Development, Construction, and Commissioning of a Fully Automated Cabling Machine for Round Multi-Layer REBCO Cables

Abstract

High-current Superconducting Links are being developed at CERN for the powering of the superconducting magnets of the LHC High Luminosity upgrade (HL-LHC). The Superconducting Links consist of an assembly of magnesium-diboride (MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) cables powering different magnet circuits. They have a total DC current capability of up to about |120| kA at 25 K. The MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> cables are connected at one side, at 4.2 K, to the Nb-Ti bus bars of the superconducting magnets and at the other side, to round high temperature superconducting (HTS) rare-earth-barium-copper-oxide (REBCO) cables operated, in helium gas, up to 60 K. We have developed, constructed, and commissioned an automated cabling machine for producing long lengths of round, multi-layer, electrically insulated REBCO cables. The machine allows precise adjustment of the cable geometry and control of the cabling parameters. It controls in high speed, with field programmable gate array (FPGA) and Linux real-time (RT) based controllers, the tension applied to the REBCO tapes, to the polyimide insulating tapes, and to the copper core of the cable. It records all cabling and process parameters in addition to the mechanical tensions and it provides the reporting needed for the quality control procedures that are integral to the fabrication of components of the HL-LHC. In this manuscript we report on the development, design and construction of the machine from the concept to the mechanical realization, including control and data acquisition systems. We also report on the commissioning on the machine via the production of round REBCO cables.