PowerFlex® 700S Drives - Phase I Control (Frame Sizes 9 & 10) 23
Step 7: Power Wiring
Wire Recommendations
Cable Types Acceptable for 200-600 Volt Installations
A variety of cable types are acceptable for drive installations. For many
installations, unshielded cable is adequate, provided it can be separated from
sensitive circuits. As an approximate guide, allow a spacing of 0.3 meters (1 foot)
for every 10 meters (32.8 feet) of length. In all cases, long parallel runs must be
avoided. Do not use cable with an insulation thickness less than or equal to 15 mils
(0.4mm/0.015 in.). Use Copper wire only. Wire gauge requirements and
recommendations are based on 75 degrees C. Do not reduce wire gauge when using
higher temperature wire.
Unshielded Cable
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. Do not use THHN or similarly coated wire in wet areas. Any wire
chosen must have a minimum insulation thickness of 15 Mils and should not have
large variations in insulation concentricity.
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. 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 Chapter 5,
“Reflected Wave” in Wiring and Grounding Guidelines for Pulse Width Modulated
(PWM) AC Drives, publication DRIVES-IN001.
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.
!
ATTENTION: National Codes and standards (NEC, VDE, BSI etc.)
and local codes outline provisions for safely installing electrical
equipment. Installation must comply with specifications regarding wire
types, conductor sizes, branch circuit protection and disconnect
devices. Failure to do so may result in personal injury and/or equipment
damage.
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