Influence of Imperfection in Vibration of Induction Motor Stator

This paper deals with electromagnetic vibration of the motor stator with imperfections. The iron stator of motor is modeled by a circular ring with imperfect masses, and the external force is modeled by the rotating distributed electromagnetic force. The solutions of forced vibration are obtained by the theoretical analysis. Moreover, the accuracy of the natural frequency of the analytical model is examined by the finite element method. The followings were made clear; (1) As imperfect mass reduces the natural frequency of the motor stator, resonant frequency becomes low. (2) The positions of the imperfect masses influence the vibration of the motor stator. (3) The influence is predictable by the equation of motion of the mode concerned