Investigation of the limit of Earnshaw's theorem in bearigless motors.

At early 1990’s one of the applicants has proposed a novel idea of the unified concept of bearingless motors. Later the applicants have proposed the second novel idea of the single drive bearingless motors, however, improvements were necessary such as the torque density, and rotational speeds. According to the Earnshaw’s theorem, at least one active positioning is necessary for successful magnetic suspension. In this research, the improvements of single drive bearingless motors have been achieved, in addition, the magnetic suspension systems with less than one active positioning have been proposed.