Typs of MCB, How its Works Single pole MCB

 Let us see the long-form and function of MCB. A miniature circuit breaker is a closed mechanical switch. This allows the circuit to be connected and disconnected from the power supply under normal conditions and also protects the circuit by automatically disconnecting the circuit breaker circuit from the power supply in the event of faults such as overload or short circuit.

Procedure: The circuit is connected to the power supply by switching the dolly up to the normal position of the circuit and the circuit can be closed by lowering the dolly. When a current greater than normal [more than 130%] flows through the circuit, the alloy strips expand and the trip lever rotates and the trip lever enters the magnetic field of the solenoid coil. So the trip mechanism is pulled down by the children switching dolly trip and the contacts are disconnected and the circuit is disconnected from the supply.

This means that in this MCB, 130% to 400% of the current has thermal action children circuit trips and 400 to 700% of the thermal and magnetic action children have circuit trips. Above 700%, fully magnetic action children make circuit trips.