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Detection of faults in the working of electric motor driven equipment

  • US 5,754,450 A
  • Filed: 06/17/1996
  • Issued: 05/19/1998
  • Est. Priority Date: 09/06/1993
  • Status: Expired due to Fees
First Claim
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1. Apparatus for monitoring the functioning of motor driven equipment comprising:

  • current sensing apparatus connectable to the power input of the motor and producing a current signal;

    signal correction apparatus receiving as input said current signal and operative to demodulate said current signal, filter said current signal to retain low frequencies thereof, and convert said current signal from analog to digital form and producing a corrected signal;

    a memory;

    a controller in operative connection with said memory, receiving said corrected signal and having a calibration state and an operation state and operative, when in the calibration state, to compute the calibration norm of said corrected signal based partly on data contained in said memory and to store said calibration norm in said memory and operative, when in the operation state, to compute the operation norm of said corrected signal based partly on data contained in said memory and to compare said operation norm with said stored calibration norm and to produce a function signal indicating the functioning of said motor driven equipment; and

    an indicating unit receiving as input said function signal and producing an output indication of the functioning of said motor driven equipment.

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