Losses in single- and multi-core superconducting composite conductors were studied experimentally in the range from 20 to 500Hz and below the current of 100A. Composites consist of Nb-60.8 Ti-2.8 Zr ternary superconducting alloy embedded in Cu matrix. Volume of He gas evaporated by the loss when sinusoidal current was passed through the wire was measured. A mechanism of the loss was investigated using a frequency dependence.
The single-core composite generates the hysteresis loss in the superconductor and the eddy current loss in Cu matrix. The loss in the multi-core composite is expressed in terms of the hysteresis in an equivalent superconductor which has same volume of superconducting filaments involved and the eddy current loss in an outer region of Cu matrix.