Fabrication of HTS Bearings With Ton Load Performance

The considerable development effort of HTS magnetic bearings with respect to heavy loads is demonstrated. Radial type 200 mm bearing in an optimized design was developed for implementation in a new 5 kWh superconducting flywheel energy storage system. A prototype bearing, consisting of a modular assembled melt textured YBCO bulk 200 mm hollow cylinder with permanent magnet rotor is presented. Axial rotor displacement causes pinning forces of 8 and 10 kN axially at a temperature of 78 K and 71 K, respectively. Maximum radial forces are 4.7 kN at sub- cooled LN2. Fabrication technology incorporates the construction and engineering of a low-weight, nonmagnetic G-10 bearing cryostat. Ultra-low heat transfer structural elements were designed and constructed to reduce the thermal loss through the support to less than 2 Watt under 1 ton load.