Low-voltage molded case circuit breakers are one of the more important protection and control components in low-voltage electrical appliances. They are mainly used in low-voltage power distribution networks in industrial and mining enterprises, high-rise buildings, hotels, hospitals, airports, 80a latching relay wharfs and modern residential communities. AC and DC electrical equipment protects it from abnormal conditions such as overcurrent, reverse current, short circuit, overvoltage and undervoltage, and can also be used in infrequently starting motors and operating conversion circuits. Intelligent low-voltage electrical appliances are more suitable for centralized control of automated substations and modern power grids.
According to the type of current, it is divided into AC AC and DC DC.
According to the arc extinguishing medium, air; vacuum; gas (rarely used in low-voltage circuit breakers)
By use category
Type A: In the case of a short circuit, the circuit breaker does not clearly specify the selective protection of another short circuit protection device connected in series on the load side, that is, in the case of a short circuit, there is no artificial short delay required for selective protection, so there is no Short-term withstand current requirements.
Type B: In the case of a short circuit, the circuit breaker is clearly specified as the selective protection of another short circuit protection device connected in series on the load side, that is, in the case of a short circuit, selective protection can be achieved, and a short time delay is artificial (adjustable) Therefore, there is a short-term withstand current requirement.