WEG CFW-11 User Manual page 44

Shielded Cables:
They are mandatory when the electromagnetic compatibility directive (2004/108/EC) shall be met, as
defined by the standard EN 61800-3 "Adjustable Speed Electrical Power Drive Systems". These cables act
mainly by reducing the irradiated emission in the radio-frequency range.
In reference to the type and details of installation, follow the recommendations of IEC 60034-25 "Guide for
Design and Performance of Cage Induction Motors Specifically Designed for Converter Supply" – refer to a
summary in Figure 3.16 on page
related to new revisions.
Keep motor cables away from other cables (signal cables, sensor cables, control cables, etc.), according to
Table 3.6 on page
The grounding system shall be well interconnected among the several installation locations such as the
grounding points of the motor and the inverter. Voltage difference or impedance between the several points
may cause the circulation of leakage currents among the equipment connected to the ground, resulting in
electromagnetic interference problems.
Table 3.6 - Minimum separation distance between motor cables and all other cables
Symmetrical shielded cables: three concentric conductors with or without a ground conductor, symmetrically
Notes:
(1) SCu = copper or aluminum external shielding.
(2) AFe = steel or galvanized iron.
(3) PE = ground conductor.
(4) Cable shielding shall be grounded at both ends (inverter and motor). Use 360º connections for a low impedance to high-frequencies. Refer
to Figure 3.17 on page 3-24.
(5) For using the shield as a protective ground, it shall have at least 50 % of the power cables conductivity. Otherwise, add an external ground
conductor and use the shield as an EMC protection.
(6) Shielding conductivity at high-frequencies shall be at least 10 % of the power cables conductivity.
Figure 3.16 - Motor connection cables recommended by IEC 60034-25
3-23. Refer to the standard for further details and eventual modifications
3-23.
Cable Length
≤ 30 m (100 ft)
> 30 m (100 ft)
PE
W
PE
manufactured, with an external shield of copper or aluminum.
Installation and Connection
Minimum Separation Distance
≥ 10 cm (3.94 in)
≥ 25 cm (9.84 in)
PE
U
V
SCu
U
W V
PEs
AFe
CFW-11 | 3-23
3