Input power conditioning, Grounding requirements, Recommended grounding scheme – Rockwell Automation 20Y PowerFlex Active Front End User Manual

Page 59

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Rockwell Automation Publication 20Y-UM001E-EN-P - July 2014

59

AFE in IP21 Rittal Enclosure—Installation/Wiring

Chapter 2

Input Power Conditioning

Certain events on the power system supplying an AFE can cause component
damage or shortened product life. This includes the following events:

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 can be caused by other equipment on the line or by events
such as lightning strikes.

The power source has frequent interruptions.

Grounding Requirements

The Active Front End 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. Check the integrity of
all ground connections periodically.

Recommended Grounding Scheme

For installations in which the AFE is within an enclosure, use a single safety
ground point or ground bus bar connected directly to building steel. All circuits
including the AC input ground conductor must be grounded independently and
directly to this point or ground bus bar.

Figure 26 - Typical Grounding Example for AFE Frame 10 in IP21 Rittal Enclosure

DC+
DC-

DC+
DC-

PE

PE

R (L1), S (L2), T (L3)

U (T1), V (T2), W (T3)

PE

Customer wiring required to
connect the AFE to the drive.

SHLD

PowerFlex 700AFE (Frame 10

shown in IP21 Rittal enclosure)

PowerFlex 750-Series Drive or PowerFlex 7-Class Drive
(PowerFlex 700S Frame 10 drive shown)

To Line PE

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