How to Choose the Release Mode of Molded Case Circuit Breaker

The release modes include: spring force release mode in energy storage state; driving force release mode of compressed air; oil pressure release mode in energy storage state; electromagnetic repulsion force release mode.

There are two choices of release methods, as follows:

1. Regardless of the type of circuit breaker, spring force release or driving force release of compressed air are mostly used in the energy storage state. Especially when the spring force is used for the opening action, the spring is kept in the compressed energy storage state under the action of the driving force in the closing state, which is locked by the mechanical hook in order to maintain the closing state.

When switching off, the hook is usually released to start the switching-off action. Therefore, no matter which way is adopted, the starting of the switching-off action of circuit breaker is called tripping, and the switching-off action is called tripping action.

2. The release mode also includes opening the valve to discharge the compressed air or oil pressure which keeps closing, supplying the way to drive the air pressure or oil pressure, and sending the pulse current to the driving electromagnetic coil, etc.

Because the action energy that must be dealt with in the final stage of tripping action is very large, some ways are to finish the tripping through several stages of control action, some ways are to use the fluid driving force at the end and mechanical tripping with small springs at the beginning, and some ways are to make the small air valve act at the beginning and finally use the spring driving force.

Circuit breaker is generally composed of tripper, contact system, arc extinguishing device, transmission mechanism, base frame and outer shell. When put into operation, the main contact has been closed by the operating handle. The free tripping mechanism locks the main contact in the closed position, and all kinds of trippers are in operation.