Rockwell Automation 20D PowerFlex 700S Drive Ph I Control, Frames 1...11 - Manual (Page 18)

1-4 Installation/Wiring
Input Power Conditioning
Certain events on the power system supplying a drive can cause component
damage or shortened product life. These conditions are divided into 2 basic
categories:
1. All Drives
– The power system has power factor correction capacitors 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 6000
volts. These spikes could be caused by other equipment on the line or
by events such as lightning strikes.
– The power source has frequent interruptions.
2. 5 HP or Less Drives (in addition to “1” above)
– The nearest supply transformer is larger than 100kVA or the available
short circuit (fault) current is greater than 100,000A.
– The impedance in front of the drive is less than 0.5%.
If any or all of these conditions exist, it is recommended that the user 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.
The impedance can be calculated using the information supplied in either
the PowerFlex Reference Manual Vol. 2 or the technical document Wiring
and Grounding Guidelines, publication DRIVES-IN001.
Grounding Requirements The drive Safety Ground-PE must be connected to system ground.
Ground impedance must conform to the requirements of national and local
industrial safety regulations and/or electrical codes. The integrity of all
ground connections should be periodically checked.
Recommended Grounding Scheme
A single point (PE only) grounding scheme should be used. Some
applications may require alternate grounding schemes, refer to the Wiring
and Grounding Guidelines for PWM AC Drives, publication number
DRIVES-IN001 for more information. These applications include
installations with long distances between drives or drive line-ups, which
could cause large potential differences between the drive or line-up grounds.
For installations within a cabinet, a single safety ground point or ground bus
bar connected directly to building steel should be used. All circuits
including the AC input ground conductor should be grounded
independently and directly to this point/bar.