Vibration suppression of the rotor system using both a ball balancer and axial control of the repulsive magnetic bearing

In this paper we describe a strategy to eliminate the disadvantages of both a ball balancer and a repulsive magnetic bearing through the simultaneous application of both to a rotor system. The resultant force of the magnetic synchronous force caused by the repulsive magnetic bearing and the unbalance force is cancelled by the ball balancer, and the vibration during the passage through the critical speed caused by the ball balancer is also reduced by the axial control of the repulsive magnetic bearing. As a result, both the vibration suppression during the passage through the critical speed and the vibration reduction to zero at the rotational speed range above the critical speed are achieved simultaneously. The vibration suppression effect of the proposed method is also validated experimentally.