1. The conttor phase loss must be replaced. This fault will cause damage caused by the load (motor) phase loss, and the superior circuit breaker trip protection, etc., which can not operate normally. The judgment method is measurement prevention (pay attention to power failure measurement), or voltage measurement (live measurement).

2. The main contact adhesion must be replaced, this fault is slightly careless will cause the occurrence of electric shock, judgment method: observe the main contact can not bounce back to the original position, part of the contactor can not be observed by naked eyes, using a multimeter measurement to prevent judgment can also be.

3. Contactor moving contact and the static contact arc contact damage caused by touch the point contact area (decrease) suggested replacement, the fault causes the superior circuit breaker tripped (thermal protection circuit breaker need belt, contact area will reduce fever), the judgment method for open contactor, observe the static contact and moving contact plane with and without depression, the suggested replacement, It can also be used after polishing the contact (it is not recommended to continue to use, power is not allowed in the operation of the first type of equipment, which will increase the failure rate of the equipment and reduce the quality of the product, so it is recommended to replace)

4. It is recommended to replace the abnormal sound of the contactor. The judgment method is not to mention. (It is not recommended to continue to use, power is not allowed in the operation of the first type of equipment, which will increase the failure rate of the equipment and reduce the quality of the product, so it is recommended to replace)