284 ACQ550-U1 User’s Manual
Technical data
Effective motor cable shields
The general rule for cable shield effectiveness is: the better and tighter the cable’s
shield, the lower the radiated emission level. The following figure shows an example
of an effective construction (for example Ölflex-Servo-FD 780 CP, Lappkabel or
MCCMK, NK Cables).
EN 61800-3 compliant motor cables
The most efficient EMC filtering can be achieved by following these rules:
• Motor cables must have an effective shield as described in section Effective
motor cable shields on page 284.
• Motor cable shield wires must be twisted together into a bundle (pig-tail) – the
bundle length must be less than five times its width – and connected to the
terminal marked (at the bottom right-hand corner of the drive).
• At the motor end, the motor cable shield must be earthed 360 degrees with an
EMC cable gland, or the shield wires must be twisted together into a bundle (pig-
tail) not longer than five times its width and connected to the PE terminal of the
motor.
• See section Motor cable length for 400 V drives, columns “EMC limits” on page
280 to check the maximum motor cable lengths and the need for filters for 400 V
drives for IEC/EN 61800-3 compliance.
WARNING! Do not use RFI/EMC filters on IT systems.
Insulation jacket
Braided metallic shield
Inner insulator
L1
L2
L3
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