Three-dimensional vibration of the rotor in the HTSC-permanent magnet flywheel system

The three dimensional vibration of the rotor in the HTSC-permanent magnet flywheel system is studied. The magnetic levitation using pinning force of the HTSC bulk material has an advantage to achieve stable levitation without control. However the transient characteristics of the levitation is not clearly understood. We have developed the flywheel system which can revolve up to 12,000 rpm, and the three dimensional vibration of the rotor are measured with laser displacement sensors. The vibration of the rotor around the mechanical resonance frequency is investigated. The rotor shows both columnar and conical behavior in the mechanical resonant state.