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