Optimized configurations of autostable superconducting magnetic bearings for practical applications

In order to establish an optimized bearing design for a flywheel for energy storage, we have studied model bearing configurations involving bulk YBCO pellets and double-dipole magnet configurations. We were interested to see what the correlation is between the maximum attainable levitation force, measured for a typical bearing gap of 3 mm, and the separation between the magnetic poles. Equal polarity (north-north) and alternative polarity (north-south) configurations were investigated. The maximum levitation force was obtained with the alternate polarity arrangement for a separation between the magnetic poles of 6 mm. It represents an increase of 19% compared to a nonoptimized configuration. Our experiments demonstrate that configurations of superconducting magnetic bearings can be optimized to obtain better levitation properties