Bearing Selection for High-Speed Electrical Machine

In this paper, various mechanical and electrical reasons and methods to prevent bearing failures are highlighted. The bearing selection for a 5 kW, 10,000 rpm switched reluctance machine (SRM) is carried out by estimating axial and radial forces acting on the rotor assembly and various other bearing parameters. The rotor weight and forces due to the rotation of unbalance residue mass is considered as radial force. To handle axial and radial forces, angular contact bearing is selected. The expected bearing life and corresponding axial loads are estimated. The selected bearings are installed in SRM. Further, the SRM is operated at various speeds with closed-loop speed control using a SiC-based asymmetric H-bridge converter. The bearing performance is validated by measuring vibration on bearing housings at a speed of 10,500 rpm.