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Rotor fault and location detector for induction motors

  • US 4,808,932 A
  • Filed: 05/15/1987
  • Issued: 02/28/1989
  • Est. Priority Date: 05/15/1987
  • Status: Expired due to Fees
First Claim
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1. A method of detecting rotor faults in an induction motor, the motor including a stator and a rotor, the rotor including a multiplicity of rotor bars, the method comprising the steps of:

  • generating a flux signal corresponding to the magnetic flux at a predefined flux detection point in the motor which is affected by the flux around each rotor bar in the motor as the rotor revolves;

    generating a synchronization signal once each revolution of the rotor, said synchronization signal occurring when a predefined position on said rotor is closest to said flux detection point;

    filtering said flux signal to reject signals in a predefined frequency band around and including the frequency at which the rotor bars pass said flux detection point; and

    synchronously time averaging the output of said filtering step, using said synchronization signal as the synchronization reference for said averaging;

    whereby statistically significant peaks in the output of said averaging step indicate the presence of a rotor bar fault, and the location of such peaks corresponds to the location of rotor bar faults with respect to said predefined position on said rotor.

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