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Controller for a motor and a method of controlling the motor

  • US 8,177,520 B2
  • Filed: 04/08/2005
  • Issued: 05/15/2012
  • Est. Priority Date: 04/09/2004
  • Status: Expired due to Fees
First Claim
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1. A method of detecting a possible entrapment event in a jetted-fluid system comprising a vessel for holding a fluid, a drain, a return, and a pumping apparatus coupled to the drain and the return, the pumping apparatus comprisinga pump comprising an inlet coupled to the drain and an outlet coupled to the return, anda motor coupled to the pump to operate the pump, the method comprising:

  • during a normal operation state,powering the motor,pumping the fluid with the pumping apparatus during the powering of the motor, the pumping act comprising suctioning the fluid from the vessel through the drain and jetting the pumped fluid into the vessel through the return,monitoring the drain for the possible entrapment event, the monitoring act comprisingmonitoring an input power of the motor, including sensing a voltage of the motor, sensing a current of the motor, determining a power factor of the motor, and calculating the input power to the motor based on the voltage, the current, and the power factor, andmonitoring the calculated input power for an indication of a possible entrapment event, andinitiating a fault state when the calculated input power is indicative of the possible entrapment event; and

    during the fault state,powering down the motor, andceasing the pumping of the fluid after powering down the motor.

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