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Refrigeration system alarm device

  • US 4,502,287 A
  • Filed: 07/18/1983
  • Issued: 03/05/1985
  • Est. Priority Date: 07/18/1983
  • Status: Expired due to Fees
First Claim
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1. An alarm apparatus, comprising:

  • power monitor means for detecting when at least one of a plurality of inputs of electrical power is below a predetermined level, said power monitor means including;

    first terminal means for receiving a first alternating current power input having a first nominal voltage or a first phase of a three-phase power system;

    second terminal means for receiving a second alternating current power input having a second nominal voltage or a second phase of said three-phase power system;

    third terminal means for receiving a third phase of said three-phase power system;

    first switch means for being switched to a first logic state when said second alternating current power input or said second phase has a voltage magnitude greater than said predetermined level or to a second logic state when said second alternating current power input or said second phase has a voltage magnitude less than said predetermined level;

    second switch means for being switched to the first logic state when said third phase has a voltage magnitude greater than said predetermined level or to the second logic state when said third phase has a voltage magnitude less than said predetermined level;

    logic gate means for indicating when either said first switch means or said second switch means is in said second state; and

    timer means, responsive to said logic gate means, for providing a control signal; and

    alarm means, responsive to said control signal, for indicating that at least one of said inputs is below said predetermined level.

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