Coupling mechanical characteristics and its effect on hybrid magnetic bearings

This paper studies on the coupling mechanical characteristics and their effect on hybrid magnetic bearings (HMB) when the radial failure and axial failure occur simultaneously in HMB with thrust magnetic bearing (TMB) and passive radial magnetic bearing. The stator is equivalent to two symmetrical semicircular plates and then the magnetic force in TMB is calculated based on vector superposition principle. However, the force equations cannot clearly express the relationship among coupling forces and stiffs. To overcome the drawback of the former equations, the TMB is equivalent to two symmetrical semicircular bearings and the linear method of axial force is used to obtain the preconditions to stabilize the HMB. Also, the stiffness of the external loads can be calculated. Furthermore, the axial motion equation is established by the static model of deep groove ball bearings. Finally, simulation and experiment are done to prove the analysis and formulation.