Magnetic thrust bearing

An active magnetic bearing for magnetically supporting a rotating shaft against axially-directed thrust loads includes a circumscribing, radially-extending disc (74) on the shaft (62) and first (66,68) and second sets (70,72) of annular electromagnets circumscribing the shaft on opposite sides of the disc. The first set (66,68) of electromagnets generates a first magnetic field coupled to the disc (74) at a first selected radius from the shaft, the magnetic field having axially-directed components for suspending the disc generally at a predetermined position between the first electromagnets. The second set (70,72) of electromagnets generates a second magnetic field coupled to the disc at a second selected radius from the shaft and displaced from the first magnetic field. The second magnetic field has axially-directed components for suspending the rotor (62) generally at the same predetermined position as the first set of electromagnets. A nonmagnetic sleeve (80) circumscribes the second set of electromagnets for magnetically isolating the first field from the second field.