Step 4: power wiring, Grounding requirements, Recommended grounding scheme – Rockwell Automation 21G PowerFlex 750-Series AC Drives User Manual

Page 131: Step 4: power

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Rockwell Automation Publication 750-IN001N-EN-P - April 2014

131

PowerFlex 750-Series AC Drives

Step 4: Power Wiring

Most start-up difficulties are the result of incorrect wiring. Every precaution must
be taken to assure that the wiring is done as instructed. All items must be read and
understood before the actual installation begins.

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 Wiring and Grounding
Guidelines for Pulse Width Modulated (PWM) AC Drives, publication

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.

Figure 78 - Typical Grounding

ATTENTION: The following information is merely a guide for proper installation.
Rockwell Automation, Inc. cannot assume responsibility for the compliance or the
noncompliance to any code, national, local or otherwise for the proper installation of
this drive or associated equipment. A hazard of personal injury and/or equipment
damage exists if codes are ignored during installation.

U (T1)

V (T2)

W (T3)

R (L1)

S (L2)

T (L3)

SHLD

PE

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