What's wrong with the AC contactor not closing

There may be multiple reasons why AC contactors do not engage. The following is a detailed introduction:
The power supply voltage of the control circuit is lower than 85% of the rated voltage, and the electromagnetic force generated by the energized electromagnetic coil is not enough to attract the moving iron core. In this case, the power supply voltage of the control circuit should be adjusted to the rated working voltage.
Insufficient or excessive spring pressure can cause the contactor to engage abnormally or slowly. It is necessary to adjust the spring pressure appropriately and replace the spring if necessary.
The gap between the dynamic and static iron cores is too large or stuck, and the shaft is rusted or deformed. In this case, the dynamic and static iron cores should be removed for inspection, the clearance should be adjusted, the shaft and support rod should be cleaned, and accessories should be replaced if necessary.
The short-circuit ring is broken. Short circuit rings of the same size should be replaced.
The coil itself is damaged. In this case, it is necessary to measure the resistance of the coil to determine if there is a fault in the coil. If the coil is damaged, it needs to be replaced.
In addition, if the wiring of the control circuit is loose, it may also cause the contactor to fail to engage. Therefore, the wiring should be tightened. If the fault still cannot be eliminated, it can be solved by measuring the coil resistance or replacing the contactor.