Wendelstein 7-X magnet power supplies: Overview and status of commissioning

There are three main magnet systems in Wendelstein 7-X, comprising in total 85 coils arranged in 22 independent circuits fed by steady state power supplies. The superconducting coil system creates the main magnetic field and consists of 70 coils, grouped in seven electrical circuits with ten coils each with an inductance of about one Henry. Each circuit is fed by one power supply with a maximum current of 20 kA and a maximum voltage of +/-30 V. The power supplies were tested so far using copper coils with one mΩ and one mH. The integral commissioning of the completed coil circuits has been running since the end of April 2015.