A circuit breaker is an automatically operate electrical switch design to protect an electrical circuit from damage caused by excess current from an overload or short circuit. Moreover, Its basic function is to interrupt current flow after a fault is detect.
Secondly, it is a switching device that interrupts the abnormal or fault current. Although, It is a mechanical device that disturbs the flow of high magnitude (fault) current and in additions performs the function of a switch. The circuit breaker is mainly design for closing or opening of an electrical circuit, thus protects the electrical system from damage.
Operation of Circuit Breaker
The circuit breaker must first detect a fault condition. In small mains and low voltage circuit breakers, this is usually done within the device itself.Circuit breakers for large currents or high voltages are usually arrange with protective relay.These typically require a separate power source, such as a battery.
Although some high-voltage circuit breakers are self-contained with current transformers, protective relays, and an internal control power source.Once a fault is detect, its contacts must open to interrupt the circuit.Moreover, it usually mechanically store energy contain within the breaker, such as a spring or compress air to separate the contacts.Circuit breakers may also use the higher current caused by the fault to separate the contacts, such as thermal expansion or a magnetic field.
Types of C.B
Circuit breakers are mainly classified on the basis of rated voltages. Circuit breakers below rated voltage of 1000V are known as the low voltage circuit breakers and above 1000V are called the high voltage circuit breakers.Therefore, The most general way of the classification of the circuit breaker is on the basis of the medium of arc extinction. Such types of circuit breakers are as follows :-
- Oil Type C.B
- Bulk Oil C.B
- Minimum Oil C.B
- Minimum C.B
- Air Blast C.B
- Sulfur Hexa fluoride C.B
- Vacuum C.B
- Air Break C.B