Working Principle Of Circuit Breakers

Circuit breakers operate based on the principle of electromagnetic or thermal tripping to interrupt the flow of current in the event of a fault.

 

Here’s how they work:

1.Detection: When an overcurrent or fault occurs in the circuit, the circuit breaker’s sensing mechanism detects the abnormal condition.

2.Tripping Mechanism: Upon detection, the circuit breaker’s tripping mechanism is activated. In thermal-magnetic circuit breakers, excessive current heats a bimetallic strip, causing it to bend and trip the breaker. In magnetic circuit breakers, a magnetic coil senses the magnetic field generated by the overcurrent and trips the breaker instantaneously.

3.Opening the Circuit: Once tripped, the circuit breaker mechanically opens its contacts, interrupting the flow of current in the circuit. This prevents further damage to the electrical system and equipment.

4.Resetting: After the fault is cleared, the circuit breaker can be manually or automatically reset, restoring power to the circuit.

 

In summary, circuit breakers operate by detecting abnormal current conditions, tripping to interrupt the circuit, and protecting electrical systems from damage due to faults.