Experimental results of an experimental three-phase AC superconducting armature

Owing to the recent development of low-loss AC superconducting conductors, 50/60-Hz applications of superconductivity in electrical engineering can be developed, and power transformers and limiters, AC cables, and full-superconducting machines can be investigated. As a first step in the realization of a full-superconducting synchronous generator, a three-phase superconducting armature has been manufactured and tested with a normal rotor inside. Cryogenic and electrical tests have been made during more than 100 h, and include transients, connection to the power grid and asynchronous start-up and operation. The results are relevant for the next step of the experiment which is to complete a 20-kVA, 3000-r.p.m. machine with a superconducting rotating field winding, which is now under construction