1993 年 59 巻 562 号 p. 1650-1656
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 of exciting force and vibration mode of the stator core is analyzed. An exciting force as an electromagnetic radial force was applied to the stator core. Analysis was performed for the case of a continuous distributed force and the case of a discrete multipoint exciting force. The vibration behavior of the core was analyzed theoretically, numerically (FEM) and experimentally 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 with the natural frequency, 2. in the discreted multipoint excitation, the core vibrates when M±N=mK. Here, N is the natural frequency mode, "is the excitation frequency mode, m is an integer, and K is the number of applied points of the exciting force.