Measurements of crossed-field demagnetisation rate of trapped field magnets at high frequencies and below 77 K

10 Jul 2018

Design requirements of next generation electric aircraft place stringent requirements on the power density required from electric motors. Future prototype planned in the scope of European project “Advanced Superconducting Motor Experimental Demonstrator” ASuMED considers a permanent magnet synchronous motor, where the conventional ferromagnets are replaced with superconducting trapped field magnets, which promise higher flux densities and thus higher output power without adding weight. Previous work has indicated that stacks of tape show lower cross-field demagnetisation rate to bulk (RE)BCO whilst retaining similar performance for their size, however the crossed-field demagnetisation rate has not been studied in the temperature, magnetic field and frequency range that is relevant for the operational prototype motor. This work investigates crossed-field demagnetisation in 2G HTS stacks at temperatures below 77 K and frequency range above 10 Hz. This information is crucial in developing designs and determining operational time before re-magnetisation could be required.