Position dependence of restoring torque in low frequency superconducting suspension

As a traditional aspect, levitation loss is often studied in the rotating superconducting suspension. On the other hand, restoring torque behavior is also an important feature for the low frequency suspension, which can be used to describe the deflection of the spinning levitation to the micro thrust or disturbance, and be utilized in the design of a fully suspending measuring setup for electric propulsion devices. However, precise measurement of position dependence of the restoring torque is difficult due to some factors such as air disturbance, uncertainty of initial suspending position, no-uniform magnetization in the levitation, etc. To reduce the impact of these factors and study mechanical properties of the spinning levitation, an integrated experimental setup is designed and established. The quantitative investigation on position dependence of the restoring torque is conducted under a steady temperature and gas pressure. The relation between spinning mechanical properties of a permanent magnet (PM) and field cooling (FC) attitudes of a superconductor is also on the discussion. Under the same FC attitude, the spinning equilibrium position of the PM is stable. The inhomogeneity of the geometry and magnetic field from the PM has a serious effect on the spinning mechanical properties.