The study of an electromagnetic levitating micromotor for application in a rotating gyroscope

An electromagnetic micromotor with alumina rotor, which is stably levitated, rotated, sensed and controlled by independent coils and capacitance structure, is presented. Levitated force with lateral stability is produced by the electromagnetic interaction between the rotor and four groups of levitation planar coils with inter and outer conductors carrying opposite phase high frequency AC current. The rotation is realized by a four-phase induction micromotor composed of the rotor and eight rotation planar coils carrying AC current. Eight pieces of sector sense electrode and the rotor constructed a no contact capacitance displacement sense system. The torque returning the rotor to its equilibrium position is produced by four groups of planar coils. The prototype device with the rotation speed of 3035 rpm, the levitation height of 200 Jim and factor scale of 0.212 V/degrees, has been designed, fabricated, tested successfully. The study illustrates that the micromotor can be applied in a rotating gyroscope. (c) 2006 Elsevier B.V. All rights reserved.