Pulsed HTS Coil Performance

HTS coils designed to carry pulsed currents have been built and tested demonstrating fast charge and discharge times on the order of a second. Gaseous Helium from 40 to 80 K is used as a coolant. Losses due to ac, hysteresis, and transport currents associated with current entry into and exiting from HTS are small and do not produce thermal transients that induce current sharing or normal transitions for reasonable margins and operating temperatures. Short lengths of HTS and small coils show current sharing before normal transitions, whereas current sharing voltages are not identified in large coils since current sharing voltages are small compared to inductive and resistive voltages. Pulse shape, duration, and frequency are varied with no degradation in performance.