What are the reasons for the noise of permanent magnet DC motors?

Update:22 Mar 2021

The basic cause of permanent magnet DC motor noise The […]

The basic cause of permanent magnet DC motor noise

The causes of permanent magnet DC motor noise are basically divided into three categories: electromagnetic noise, mechanical noise, and aerodynamic noise.

Electromagnetic noise is a kind of low-frequency noise generated by the magnetic field pulsation in the gap of the motor, which causes the vibration of the stator, rotor and the entire motor structure. Its value is determined by the electromagnetic load and motor design parameters.

1. Electromagnetic noise is divided into constant electromagnetic noise and electromagnetic sound related to the load. The main reason is that the stator and rotor slots are not properly matched, the stator and rotor are eccentric or the air gap is too small, and the length is inconsistent.

2. Mechanical noise is the friction and impact of the running part of the motor, and the noise caused by structural resonance. The main reason is the processing technology, processing accuracy, assembly quality and other problems.

3. Aerodynamic noise is the noise caused by the heat dissipation of the motor fan, which has an impact on the size and balance of the fan.

In addition, the permanent magnet DC motor bearings are worn, the power supply voltage is too high or too low, the motor lacks phase, the winding insulation is aging, the motor is not firmly installed, the pulley is unbalanced, and the carrier frequency of the inverter is set too low. One of the factors.