Vibration test and analysis of novel locking device for magnetic bearing flywheel

To verify the protective effect of novel repeated locking device for magnetic bearing flywheel during satellite launch vibration, swept-sine vibration and random vibration in three principal axes are carried out. Two methods are used for evaluating the protective effect. Macroscopically, the eddy current displacement sensor is applied to measuring the vibration displacement between the stator and the rotor. Microscopically, the locking contact surfaces are investigated by SEM (scanning electron microscopy) and EDS (energy dispersive spectroscopy). The results show that the maximum macroscopic vibration displacement is 45 microns, less than the protect gap of 100 microns. It indicates that the novel repeated locking device can effectively carry out the locking protection function to the flywheel system. Moreover, microscopic analysis discloses that two wear mechanisms of brittle fracture and fatigue facture occurre in locking contact surfaces, with the occurrence of oxidation. The microscopic protective effect can be improved by means of suppression fretting wear.