A report presents information on an earlier work on active magnetic bearings with high-critical-temperature superconducting coils. To recapitulate, the device is a homopolar radial-type active magnetic bearing with a bias coil and control coils made of a high-critical-temperature superconductor. The report discusses major features of the design and operation of the bias and control coils, measurements of ac power losses in the control coils, and results of experiments in which the device was operated at the temperature of liquid nitrogen. The experimental findings and conclusions stated in the report are nearly identical to those noted earlier. One particularly notable conclusion is that ac losses appeared to be related to coil inductances and that it may therefore be possible to reduce these losses by winding the control coils from twisted, multifilamentary forms of the superconductor.

This work was done by G. V. Brown, E. DiRusso, and A. J. Provenza of John H. Glenn Research Center. Inquiries concerning rights for the commercial use of this invention should be addressed to

John H. Glenn Research Center, Commercial Technology Office, Attn: Steve Fedor, Mail Stop 4-8, 21000 Brookpark Road, Cleveland, Ohio 44135

Refer to LEW-16419.