Control aspects of superconducting magnets for magnetic suspensions and bearings

The paper describes some theoretical and experimental considerations aimed at identifying the main characteristics of high Tc/sub /superconducting magnets for use in controlled applications such as magnetic suspensions and bearings. The theoretical model is formulated to represent the requirements necessary for such applications, and some experiments reinforce this by assessing the effects of periodic variations in both excitation and reluctance over a range of frequencies. In this way a clear understanding can be obtained of the factors which affect the losses in the superconductors, and also the drive voltage requirements are identified for different operating conditions.< >