Experimental evaluation of the effect on AC loss of a polygonal arrangement in YBCO assembled conductors

The AC transport current loss in a YBCO polygonal arranged assembled conductor depends on its arrangement. The azimuthal magnetic field produced by the currents in neighboring tapes affects the current distribution in each tape, and it is anticipated that the AC loss reduction effect is greatest with a round form. To clarify the AC loss characteristics in a polygonal arranged YBCO assembled conductor, we investigated the influence of tape distances and the angle number in the polygon. To evaluate distance, we measured the AC losses in a YBCO hexagonally assembled conductor which was arranged with distances ranging from 0.2 mm-4.0 mm. To evaluate polygonal shapes, we compared YBCO polygonal assembled conductors which were arranged as a square, pentagon, hexagon, octagon or decagon at a distance of 0.5 mm. The experimental results show that the AC loss reduction effect is greatest when the polygon is arranged as a round shape.