Development of Magnetically Levitated Motor Driven at Extremely Low Temperature

A cryogenic motor with active magnetic bearings (AMBs) which works in liquid nitrogen is discussed in this paper. The cryogenic motor is composed of two AMBs, four displacement sensors, a permanent magnet (PM) motor, etc. In order to check the stability for the rotor, FFT (fast Fourier transform) analysis for the levitated rotor in the radial direction is performed. Displacement of rotor in the axial direction is studied during rotation.