3WL air circuit breakers
3.3 Metering functions
3WL/3VL circuit breakers with communication capability - PROFIBUS
System Manual, 03/2011, A5E01051353-02
49
Connection
On the primary side, the voltage converter can be star or delta-connected. On the secondary
side, it is always star-connected to the auxiliary conductor plug-in system (X8:5 to X8:8). The
figure below shows the connection of the voltage transformer for operating with a metering
function. On the primary side, the transformer can be star or delta-connected. Refer to the
Operating Instructions for details.
VHFRQGDU\
SULPDU\
;
;
;
;
D
E
F
Q
$
$
%
%
&
&
/
/
/
Figure 3-11 Connection of the voltage transformer for metering function
Maximum distance from voltage transformer
The maximum distance depends on the cross-section and the required accuracy class.
Assuming a cross-section of 1.5 mm
2
, the maximum distance from the voltage transformer is
50 m for Class 0.5, and 100 m for Class 3. If electromagnetic interference is expected,
shielded cables must be used.
Parameters for setting the measured value
To determine the measured values, the data of the voltage transformer must be taken into
account and set in the metering function. This includes:
● Primary voltage of the voltage transformer (factory setting: 400 V)
● Secondary voltage of the voltage transformer (factory setting: 100 V)
● Type of connection on the primary side (factory setting: star)
If the parameters have to be changed, the following setting options are available:
● With the BDA PLUS
● With the display of the ETU76B
● Data set 128 via PROFIBUS DP
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