Comparative study of AC superconducting strands and cables with copper-manganese and copper-nickel matrices

Comparative study was carried out on characteristics of model NbTi superconducting strands and (6+1) cables with copper-nickel (up to 29 wt.% nickel) and copper-manganese (up to 13.5 wt.% manganese) matrices. Hysteresis losses per cycle are presented for 0.2 mm strands at field amplitude from /spl plusmn/0.5 up to /spl plusmn/3 T. The contribution of own hysteresis of magnetization of copper-manganese matrix into integrated losses appreciably increases at fields above 1 T, while at fields below 1 T losses are comparable for both copper-nickel and copper-manganese strands. Losses at frequency up to 45 Hz and field amplitude up to 1 T for the CuMn cable without transport current are identical to those at slowly varying field. Rate dependencies of critical current in the cables are presented at linear build up of transport current. Critical currents in the CuMn cable at linear current building up and sweep rate exceeding that required for commercial frequency are not less than DC (/spl ges/260 A at 1 T).