Cut off and turn on the load circuit, and cut off the faulty circuit to prevent the accident from expanding and ensure safe operation. The high-voltage circuit breaker needs to break the 1500V, current 1500-2000A arc, these arcs can be stretched to 2m and still continue to burn without being extinguished. Therefore, arc extinguishing is a problem that high-voltage circuit breakers must solve.
Low-voltage circuit breakers are also called automatic air switches, which can be used to connect and break load circuits, and can also be used to control motors that start infrequently. Its function is equivalent to the sum of some or all of the functions of knife switches, overcurrent relays, voltage loss relays, thermal relays and leakage protectors. It is an important protective electrical appliance in low-voltage distribution networks.
Low-voltage circuit breakers have a variety of protection functions (overload, short circuit, undervoltage protection, etc.), adjustable action value, high breaking capacity, convenient operation, safety, etc., so they are currently widely used. Structure and working principle The low-voltage circuit breaker is composed of operating mechanism, contacts, protection devices (various releases), arc extinguishing system, etc.