Segmented Magnetic Thrust Bearings: Analytic Models and Predictions of Significant Improvement in Dynamic Performance

Non-laminated magnetic thrust bearings typically exhibit reduced dynamic performance due to eddy currents compared to laminated bearings. Segmented stators have been introduced to increase actuator performance by disrupting eddy current paths in the same manner as laminations in radial magnetic bearings. However, due to manufacturing limitations thrust bearing stators cannot be easily segmented to the extent that they would be considered fully laminated. Therefore, eddy currents continue to affect the dynamic performance significantly. Since analytic models of segmented stators do not presently exist the bearing design process requires the use of finite element analysis (FEA) and experimentation. Here we show, using finite element analysis, that a small number of cuts dramatically improves bandwidth of non-laminated magnetic actuators, validating the segmented design strategy. In addition, existing analytic models of non-laminated magnetic bearings are adapted to a segmented geometry and validated via FEA. Close agreement shows that the analytic model, rather than time consuming FEA, may be used in the design process.