Analysis of Mass Unbalance Torque on a Spinning Superconducting Rotor

A spherical superconducting rotor is spinning at low temperature of 4.2 K. The mass unbalance torque is generated by gravity, inertia, and suspension force acting on the rotor that has a mass eccentricity. An analytical model is proposed to calculate the mass unbalance torques on the rotor. Analytical results show that the mass unbalance torque due to the axial mass eccentricity affects the rotor drift, and that the radial mass eccentricity affects the rotor speed and the vibration.