Quick release for vacuum circuit breaker - has low inertia mechanism mounted directly on live pole

摘要

The trip mechanism for a vacuum circuit breaker enables a quick normal tripping action as well as a quick trip immediately following circuit breaker closure. The latter condition is representative of closing the breaker onto a fault. The increase in speed is achieved by reducing the mass, and hence the inertia, of the release mechanism. The desired reduction in mass is achieved by mounting the release mechanism directly on one pole of the circuit breaker, at high potential. A lever operated by a boss on the contact operating bolt sets the latch when the circuit breaker is closed. At the same time the connected rod and spring system engages the lock which holds the contacts closed. To initiate a trip the latch is released. The springs rapidly move the light rod such that the attached lever turns the bolt to the free position allowing the trip springs to part the contacts.