Measurement of joint resistance of Bi-2223/Ag tapes using one-turnshorted coil

摘要

Considering the application of high Tc superconductor to power cables, the loss at conductor joint would be very important. Therefore, we have carried out a measurement of joint resistance of Bi-2223/Ag tapes at 77 K. A one-turn coil was wound by Bi-2223/Ag tape. Both ends of the tapes were overlapped and soldered to each other. The samples have different overlap-lengths. DC current is induced in the one-turn HTS shorted coil by energizing the excitation coil wound by copper wire closely located to the HTS coil. The magnetic flux density in the HTS coils was measured by a Hall element. From these data, we estimated the current induced in the HTS shorted coil. The decay of the persistent current in the coil was measured and the joint resistance was calculated. We examined the effect of the lapped part length on the joint resistance