A circuit breaker is a Manually or automatically operated electrical switch designed to protect an electrical circuit from damage caused by overcurrent, typically resulting from an overload or short circuit.
A circuit breaker is a device which can stop the flow of electricity around a circuit by switching itself to prevent excessive current, as that caused by a short circuit, from damaging the apparatus in the circuit or from causing a fire.
Importance Of Circuit Breaker
in This modern Century, power system has to work with huge power network and huge numbers of connected electrical different types of equipment. Now During short circuit or any types of electrical fault, these equipment, as well as the power network, suffer a high stress of fault current in them which may damage the equipment and networks permanently.
So for timely disconnecting and reconnecting different parts of electrical power system network for protection and control, there must be some special type of switching protection devices which can be operated safely under huge current carrying condition and protect the network. During the interruption of huge current, there would be large arcing in between switching contacts, so care should be taken to quench these arcs in the circuit breaker in a safe manner. The circuit breaker is the special device which does all the required switching operations during high current carrying condition.
For saving this equipment and the power networks the fault current should be cleared from the system as quickly as possible. Again after the fault is cleared, the system must come to its normal working condition as soon as possible for supplying reliable quality power to the receiving ends. In addition to that for proper controlling of the power system, different switching operations are required to be performed.
Circuit breaker essentially consists of fixed and moving contacts. These contacts are touching each other and carrying the current under normal conditions when the circuit is closed. When the circuit breaker is closed, the current carrying contacts, called the electrodes, engaged each other under the pressure of a spring.
During the normal operating condition, the arms of the circuit breaker can be opened or closed for a switching and maintenance of the system. To open the circuit breaker, only a pressure is required to be applied to a trigger.
Whenever a fault occurs on any part of the system, the trip coil of the breaker gets energized and the moving contacts are getting apart from each other by some mechanism, thus opening the circuit.
Types Of Circuit Breaker
According to different Factor, there are different types of the circuit breaker.
According to their arc quenching media, the circuit breaker can be divided into-
- Oil circuit breaker.
- Air circuit breaker.
- SF6 circuit breaker.
- Vacuum circuit breaker.
According to their services, the circuit breaker can be divided into-
- Outdoor circuit breaker
- Indoor breaker.
According to the operating mechanism of circuit breaker, they can be divided as-
- Spring operated circuit breaker.
- Pneumatic circuit breaker.
- Hydraulic circuit breaker.
According to the voltage level of installation types of circuit breaker are referred as-
- High voltage circuit breaker.
- Medium voltage circuit breaker.
- Low voltage circuit breaker.