Abstract: A first DC-linked AC converter with a machine converter (6) with controllable turn-on thyristors is connected in parallel with a second DC-linked AC converter with a machine converter (4) equipped with so-called gate-turn-off (GTO) thyristors which can be turned off. The second DC-linked AC converter with a machine converter equipped with controllable turn-on and turn-off thyristors is particularly adapted to feed a drive for pumps and fans where an exceedingly small torque and a small output power is required at low rotation speeds. The second DC-linked AC converter equipped with GTO thyristors is controlled so as to supply predominantly the reactive power for the asynchronous machine (5) and the commutation reactive power for the normal thyristor converter (6) minus the reactive power of the capacitors (C.sub.R).