The Levitation Characteristics of the Noncontact Rotating System Using HTS Bulks Trapped by Permanent Magnets

We have studied a noncontact magnetic levitation system using the ring-shaped high-temperature superconducting (HTS) bulks and ring-shaped permanent magnets (PMs). Because HTS bulks were magnetized by PMs fixed between the HTS bulks, these PMs levitated with strong restoring force. We used the stator coil to rotate the iron shaft that was combined with PMs. In order to rotate the shaft stable, a restoring force of the radial direction was important. Thus, we placed ring-shaped PMs that magnetized in the radial direction with the inner part of the HTS bulks. In this rotating system, we focused on two parameters, the rotation and the control. In the rotation, we measured the maximum rotational speed and the axial vibration caused by increasing of rotational speed. In the control, we measured slippage from the convergence position when rotated by 60°. In addition, we compared the slippage by changing the conditions.