×

Faulted circuit detector having isolated indicator

  • US 5,475,371 A
  • Filed: 12/18/1992
  • Issued: 12/12/1995
  • Est. Priority Date: 06/25/1990
  • Status: Expired due to Term
First Claim
Patent Images

1. An apparatus for detecting the presence of faults on an electrical conductor;

  • comprising;

    mean for sensing an overcurrent condition in the electrical conductor, said sensing means comprising a temperature compensation circuit for negating the effect of temperature change on said sensing means;

    means remote from said sensing means for indicating the presence of an overcurrent condition in the electrical conductor;

    means for communicating the presence of an overcurrent condition sensed by said sensing means to said indicating means;

    means for automatically resetting said indicating means;

    means for disabling the automatic operation of said resetting means when a predetermined minimum voltage is not present on the electrical conductor; and

    said temperature compensation circuit comprisinga current transformer having a wire coil, said wire coil having a positive temperature coefficient;

    a thermistor having a negative temperature coefficient; and

    a resistor connected in parallel with said thermistor, said resistor having a negligible resistance change at temperatures within the range of approximately -40 degrees C. to +85 degrees C.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×