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Emergency lighting system

  • US 4,323,820 A
  • Filed: 03/27/1980
  • Issued: 04/06/1982
  • Est. Priority Date: 03/27/1980
  • Status: Expired due to Term
First Claim
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1. A system for controlling the operation of an emergency device connected to a power line having a switch therein comprising a secondary power source for powering said emergency device, means for detecting a first loss-of-power condition resulting from the opening of said switch and a second loss-of-power condition resulting from a line failure even when said switch is closed, means responsive to the detection only of said second condition for enabling the continued powering of said emergency device from said secondary power source, said secondary power source, said detecting means and said enabling means all being contained at the location of said emergency device, control means for initially causing said emergency device to be powered from said secondary power source immediately responsive to the loss of power on said power line, and means for controlling said enabling means to operate only a predetermined time interval after said loss of power.

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