A circuit breaker is a switchgear that can close, carry and break the current under normal circuit conditions and can also close, carry and break the current under abnormal circuit conditions within a specified time. Circuit breakers are classified into high-voltage circuit breakers and low-voltage circuit breakers based on their application scope. The boundary between high and low voltage is rather ambiguous. Generally, those above 3kV are referred to as high-voltage electrical appliances.
Circuit breakers can be used to distribute electrical energy, infrequently start asynchronous motors, and protect power lines and motors, etc. When they experience severe overloads, short circuits, undervoltage and other faults, they can automatically cut off the circuit. Their function is equivalent to a combination of fuse switches and overheat and underheat relays, etc. Moreover, after breaking the fault current, it is generally not necessary to change the components. It has been widely applied.
Distribution is an extremely important link in the generation, transmission and use of electricity. The power distribution system includes transformers and various high and low voltage electrical equipment. Low-voltage circuit breakers are widely used electrical appliances.