Dynamic Study of Vertical Suspension Rotor Falling on Active Clearance Elimination Protective Bearing

Active magnetic bearing system (AMB) has the advantages of high speed, no friction and long life. As the safety guard of AMB, traditional protective bearings can withstand the impact of unexpected rotor drops. Active clearance elimination protective bearing is capable of actively eliminating the drop clearance at the moment of rotor drop, thereby enhancing the impact resistance of the protective bearing.

Based on vertical magnetic bearing system, the objectives of this paper are the traditional protective bearing (PB), and a new type of active clearance elimination protective bearing (ACEB) which can actively reduce the axial drop protection clearance of the rotor to improve the impact resistance of the protective bearing.

In this paper, the dynamic model of vertical rotor, protective bearing and collision are established, and the dynamic response of vertical magnetic suspension rotor falling on ACEB and traditional protective bearing (PB) is calculated and simulated respectively. Finally, the drop test was carried out on the protective bearing performance test machine of vertical magnetic suspension system.

The simulation and test results show that: Compared with the traditional PB, the new ACEB can rapidly reduce the rotor axial drop protection gap at the moment of magnetic bearing failure, effectively reduce the rotor's axial and radial impact strength on the bearing inner ring, and improve the impact resistance.