Noise and vibrations of electrical machines and drives; their production and means of reduction

This paper presents a review of the experimental and theoretical investigations conducted by the author and his associates on the problems of noise produced by rotating electrical machines. After discussing the nature of the problems and the mechanism of production of acoustic noise, a detailed description of the vibrational behaviour of stators is provided. The electromagnetic excitation forces play an important role in the production of the noise. Procedures for the determination of radial-forces with particular reference to squirrel-cage induction machines are provided. Possible means to reduce the noise in such machines are then discussed. Further, the noise problems of specially designed reluctance motors are discussed. Some theoretical and experimental results for these machines and special drives are also reported.