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4.1 Overview of Power Connections
The recommended grounding method is shown in Figure 4-1.
4.1.1 Safety Ground - (G)
This is the safety ground for the drive that is required by code. One of these points must be connected
to adjacent building steel (girder, joist), a floor ground rod, or bus bar. Grounding points must comply
with national and local industrial safety regulations and/or electrical codes.
See recommended tightening torques in Table 4-1.
Note: A line reactor is recommended
and must be purchased separately.
AC Main
Supply
Safety
Four Wire
Ground
Wye
Driven Earth
Ground Rod
(Plant Ground)
4.1.2 Motor Ground
The motor ground must be connected to one of the ground terminals on the drive. Use UL Listed Fork
terminals for ground connections.
4.1.3 Shield Termination
Either of the safety ground terminals located on the power terminal block provides a grounding point
for the motor cable shield. The motor cable shield connected to one of these terminals (drive end)
should also be connected to the motor frame (motor end). Use a shield terminating or EMI clamp to
connect the shield to the safety ground terminal. When shielded cable is used for control and signal
wiring, the shield should be grounded at the drive end only, never at both ends.
4.1.4 RFI Filter Grounding
Using single-phase drives with integral filter, or an external filter with any drive rating, may result in
relatively high ground leakage currents. Therefore, the filter must only be used in installations with
grounded AC supply systems and be permanently installed and solidly grounded (bonded) to the
building power distribution ground.
MN762S
Figure 4-1 Recommended System Grounding
.
L1
Optional
L2
Line
Reactor
L3
Earth
Route all 4 wires L1, L2, L3 and Earth (Ground)
together in conduit or cable.
Route all 4 wires U, V, W and Motor Ground together
in conduit or cable.
Connect all wires (including motor ground)
inside the motor terminal box.
Use UL Listed Fork terminals for ground connections.
Drive
Note: Wiring shown for clarity of grounding
L1
L2 L3
U V W
Optional
Load
Reactor
Chapter 4
Power Wiring
Method only. Not representative of
actual terminal block location.
Note: A load reactor is recommended
and must be purchased separately. .
Ground per NEC and
Local codes.
Power Wiring 4-1
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