Berges electronic
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D–51709 Marienheide-Rodt
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Tel. 02264/17-0
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Fax 02264/17126
Operating manual
21.12.98
ACP 3000 — 0.37–15.0
04_GB
16
The scope of noise suppression measures depends on the limit value class, the local situ-
ation and the application.
The following notes refer to a mains power supply that is not “contaminated” by high fre-
quency 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.
Basically, it is not the cross section of the conductor that is important for radio-frequency
interference suppression but the surface area. Since the high-frequency interference does
not flow through the entire cross section but mainly on the outer surface of the conductor
(skin effect), braided copper tapes of corresponding cross section should be used.
All conductive housing parts must be interconnected using corresponding lines. Minimum
cross sections are prescribed for a fault case at 50 Hz (referred to the range of the safety
regulations) which must be observed under all circumstances.
The inverter and all other components used for interference suppression (especially also
the shield of the motor cable) should be contacted over as large an area as possible when
connected to metal (control panels, switchgear cabinets and similar) (skin effect). Remove
the paint at the respective areas to ensure good contacting over a large area!
A central earthing point should be used for interference suppression (e.g. equipotential
bonding strip or centrally at an interference suppression filter). The earthing lines are routed
to the respective terminals radially from this point. Conductor loops of the earthing lines
are impermissible and can lead to unnecessary interference.
The shield cross section must not be reduced when the shield is connected to continuing
lines. This would give rise to RF resistance at a cross section reduction, and the resulting
RF energy would consequently not be discharged but radiated. Shields – particularly
shields of control lines – must not be contacted via pin contacts of plug connectors. In these
cases, the metallic hand guard of the plug connector should be used for large-area connec-
tion of the shield.
Use a shielded motor cable (earthed over a large area at both sides). The shield should be
routed uninterrupted from the PE terminal of the inverter to the PE terminal of the motor.
If a shielded motor line cannot be used, the unshielded motor line should be laid in a metal
duct. The metal duct must be uninterrupted and adequately earthed. The following points
are prescribed if radio interference suppression is to be realized in accordance with EN
55011, EN 55014 and EN 50081-1:
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Preceding the unit by a mains filter or a mains filter and a output choke (mains filter and
output choke not included in the scope of delivery).
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Laying the motor cable in a shielded configuration.
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Laying the control cable in a shielded configuration.
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Observe general RFI suppression measures (refer to the chapters 3.3.1 and 3.3.4).
Lay motor, mains power and signal cables as far away from each other as possible and sep-
arately.
If a mains filter is used, the smallest possible spatial distance from the frequency inverter
must be selected so that both units can be connected by short connection leads.
If an output choke is used (option), it must be fitted in the direct vicinity of the inverter and
connected to the inverter via screened cables 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 intercept with a power cable, they should do so at an angle of 90°.
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