Operating principle of Circuit breaker

A circuit breaker as a switching and current interrupting consist of fixed and moving contacts, which are touching each other and carry the current under normal condition. When the circuit breaker is closed, the current carrying contacts, called the electrodes, engage each other under the pressure of a spring.

Whenever a fault occurs on any part of the power system, the trip coils of the breaker get energized and the moving contacts are pulled

The tripping circuit is a coil which can be energized and produce a magnetic field that attract an armature that can be able to handle with the mechanical system to open or close the contact of the circuit breaker