English (GB)
5
3.2.4 Setting the switch point
The switch point has to be set after every connection
or re-connection of the leakage sensor to the
ALR 20/A Ex.
Proceed as follows, see fig.
1. Turn the adjusting screw (2) on top of the
ALR 20/A Ex housing counter clockwise until the
indicator light (4) is on (indicator light signalling a
fault).
2. Turn the adjusting screw (2) slowly in the
opposite direction until the indicator light (4) is
off.
3. Continue turning the adjusting screw (2)
approximately a quarter (from 60 ° to 90 °) in the
same direction as under step 2.
3.2.5 Testing the leakage sensor
Two wires lead from ALR 20/A Ex to the sensor; they
supply the sensor and also lead a variable current
signal, depending on the amount of water in the gear
oil. This current measured by the ALR 20/A Ex
decreases as the amount of water in the oil
increases and it will be compared with a manually
adjustable switch point. If the limit of this switch point
is exceeded, the relay will switch to "error" mode.
Also, in case of a short circuit or a cable break the
relay will automatically switch to "error" mode.
Testing with connected ALR 20/A Ex
In order to test the status or the functionality of the
leakage sensor and the ALR 20/A Ex, the current
flowing through the sensor must be measured. See
fig.
The table below helps to make a conclusion
depending on the current measured:
*
Depending on switch point setting
Fig. 2
Wiring for testing with ALR 20/A Ex
CAUTION
Electric shock
Minor or moderate personal injury
- When the power supply is on, the
settings of the switch point must only be
conducted with suitable and isolated
tool.
Current
[mA]
Meaning
Cause
Relay
status
< 0.5
No floating
current
Break of power
cable
Error
0.5 - 5
Low
current
Sensor detects
water in oil
Error
5-11
Normal
current
Sensor detects
few water or no
water in oil
*
> 11
Too high
current
Short circuit in
power cable
Error
TM
0
7
4
099
0
919
L N
5 A
250 V
A
Summary of Contents for ALR 20/A Ex
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