Current operating circuit with incorporated safety function

摘要

The circuit has a safety function provided by monitoring at least one emergency- off switch, or door contact, for automatic cut-out of the operating current for one or more electrical loads. At least 2 capacitors (32,48) are connected at one side in series with respective resistors (28,44), coupled via switch elements (16,72) to one voltage terminal and via a further resistor (60) to a second voltage terminal, to which the capacitors are connected on their other side. At least 2 relays (20,24) each provide a series circuit with a control element (36,54) and a switch contact (38,52), connected to one of the capacitors and to the first voltage terminal via a controlled electronic switch (40,56) and connected in common to the other voltage terminal via a further electronic switch (62).