Winding technique for HT-7U Tokamak magnet coils

On-site winding of magnet coils of HT-7U started in September 1998, using a numerically controlled winding machine. Magnet coils are all forced-flow superconducting coils, consisting of superconducting Toroidal Field (TF) coils and superconducting Poloidal Field (PF) coils. All of TF and PF coils will use NbTi Cable-in-Conduit Conductor (CICC) cooled with supercritical helium. This paper reports on the set up of a new winding facility with unique capabilities for continuous winding of long length CICC. An analytical method used to predict conduit springback before winding is presented and the results are compared to the ones obtained during winding. Research and development of winding of the TF Dummy Coil (TFDC) has been carried out and a winding method has been developed by winding trials. Windings of the TFDC and CS Model Coil (CSMC) have been successfully completed by using the developed technique. In R&D, long dummy conductor and short sample jackets have been used to demonstrate a plastic deformation characteristic of CICC during the winding process. The developed winding method can be applied to fabricate all TF and PF coils.