Development of a Vacuum Pump using Axial-Gap Self-Bearing Motor and Superconducting Magnetic Bearing

In recent years, superconducting technology has rapidly advanced and has been applied to several devices like magnetoencephalography(MEG) and magnetic resonance imaging(MRI). Superconductivity occur at extremely low temperatures, hence liquid helium is always used to achieve it. In order to conserve liquid helium, a circulation system has been recently developed. In the developed system, a pump will be used for cooling liquid helium. In addition, this pump will improve the capability of medical devices that use superconducting coils. In this paper, we propose the development of a vacuum pump that can be used at extremely low temperatures by using axial self bearing motor (ASBM) and superconducting magnetic bearing (SMB). The pump has the advantages of no friction, as there is no contact, high efficiency and no maintenance. The design of the pump is presented, and the control method is theoretically and practically analyzed. We performed an experiment to confirm that the reliability of the proposed vacuum pump.