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Method and apparatus for sensing fault conditions for an elevator active roller guide

  • US 5,824,976 A
  • Filed: 03/03/1997
  • Issued: 10/20/1998
  • Est. Priority Date: 03/03/1997
  • Status: Expired due to Term
First Claim
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1. A method of fault-sensing for an elevator active roller guide (ARG) having a current-driven force actuator for positioning an elevator car horizontally within a vertical hoistway, the actuator having a magnet with a coil, the magnet spaced a variable magnitude gap from a reaction bar, the reaction bar connected to a roller on a rail extending along the vertical hoistway, the ARG establishing more or less current in the coil in order to draw the elevator car with more or less force closer to the reaction bar for changing the gap, the ARG including a means for measuring flux density in the gap created by the current, means for signaling the magnitude of current used to drive the actuator, and means for signaling the magnitude of flux density in the gap, the method of fault-sensing comprising the steps of:

  • a) sensing a signal indicating a new magnitude of current and a signal indicating a new magnitude of flux density;

    b) determining from the flux density and the current a magnitude of the gap;

    c) comparing the magnitude of the gap to a range defined by a maximum and minimum allowed magnitude of the gap, and providing a signal indicating whether the magnitude of the gap is outside the range; and

    d) determining if the magnitude of the force and the magnitude of the current are each less than a respective limit, and providing a signal corresponding to the determination.

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