Rockwell Automation System Design for the Control of Electrical Noise - Manual (Page 59)

Publication GMC-RM001A-EN-P — July 2001
Chapter
7
Power Distribution
Chapter Objectives This chapter describes bonding, segregating, shielding, and filtering
techniques when routing AC and DC power. This chapter covers the
following topics:
• Understanding noise in power wiring
• Three-phase power supplies
• Single-phase power supplies
• 24V dc power supplies
Understanding Noise in
Power Wiring AC and DC power wiring usually extends to all parts of a system.
Without precautions, noise coupled into any power wiring conductor
is distributed throughout the entire system.
Three-Phase Power
Supplies To avoid noise related problems caused by three-phase power
supplies, observe the following guidelines.
• Treat three-phase wiring as dirty.
• Include line filters for loads that create noise, such as PWM
devices.
Line Filters
Observe the following guidelines when installing line filters.
• Install an individual filter as close as possible to each PWM load
(this is the preferred configuration).
• Install the filter and PWM device on the same panel.
• Treat wiring between filter and drive as very-dirty (provide
shielding as required).
• Segregate input and output wiring as far as possible.