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Generally
The ADL-111Q96/xxVDC is intended for insulation monitoring on a DC voltage IT
power network. The special characteristic of an IT power network is the fact that no
live conductor is connected directly to earth. The ADL-111Q96/xxVDC is connected to
the power network by connecting the terminal marked L- to the negative pole. The PE
input is then connected to the safety cable. To be able to monitor any kind of
insulation failure, all accessible conductive building structures must be connected to
the cable PE (protective earth).
Installation
If a test function is requisite, an arrangement based on a known resistor and a push-
button can be mounted as illustrated on the drawing below. The value of the resistor
can be any value from 0Ω to the max. allowed insulation value.
The ADL-111Q96/xxVDC is intended to be supplied from the IT network under
supervision, but it can also be supplied from another source with the same voltage
level as the IT network. If the ADL-111Q96/xxVDC is supplied from a separate voltage
source, the IT network can also be monitored in power-down condition. In this
situation, if no load is connected to the power lines, it will be necessary to make a
connection between the positive and the negative conductor on the IT network by
means of e.g. a low ohmic resistor or a lamp.
Switchboard test arrangement
+
DC Source
PE
1
*
Instrument
*
recommended values
Tel.: (+45) 9614 9614 • Fax: (+45) 9614 9615 • E-mail: deif@deif.com
Page 2 of 7
TEST
3
2
PE
L
Test
resistance
24V
1k
110V
5k
220V
10k
*
+
X2
X1
Instrument shown as
self powered
Relay contact 1,3,2
Supply on
NE
ND
No alarm
Alarm
1-3
1-2
1-2
1-3
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