Generation and control of electromagnetic noise

Update:19 Jan 2019
Summary:

The low-frequency noise generated by the vibration of t […]

The low-frequency noise generated by the vibration of the magnetic field in the air gap of the motor caused by the vibration of the stator, the rotor and the whole motor structure is electromagnetic noise. From the perspective of the influence of the magnetic field, the electromagnetic noise is mainly caused by the asymmetry of the magnetic force wave and the magnetic flux distribution. of.

1 fixed, the eccentricity of the rotor, or the asymmetry of the magnetic circuit, will cause the magnetic flux distribution asymmetry and the phenomenon of large force on one side and small force on one side, and then electromagnetic noise. Therefore, during design or processing, The roundness of the rotor must meet the requirements. The magnetic circuit must be symmetrical and uniform. The processing accuracy of the end cover of the aluminum shell motor and the assembly of the stator core into the frame are related to the coaxiality of the stator and the rotor. The motor is very important.

2 There are fundamental wave potentials and harmonic potentials in the rotor windings. They interact to generate a series of force waves. The frequency of the fundamental magnetic field is low, the effect is not significant; the force wave generated by the harmonic magnetic field The noise caused is related to the magnitude and frequency of the force wave. Select the appropriate stator and rotor groove fit in the process, and use the chute method to avoid the generation of lower order force waves.