1. The three-phase current of the three-phase asynchronous motor must be balanced. For a three-phase asynchronous motor, the difference between the current of any one of the three-phase currents and the average of the other two-phase currents must not exceed 10% to ensure the safe and normal operation of the motor. If the current value of the single phase and the average value of the other two phases exceed the specified limit, it indicates that the motor is faulty, and the cause must be identified. The fault can be continued after the fault is removed. Otherwise, the fault range will be enlarged, resulting in an accident of burning the motor.

2. The three-phase asynchronous motor maintains normal temperature. Always check the temperature of the bearings, stators, casings, etc. of the motor for abnormalities, especially for voltage-free, current and frequency monitoring facilities and motors without overload protection. Monitoring temperature rise is especially important. If the temperature rise near the bearing is found to be too high, stop immediately and check for damage or lack of oil. Whether the bearing rolling element or the raceway surface is cracked, scratched or damaged, whether the bearing clearance is too large, and whether the inner ring rotates on the shaft or the like. When the above situation occurs, the new bearing must be replaced before the operation can be carried out, otherwise the bearing will be further damaged and cause collapse, causing a broom and burning the motor.

If the temperature and temperature rise of the motor meet the specified requirements, a thermometer can be inserted into the motor sling and fixed with a cotton lump to observe the temperature of the motor at any time.