Performance of repulsive type magnetic bearing system under nonuniform magnetization of permanent magnet

A permanent magnet bearing system utilizes the repulsive forces between the stator and rotor permanent magnets (PM) for the levitation of the system and it results a simplified axial control scheme. A repulsive type magnetic bearing system based on the above principle was fabricated in the authors' laboratory. Material characteristics and the configuration of the permanent magnets are the central component for this type of bearing system. Due to aging or as both the magnets are repelling each other, there will be demagnetization of the permanent magnet, resulting the field distribution along the magnet's periphery nonuniform. In this paper, the effect of this magnetization nonuniformity on the performance of the bearing system has been studied.