determines the speed of the motor and for a time duration which determines the power supplied to the motor, said switching occurring in response to pulses, means for supplying a pulse train in response to a speed signal, said pulse train having a frequency which determines the speed of the motor, and means responsive to said speed signal for providing a width modulated pulse for controlling the duty cycle of said switching means, the improvement comprising means for deriving a signal indicative of DC line current, means for comparing said speed signal and said current indicative signal and deriving an error signal, means for generating another pulsewidth modulated signal as a function of said error signal, and means for controlling the duty cycle of the switching means as a function of said another signal.

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