WEG CFW-11 User Manual page 39

Installation and Connection
Keep motor cables away from other cables (signal cables, sensor cables, control cables, etc.), according to
table 3.5.
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.
3
Symmetrical shielded cables: three concentric conductors with or without a ground conductor,
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 3.16.
(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.
Connection of the motor cable shield to ground: Make a connection with low impedance for high frequencies.
Example in the figure 3.16. In inverters without the Nema1 kit, connect the motor cable shield to the ground
in a similar mode, with the clamp at the inverter inner part, according to the figure 3.16.
Figure 3.16 - Example of the motor cable shield connection at the inner part of the Nema1 kit supplied with the product
3-20
Table 3.5 - Minimum separation distance between motor cables and all other cables
Cable length
≤ 30 m (100 ft)
> 30 m (100 ft)
PE
PE
symmetrically manufactured, with an external shield of copper or aluminum.
Figure 3.15 - Motor connection cables recommended by IEC 60034-25
Minimum separation distance
≥ 10 cm (3.94 in)
≥ 25 cm (9.84 in)
PE
U
W V
SCu
Assemble the grounding
clamp in this position when
it's not used Nema1 kit.
U
W V
PEs
AFe