Test results of a demonstration HTS magnet for minesweeping

American Superconductor completed building a demonstration HTS minesweeping magnet for airborne superconducting mine countermeasure system in December 1999, The demonstration magnet consisted of a single-layer HTS coil wound on a 457-mm G-10 mandrel, and housed in a 560 mm diameter by 1.5-m long stainless steel vacuum vessel. It is conduction cooled with a two-stage cryocooler. It has a magnetic moment of 15 kAm/sup 2/. The magnet was successfully ramped up to 400 A at /spl sim/35 K. The magnet current was kept at 400 A for six hours without any voltage run-away. The magnet was also successfully tested for 50% AC modulation (200 A to 400 A) with a trapezoidal current waveform. Experimental data from these tests are presented.