12.4. Interference suppression measures/EMC (electromagnetic
compatibility)
Electrical/electronic devices are capable of influencing or disturbing each other through connecting
cables or other metallic connections. Electromagnetic compatibility consists of the factors interference
resistance and interference emission. Correct installation of the inverter in conjunction with any
possible local interference suppression measures has a crucial effect on minimizing or
suppressing mutual interference.
The following note refer to a mains power supply that is not ‘‘contaminated’’ by high frequency
interference. Other measures may be necessary to reduce or suppress interference if the mains voltage
is ‘‘contaminated’’. No generally valid recommendations can be given in such cases. Please consult
BERGES if all recommended interference suppression measures should not produce the desired
result.
• When secured on metal (control panels or control cabinets etc.), the inverter should be installed
using screws with additional serrated washers (to link the inverter metallically to the earthed base
surface).
• Use a shielded motor cable (earthing on both sides). The shield should be laid without interruption
from the inverter’s PE terminal to the motor’s PE terminal . If a shielded motor cable cannot be used,
the unshielded motor cable should be laid in a metal duct. This metal duct must not be interrupted
and must be adequately earthed.
The following points must be observed if radio interference suppression is to be realized in accordance
with EN 55011, EN 55014 and EN 50081-1 :
• Line-side connection of a mains filter and a output choke (the mains filter and output choke are not
contained in the scope of delivery).
• Lay the motor cable so that it is shielded.
• Lay the control cable so that it is shielded.
• Observe the general measures for radio interference suppression (also refer to the whole chapter
‘‘Interference suppression measures/EMC (electromagnetic compatibility)’’.
• When connecting the shield to cables leading further, the cross section of the shield should not be
tapered.
• Lay motor, mains power and signal cables separately and, as far away from each other as possible
and separately.
• When using a mains filter, place it at the shortest possible distance from the inverter to be able to
connect both devices by means of short connecting cables.
• When using an output choke (option), place it in the direct proximity of the inverter and connect it
with the inverter using a shielded cable which is earthed at both ends.
• Shielded signal cables should be laid at a minimum distance of 10 cm from power cables running
parallel. A separate earthed metal cable duct is advisable for such signal cables. If signal cables
intersect with a power cable, they should do so at an angle of 90°.
We recommend that control cables with a length of more than 1 m be twisted or laid in a shielded
configuration and earthed at both sides.
BERGES electronic
29.05.98 Operating manual ACM-D2 17
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