An explosive opening superconducting switch

A superconducting YBCO tube was tested as an opening switch to demonstrate novel switching concepts for inductive energy storage. The tube was connected in series with a 1.2-mH inductor and a 4800- mu F capacitor bank which was charged to a predetermined level and discharged through the circuit. No measurable dissipation was observed for test discharges of 8-ms duration, with maximum pulse amplitude increasing for each test while the YBCO was superconducting at 77 K. At the highest current pulse maximum of 95 A, the switch was opened by exploding a short length of detonating cord inserted into the center of the tube. The current decreased to zero, and the voltage increased to maximum in approximately 160 mu s, resulting in a voltage gain of over 25 for current commutation purposes.