As will be described in still more detail below, in this case the first value is preferably higher than the second value, which in turn is higher than the third, which is higher than the fourth value. The voltage at the first terminal 120 can be influenced as a function of a total electrical resistance between the terminals 120 and 125. For this, the driver 155 can comprise a sampling device 165 for voltage and/or a sampling device 170 for current at the first terminal 120. The second terminal 125 preferably has a predetermined potential relative to the intermediate circuit voltage 135. In particular, the second terminal 125 can be connected to one of the potentials of the intermediate circuit voltage 135, in the representation shown in FIG. 1 with the low potential.

The processing device 160 can be connected to the switches 130 of the loads 105, in order to determine that a load 105 is or should be switched on. In a further embodiment the processing device 160 can also receive a logic signal representing a demand to switch on a load 105 and thereupon actuate a corresponding switch 130. The switches can in particular be made in the form of electrically actuated current control valves.

It is proposed to design the control device 160 so that it increases the voltage applied between the terminals 120 and 125 temporarily to a first value when, in particular, a previously non-energized load 105 is connected to the terminals 120, 125. Thereafter the voltage should be reduced after a predetermined waiting time to a second value and optionally, after a further predetermined waiting time, to a third value.