AC loss in superconducting wires operating in a wind turbine like generator

We have manufactured a small circular superconducting coil impregnated with epoxy fibreglass. The coil was wound from a Bi-2223/Ag superconducting wire and it was tested in liquid nitrogen at 77 K. Current-voltage characteristic and the AC losses of the coil were measured and compared with the measurements on the original tape. The AC losses of the coil are approximately 10 times higher than the losses of the tape and they have been measured in two different experimental arrangements, one with directly connected and the other with transformer coupled power supply. Measurements in both arrangements resulted in the same AC loss characteristic. This work was done as a part of the Superwind project which aims to build a series of test coils and a spinning model of a generator to investigate AC loss and stability of the coils in wind turbine like conditions.