KEB COMBIVERT F6 Instructions For Use Manual - page 55
4.2.5.3 Motor cable length and conducted interferences at AC supply
The maximum motor line length is depending on the capacity of the motor cable as well
as on the EMC emitted interference. External measures must be taken here (e.g. the
useofalinefilter).Thefollowinginformationisvalidfortheoperationunderratedcon-
ditionsandtheuseofKEBlistedfiltersunderchapter
Inverter
size
Max. motor cable length shielded
max. leakage
current
(at f
N
≤ 100 Hz)
category c2
Motor cable (standard)
Motor cable (low capacitance)
21
50 m
100 m
< 5 mA
22
23
24
Table 21: Max. motor cable length
Thelinelengthcanbeincreasedsignificantbyusingmotorchokesormotor
filters.KEBrecommendstheuseofmotorchokesorfiltersforalinelengthupto
50 m.
4.2.5.7 Selection of the motor cable
The correct cabling as well as the motor cable itself play an important part in case of
low power in connection with long motor line lengths. Low-capacitance cable (phase/
phase<65 pF/m, phase/screen<120 pF/m) at the inverter output have the following ef-
fects:
• allow major motor cable lengths (=> motor line length)
• better EMC properties (reduction of the common-mode output currents to earth)
PE
PE
PE
V
U
W
The use of shielded motor cables with symmetrical structure is
recommended for higher motor power (from 30 kW). In these
cables the protective earth conductor is tripartite and evenly ar-
ranged between the phase lines. A cable without protective earth
conductor can be used if local regulations so permit. Then the
protective earth conductor must be laid externally. Certain cables
also permit the shield for the use as protective earth conductor.
For this, observe the details of the cable manufacturer!
Figure 21: Symmetrical motor cable
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cONNecTION OF THe POWer UNIT