Rockwell Automation 1336T Wiring and Grounding Guide, (PWM) AC Drives - Manual (Page 25)

Rockwell Automation Publication DRIVES-IN001M-EN-P - March 2014 25
Chapter
2
Power Distribution
This chapter discusses different power distribution schemes and factors that can
affect drive performance.
System Configurations The type of transformer and the connection configuration feeding the drive have
an important role in drive performance and safety. This section includes a brief
description of some of the more common configurations and their qualities and
shortcomings.
Delta/Wye with Grounded Wye Neutral
Delta/Wye with Grounded Wye Neutral is the most common type of
distribution system. It provides a 30° phase shift. The grounded neutral provides
a direct path for common mode current caused by the drive output (see
Chapter 3 and Chapter 6 ).
Rockwell Automation recommends the use of grounded neutral systems for these
reasons:
• Controlled path for common mode noise current
• Consistent line-to-ground voltage reference that minimizes insulation
stress
• Accommodation for system surge protection schemes