How to recognize superconducting rotor sound by AE

New evaluating methods for rotating superconducting magnets have been developed by observing acoustic emission (AE) from the rotating machine. First, by measuring the AE level, we can learn whether the conductor is changing from a super to a normal state or not. Secondly, we can get to the area of the magnet the normal state was propagated in by comparing the AE signals level of each channel. Thirdly, we can estimate how large a quenched magnetic energy to dissipated in the magnet by measuring the recovery of time constant of the AE signals. Fourthly, we can detect the difference between the AE just before and after the jumps of heat flux by analysing the AE spectrum. Finally, we report how we can predict from what areas the incoming natural quench of the magnet will be initiated, by monitoring the AE level of each channel.