AE SPECTRA DURING SUPER-TO-NORMAL TRANSITION IN A SUPERCONDUCTING ROTOR

We discovered new quantitative relations regarding AE spectra and supe r-to-normal transition in a rotating superconducting machine. Hence, w e have reported mainly qualitative evaluation of AE from the rotating superconducting machine, such as AE and super-to-normal transition, AE and normal propagation, AE and quench magnitude, AE versus heal and c hanges in magnetic flux, and a prediction of the area to a certain poi nt [H. Nomura et al. Ultrasonics 34 (1996) 307-309]. By repeating the experiments, interesting quantitative relations were found in the AE s pectrum's main frequency which shifts, according to changes in the mag netic field, the rotational speed and the transport current. Furthermo re, these shifts can be explained using simple arithmetic. These disco veries will be useful for both evaluating and monitoring the supercond ucting rotor. (C) 1998 Elsevier Science B.V.