A cryogen-free superconducting magnet for Maglev applications: design and test results

A novel cryogen-free superconducting magnet for use in levitating and propelling Maglev vehicles has been developed and tested. The magnet is conduction-cooled by a two-stage CTI Cryodyne-1020 Gifford-McMahon cryogenic refrigerator. YBCO high-Tc superconducting current leads are incorporated in order to minimize the heat leak to the magnet. A low eddy-current cryostat has been fabricated using fiberglass-reinforced epoxy structures with subdivided stainless steel permeation barriers. The magnet has been cooled to approximately 10 K and ramped to the design current of 100 amps DC. The magnet has also been operated with a 20 Hz, +/-15 amp sinusoidal excitation. Test results for the thermal and magnetic performance of the magnet are presented.<
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