Rockwell Automation 25B PowerFlex 520-Series Adjustable Frequency AC Drive User Manual User Manual
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Rockwell Automation Publication 520-UM001G-EN-E - September 2014
Chapter 1
Installation/Wiring
UL installations above 50
°C ambient must use 600V, 90 °C wire.
UL installations in 50
°C ambient must use 600V, 75 °C or 90 °C wire.
UL installations in 40
°C ambient should use 600V, 75 °C or 90 °C wire.
Use copper wire only. Wire gauge requirements and recommendations are based
on 75
°C. Do not reduce wire gauge when using higher temperature wire.
Unshielded
THHN, THWN or similar wire is acceptable for drive installation in dry
environments provided adequate free air space and/or conduit fill rates limits are
provided. Any wire chosen must have a minimum insulation thickness of 15 mils
and should not have large variations in insulation concentricity.
Shielded/Armored 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. Strong consideration for shielded cable should
be given in installations with sensitive equipment such as weigh scales, capacitive
proximity switches and other devices that may 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 communications /
networking are also good candidates for shielded cable.
Shielded cable may also help reduce shaft voltage and induced bearing currents
for some applications. In addition, the increased impedance of shielded cable may
help extend the distance that the motor can be located from the drive without the
addition of motor protective devices such as terminator networks. Refer to
Reflected Wave in “Wiring and Grounding Guide, (PWM) AC Drives,”
publicatio
Consideration should be given to all of the general specifications dictated by the
environment of the installation, including temperature, flexibility, moisture
characteristics and chemical resistance. In addition, a braided shield should be
included and be specified by the cable manufacturer as having coverage of at
least 75%. An additional foil shield can greatly improve noise containment.
A good example of recommended cable is Belden® 295xx (xx determines gauge).
This cable has four (4) XLPE insulated conductors with a 100% coverage foil and
an 85% coverage copper braided shield (with drain wire) surrounded by a
PVC jacket.
WARNING: The distance between the drive and motor must not exceed the
maximum cable length stated in the Motor Cable Length Restrictions Tables in
“Wiring and Grounding Guide, (PWM) AC Drives,” publication
.
ATTENTION: Do not use THHN or similarly coated wire in wet areas.