Experience gained during manufacture and testing of the W7-X superconducting magnets

The optimised stellarator Wendelstein 7-X (W7-X) is presently being assembled at the Greifswald branch of IPP. The specific field configuration of W7-X is realised by a periodic arrangement of 50 non-planar and 20 planar superconducting coils in five modules. The winding packs are wound from a cable-in-conduit conductor and embedded in massive steel casings. Tests during production and at operational conditions are performed to verify that essential requirements are met. Manufacture of the non-planar and planar magnets is in an advanced stage. The manufacturer had to solve several problems and consider major design changes during advanced stages of manufacture. Meanwhile, several coils have been delivered and tested and assembly of the first half-module has started. The paper gives an overview of the production status and highlights the lessons learned during fabrication and test of the coils.