Traction converter circuit for coupling to a electrical supply network

The device has at least one static frequency changer drive system (4) with first and second sub-devices (2,3) connected by a d.c. circuit (5) and the first sub-device connected to an a.c. source (1) via a transformer (8) and a supply network configuration switch (9) when the circuit is a.c. driven. A mains static frequency changer (11) is connected on the a.c. side to a third transformer winding (12) and on the d.c. side via the configuration switch to a d.c. source (13) when the circuit is d.c. driven.