Parasitic radial rotating force in magnetically levitated cage induction machines

The homo-polar DC flux, which is generated in the air gap of a magnetically levitated two-pole induction machine by the by-pass flux of a nearby axial magnetic bearing, modulates the two-pole fundamental field of the induction motor. The additional modulation field wave generates a radial force, which rotates with the fundamental electric stator frequency. This disturbing force is analyzed and calculated. A comparison to measurements is given.