The Transient Stability of HTS Coils With and Without the Insulation and With the Insulation Being Replaced by Brass Tape

In the case of motors and generators, the benefits of using high-temperature superconducting (HTS) coils could be represented by the reduction of 50% in both losses and sizes compared to the conventional machines of the same rating. However, it is hard to establish the quench detection and protection devices for the HTS coils applied to the rotors of motors and generators. Therefore, the stability of the coils is lower than the quiescent coils applied to NMR, MRI, and so on. Therefore, it is important to improve the self-protection ability of HTS coils. We have been developing a novel self-protection method, which removes the insulation turn-turn winding and inserts various metal tapes instead of the insulation. In our previous research, the higher self-protection ability for the thermal disturbances in the HTS coils removed the insulation and inserted Cu tape has been proved. This paper presents the results of an experimental study for the quench current using the insulated, the noninsulated, and the Brass tape inserted HTS coils in liquid nitrogen and background magnetic fields. Also, the measured quench currents of each coil will be discussed.