Induction bearings

Abstract: A self stabilizing homopolar induction bearing withintegrated touch down bearings has been developed forhigh-speed applications like flywheels, small gas turbines andcompact vacuum cleaners.Stability is achieved without any control electronics thanksto stabilizing eddy currents induced by permanent magnets. Eddycurrent losses are reduced to a minimum using a homopolardesign with ring magnets instead of multipole or halbacharrays.The bearing currents and forces are simulated using steadystate 3D-FEM analysis, which is enabled thanks to theimplemented Minkowskij transform. From these results ananalytical model has been developed, and the results arecompared.Efforts are made to develop a qualitative understanding ofthe bearing physics. Results are converted into usefulrotordynamic data that is easily understood by machineengineers.Finally some experiences from the first experimental testruns at 90.000 RPM are discussed.Keywords:Magnetic bearing, eddy current, inductionbearing, eddy current bearing, high speed, homopolar, gasturbine, flywheel