A circuit breaker is a switching device capable of closing, carrying and breaking the current under normal circuit conditions and closing, carrying and breaking the current under abnormal circuit conditions within a specified time. Circuit breakers are divided into high voltage circuit breakers and low voltage circuit breakers according to their scope of use.
Circuit breakers are generally composed of contact systems, arc extinguishing systems, operating mechanisms, trip units, and housings.
The circuit breaker is a basic low-voltage electrical appliance. The circuit breaker has overload, short circuit and under voltage protection functions, and has the ability to protect the line and power.
Breaker free trip: At any time during the closing of the circuit breaker, if the protective action is connected to the trip circuit, the circuit breaker can be completely and reliably opened, which is called free trip. The circuit breaker with free tripping can ensure that the circuit breaker can be quickly opened when the circuit breaker is closed and short-circuited, which can avoid expanding the scope of the accident.
Circuit breakers can be used to distribute electrical energy, start asynchronous motors infrequently, and protect power lines and motors. They can automatically cut off the circuit when they encounter serious overload or short circuit and undervoltage faults. Their function is equivalent to fuse switches In combination with thermal relays. In addition, there is generally no need to change parts after breaking the fault current.
In the generation, transmission and use of electricity, power distribution is an extremely important link. The power distribution system includes transformers and various high- and low-voltage electrical equipment. Low-voltage circuit breakers are a large-scale and widely used electrical appliance.