Effect of Rotor Eccentricity on the Electromagnetic Vibration for Line-Start Permanent Magnet Synchronous Motor

Abstract

Rotor eccentricity is a common fault during the manufacture of motors, and it causes the air-gap length around circumference being ununiform. Furthermore, the ununiformly distributed air-gap length will significantly affect the air-gap flux density distribution, as well as the electromagnetic force distribution acting on the stator core surface. In the result, lower-order electromagnetic force with much more frequency component will appear in motors with rotor eccentricity. As for the line-start permanent magnet synchronous motor (LSPMSM) which has slots on both stator and rotor sides, the effect of rotor eccentricity on the electromagnetic vibration is much more significant than motors with one-sided slots. This paper analytically calculated the electromagnetic force distribution of LSPMSM with static and dynamic rotor eccentricity. The effect of rotor eccentricity on the order and frequency components of the electromagnetic force in LSPMSM is analyzed.