Basic Aspects for Superconducting Electric Machines

This chapter describes the basic aspects for superconducting electric machines. The theoretical analysis of the direct current transformer is presented. Superconducting currents are decided by the local electric, and magnetic fields the London equations and the interactions between currents are different from those in normal metals. In case of the heavy current transfer, it is of little use to divide a super-current only into many wires in order to keep the magnetic fields of the current below the critical field. It is better to divide a pair of the forward and the backward currents into many parallel plates in such a way that forward comes next to backward. In this way, the currents adjoining each other and flowing in the opposite direction interact to sustain each other, and increase the critical field. It may be possible to make a superconducting transformer of very simple structure, by using superconducting parallel plates.