Planar Rotational Magnetic Micromotors

Abstract

Planar magnetic micromotors hold great promise for novel sensor systems. They can be fabricated by thick Photoresist technologies such as LIGA to which surface micromachining and assembly is added in order to provide high quality magnetic materials and submicron bearing tolerances. Processing of this type has been used to fabricate reluctance machines with fully integrated current windings. Maximum achieved rotational speeds of 150000 rpm with output torques of roughly 100 x 10⁻⁹ Nm have been achieved for preliminary structures which can be further improved with magnetic bearings and hysteresis motor designs. The reported structures contain Photodiode shaft encoders which facilitate motor dynamic data extraction and offer the possibility of closed loop operation.