Guess you don't know, the frequency of the inverter switch has a noise impact on the motor?

What is the impact of frequency converter switching frequency on motors? Today, Hengli Motor will talk about the impact of the switching frequency of the frequency converter on the motor. The higher the switching frequency of the frequency converter on the motor, the smaller the vibration of the motor, the lower the operating noise, and the less heat generated by the motor. But the higher the switching frequency, the higher the frequency of harmonic current, the more severe the skin effect of the motor stator, the greater the motor loss, and the lower the output power.

The influence of frequency converter switching frequency on motor noise

The noise of electric motors comes from three aspects: ventilation noise, electromagnetic noise, and mechanical noise. Ventilation and mechanical noise will not be analyzed here, only the electromagnetic noise problem after using a frequency converter will be analyzed as follows. The output voltage and current of the frequency converter contain certain components of high-order harmonics, which increase the high-order harmonic magnetic flux in the air gap of the motor, resulting in increased noise. Its characteristics are:

1. Due to the resonance between the lower harmonic components output by the frequency converter and the natural frequency of the rotor, the noise near the natural frequency of the rotor increases;

2. Due to the high-order harmonics output by the frequency converter causing resonance in the iron core, casing, bearing seat, etc., the noise near the natural frequency increases;

3. The noise is directly related to the switching frequency, and when the switching frequency is high, the relative noise is small;

4. After testing, it was found that when the motor operates at variable frequency, the noise is only 2dB higher than when it operates at 50Hz, indicating that the impact is not significant. Its absolute value is around 70dB;

5. The use of variable frequency motors can reduce noise by 6-10dB under the same operating parameters.

The above statement originates from the internet and does not represent the viewpoint of Hengli Motors