Investigation of AC losses for HTS coils with parallel wound copper tapes

In some applications, copper wires or tapes are used in parallel with HTS tapes for fabricating magnet coil to enhance its mechanical and electrical stability. The addition of the copper tapes might increase AC loss of the coil. In this work, we investigated the AC loss of HTS coils with strengthening copper tapes. Two HTS coils are fabricated. One is made of HTS tapes only; the other is made of HTS tapes and parallel copper tapes. The HTS tape is G1 Bi-2223/Ag tape with 4.6 mm width and 0.22 mm thickness. The width and thickness of copper tape are 5 mm and 0.1 mm respectively. The inner and outer diameters of the coils are 70 mm and 90mm respectively, with a height is 45 mm. AC loss of the coils was measured by weighting the liquid nitrogen evaporating rate under different AC loads. The experimental data show that the copper tape does not substantially increase the AC loss of the coils.