Abstract: The influence of rotor system resonance on motor noise cannot be ignored. Firstly, the influence of rotor system on the structure mode of motor is studied by modal simulation and test method. Considering the rotor system model can reflect the actual state of the motor better. And the low frequency modes are more abundant. Secondly, the sensitivity of rotor system resonance to the spatial order of radial electromagnetic force is analyzed by harmonic response simulation. The resonance of rotor system is very sensitive to the first order radial force. The influence of resonance of rotor system on air gap, electromagnetic force and noise is studied. When the rotor system resonates, it will cause dynamic eccentricity, and the air gap changes with time and space. Then the electromagnetic force appears near the original frequency, and the additional electromagnetic force of space order ±1 appears. Finally, the accuracy of simulation analysis is verified by test.

Key words: Rotor assembly, Resonance, Noise of motor, Air gap, Radial electromagnetic force