Analysis of vibration modes for large induction motor

Induction motors are widely used in various industrial applications. Accompanying with the increase of rating and quality requirement, more attention has to be paid to the reduction of vibration and noise for the design of large induction motors. Much research work in this area needs to be done. It is well known that large vibration will be generated when the natural frequency of the machine coincides with or is close to the frequency of the force which is applied to the stator. In this paper, the mechanical characteristics of the stator for a large induction motor are studied by means of finite element analysis. The natural frequency and harmonic response of the stator are analyzed based on the calculated electromagnetic force.