CRITICAL-CURRENT DENSITY AND BEST TRANSPORT CURRENT OF AN AG-SHEATHEDBI-2223 TAPE CONDUCTOR

A critical current density of as high as 66,000 A/cm(2) has been achie ved in an Ag-sheathed Bi-2223 superconductor. Also a coil wound with t he same kind of wires has generated a magnetic field of 1.5 T. The con ductors of this coil consisted of six elemental conductors connected i n parallel. The reason why the parallel conductors were used was that it was difficult to fabricate a single conductor which had the capabil ity of passing a large amount of current at a high critical current de nsity. In an Ag-sheathed Bi-2223 superconductor, one limiting factor p revents a single conductor from having a large current-passing capabil ity and the highest critical current density, at the same time. A larg er amount of current passes through a conductor with a larger cross-se ction. However, we can only realize a higher critical current density with a conductor of a smaller cross-section. This core size limitation (CSL) gives rise to many problems that need to be solved when conside ring large scale applications in the electrical engineering field with Ag-sheathed Bi-2223 superconductors. (C) 1996 Elsevier Science Limite d and Techna S.r.l.