Rockwell Automation SA3100 AC Power Modules - Manual (Page 40)

3-22 SA3100 Power Modules
3.14 Grounding the Drive and Motor
Refer to figure 3.11 for recommended grounding. The Power Module must be
connected to the system ground at the power earth (PE) terminal provided on the
power terminal block (TB1). Ground impedance must conform to the requirements of
national and local industrial safety regulations (NEC, VDE 0160, BSI, etc.) and should
be inspected and tested at appropriate and regular intervals.
Within a cabinet, a single, low-impedance ground point or ground bus bar should be
used. All circuits should be grounded independently and directly. The AC supply
ground conductor should also be connected directly to this ground point or bus bar.
3.14.1 Grounding the Power Module Safety Ground (PE)
The PE (power earth) ground is the safety ground required by code. This point must
be connected to adjacent building steel (girder, joist) or to a floor ground rod, provided
grounding points comply with NEC regulations. If a cabinet ground bus is used, refer
to section 3.5.
3.14.2 Grounding the Motor Cable
The ground conductor of the motor cable (Power Module end) must be connected
directly to the Power Module earth ground terminal (PE), not to the cabinet bus bar.
Grounding directly to the Power Module (and filter, if installed) provides a direct route
for high frequency current returning from the motor frame and ground conductor. At
the motor end, the ground conductor should be connected to the motor frame ground.
If shielded or armored cables are used, the shield/armor should be grounded at both
ends as well.
!
ATTENTION:The user is responsible for conforming with all local,
national, and international codes applicable to the grounding of this
equipment. Failure to observe this precaution could result in damage to,
or destruction of, the equipment.
Figure 3.11 – Recommended Grounding
MOTOR
GROUND ROD
U(T1)
V(T2)
W(T3)
PE/GND
SHIELD
SHIELD
OPTIONAL
MOTOR TERMINATOR
GROUND PER
PE
LOCAL CODES
MOTOR
FRAME
OPTIONAL
COMMON MODE
CHOKE
ISOLATION
TERMINATOR
CONDUIT
4 WIRE CABLE
R(L1)
S(L2)
T(L3)
+DC
–DC GROUNDING
RESISTOR