Behaviour of a One Ton Rotor Being Dropped into Auxiliary Bearings

The vibrational behaviour of a one ton compressor rotor being dropped into the auxiliary bearings in case of a failure of its magnetic bearings is reported. The auxihary bearings are ball bearings with a clearance between rotor and inner race. The results are based on tests and theoretical investigations. The most critical condition, which can occur, is a whirling motion of the rotor with approximately the clearance as the radius of the orbit. A whirling for an extended period of time must be prevented by an appropriate design.