Power supply apparatus for field devices

An apparatus for supplying DC power to a field device, such as a motor, starter or actuator, includes a multi-pole main switch and a DC voltage supply device, both of which are connected at their respective AC-voltage input sides to a line voltage via a line protection. The DC-voltage side of the DC voltage supply device is connected via a two-pole switch to respective lines of the same power cable that connects output terminals of the apparatus to the field device. The multi-pole main switch and the two-pole switch are ganged. This approach eliminates a separate DC power cable between the apparatus and the field device.