Transient characteristics of a GdBCO racetrack pancake coil without turn-to-turn insulation

Abstract

This paper reports the transient characteristics of two types of magnetically coupled GdBCO racetrack pancake coils: (1) a pair of insulated coils (INS-INS coils) and (2) a pair of non-insulated coils (NI-NI coils). In order to investigate the electromagnetic behavior of the INS-INS and NI-NI coils, charging/sudden discharging tests were performed with respect to the distance between primary and secondary coils of the coil pairs. The charging/sudden discharging test results show that the amount of induced current and measured axial magnetic field decreased with increasing distance between the primary and secondary coils. Additionally, charge and discharge delays were clearly observed in the NI-NI coils. The simulated results show good agreement with the experimental results, which validates the proposed approach involving an equivalent circuit model.