Auto-eliminating Clearance Auxiliary Bearings for Active Magnetic Bearing Systems

An auto-eliminating clearance auxiliary bearing (ACAB) for Active Magnetic Bearing systems (AMBs) has been conceived and a prototype system tested. In the ACAB, a ball bearing is directly mounted on a rotor, and the outer race of the ball bearing is surrounded by a series of interconnected supporters. In the open position, a clearance exists between the outer race and the ACAB supporters. When the rotor mounted with ball bearing drop on ACAB supporter(s) due to either an AMB system failure or transient shock, the generated friction between the outer race and supporter(s) will rotate the supporters circumferentially to eliminate the clearance and re-center the ball bearing and rotor. Since the clearance is eliminated, the impact force between the outer race and supporters is reduced and the possibility of backward whirl is eliminated. This paper presents the design methodology of those supporters. And a preliminary feasibility prototype experimental rig was established under the situation of simulated AMB system failure. Experimental results demonstrate feasibility of the ACAB.