Experimental and Theoretical Research on Rotor Surface Losses of a Radial Magnetic Bearing Considering Manufacturing Processes

This paper deals with the issue of manufacturing processes leading to rotor surface losses through analytical, finite element analysis (FEA) and experimental methods. Based on experiments, it is found that the rotor surface losses make the rotor temperature of radial magnetic bearings (MBs) higher than expected, and thermal ablation appeared on the rotor surface. First, we investigate the mechanism of rotor surface loss in radial MBs using an improved analytical method. The FEA is then used to validate the analytical results and explore the correlation between the degree of short-circuit faults on the rotor surface and the surface losses. This yields a more comprehensive understanding of the loss characteristics and provides ideas for improving manufacturing methods to reduce surface losses. Finally, a simple method of rotor outer circle machining, namely finish turning with fine feed, is proposed. Comparison prototypes were manufactured using the proposed method and the conventional method. The results demonstrate that the proposed method can effectively reduce the rotor surface losses of radial MBs.