Baumuller BM5300 Series - Page 276

Power chokes
Instruction handbook b maXX 5000
Document No.: 5.09021.16 Baumüller Nürnberg GmbH
276
of 328
11.5
Example:
A transformer with a u
k
value of 5%, 400 V rated voltage and 500 kVA output is operated
in a 50 Hz mains. A device with the corresponding three-phase power choke, with 4 % u
k
,
is connected to this mains.
Thus, the transformer has an inductance of
L
transformer
u
k
U
N
2

2  fS
N

-----------------------------
005 400
2
V
2

2  50Hz 500kVA 
-------------------------------------------------------- 51H== =
The inductance of the power choke is then calculated at
L
choke
u
k
U
N

3I
N
2  f
--------------------------------------
400V 0 04
3 164A 2  50Hz 
------------------------------------------------------------- 179H== =
Thus, the effective inductance for the device is
L
Total
= L
Transformer
+ L
Choke
= 230 µH,
This corresponds to a u
k
value for the device of 5.13% relative to the phase voltage.
Power choke 
type key