Disk-shaped superconducting rotor under a rotating magnetic field:: Speed dependence

As part of the design of small axial-flux induction motors using disk-shaped rotors made from YBCO bulks, in previous work we studied the behavior of such disks under a rotating 2-pole magnetic field and gave an explanation of the results. That work yields information on such internal parameters as pinning forces and pull-out torque, and good estimates of the damping and Magnus coefficients. As in conventional motors, one expects to find dependence of these parameters on the magnetic field speed-the synchronous speed. In the present work, this dependence is studied and the previous model is improved.