Rockwell Automation 20Y PowerFlex Active Front End - Manual (Page 62)

62 Rockwell Automation Publication 20Y-UM001E-EN-P - July 2014
Chapter 2 AFE in IP21 Rittal Enclosure—Installation/Wiring
Shielded Cable
Shielded cable contains all of the general benefits of multi-conductor cable with
the added benefit of a copper braided shield that can contain much of the noise
generated by a typical AC drive. Strongly consider shielded cable in installations
with sensitive equipment such as weigh scales, capacitive proximity switches, and
other devices that can be affected by electrical noise in the distribution system.
Applications with large numbers of drives in a similar location, imposed EMC
regulations, or a high degree of communication and networking are also good
candidates for shielded cable.
Consider all of the general specifications dictated by the environment of the
installation, including temperature, flexibility, moisture characteristics, and
chemical resistance. In addition, include a braided shield, specified by the cable
manufacturer as having coverage of at least 75%. An additional foil shield can be
greatly improve noise containment.
A good example of recommended cable is Belden® 29528 - 29532 (AWG-1
through AWG-410). This cable has three XLPE insulated conductors plus
ground with a spiral copper shield surrounded by a PVC jacket.
Armored Cable
Cable with continuous aluminum armor is often recommended in drive system
applications or specific industries. It offers most of the advantages of standard
shielded cable and also combines considerable mechanical strength and resistance
to moisture. It can be installed in concealed and exposed manners, and removes
the requirement for conduit (EMT) in the installation. It can also be directly
buried or embedded in concrete.
Because noise containment can be affected by incidental grounding of the armor
to building steel when the cable is mounted, we recommend the armor cable have
an overall PVC jacket. See Chapter 2, ‘Wire Types’ in Wiring and Grounding
Guidelines for Pulse Width Modulated (PWM) AC Drives, publication
DRIVES-IN001.
Interlocked armor is acceptable for shorter cable runs, but continuous welded
armor is preferred.
Best performance is achieved with three spaced ground conductors, but
acceptable performance below 200 HP is provided by use of a single ground
conductor.
Recommended shielded/armored wire is listed in Table 11 .