Grounding Connections - WEG CFW11W G2 Series User Manual

The grounding system must present a good interconnection between the different locations of the installation,
„
such as between the motor and of the inverter grounding points. Voltage or impedance differences between
the different points may cause the flow of eddy currents between the devices connected to the ground, leading
to problems of electromagnetic interference.
Table 3.13: Minimum separation distance between the motor cables and the others
U
W V
SCu
Symmetric shielded cables: three concentric conductors with or without ground conductors built symmetrically with a copper or
Note.:
(1) SCu = copper or aluminum external shield.
(2) AFe = galvanized iron or steel.
(3) PE = ground conductor.
(4) The cable shield must be grounded on both sides, inverter and motor. 360º connections must be made for a low impedance for high frequencies.
(5) For the shield to act as protective earth, it must have at least 50 % of the conductivity of the phase conductors. Otherwise, use an additional ground
conductor outside the shielded cable; the shield will then be used as EMC protection.
(6) The conductivity of the shield for high frequencies must be at least 10 % of the conductivity of the phase conductors.
Figure 3.31: Cables recommended by IEC 60034-25 to connect the motor

3.2.8 Grounding Connections

DANGER!
Do not share the grounding wiring with other devices that operate with high currents (e.g., high power
motors, welding machines, etc.).
ATTENTION!
The neutral conductor of the line that powers up the inverter must be solidly grounded; however, this
conductor must not be used to ground the inverter.
DANGER!
The inverter must be connected to a protective earth (PE).
Observe the following:
Connect the grounding points of the inverter to a specific grounding rod, or specific grounding
„
point or to the general grounding point (resistance ≤ 10 Ω).
Use a minimum cable gauge for connection to the ground as indicated in
„
if local standards require different gauges, they must be observed.
For compatibility with IEC 61800-5-1 standard, use at least one copper cable of 10 mm² to connect
„
the inverter to the protective earth, since the leakage current is higher than 3.5 mA AC.
Minimum Separation
Wiring Length
Distance
≤ 30 m ≥ 10 cm
> 30 m ≥ 25 cm
PE
U
PE
W V
PE
SCu
aluminum external shield.
Installation and Connection
U
W
PEs
Table 3.14 on page
CFW-11W G2 | 3-27
3
V
AFe
3-28.