Publicidad
ENGLISH
Danger
The terminal strip of the NRS -3 is live during opera-
tion.
This presents the danger of electric shock.
Cut off power supply before fixing or removing the
housing cover.
Purpose
Two-channel low-water-level alarm with test button used
in combination with GESTRA multiple level control elec-
trode type ER 5 . . . or level control electrode type ER 6.
Installation
. With mounting clip
Snap unit onto 35 mm supporting rail.
. Without mounting clip
Loosen cover screws and unplug unit from its base.
Unscrew mounting clip. Drill the holes in the base
marked ∅ 4.3 mm. Fasten base with two screws M 4
onto mounting panel.
Wiring
Wiring should be carried out in accordance with wiring
diagram (see diagram opposite or inside cover of plug-in
unit). The mains voltage is indicated on the name plate.
For wiring to the electrode screened cable, e. g. x
x 0.6 mm
is recommended. The max. length must not
exceed 00 m. The screen should only be connected to
terminal of the NRS -3, but not at the electrode.
The screen must not have contact with any metal part
of the plant.
To introduce cable, remove cable entries in the base.
After wiring replace cover and tighten screws.
4
Performance Tests
. With the electrode connected, but exposed, both lamps
2
MIN/LW and
must light up.
. If the electrode is immersed or its measuring tip con-
nected to the electrode body with the aid of a wire,
lamps and must not light up. After pushing the
button "Test", the lamps should light up again.
3. The electrode supply voltage is VAC ± 0 %. It can
be measured with the electrode exposed between the
electrode tip and the earth connection with the aid of
a high-impedance voltmeter (≥ 00 kΩ/V).
4. If the terminals 9 and 0 are linked, the internal in-
terlocking is activated, i. e. on re-immersion of the
electrode the level switch continues to signal low-level
alarm unless the "Reset" button has been pressed.
Note
Before unplugging cover of NRS -3 cut off power.
Relay Arc Suppression for
Inductive Loads
When switching off inductive loads voltage peaks are
produced that may reach several times the mains voltage.
The result is:
. The operation of control and measuring systems may
be impaired by interference caused by the voltage
peaks.
. The life of the relay contacts is reduced by the electric
arcs formed.
We therefore recommend that inductive loads are pro-
vided with commercial arc suppressor RC combinations
(e. g. 0. µF/00 Ω).
Concerning Figure 1:
1
RESET
2
MIN/LW
3
TEST
4
Screws to fasten cover to base
5
Cable entries
6
Holes to be drilled to 4.3 mm diameter
for installation of unit in boiler panel
7
Hole drilled for mounting clip
8
Base
9
Cover
0
Mounting clip for 35 mm supporting rail
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