ACS550 User’s Manual 275
Technical data
Recommendation for conductor layout
The following figure compares conductor layout features in motor cables.
Effective motor cable screens
The general rule for cable screen effectiveness is: the better and tighter the cable’s
screen, 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 screen as described in section Effective
motor cable screens on page 275.
• Motor cable screen wires must be twisted together into a bundle (the bundle
length must be less than five times its width) and connected it to the terminal
marked (at the bottom right-hand corner of the drive).
• At the motor end, the motor cable screen must be earthed 360 degrees with an
EMC cable gland, or the screen wires must be twisted together into a bundle 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
272 to check the maximum motor cable lengths and the need for filters for 400 V
drives for IEC/EN 61800-3 compliance.
Symmetrical shielded cable: three phase
conductors and a concentric or otherwise
symmetrically constructed PE conductor, and a
shield
Recommended (CE & C-Tick)
PE
conductor
and shield
A separate PE conductor is required if the
conductivity of the cable shield is < 50% of the
conductivity of the phase conductor.
Not allowed for motor cables (CE & C-Tick)
Shield
PE
PE
Allowed for motor cables with phase
conductor cross section up to 10 mm
2
.
A four-conductor system: three phase
conductors and a protective conductor, without a
shield.
Allowed (CE & C-Tick)
Shield
Shield
Insulation jacket
Braided metallic screen
Inner insulator
L1
L2
L3
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