10/05 AWB8230-1541GB
EMC compliance
33
Screening
Unscreened cables behave like antennae, i.e. they act as
transmitters and receivers. To ensure EMC-compliant connection,
screen all interference-emitting cables (frequency inverter/motor
output) and interference-sensitive cables (analog reference and
measured value cables).
Screening control and signal cables
The following figure shows a sample protective circuit for the
control signal terminals.
The effectiveness of the cable screen depends on a good screen
connection and a low screen impedance. Use only screens with
tinned or nickel-plated copper braiding, braided steel screens are
unsuitable. The screen braid must have an overlap ratio of at least
85 percent and an overlap angle of 90°.
Screening motor supply cables
The screened cable between frequency inverter and motor should
be as short as possible. Connect the screen to earth at both ends
of the cable using a large contact surface connection.
Lay the cables for the supply voltage separately from the signal
cables and control cables.
h
To increase operational reliability, screen analog and
digital control signal cables and lay them well away from
the power cables.
Figure 30: Control terminal connection (factory setting)
2 1
P24
H O
L
ZB4-102-KS1
15
M4
PE
2
Cu 2.5 mm
PES
PES
1
2
3
M
R1 REV FWD
4K7
M
F 20 m
h
With the optional ZB4-102-KS1, you can connect the
control cable screens at one end. Order this item
separately.
Figure 31: Sample motor cable
a C screen braid
b PVC outer sheath
c Drain wire (copper strands)
d PVC core insulation
3 x black, 1 x green/yellow
e Textile braid and PVC inner material
b
a
e
d
c
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