Interstrand coupling loss in different stages of a multi-strand cable exposed to an external magnetic field

This paper focuses on interstrand coupling loss in different twisting stages of a multi-strand cable. The AC loss of the 1st and the 2nd stage (6+1) n cabled conductor consisting of identical NbTi/Cu strands are compared with the single strand AC loss. The AC loss is measured in a transverse magnetic field with frequencies up to 15 Hz by pick-up and calorimetric method. For the 1st stage cable, no loss increase compared to that of the strand is obtained and the loss does not depend on the transverse force applied. However, non-negligible interstrand coupling loss is obtained in the 2nd stage cable. The reduction of the interstrand coupling loss is also considered.