Safety instructions
13
isoPV425_D00028_09_M_XXEN/05.2018
2.3 Intended use
The ISOMETER® of the isoPV425 series monitors the insulation resistance R
F
of
unearthed AC/DC main circuits (IT systems) with nominal system voltages of
3(N)AC, AC/DC 0 … 690 V or DC 0 …1000 V. DC components existing in
3(N)AC, AC/DC systems do not influence the operating characteristics, when
a minimum load current of DC 10 mA flows. A separate supply voltage U
s
al-
lows de-energised systems to be monitored as well. The ISOMETER® is always
used in conjunction with the AGH420.
To ensure that the ISOMETER® functions correctly, an internal
resistance of
≤
1 kΩ must exist between L1/+ and L2/- via the
source (e.g. the transformer) or the load.