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Transmitter
96 97
99
98
91 92 93 95
50
12
L1 L2
L1
PE
L3
W PE
V
U
F1
L2
L3
N
PE
130BA175.12
18
53
37
55
54
M
3
5 kΩ
Illustration 3.19 Electrical Connection Diagram
3.4.4.2 Earthing of Screened Control Cables
Correct screening
The preferred method in most cases is to secure control
and cables with screening clamps provided at both ends
to ensure best possible high frequency cable contact.
If the earth potential between the frequency converter and
the PLC is different, electric noise may occur that will
disturb the entire system. Solve this problem by fitting an
equalizing cable next to the control cable. Minimum cable
cross section: 16 mm
2
.
1
2
PE
FC
PE
PLC
130BB922.11
PE
PE
Illustration 3.20 Screening of Control Cables
1
Min. 16 mm
2
2
Equalizing cable
Table 3.13 Legend
50/60 Hz ground loops
With very long control cables, ground loops may occur. To
eliminate ground loops, connect one end of the screen-to-
ground with a 100 nF capacitor (keeping leads short).
100nF
FC
PE
PE
PLC
130BB609.11
Illustration 3.21 Screening for 50/60 Hz Ground Loops
Avoid EMC noise on serial communication
This terminal is connected to earth via an internal RC link.
Use twisted-pair cables to reduce interference between
conductors. The recommended method is shown in
PE
FC
PE
FC
130BB923.11
PE
PE
69
68
61
69
68
61
1
2
Illustration 3.22 Screening for EMC Noise Reduction, Serial
Communication
1
Min. 16 mm
2
2
Equalizing cable
Table 3.14 Legend
Alternatively, the connection to terminal 61 can be
omitted:
PE
FC
PE
FC
130BB924.11
PE
PE
69
69
68
68
1
2
Illustration 3.23 Screening for EMC Noise Reduction, Serial
Communication, without Terminal 61
1
Min. 16 mm
2
2
Equalizing cable
Table 3.15 Legend
3.4.4.3 RFI Switch
Mains supply isolated from earth
When the frequency converter is supplied from an isolated
mains source (IT mains, floating delta and grounded delta)
or TT/TN-S mains with grounded leg, set the RFI switch to
[Off] via
14-50 RFI Filter
on the drive.
Otherwise, set
14-50 RFI Filter
to [On].
For further information, refer to:
System Integration
VLT
®
Decentral Drive FCD 302
42
MG04H102 - VLT
®
is a registered Danfoss trademark
3
3