Abstract
This paper shows the rotation characteristics of a self-bearing motor in liquid nitrogen aiming at continuous drive between room temperature and liquid nitrogen temperature by using an eddy current sensor having two sensor coils. Two sensor coils is used to detect an axial displacement of the rotor and keep the sensor output at the center position constant regardless of temperature changes. The axial displacement and rotation speed of the rotor are actively controlled by the self-bearing motor. The other degree-of-freedom are passively supported by repulsive permanent magnet bearings. In the experiment, the self-bearing motor, displacement sensor and the permanent magnet bearings are installed in liquid nitrogen and rotation test is carried out. In the presentation, experimental results on continuous drive between room temperature and liquid nitrogen temperature are shown.
