Quench and recovery characteristics of HTS tapes under oscillating over-currents with different frequencies

Quench and recovery characteristics of Bi-2223/Ag high-temperature superconductor (HTS) tapes under oscillating over-currents with different frequencies have been observed. The experiment is carried out using an oscillating circuit consisted of capacitance and inductance, which produces oscillating currents with different frequencies. The HTS tapes are immersed in liquid nitrogen bath. The frequencies of the oscillating currents fed to HTS tapes are 180.8, 333.3, 434.8, 751.9, and 2016.1 Hz, respectively. In order to confirm the critical current of the tapes, dc current is fed to the tapes first. The magnitude of the oscillating currents is from a small current to 179 A, which is 2.5 times larger than the dc critical current of the tapes. The experimental result shows that the normal voltage generated by the over-current disappears fast after the end of the oscillating over-current, which shows that HTS tapes have good superconducting-to-normal conducting recovery characteristics under oscillating current with high frequency. The experimental results will encourage the possibility of the important applications of HTS tapes in pulsed power.