Impact of Eccentricity and Demagnetization Faults on Magnetic Noise Generation in Brushless Permanent Magnet DC Motors

Abstract – Vibrations and noise in electrical machines are directly related to the characteristics of the radial forces on one hand, and mechanical behavior on the other [1, 4]. The characteristics of these forces depend on the air gap flux density, which is also influenced by other factors, such as stator slots and poles, saturation level, winding type, and certain faults. The aim of this work is to investigate the effect of eccentricity and demagnetization faults on electromagnetic noise generated by the external surface of Permanent Magnet Synchronous Machine [PMSM]. For this purpose, an analytical electro-magnetic vibroacoustic model is developed. The results confirm the effect of eccentricity and demag-netization fault in generating some low modes radial forces