Testing of the world's largest Bi-2223 high temperature superconducting coil

Three large high temperature superconducting coils were used in the 15 kV c lass Fault Current Limiter (FCL), designed and fabricated as part of a Phas e II US DoE Superconductivity Partnership Program. Each of these solenoids measures 1.0 m in diameter and 0.75 m long. Each coil is designed to carry 2000 Adc and withstand an ac ripple of 16 A at 120 Hz. Each coil is wound f rom 15 km of Bi-2223 sliver tapes and has an inductance of 4 mil. These coi ls were co-designed by General Atomics (GA) and Intermagnetics General Corp oration (IGC) and constructed at the latter. GA provided the cryogenics and auxiliary components for the overall cryomagnetic assembly, Each coil is c ooled by three cryocoolers and the designed operating temperature is 35 K. This paper presents the design specification of these coils. A brief descri ption of the cryogenic & auxiliary setup is given and results from the ther mal & electrical testing, that took place at General Atomics from April 13 to May 20, 1999, are presented.