SIEMENS
SINAMICS DCM
Accessories and supplementary components
Commutating reactors
4/18
Siemens D 23.1 · 2014
4
■
Overview
Commutating reactors
A converter must always be connected to the line supply
through a commutation inductance. This must have at least 4 %
u
K
! The commutation inductance can be in the form of a con-
verter transformer or, for the appropriate line supply, in the form
of a commutating reactor.
A line supply can be considered to be "stiff
" if the power ratio
P
s
/
S
k
≤
0.01. Even for stiff line supplies, the commutation induc-
tance must have a
u
K
of at least 4 %!
For high-rating converters, the line reactance, i.e. the finite fault
level (short-circuit power) of the line supply must be taken into
account; this also results in higher
u
K
values. Recommendation
for the ratio of the line supply fault level (short-circuit power) to
the apparent drive power > 33:1.
The commutating reactors are dimensioned according to the
rated motor current in the armature or field circuit.
Operation with line frequencies of 50 Hz and 60 Hz
The rated currents
I
Ln
of the reactors, specified in the table,
apply for operation with a line frequency
f
= 50 Hz. It is permis-
sible to operate the reactors with a line frequency
f
= 60 Hz. In
this case, the next-higher voltage level must be selected (e.g.
480 V instead of 400 V).
At the same time, the voltage drop
∆
V
increases by 8 %.
Arrangement of reactors and radio interference suppression filters
(1)
The commutating reactor in the field circuit is dimensioned for the
rated motor field current.
(2)
The commutating reactor in the armature circuit is dimensioned for
the rated motor armature current.
The line current is 0.82 times the DC current.
(3)
The radio interference suppression filter for the armature circuit is
dimensioned for the rated motor armature current.
The line current is 0.82 times the DC current.
(4)
The radio interference suppression filter for the field circuit is
dimensioned for the rated motor field current.
(5)
The electronics power supply itself does not require a radio inter-
ference suppression filter. Current consumption 1 A at 400 V, 2 A at
230 V.
(6)
If the power supply voltages for the armature circuit, field circuit and
electronics power supply are the same, then the voltage for the field
and electronics power supply can also be taken after the radio inter-
ference suppression filter for the armature circuit.
230 V
NC
5U1
5N1
5U1
5W1
3U1
Field
SINAMICS DC MASTER
Armature
3W1
1U1
1V1
1W1
3C
3D
M
1C1
1D1
5W1
400 V
400 V
Line supply voltage
Power supply
230 V AC or 400 V AC
(1)
(5) (6)
(5) (6)
(4) (6)
(3) (6)
(2)
G_D023_EN_00004a
5N1
© Siemens AG 2014