AC losses of HTS coils carrying transport current

In the paper, the authors report the experimental results for AC losses in an HTS coil carrying AC transport current. The tests of AC losses were performed by the electrical method at 77 K and 4.2 K. The HTS tape consists of 55 multifilamentary silver-sheathed BSCCO 2223 tape without twisting. The sample coil was made by the react-and-wind method using insulated tape conductor. The coil has an inner diameter of 46 mm, outer diameter of 87 mm, height of 14.5 mm, and the number of turns is 300. The measured AC losses were compared with the conventional theory based on the critical state model. In the region of low transport current, the theoretical results agreed well the experimental results. The authors also investigated the distribution of the AC losses in the coil to study the effects of magnetic field distribution on AC losses.