Analysis of magnetic forces in magnetically saturated permanent magnet motors by considering mechanical and magnetic coupling effects

Vibrations of magnetically induced origins are becoming more serious with the trend of high speed use in industrial applications. Vibration of motors with the rotor eccentricity, which may result from working allowances or errors in manufacturing processes, is a coupled phenomenon between mechanical and magnetic performance and dynamic characteristics of permanent magnet motors. This article investigates magnetic forces for interior permanent magnet (IPM) motors when the rotor eccentricity exists. An IPM motor, widely used in high speed applications, is significantly effected by the rotor eccentricity due to the magnetic saturation. Due to the magnetic saturation, amplitudes and frequency contents of magnetic forces for IPM motors are worse in vibration viewpoint than those for without the rotor eccentricity. (C) 2002 American Institute of Physics.