Noise of Ball Bearing in Electric Motor

There are many performances of electric motors equipped with rolling bearings, and one of the most important performances is running noise. Especially, for a small three phase a-c induction motor, quiet running is demanded. However, the component noises in the motor noise are not well known and the influences of ball bearing on the motor noise are not made clear. Therefore, to abate the motor noise, we must study it. So, in the first place, the noise of a small three phase a-c induction motor was divided into several component noises, and ones influenced by ball bearings were found out ; next, the influences of ball bearings were examined, lastly the causes of the influences were made clear in the present paper. As a result of the above studies, we could establish the most suitable treatment of ball bearings theoretically, and further obtain new knowledges on fitted ball bearing noise.