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Ground fault indicator

  • US 4,414,543 A
  • Filed: 09/25/1980
  • Issued: 11/08/1983
  • Est. Priority Date: 09/25/1980
  • Status: Expired due to Term
First Claim
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1. A ground fault indicator for indicating the occurrence of a ground fault current in multi-conductor electrical mains, comprising, in combination:

  • magnetic circuit means comprising a helical magnetic pole piece having axially displaced ends encircling the conductors of the mains and forming a magnetic field between said axially displaced ends substantially parallel to the axis of said conductors dependent on the vector sum of the individual currents in the conductors;

    magnetic sensing means disposed between said axially displaced ends and producing a control effect in response to said magnetic field exceeding a predetermined threshold level;

    status indicating means having a reset-indicating state and a fault-indicating state; and

    circuit means for conditioning said status indicating means to said fault-indicating state in response to said control effect.

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