Rockwell Automation 1336E IMPACT Adjustable Frequency AC Drive User Manual V 1-4.XX - Manual (Page 37)

Mounting and Wiring Your 1336 IMPACT Drive 2-19
Some installations require armored cable instead of shielded cable.
Refer to the following table:
Armored Cable
Armored cable also provides effective shielding. Ideally, you should
ground armored cable only at the drive (PE) and motor frame. Some
armored cable has a PVC coating over the armor to prevent incidental
contact with grounded structure. If, due to the type of connector, you
must ground the armor at the cabinet entrance, use shielded cable
within the cabinet to continue as far as possible with the coaxial
arrangement of power cable and ground.
In some hazardous environments, you cannot ground both ends of the
cable armor. This is because of the possibility of high current
circulating at the input frequency if the ground loop is cut by a strong
magnetic field. This only applies in the proximity of powerful
electrical machines. In this case, make the ground connection at one
end through a capacitance that blocks the low, line frequency current
but presents a low impedance to RF. Due to the highly pulsed nature
of the circulating current, the capacitor type used must be rated for
AC-to-ground voltage. Consult the factory for specific guidelines.
Conduit
If you use metal conduit for cable distribution, use these guidelines:
• Drives are normally mounted in cabinets, and ground connections
are made at a common ground point in the cabinet. If the conduit
is connected to the motor junction box and the drive end, you do
not need any additional conduit connections.
• Route no more than three sets of motor leads through a single
conduit. This minimizes cross talk that could reduce the
effectiveness of the noise reduction methods described. If more
than three drive/motor connections per conduit are required, use
shielded cable. If practical, each conduit should contain only one
set of motor leads.
Condition: Insulation Type: Example:
Dry
PVC 1
1 For input voltages in excess of 230 V AC, motor cables greater than 15 m (50 ft), or
wire with less than 15 mil of insulation, wire with XLPE insulation is recommended.
Contact Rockwell Automation if you have questions.
THHN
XLPE XHHW-2
Wet XLPE XHHW-2
!
ATTENTION: To avoid a possible shock hazard
caused by induced voltages, ground unused wires in the
conduit at both ends. For the same reason, if a drive
sharing a conduit is being serviced or installed, disable
all drives using this conduit to eliminate the possible
shock hazard from cross coupled drive motor leads.