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Electro Mechanical Protection Relays

A protecion relay is a type of switch used in electrical circuits to monitor and protect against an overload or fault condition. The protection relay may operate by monitoring any type of electrical measurement, include current, voltage, and frequency. Electro mechanical protection relays are often used in larger scale power distribution applications. Rather than using a bimetallic strip of metal to open like in a traditional circuit breaker, an electro mechanical relay uses two electromagnetic coils, one to open the breaker contacts and one to close them. The protective relay monitors for the overload or fault condition, then energizes the open coil when a fault is detected.