Cable, Standard I/O; Cabie Trays And Conduit - Allen-Bradley PowerFlex 70 Reference Manual

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Cable, Standard I/O

Cable, Standard I/O
CabIe Trays and
Conduit
For analog and encoder cable selection, see
selection can be found on
Conduit must be magnetic steel and be installed so as to provide a
continuous electrical path through the conduit itself.
Care must be taken when pulling wire to avoid nicking the wire.
Nylon-coated wire such as THHN or THWN is subject to insulation
damage when it is pulled through conduit, particularly if 90º bends are
present. Nicking can significantly reduce or remove the insulation. Water
based lubricants should not be used with nylon coated wire such as THHN.
Important: Because of the nature of the drive PWM output and the
reflected wave phenomenon, it is preferable to have each set of
drive motor/power cables in an individual conduit. If this is not
possible, do not route more than 3 sets of drive cables in one
conduit. It is important that the allowable fill rates specified in
the applicable national or local codes Not Be Exceeded.
ATTENTION: To avoid a possible shock hazard caused by
!
induced voltages, unused wires in the conduit must be grounded at
both ends. For the same reason, if a drive sharing a conduit is being
serviced or installed, all drives using this conduit should be
disabled. This will help minimize the possible shock hazard from
"cross coupled" motor leads.
When laying cable in cable trays, do not randomly distribute them. Cables
for each drive should be bundled together and anchored to the tray (see
Figure 2.5). A minimum separation of one cable width should be
maintained between bundles to reduce overheating and cross-coupling.
Current flowing in one set of cables can induce a hazardous voltage and/or
excessive noise on the cable set of another drive, even when no power is
applied to the second drive. Dividers also provide excellent separation.
Figure 2.5 Cable Placement
Random Placement
Not Recommended
or
Bundled & Anchored to Tray
Recommended
For further information, refer to "Wiring and Grounding Guidelines for
PWM AC Drives," publication DRIVES-IN001A-EN-P.
page 2-15. Digital input cable
page 2-51.