Circuit breaker A switching device capable of closing, carrying, and interrupting current in normal circuit conditions and of closing, carrying, and interrupting current in abnormal circuit conditions within a specified period of time.The circuit breaker is generally composed of contact system, arc extinguishing system, operating mechanism, release device, shell and so on.The circuit breaker is divided into high voltage circuit breaker and low voltage circuit breaker according to its use range. The dividing line between high and low voltage is fuzzy. Generally, the circuit breaker above 3KV is called high voltage electrical appliance.
The working principle of circuit breaker is that when the short circuit, the magnetic field generated by the large current overcomes the counterforce spring, the tripper pulls the operation mechanism, and the switch trips instantaneously.When the overload, the current increases, the heat increased, the bimetallic sheet deformation to a certain extent to promote the mechanism action, the greater the current, the shorter the action time.The circuit breaker has the electronic type, the use of the transformer to collect the current size of each phase, compared with the set value, when the current is abnormal when the microprocessor sends a signal, so that the electronic trip to drive the operation mechanism action.
The main function of a circuit breaker is twofold
(1) Control effect.According to running need namely, put or cut off part of electric power equipment or line.
(2) Protective effect.That is, in the case of power equipment or line failure, relay protection and automatic device acting on the circuit breaker will quickly remove the fault part from the power grid to ensure the normal operation of the non-fault part of the power grid.
