What is the reason why the universal circuit breaker cannot be closed?

Universal circuit breakers are often called frame circuit breakers because they are wrapped in a frame. This term is still very common today. During the use of universal circuit breakers, the main contacts may not close or disconnect automatically during closing, causing some unnecessary damage. The reasons may be as follows:

(1) Since the energy release coil often passes a large current, the coil overheats and causes unstable operation.

(2) Since the relay is under high voltage for a long time, the contact surface oxidizes, the contact resistance increases, and the contact cannot be connected and work normally.

(3) Since the stator and rotor in the motor are misaligned and rub against each other, a lot of heat is generated, causing the motor speed to be unstable or even stop, causing the universal circuit breaker to fail to work normally.

Generally speaking, the more common solutions to the above phenomena are: After the relay contacts are oxidized, the relay cover can be removed and each contact can be polished with sandpaper. After reinstallation, the universal circuit breaker works stably. If the rotor bearing is tilted and there is friction between the rotor and the stator, just move the bearing to the right position, fix it, and then put the cover on for a test run, and everything will return to normal.