Abstract: Low voltage electric switchgear equipment includes a central programmer unit electrically interconnected with electronic main and branch circuit interrupters within the same enclosure and used with a multi-phase power distribution circuit. Indicating diodes are arranged on each of the circuit interrupters for signaling the occurrence of an overcurrent condition. The same indicating diodes are arranged for responding to address commands generated by the field programmer as to the exact location of each circuit interrupter within the enclosure.
Type:
Grant
Filed:
January 9, 1990
Date of Patent:
September 24, 1991
Assignee:
General Electric Company
Inventors:
Indrajit Purkayastha, Clinton K. Martin
Abstract: A non-fragmenting surge arrester core comprising a conductive core comprising a series array of non-linear resistor elements stacked in face-to-face contact between the inner end faces of a pair of terminal end pieces encased within a plastic impregnated jacket of bi-directional weave fabric woven of high tensile strength strands of which the strands of one of the bi-directional orientations have a greater tensile strength than the strands of the other bi-directional orientation with the greater strength fabric strands aligned lengthwise of the jacket. A tensioned constrictive hoop of high tensile strength material compressively circumscribes a portion of the jacket weave fabric overlying a peripheral area of the terminal end pieces between its two end faces, which peripheral area preferably conforms to a curvelinear depression groove circumscribing the terminal end pieces.
Abstract: A differential protection circuit includes a pair of current transformers each having a secondary winding and each being inductively coupled to a power conductor at a different location. The secondary windings of these transformers are electrically connected in series with each other in a loop in a bucking arrangement. A resistor is connected in parallel with the secondary winding of each transformer. Control circuits are connected to sense a voltage signal appearing across the resistor and to take appropriate action when the sensed voltage reaches a predetermined level. An additional winding on one of the transformers provides isolation between the loop and one of the control circuits to prevent false tripping of the differential protection circuit.