ABB ACH550-UH User Manual page 316

1-312
Recommendation for conductor layout
The following figure compares conductor layout features in motor cables.
Symmetrical shielded cable: three phase
conductors and a concentric or otherwise
symmetrically constructed PE conductor, and a
shield
Not allowed for motor cables (CE & C-Tick)
A four-conductor system: three phase
conductors and a protective conductor, without a
shield.
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).
Insulation Jacket
EN 61800-3 compliant motor cables
To comply with EN 61800-3 requirements:
• Motor cables must have an effective screen as described in
screens
• 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
• Motor cables must be grounded, at the motor end, with an EMC cable gland. The
ground must contact the cable screen all the way around the cable.
• For EN 61800-3 First Environment, Restricted Distribution (CISPR11 Class A),
and EN 61800-3 Second Environment compliance, the drive includes an internal
filter that provides compliance for at least 30 m (100 ft.) motor cable lengths. For
some drives, longer cable lengths require an additional, external RFI/EMC filter
as specified in the table below. The RFI/EMC filters are separate options and
Technical data
Recommended (CE & C-Tick)
PE
Conductor
and Shield
PE
Braided Metallic Screen
above.
(at the bottom right-hand corner of the drive).
Allowed (CE & C-Tick)
A separate PE conductor is required if the
conductivity of the cable shield is < 50% of the
conductivity of the phase conductor.
Shield
Allowed for motor cables with phase
conductor cross section up to 10 mm
Inner Insulator
L2
L1
L3
ACH550-UH User's Manual
Shield
PE
Shield
2
.
Effective motor cable