Rockwell Automation SA3100 AC Power Modules - Manual (Page 41)

Installation Guidelines 3-23
3.14.3 Grounding Discrete Control Wiring
The control and signal wiring must be grounded at a single point in the system, remote
from the Power Module (i.e., the 0V or ground terminal should be grounded at the
equipment end, not at the drive end). If shielded control wires are used, the shield
must also be grounded at this point.
Refer to the PMI Regulator instruction manual (S-3057) and to the sales order
installation requirements for more information about grounding control and signal
wiring.
3.14.4 Grounding Resolver/Encoder Wiring
Resolver or encoder cables must be routed in grounded steel conduit. The conduit
must be grounded at both ends. Ground the cable shield at the Power Module end
only.
3.14.5 Grounding Signal Wiring Shields (TE)
The TE (true earth) terminal block is provided for signal wiring shields. It must be
connected to an earth ground by a separate continuous lead. This block accepts wire
sizes from 0.30 mm
2 to 2.1 mm 2 (14 to 22 AWG). Maximum torque is 1.36 N-m
(12 lb.-in.). Use copper wire only. See figure 3.6 for terminal block locations.
3.14.6 Protecting Sensitive Circuits from High Frequency Ground
Currents
The paths through which the high frequency ground currents flow should be identified,
and the area enclosed by these paths should be minimized. Sensitive circuits must
not share a path with such currents. Always separate control and power cabling. Do
not run control and signal ground conductors near, or parallel to, a power ground
conductor.
3.14.7 Protecting the Power Module from Externally Generated
Interference
Normally, no precautions beyond the guidelines provided in this manual are required
to protect the Power Module from externally generated interference. It is
recommended, however, that the coils of DC energized contactors associated with
drives be suppressed with a diode or similar device, since they can generate large
electrical transients.
In areas subject to frequent lightning strikes, additional surge suppression is
advisable. Suitable MOVs should be connected between each line and ground.