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 supercon ducting strands and (6+1) cables with copper- nickel (up to 29 wt. % nickel ) and copper- manganese (up to 13.5 wt. % manganese) matrices. Hysteresis l osses per cycle are presented for 0.2 mm strands at field amplitude from +/ - 0.5 up to +/- 3 T. The contribution of own hysteresis of magnetization of copper-manganese matrix into integrated losses appreciably increases at fi elds above 1 T, while at fields below 1 T losses are comparable for both co pper-nickel and copper-manganese strands. Losses at frequency up to 45 Hz a nd field amplitude up to I T for the CuMn cable without transport current a re identical to those at slowly varying field. Rate dependencies of critica l current in the cables are presented at linear build up of transport curre nt. Critical currents in the CuMn cable at linear current building up and s weep rate exceeding that required for commercial frequency are not less tha n DC (greater than or equal to 260 A at 1 T).