Electrical Characteristics of Twisted Soldered-Stacked-Square (3S) Wires Consisting of HTS Narrow Tapes with 1mm Width

Abstract

To reduce the effect of external magnetic field, we proposed a novel wire with a square cross section of 1 mm × 1 mm which is named Soldered-Stacked-Square (3S) HTS wire. 3S HTS wire has great advantages in HTS applications due to its small square dimension, but it is inevitable to endure twisting. To study the twist structure of 3S HTS wire, a series of twisted 3S HTS wire samples are prepared, and we evaluate the typical electrical characteristics: twist pitch, critical current, self-field AC loss and so on. It is shown that the critical current of twisted 3S wire is constant up to a twist pitch of 80 mm, and the minimum twist pitch is approximately 50 mm. Measured AC losses are independent of frequency and are in good agreement with the thin strip theoretical values. Specially, measured AC losses are a little smaller than the thin strip theoretical value when peak transport current is reaching critical current. Besides, the measured AC losses of twisted 3S wire and 3S wire are almost identical.