AN ELECTROSTATIC TOP MOTOR AND ITS CHARACTERISTICS

Researchers have proposed variable-gas electrostatic actuators (VGEA) such as the electrostatic linear actuator (ESLAC) [1, 2]. As part of this study, we report in this paper another type of VGEA named the electrostatic top motor (ESTOM). Basically, the ESTOM is composed of two parts: one is a concave conical stator with striped electrodes (driving electrodes) and a ground electrode, with an insulation layer covering the driving electrodes; the other is a convex conical rotor with a conductive material covering its surface. A rotor rotates on a stator by applying voltage to the driving electrodes on the stator. Two types of ESTOM were fabricated: a scale model by a conventional method and a micromodel by semiconductor processes. The stator of the micromodel is 2 mm in cone diameter and has a depth of 0.2 mm. The scale model is a hundred times as large as the micromodel. The scale model was tested to obtain characteristics, such as the relationship between driving voltage and the torque, and so on. The results were compared to the electrostatic field analysis and we discuss the differences. The micromodel is operated by an open-loop control. The rotation of the rotor was observed at an applied voltage of 80-120 V. © 1990.