Spring-Charged Operating Mechanism — Power Circuit Breaker

Drive mechanism for opening and closing a power circuit breaker (IEC 62271-100) in which a motor or hand crank charges a closing spring, which then rapidly releases the required energy on a closing command to close the contacts at sufficient making speed, independent of any fluctuations in the auxiliary supply voltage at that moment. A separate opening spring, charged when the breaker closes, provides the energy to open the contacts rapidly on a tripping command (manual or via a protection relay). The mechanism typically has a 'spring charged' indication on the front of the breaker; an uncharged closing spring means the breaker cannot be closed remotely until the spring is recharged, which is relevant when assessing operational readiness during an inspection.