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Phase controller for processing current and voltage faults

  • US 4,811,136 A
  • Filed: 12/24/1987
  • Issued: 03/07/1989
  • Est. Priority Date: 12/24/1987
  • Status: Expired due to Fees
First Claim
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1. A current and voltage fault processing system for disconnecting an electrical load from a first power source upon the detection of a current fault in the load and disconnecting the first power source from the load and connecting a second power source to the load upon the detection of a voltage fault in the first power source comprising:

  • (a) a first switching means disposed in series with the load and the first power source, conduction of the first switching means being controlled by a first control signal having first and second levels and passing current to the load when the first control signal is at the first level and blocking current flow when the first control signal is at the second level;

    (b) a shunt circuit, coupled in parallel with the first switching means, the shunt circuit containing a second switching means coupled to an impedance which limits the amount of current drawn by the load when the impedance is in series with the load, conduction of the second switching means being controlled by a second control signal having first and second levels and passing current to permit current flow through the impedance of the shunt circuit when the second control signal has the first level and blocking current flow when the second control signal has the second level;

    (c) means for generating the first control signal, responsive to a voltage level of the first power source, the means for generating the first control signal generating the first level of the first control signal in response to not detecting a voltage fault condition in the first power source and generating the second level of the first control signal in response to detecting a voltage fault condition in the first power source; and

    (d) means for generating the second control signal, responsive to a current level drawn from the first power source by the load, the means for generating the second control signal generating the first level of the second control signal in response to detection of a current flow between the first power source and the electrical load exceeding a maximum amount and generating the second level of the second control signal in response to detection of a current flow between the first power source and the electrical load not exceeding the maximum amount.

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