1, The difference in function between circuit breakers and fuses
(1) Different working principles
A circuit breaker is a type of switchgear that can connect, carry, and disconnect current under normal and fault conditions. It mainly relies on internal operating mechanisms and release devices to achieve protection functions. When overload, short circuit and other faults occur in the circuit, the release will produce corresponding actions according to the current size and duration, driving the operating mechanism to trip the circuit breaker and cut off the circuit. There are various types of release devices, including electromagnetic release devices, thermal release devices, and electronic release devices. Different types of release devices play a role in different fault situations. For example, thermal release devices are mainly used for overload protection, which push the release mechanism through the bending of bimetallic plates due to heat; Electromagnetic release is used for short-circuit protection, utilizing electromagnetic force to quickly operate.
(2) Protect characteristic differences
Circuit breakers have multiple protection functions. In addition to basic overload and short-circuit protection, they can also be equipped with functional modules such as leakage protection, undervoltage protection, and overvoltage protection to achieve comprehensive protection of the circuit. Moreover, the protection action time of the circuit breaker can be adjusted according to actual needs, with a certain degree of selectivity. It can only cut off the faulty line in a multi-level distribution system, ensuring normal power supply to non faulty areas.
Fuses mainly focus on short-circuit protection. When short-circuit current occurs, they can quickly melt and cut off the circuit with high breaking capacity. But for overload protection, the response speed of fuses is relatively slow, and once the fuse melts, a new fuse needs to be replaced, making it impossible to restore power supply through simple operation like circuit breakers.
