When the voltage of the power supply system is low, it may cause the AC contactor not to pick up but shake. The working voltage should be checked. If the power load permits, the thick conductor should be replaced.

The main or auxiliary contacts are often stained or burred, which causes the contactor to be unable to suck or shake.

AC contactor coil inter-turn short circuit, resulting in contactor can not pick up but shake.

The mechanical plug or reset spring of AC contactor core has not been adjusted properly.

In the control circuit, the button contacts badly or the terminal contacts badly.

When the end of the electromagnet enters the foreign body, this phenomenon will also occur.

The control power supply voltage does not match the coil voltage.