Siemens 6SN1123-1AA00-0DA2 Configuration Manual page 214

05.08
05.01
Note
S
S calculation of
n
the matching
S
transformer for
several loads
S
Consequently, the required rated power S
culated.
Note:
The system fault level at the plant connection S
dimensioning/selecting the matching transformer.
From the rated power (Sn
be used for the matching transformer.
© Siemens AG 2012 All Rights Reserved
SIMODRIVE 611 Configuration Manual (PJU) – 02/2012 Edition
Case 3:
If S is less, then a transformer with a higher rating must
K plant
be selected, e.g. S
3000  820  3
+
S
n2
(3000 – 820)  100
S > S % S
n2 n1
The matching transformer requires a rated power S
at a uk of 3%.
Case 4:
When compared to Case 3, the uk of the matching transformer
is reduced to, e.g. uk = 1%:
3000  820  1
+
S
n2
(3000 – 820)  100
⇒ S
S > S
n1 n2
The matching transformer requires a rated power S
at a uk of 1%.
for the matching transformer can be reduced by reducing uk.
n2
Condition a)
The rated power (Sn) of the matching transformer must always be:
w 1.27  Pn (I/R module [kW])
S
n1
Condition b)
In order to avoid faults and disturbances at the other loads, that are con-
nected to the secondary side of the matching transformer, the sum of the
system fault level (short–circuit power) of the plant connection and that of
the matching transformer at the connection point (S
tain at least the values shown in Table 7-1, Chapter C.1.3. Depending on the
vector group of the transformers, e.g. YYn0, asymmetric loading of the N/MP
may not be permitted.
 S
S
+
K plant K line
S
n2
(S – S
K plant K line
or S
1
7 Line Supply Connection
7.2 Voltage matching
= 3000 kVA; otherwise as for Case 1:
K plant
= 34 kVA
is decisive
n2
= 11.3 kVA
is decisive
n1
[kVA]
line supply) must con-
K
of the matching transformer is cal-
n2
 uk
[kVA]
)  100
plant plays a decisive role in
K
) calculated under a) and b), the higher must
n2
of 34 kVA
n
of 21 kVA
n
7
7-213