Siemens SIMODRIVE 611 digital Configuration Manual page 205

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05.01 05.08
S calculation of
n
the matching
transformer for an
NE module
Note:
Examples
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SIMODRIVE 611 Configuration Manual (PJU) – 05/2008 Edition
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S
Condition a)
The rated power (Sn) of the matching transformer must be:
S w 1.27  Pn (I/R module [kW])
n1
Example: The minimum rated power of a matching transformer
for I/R module 16/21 is 21 kVA.
S
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 6-6, Chapter 6.3.1. Depending on the
vector group of the transformers, e.g. YYn0, asymmetric loading of the N/MP
may not be permitted.
Consequently, the required rated power S
culated.
S  S
K plant K line
S +
n2
(S – S
K plant K line
This means:
Sn1, Sn2 Calculated rated power of the matching transformer
uk Short–circuit voltage of the matching transformer as % (see Table 7-1)
S Short–circuit power.
K
S if necessary, consult the utility company
K plant
S = at least the value contained in Chapter 6.3.1,Table 6-6
K line
The system fault level at the plant connection S
dimensioning/selecting the matching transformer.
From the rated power (Sn or S
1
be used for the matching transformer.
Matching transformer for 16/21 kW I/R module sinusoidal current:
uk matching transformer = 3%; S
sinusoidal current according to Table 6-6: S
based on a) S = 1.27  16 kW = 21 kVA
n1
based on b) Calculation of Sn2
Case 1:
S
+
n2
S > S ⇒ S
n2 n1
The matching transformer requires a rated power S
at a uk of 3%.
Case 2:
If the uk of the matching transformer is less than, e.g. uk=1%
for otherwise unchanged conditions for Case 1:
S +
n2
⇒ S
S > S
n1 n2
The matching transformer requires an Sn rated power of 21 kVA
at a uk of 1%.
sales@aotewell.com
7 Line Supply Connection
7.2 Voltage matching
[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
= 50000 kVA ; S
K plant K line
= 1120  0.73 = 820 kVA
K line
50000  820  3
= 25 kVA
(50000 – 820)  100
is decisive
n2
50000  820  1
= 8.3 kVA
(50000 – 820)  100
is decisive
n1
Industry Automation
for I/R 16/21 kW
of 25 kVA
n
7-205
+86-755-8660-6182
7