Abstract
A multifilamentary NbTi composite conductor, which contains about 10 thousands sub-micron diameter filaments, has been manufactured in long lengths. Fine filament size of 0.52μm, a tight twist pitch of 1.13mm for the wire diameter of 0.11mm and Cu-CuNi mixed matrix resulted in strongly reduced a. c. losses; the hysteresis loss and the coupling loss were observed to be 73kW/m3 and 56kW/m3 respectively in the alternating magnetic field of 50Hz with an amplitude of 1.5T.
A triplex conductor was constructed by cabling three strands at a twisting pitch of 2.4mm. Several small coils wound from this cable were operated at 50Hz. One of the coils generated a maximum field of 1.52T at the operation current which was very close to the static critical current. Preliminary design studies have shown that, if this conductor is used in superconducting armature windings of rotating machines, considerable economical benefits are obtained compared with conventional armatures.
These results will open new prospects for industrial applications of superconductivity in high ramp rate pulsed magnets and power frequency devices.
