Electric motors are widely used in industry today. Before using some idle motors, the quality of the motor must be measured before they can be used. 

How to judge the quality of a motor mainly has two parameters？One is to measure the resistance value of the motor coil, and the other is to measure the insulation resistance between the coil and the shell. The method of measuring resistance of a three -phase motor is the same as that of a single-phase motor, but the method of measuring coil resistance is different. Motor failure is nothing more than two major components: mechanical and electrical.

Mechanical aspects:

1. Whether the bearing is missing or damaged.

2. Whether the end cover is "running sleeve" and whether the bearing is "running sleeve".

The main electrical aspects include:

1. Whether the insulation resistance is qualified.

2. Whether the three-phase DC resistance is qualified or not, measure it with a double-arm bridge.

3. Whether the rotor is broken or not, the DC resistance of the motor is an important basis for judging the motor.

Here's how to quickly judge whether the motor is good or bad:

1. Use a multimeter to measure the DC resistance of the three-phase winding of the motor. The closer the three measurements are, the better. When the winding resistance is qualified within 2%. When the difference is greater than 10%, there may be a short circuit with a small resistance.

2. Use a 500V insulation shaker to measure the three-phase winding resistance and the insulation resistance to ground (opposite situation). The insulation resistance of the motor for long-term storage should be greater than 0.5 trillion euros. Can use. If it is less than 0.1 trillion ohms, it means that the motor is wet and can only be used when it is dry. Damaged insulation resistance.

3. The rotor of the rotating motor should be relaxed freely, without noise and friction sound, indicating that the bearing and air gap are normal.