A first functional current excited planar rotational magnetic micromotor

Complete integration and successful testing of a planar rotational magnetic micromotor have been demonstrated. The configuration is that of a three-phase variable reluctance stepping motor with 6 stator poles and 4 rotor poles. Stator and rotor heights of up to 300 μm are available and rotor diameters of 285 μm and 423 μm were tested. Maximum rotational speeds which have been achieved with open loop excitation exceed 30000 rpm and show no change with operation in vacuum. After testing to more than 5×10⁷ rotation cycles, deviations from initial operation are not observed. Vertical reluctance forces are used to levitate the rotor up to 50 μm over the substrate. Position signals are available via integrated photodiodes which allow the rotor speed to be monitored and provide the groundwork for an active closed-loop system