China's big motor suppliers provide high-quality motors. How to judge the quality of motors, we can try the following methods:
The first step is to check whether the insulation resistance of the motor coil is greater than 0.5 megohm with an insulation resistance shaker. If it is greater than 0.5 megohm, it means that the insulation performance of the motor is good; the second step, use a multimeter to test the 3 windings of the motor If the DC resistances of the three windings are the same or the DC resistances of the three windings are the same or the deviation of the DC resistances of the three windings is small, it means that there is no short circuit between the three windings. Whether the disk does not move, abnormal noise, etc., the fourth step is to power on without load, check whether the 3-phase current of the motor is balanced, whether the motor is running smoothly, temperature rise, abnormal noise, etc., after the above 4 steps, if all are normal, Then this motor is good.
Off-line motors can be judged by the following methods.
1. Use a multimeter to measure the DC resistance of the three-phase windings of the motor. The closer the results of the three measurements are, the better. When the phase difference is more than 10%, the phase with the smaller resistance may have an inter-turn short circuit.
2. Use a 500v insulation shaker to measure the insulation resistance between phases of the three-phase winding and the insulation resistance to the ground (to the chassis). The insulation resistance of the motor that has been stored for a long time should be more than 0.5 megohm and it can be used. More than 0.1 megohm and less than 0.5 megohm indicate that the motor has been damp and can be used after drying. Very low insulation resistance means that the insulation has been damaged.
3. Rotating the motor rotor should be easy and free, and there is no noise or friction, indicating that the bearing and air gap are normal.
