Multiple pulse rectifier control circuit - has timing cycle monitoring device preventing cycle from falling below minimum value

摘要

The rectifier is controlled by the mains supply and generates quickly variable d.c. currents of very different intensities from a polyphase a.c. mains through ignition angle controlled thyristors. Ignition pulses are applied to the thyristors, whose phase relation to the mains voltage is determined by control pulses in accordance with a control voltage. A timing cycle monitoring device (18) has a timing element to which control pulses are applied. The device (18) has a limit monitoring device which prevents the timing cycle determined by the above time element from falling below a minimum value, thus holding it at the limit value.