Force relaxation and hysteresis in a frictionless superconducting magnetic bearing

In this work, the mechanical behaviour of a frictionless superconducting magnetic bearing (SMB) is presented. The bearing is a thrust bearing composed of a YBaCuO superconducting disk and a NdFeB ring permanent magnet. A clear hysteretic behaviour of the radial and axial forces was observed. Finally, a relaxation in the levitation force of about 12%–15% of the initial levitation force was estimated. Similar force relaxation was observed in the radial force.