DKR Drive Controllers
Planning the electrical connections
6-11
DOK-DIAX03-DKR********-PR02-EN-P
Autotransformers
CAUTION
Damage to the autotransformer if it is not sized
large enough!
⇒
Please note the following guidelines.
⇒
Dimension the power S
Netz
of a possibly required autotransformer in
terms of the rated motor power or at least, however, in terms of the
actual continuous motor power:
DauerMotor
NetzDKR
P
I
*
8
,
1
=
NetzDKR
NetzDKR
Netz
I
U
S
*
*
3
=
I
NetzDKR
:
mains current [A]
P
DauerMotor
:
actual continuous power of the motor [kW]
S
Netz
:
power of the autotransformer [kVA]
U
NetzDKR
:
mains voltage [V]
Fig. 6-11:
Formula to determine the power of the autotransformer
⇒
Make sure that the inductive components of the relative short-circuit
voltage u
KX
are less than 4 %:
%
100
*
1
1
Nenn
KX
KX
U
u
u
=
u
KX1
:
primary short-circuit voltage (inductive components) [V]
U
Nenn1
:
rated voltage of the transformer, input side [V]
Fig. 6-12:
Formula to determine the inductive components of the primary mains
voltage
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