Abstract: A conversion circuit for converting an alternating current into a feed current for an electrochemical process is provided with at least one supply terminal for supplying an alternating feed current, a rectifier circuit for rectifying a supplied alternating feed current, and an output stage for supplying the rectified current to a device in which the electrochemical process is taking place. The conversion circuit is further provided with an input stage connected between the supply terminals and rectifier circuit, which input stage, when in use, confers upon the conversion circuit a substantially reactive input impedance.

Abstract: A pump or turbine is disclosed which includes a housing provided with at least one chamber, a rotor, which is rotatably mounted on a shaft in the chamber, an inlet, which communicates with the chamber at least at the location of the shaft, and an outlet channel, which communicates with the chamber at least at the periphery of the rotor. The pump or turbine moreover comprises at least one bypass channel, a first end of which opens into the outlet channel of the pump and a second end of which forms an inlet. The bypass channel may be used for increasing the propelling force or for pumping slurries, for example.