US 4,233,640 AGranted

Ground fault apparatus and protection system

AssigneeGeneral Electric Company

InventorsKeith W. Klein, Joseph M. Palmieri, Gregory C. Eckart

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Abstract

A unique ground fault circuit interrupting (GFCI) device is utilized to control either an industrial circuit breaker or a contactor in protecting a large power distribution circuit against ground faults. The GFCI device is equipped with plural sets of switch contacts which are actuated incident with tripping of the GFCI device. The particular switch contacts are selected to control energization of an actuator adapted to the circuit breaker or contactor, depending on the actuator type. A ground fault sensor responds to ground faults on the distribution circuit by injecting a current imbalancing signal into the GFCI device, causing it to trip. The consequent switch contact actuation initiates operation of the circuit breaker or contactor to interrupt the distribution circuit.

A ground fault circuit interrupting (GFCI) device for use in a system protecting power distribution circuits against ground faults, said GFCI device comprising, in combination:

A. a molded case consisting of base and a cover;
B. a switch operating mechanism mounted within said case, said switch operating mechanism including
(1) a movable contact carrier biased toward an open circuit position,
(2) a spring biased reset operator mounted for protrusion through an opening in said cover,
(3) a latch conditioned by depression of reset operator to engage said carrier pursuant to positioning the latter to its closed circuit position, and
(4) a solenoid operable upon electrical energization to disengage said latch from said carrier, whereupon said carrier springs to its open circuit position.
C. a first switch consisting of a first stationary contact mounted within said case and a first movable contact mounted by said carrier, said first stationary and movable contacts being engaged while said carrier is in its closed circuit position and disengaged while said carrier is in its open circuit position;
D. a ground fault module mounted within said case, said module including
(1) a current transformer having at least one primary winding, and
(2) electronic means responsive to a net primary current excitation of said transformer for initiating energization of said solenoid pursuant to unlatching said carrier for movement to its open circuit position;
E. a normally open second switch disposed within said case in a position to be engagably actuated to its closed condition by said carrier in moving to its open circuit position;
and
F. an externally accessible terminal board carried by said case and including
(1) a first terminal internally wired to said module,
(2) a second terminal internally wired to said solenoid and said module through said first switch,
(3) a third terminal internally wired to said second terminal through said second switch,
(4) a fourth terminal, and
(5) a fifth terminal internally wired to said fourth terminal through said one transformer primary winding.

15 more elements

Abstract

Claims11