1988 年 23 巻 4 号 p. 192-198
In order to study stability and A.C. losses in A.C. superconducting coils, the authors have developed two 50kVA class coils and operated it at 50Hz. These coils were made of an ultra-fine multifilamentary superconducting 42-strand cable. Nevertheless the conductor has CuNi matrix without Cu, one coil could be operated continuously at nearly 50kVA. The coil was quenched at 173A r.m.s., whose peak value was about 87% of the short sample D. C. critical current. Maximum field was 1.59T. To prevent wire motions and retain helium ventilation, the cable was embedded in grooves on coil formers made by fiber reinforced plastic. The apparent normal zone propagation velocity is much larger than the calculated adiabatic propagation velocity.