SEG Electronics GmbH
Manual MRG3
16
DOK-TD-MRG3, Rev. D
There are three possibilities to measure the residual voltage:
directly in the star point
based on the open delta winding
based on star-connected phase voltages
For detailed description of this function, refer to chapter 4.7.3.
For direct star point measurement as well as for the measurement out of the open delta winding,
the MRG3 is equipped with a proper measuring input. For this purpose, the code plug is set to posi-
tion “1:1”. For detection of the residual voltage based on the three star-connected phase voltages,
adjust the code plug to “3PHA”. The code plug’s default position is “1:1”.
3.1.9 Low/high range of the digital inputs
The MRG3 is equipped with a power supply unit so that the supply voltage can be freely selected.
This means, that the switching threshold of the digital inputs has to be defined dependent on the
supply voltage. It is possible to adjust two switching threshold ranges:
a low range with a switching threshold of
U
AN
>= 10 V;
U
AB
<= 8 V = connector plugged; or
a high range with a switching threshold of
U
AN
>= 80 V;
U
AB
<= 60 V = connector unplugged.
Figure 3.11: Selection of low/high range of the digital inputs
