Instructions for Design of Drives in Conformance with EMC Regulations 05.2003
6SE7087-6QX70 (Version AD) Siemens AG
3-6 Compendium Motion Control SIMOVERT MASTERDRIVES
M
3 ~
Z
N
Z
E
I
S
Frequency converterLine filter Shielded motor supply cable
Fig. 3-3 Flow of the noise current with shielded motor cable
A shielded motor cable with a shield connected at both sides causes
the noise current to flow back to the frequency converter through the
shield.
Although (almost) no voltage drop arises across impedance Z
E
for
shielded motor cables, the voltage drop across impedance Z
N
can
affect other electrical units.
For this reason, a radio interference suppression filter should be
installed in the supply feeder cable to the frequency converter.
Arrangement of the components as per the following figure.
1U2
Radio interference
suppression filter
TN supply
or
TT supply
Load
Supply
L1
Line reactor
SIMOVERT
MASTERDRIVES
Mounting panel
M
3~
Shielded motor
cable
1V2
1W2
1U1
1V1
1W1
L2
L3
PE
L1'
L2'
L3'
PE'
U1
V1
W1
PE1
U2
V2
W2
PE2
Fig. 3-4 Arrangement of the components
Radio interference suppression filters and frequency converters must
be connected through a low-ohmic resistance for the high-frequency
noise currents. In practice, this requirement is best satisfied by
mounting the frequency converters and radio interference suppression
filters on a common panel. Frequency converters and radio interference
suppression filters must be connected to the mounting panel through
the largest possible surface area.
The SIMOVERT MASTERDRIVES must be installed in an enclosed
cabinet in order to limit the radio interference radiation. In particular,
the radio interference radiation is determined by the control section with
its microprocessor and it is therefore comparable with the noise emitted
from a computer. If there are no radio transmission services in the
immediate vicinity of the SIMOVERT MASTERDRIVES, there is no
need for a high-frequency-sealed cabinet.
Radio interference radiation is not limited if the units are installed in
racks. In this case, adequate shielding should be provided by suitably
designing the equipment room/area.
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