Composition of miniature circuit breakers

A miniature circuit breaker consists of the following main parts:

1. A disconnectable contact connection. This consists of fixed contacts and a moving contact.

2. A device composed of a metal cylinder or insulated cylinder, housing the disconnectable contact connection, arc-extinguishing device, and transmission mechanism.

3. A transmission mechanism that drives the contacts.

4. Arc-extinguishing device.

When a miniature circuit breaker breaks a circuit, it mechanically separates the moving contact from the fixed contact. When closing, the opposite mechanical movement closes the moving contact with the fixed contact. During the operation of connecting and disconnecting the load circuit, an electric arc will be generated between the fixed and moving contacts. The arc generated during the breaking process is much more severe than that generated during the closing process. When the breaking current is large, especially when breaking a short circuit, the arc is very large, and disconnecting the circuit is often very difficult.