Westinghouse 1876904A Electromechanical Overcurrent Relay

The Westinghouse 1876904A Electromechanical Overcurrent Relay (Type CO-6) provides inverse-time overcurrent protection for electrical power systems using an induction-disc operating principle. It monitors current through connected current transformers and, when preset pickup levels are exceeded, delivers a trip signal to associated circuit breakers to protect feeders, transformers, motors, and distribution circuits from overload and fault conditions. Designed for panel mounting in substations, switchgear, and industrial power distribution, the CO-6 offers adjustable time–current characteristics for selective coordination and reliable fault protection. This Westinghouse relay is intended for utility and industrial power systems, initiating circuit breaker trips during faults, with common replacement options including ABB REF615, Siemens SIPROTEC 7SJ62, and Schneider Electric Easergy P3.