Solid state overcurrent protection system for circuit breakers
AssigneeSPD Technologies Inc.
InventorsEdward R. O'Brien, III, Edward Rifkin
Life of this patent
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Abstract
A device for detecting a primary fault current at a three phase current system and converting the detected fault current into mechanical action for breaking the circuit includes circuitry for breaking the circuit in response to a selected secondary current substantially instantaneously rising to a predetermined level and a device for adjusting the predetermined level.
Claims13
In a three phase current system, a device for detecting a primary fault current and converting said detected fault current into mechanical action for breaking the circuit in which said primary fault current occurred, comprising:
- a. means receiving said three phases of primary current, for providing corresponding phases of secondary current and choosing the largest magnitude secondary current as output therefrom;
- b. means for providing voltage proportional to said largest magnitude secondary current;
- c. means, connected to an object of said proportional voltage providing means, for moving a trip member providing said mechanical action;
- d. means for directing said largest magnitude secondary current through said trip member moving means;
- e. means for actuating said current directing means upon said voltage proportional to said largest magnitude secondary voltage substantially instantaneously rising to a predetermined first level;
- f. means for adjusting said predetermined first level;
- g. means for actuating said current directing means upon said voltage proportional to said largest magnitude secondary current reaching a second level and remaining at said second level for a predetermined time interval;
- and
- h. means for adjusting said predetermined time interval.
In a three phase current system, a device for detecting a primary fault current and converting said detected fault current into mechanical action for breaking the circuit in which said primary fault current occurred, comprising:
- a. means receiving said three phases of primary current, for providing corresponding phases of secondary current and choosing the largest magnitude secondary current as output therefrom;
- b. means of providing voltage proportional to said largest magnitude secondary current;
- c. means, connected to an output of said proportional voltage providing means, for moving a trip member providing said mechanical action;
- d. means for directing said largest magnitude secondary current through said trip member moving means;
- e. means for actuating said current directing means upon said voltage proportional to said largest magnitude secondary voltage substantially instantaneously rising to a predetermined first level;
- f. means for adjusting said predetermined first level;
- g. means for actuating said current directing means upon said voltage proportional to sd largest magnitude secondary current reaching a second level and remaining at said second level for a predetermined time interval;
- h. means for adjusting said predetermined time interval including switching means for connecting passive impedance providing means into a closed circuit.
Dependencies are inferred from the claim text.