A Study for Acoustic Radiation Properties of Cylindrical Structures

Abstract

Inverters and gaps between rotor-stator generally introduce numerous harmonics in the electromagnetic force waves, which may cause a significant increase in the vibration and acoustic noise of motors. Therefore, these noise and vibrations have to be reduced at motor design stage. The widely used numerical analysis software can perform the multiphysics analysis under the integrated environment such as the electromagnetic-vibration-acoustic collaborative analysis. However, this method has an increase of computational cost resulting from a model size, which may cause difficulty of using at the design stage. In this paper, we proposed a simple calculation model in order to alleviate these computational cost for these collaborative analysis. Firstly, vibration analysis of motor was simplified as mobility transform matrix by using double beam cylindrical structures. Secondly, acoustic analysis was simplified by using acoustic radiation efficiency. In this investigation, we verified the acoustic radiation properties of a cylindrical structures from the viewpoint of the acoustic radiation efficiency by both of experiment and analysis. Finally, the proposed model was validated by comparing predicted acoustic noise level with an experimental one of an industrial motor.