When the motor is running, the noise is abnormal and there is abnormal noise
1. Causes of failure ① The bearing is worn or there are foreign objects such as sand particles in the oil; ② The rotor core is loose; ③ The bearing lacks oil; ④ The power supply voltage is too high or unbalanced.
2. Troubleshooting ① Replace the bearing or clean the bearing; ② Repair the rotor core; ③ Lubricate; ④ Check and adjust the power supply voltage.