1. Almost half of the burning of the motor is caused by the lack of phase operation of the motor.

The lack of phase often causes the motor to be unable to run or slow after starting, or the rotating powerless current increases with the phenomenon of "buzzing". If the load on the shaft does not change, the motor is in a serious overload state, and the stator current will reach 2 times or more of the rating. In a short period of time, the motor will heat up or even burn out. The main reasons for the lack of phase operation are as follows.

(1) If one phase power outage is caused by the failure of other equipment on the power supply line, the other three-phase equipment connected to the line will run without phase.

(2) The circuit breaker or contactor phase is missing due to the burning of bias voltage or poor contact.

(3)Phase loss caused by aging and wear of motor incoming line.

(4) The one-phase winding of the motor is broken, or the one-phase joint in the junction box is loose.

2. Other causes of non-mechanical electrical faults

The increase of motor temperature caused by other non-mechanical electrical faults may also lead to motor failure in serious cases. If the ambient temperature is high, the motor lacks fan, and fan is incomplete or lacks fan cover. In this case, forced cooling must be made to ensure ventilation or replacement of vane, otherwise the normal operation of the motor can not be guaranteed.

To sum up, in order to adopt the correct method to deal with the motor fault, we must be familiar with the characteristics and causes of the common motor fault, grasp the key factors, check and maintain regularly. In this way, we can reduce detours, save time, eliminate faults as soon as possible, and make the motor in normal operation state. So as to ensure the normal production of the workshop.