The TPX superconducting magnet fabrication process

The TPX Toroidal Field (TF) and Poloidal Field (PF) Coils use both Nb₃Sn and Nb-Ti internally cooled, cabled superconductor (ICCS). A prime consideration in the design of the coils was the minimization of joints in the conductor cable to save space, reduce heating losses sand increase reliability. Therefore, the traditional double pancake approach was discarded in favor of the continuously wound coil. The recently developed use of the roll bender in winding the coils permits the backwinding, which is required in this geometry. The Nb₃Sn TF coils, the central solenoid coils and inner-most PF coils require the wind-react-insulate sequence. The Nb-Ti outer PF Coils are also insulated after the coils are wound because the insulation system used in all the coils requires the insulation of rigid polyimide sheet between turns and pancakes before Vacuum Pressure Impregnation (VPI) of the glass epoxy system. This paper proposes and discusses a manufacturing plan based upon the use of the roll bender in the winding of the coil, and a special fixture to spread apart the turns of the coil and permit the application of the insulation materials prior to VPI