Low-voltage circuit breaker is a switching device that can switch on, load and analyze the current under normal circuit conditions, but also under specified abnormal circuit conditions (such as short circuit), and load a certain time and break current. It plays a protective role in short circuit and overload of electrical appliances, as well as undervoltage (voltage loss) protection and long-distance breaking circuit.

    According to the structure of low-voltage circuit breaker, it can be divided into two types: universal type (frame type) and plastic shell type (device type). Because of its compact structure, reliable performance and safe use, circuit breakers are widely used in various construction sites as switching devices such as power distribution, cables, motors and welding machines.

    The circuit breaker should be carefully maintained in use, and its specific operating points are as follows.

    (1) Before the circuit breaker is put into operation, the rust-proof grease of the magnet working face should be removed to avoid affecting the reliability of the work

    (2) Before the circuit breaker is put into operation, it should be checked whether its installation is firm, whether all bolts are tightened, whether the circuit connection is reliable, and whether the shell has dust or not.

    (3) Before the circuit breaker is put into operation, it should check whether the setting current and setting time of the tripper meet the requirements of the circuit and whether the setting value of the factory changes.

    (4) Circuit breakers in operation should be regularly cleaned and repaired, and attention should be paid to abnormal sound and odor.

    (5) There should be no burr and ablation marks on the contact surface of circuit breaker in operation. When the contact wears down to less than 1/3 of the original thickness, new contacts should be replaced.

    (6) The metal particles on the wall and grid of the arc extinguishing chamber should be removed when the circuit breaker in operation breaks the short circuit current or runs for a long time. The arc extinguishing chamber should not be damaged.

    (7) The tripper with bimetallic disc type shall not be "re-buckled" immediately after the circuit breaker is interrupted due to overload. It shall be cooled for several minutes to reset the bimetallic disc before it can be "re-buckled".

    (8) The transmission mechanism in operation should be regularly lubricated.

    (9) After regular overhaul, several switch-off tests should be carried out without charge to check its reliability.

    (10) Check the current setting value and delay of each release regularly, especially the semiconductor release regularly, and check its working condition with the test button.

    (11) In operation, it is also necessary to check whether the lead and conductive parts are overheated or not.

    In a word, only by careful maintenance can the performance of low-voltage circuit breakers be ensured to be reliable and safe to use.