Circuit Breaker Working Principle

Описание: The primary function of a circuit breaker is to protect an electrical circuit from damage caused by excess current. It interrupts the flow of electricity in the event of a fault or overload. Here's how a circuit breaker typically works:

1. **Switch Mechanism**: A circuit breaker consists of a switch mechanism that can be manually operated (as in the case of residential circuit breakers) or automatically operated (as in the case of industrial or commercial circuit breakers).

2. **Contacts**: Inside the circuit breaker, there are electrical contacts that are normally held closed under spring tension. These contacts allow electricity to flow through the circuit when the breaker is in the closed position.

3. **Bimetallic Strip or Magnetic Coil**: Circuit breakers have a sensing mechanism that detects the current passing through the circuit. This mechanism can be a bimetallic strip or a magnetic coil.

**Bimetallic Strip**: In thermal-magnetic circuit breakers, a bimetallic strip is used to sense the heat generated by the current passing through the circuit. When the current exceeds a certain threshold for a certain period, the bimetallic strip heats up and bends, tripping the breaker.

**Magnetic Coil**: In magnetic circuit breakers, a magnetic coil is used to sense the magnetic field generated by the current passing through the circuit. When the current exceeds a certain threshold, the magnetic field becomes strong enough to pull a plunger, tripping the breaker.

4. **Trip Mechanism**: When the sensing mechanism detects an overload or fault condition, it triggers the trip mechanism of the circuit breaker. This causes the switch mechanism to open, interrupting the flow of electricity in the circuit.

5. **Arc Chute**: As the contacts open, an arc may form between them due to the remaining electrical energy in the circuit. To extinguish this arc and prevent damage to the contacts, circuit breakers are equipped with an arc chute. The arc chute is designed to redirect the arc into a series of plates, where it is cooled and extinguished.

6. **Resetting**: After the fault or overload condition is cleared, the circuit breaker can be manually reset (for manually operated breakers) or automatically reset (for some types of industrial breakers). Resetting the circuit breaker restores power to the circuit and closes the contacts.

Overall, circuit breakers play a crucial role in electrical safety by protecting circuits from damage due to overload, short circuit, or other faults. They are essential components of electrical distribution systems in residential, commercial, and industrial settings.