VIBRATION RESPONSE ANALYSIS OF INDUCTION-MOTOR STATOR CORE - (VIBRATION RESPONSE OF DISTRIBUTED EXCITATION AND MULTIPOINT EXCITATION)

The induction motor is used in many industries. These days motor noise reduction is often required due to environmental concerns. This paper is concerned with the reduction of motor noise. The relationship betw een exciting force and vibration mode of the stator core is analyzed. An exciting force as an electromagnetic radial force was applied to th e stator core. Analysis was performed for a continuous distributed for ce and a discrete multipoint exciting force. The vibration behavior of the core was analyzed theoretically, numerically (FEM) and experiment ally with respect to modes, frequency and phase of exciting force. It has been confirmed that: 1. in the continuous distributed excitation, the core vibrates when M=+/-N and the exciting frequency coincides wit h the natural frequency; 2. in the discrete multipoint excitation, the core vibrates when M+/-N=mK. Here, N is the natural frequency mode, M is the excitation frequency mode, m is an integer, and K is the numbe r of points at which the exciting force is applied.