Abstract: A disk spindle motor having a permanent magnet central shaft. A pair of annular, non-magnetic combination thrust and journal bearings having truncated-conical outer surfaces are spaced apart on the shaft. The bearings coact with complementary surfaces of the hub of a motor rotor. Shaft end caps connect the shaft to base means and have radially extending shoulders which define annular gaps with the rotor and function as ferrofluidic seals.

Abstract: An electric motor including an integral ferrofluid bearing provides significant reduction in non-repeatable runout, stray flux, and audible noise over conventional motors using ball bearings. The motor includes a hub and a base, with the base attached to a tapered magnetically permeable shaft which defines an inner bearing race, and the hub attached to an internally tapered, magnetically permeable sleeve which defines an outer bearing race. Permanent magnets surround and are rotatable with the sleeve to provide mangetic fields which interact with the stator winding to cause rotation of the hub and sleeve. In addition, the permanent magnets form magnetic flux paths with the shaft and the sleeve to maintain ferrofluid lubricant between the inner and outer bearing races.

Abstract: A windmill electric heater converts wind energy to heat energy. A windmill drives a rotor of an eddy current heater. Magnetic fields are provided at an air gap between the rotor and a stator of the eddy current heater. Rotation of the rotor with respect to the stator causes eddy currents, and therefore heat, to be generated in the rotor. The heat generated in the rotor is drawn off for beneficial use such as in heating a house or other building. Excitation of the magnetic fields (and therefore the amount of heat generated) is controlled as a function of sensed parameters such as wind velocity, ambient temperature of the surroundings to be heated and temperature of the eddy current heater.

Abstract: A disk spindle motor having a permanent magnet central shaft. A pair of annular, non-magnetic combination thrust and journal bearings having truncated-conical outer surfaces are spaced apart on the shaft. The bearing coact with complementary surfaces of the hub of a motor rotor. Shaft end caps connect the shaft to base means and have radially extending shoulders which define annular gaps with the rotor and function as ferrofluidic seals.