SUPERCONDUCTING BEARINGS FOR HIGH-LOAD APPLICATIONS

Progress in the application of high temperature superconducting ceramic materials to magnetic bearings and the prospects for higher load devices is reviewed. In particular we present experimental evidence from two studies at Cornell. New measurements from a hybrid superconducting bearing show the possibility of peak magnetic pressures of 60 N/cm2 higher in the temperature range of 20-degrees-40-degrees-K using a wire wound coil of Nb-Sn wire as the source of magnetic field and a melt-quenched processed YBa2Cu3O7 bulk superconductor as the other half of the bearing. In a second experiment we demonstrate an 0.85 kg levitated rotor at 28,000 RPM and 5 kJ stored energy. This experiment, conducted at 78-degrees-K, demonstrates a six-component discrete-clement YBCO bearing with a rare earth ring magnet. Stiffness and spin-decay measurements are reported. These experiments point the way to large rotor levitation of 10-100 kg in the near term and 1000 kg rotors in the not too distant future.