Rockwell Automation Publication 20A-IN009E-EN-P - January 2015 19
PowerFlex 70 Adjustable Frequency AC Drive
Input Power Conditioning
Some events on the power system supplying a drive can cause component damage
or shortened product life. These events are divided into two basic categories that
are described below:
•All Drives
– The power system has power factor correction capacitors that are
switched in and out of the system, either by the user or by the power
company.
– The power source has intermittent voltage spikes in excess of 6000V.
These spikes could be caused by other equipment on the line, or by
events such as lightning strikes.
– The power source has frequent interruptions.
• 5 Hp or Less Drives (in addition to all drives above)
– The nearest supply transformer is larger than 100 kVA, or the available
short circuit (fault) current is greater than 100,000 A.
– The impedance in front of the drive is less than 0.5%.
If any or all of these conditions exist, we recommend that you install a minimum
amount of impedance between the drive and the source. This impedance could
come from the supply transformer itself, the cable between the transformer and
drive, or an additional transformer or reactor. To calculate the impedance, use the
information that is supplied in the Wiring and Grounding Guidelines for Pulse
Width Modulated (PWM) AC Drives, publication DRIVES-IN001
.
Single-phase Input Power
The PowerFlex 70 drive is typically used with a three-phase input supply. The
drive is listed by Underwriters Laboratories (UL) to operate on single-phase
input power. Single-phase operation provides 50% of the three-phase rated
current. See Ta bl e 1 1
on page 27 through Ta bl e 13 on page 29.
Generator Input Power
Contact technical support for details on how to power a drive properly when
using generator power. See Rockwell Automation Support on the back cover.
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