Improvement of stability against vibration at the mechanical resonance in attractive type HTS-permanent hybrid magnet bearing

Abstract

The hybrid magnetic bearing using permanent magnets and the high temperature bulk super conductor (HTS) is developed. Pinning force of the HTS is used to generate levitation and guidance force. The dynamic characteristics of the rotor in the hybrid system are studied. The rotor which is supported by the hybrid magnetic bearing rotates up to 5,000 rpm. Then, the vibration of the rotor is measured until the end of the resonance state. Three-dimensional FEM analysis of flux of the systems is undertaken. The relationship between the static characteristics and the dynamic ones of the rotor is considered, and experimental results of the hybrid system is compared with that of the non-hybrid one. In the hybrid system, the flux of the permanent magnet of the rotor is attracted by the stator one. Therefore, vibration of the hybrid system is shown to be smaller than that of the non-hybrid one.