Mechanism for hand closing of circuit breakers

IN THE ORDINARY application of power circuit breakers, the most desirable method of operation consists of d-c solenoid mechanisms for closing and tripping, supplied by a storage battery. When this is not suitable, the next choice is a dry metallic rectifier for closing from some a-c source and either current transformers or a capacitor device for a-c tripping. In some applications requiring only a single isolated circuit breaker, these methods of operation may not be desirable because of battery maintenance or because an auxiliary control transformer for a rectifier supply would have to be connected to the incoming line ahead of the circuit breaker.