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Safety device for elevator

  • US 5,083,634 A
  • Filed: 05/01/1991
  • Issued: 01/28/1992
  • Est. Priority Date: 05/09/1990
  • Status: Expired due to Fees
First Claim
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1. A safety device for use in an elevator in which an inverter controls the operation of an electric motor for winding up a cage thereof, said safety device comprising:

  • harmonic wave component detecting means for detecting a harmonic wave produced by said inverter; and

    means for producing an emergency stop instruction when said harmonic wave component detected by said harmonic wave component detecting means exceeds a predetermined reference voltage.

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