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Sum current measurement
If the current measurement is carried out via
two current transformers, the total transformer
ratio must be set to the UMG96L.
Example: Sum current transformer
A current measurement is carried out via one
current transformer with a ratio of 1000/5A and
another one with a ratio of 200/5A. The sum
measurement is carried out with a sum trans-
former 5+5/5A.
The UMG96L has to be programmed as fol-
lows:
Primary current:
1000A + 200A =
1200A
Secondary current:
5A
Current measurement
The current measurement is carried out via ../
5A or ../1A current transformers. In case that
the current has to be measured by an Ampere-
meter in addition to the UMG96L, the Ampere-
meter has to be connected in series to the
UMG96L.
In mains with voltage up to 300VAC against
ground, currents up to 5A can be connected
and measured directly to the UMG 96L.
Attention!
Current transformers may not be han-
dled in open condition of the secondary,
as the secondary clamps can lead live
voltage.
Attention!
Prior to connecting or exchanging the
UMG 96L, the secondary clamps of the
external current transformers have to be
short circuited.
Diagr. Connection example: UMG96L with
Amperemeter in series.
Ꮨ
Ꮨ
Attention!
The program allows current and voltage
transformer ratio setting only, if the maxi-
mum phase power can reach up to
50.0MW and the sum power can reach a
maximum value of 150.0MW.
L l
K k
A
l
k
UMG96L
Verbraucher
Consumer
Einspeisung
Supply
Verbraucher 1
Consumer 1
Verbraucher 1
Consumer 1
Einspeisung 1
Supply 1
Einspeisung 1
Supply 1
UMG96L
L l
K k
L l
K k
AK AL
K l
k l
BK Bl
Inaccuracy
The inaccuracy of the current measuring input
is +- 1% of the measuring range (5A). There-
fore, the inaccuracy of the current measure-
ment is +-50mA.
Example: Inaccuracy
With a current transformer 200/5A, the meas-
uring range is 200A. The inaccuracy is +-1% of
200A = +-2A.
Resolution
The maximum resolution of the current meas-
uring inputs is 10mA. The indication changes
in 0.01A steps.
Example: Resolution current transformer 200/
5A
With a current transformer ratio of 200/5A, a
resolution of 10mA*40 = 400mA is effected.
The display changes in 0.4A steps.
Small currents
The minimum working current is 20mA. At short
circuited or open current measurement input,
the UMG 96L can indicate a small current. This
current is within the range of the allowed meas-
urement inaccuracy.
