Characterization of non-contact torque transfer and switching system for superconducting flywheel

Superconducting flywheel energy storage system can store the energy for a long duration, in that the main body of a flywheel is placed in a vacuum chamber to minimize rotational loss, and is separated from a generation motor. The superconducting flywheel device need a non-contact system which can transfer the rotational torque without contact. A combination of two permanent magnets can transmit the power without contact. We calculated the torque forces and the field distributions of two types of magnetic arrays; repulsive type and Halbach type. Both magnetic circuits have respective inner and outer diameters of 61.5 and 144 mm and consist of eight poles of Fe-Nd-B permanent magnets 30 mm in thickness. We also studied the effects of the number of poles and the size on the transferable torque forces and found that a practical torque transfer and switching systems can be constructed with a combination of permanent magnetic circuits.