Stiffness and damping of an axial superconducting magnetic bearing

An axial superconducting magnetic bearing with radial symmetry has been designed using NdFeB permanent magnets levitating on a set superconducting monoliths of YBCO, prepared by top-seeded-melt-texturing technique. The air gap, stiffness and damping of the bearing, has been measured for different field cooling distances. The elastic constants for axial and radial displacement have been obtained from frequency and decay rate of the free vibration curves, taken for different air gaps. The resulting data indicate that the bearing stiffness is dependent on the cooling distance and exhibits no significant dependence on the oscillation amplitude. Conversely, the damping factor exhibits a strong dependence on oscillation amplitude.