Rockwell Automation System Design for the Control of Electrical Noise - Manual (Page 60)

Publication GMC-RM001A-EN-P — July 2001
7-2 Power Distribution
Commercial filters are tested, as shown in the figure below, with all
devices properly bonded to a conductive metal ground plane. Proper
bonding techniques are essential to achieve the published attenuation
figures. Refer to the chapter High Frequency (HF) Bonding for more
information on bonding.
Figure 7.1
Filter test set-up
In the example below, noise couples directly from the filter input
wires to the filter output wires and bypasses the filter. You can avoid
this common mistake by shielding and/or segregating the cables and
reducing the cable length.
Figure 7.2
Improper line filter installation example
IMPORTANT
The effectiveness of the line filter depends solely on
the HF bond between filter case and drive chassis.
Measuring
Instrument Signal
Generator
Filter under test
Ground Plane - conductive metal panel
AC Line
Close spacing
Unshielded cable
Long distance
PWM Drive
AC
Line Filter
ATTENTION
!
To avoid personal injury and/or damage to
equipment, ensure AC line filter capacitors are
properly connected to safety (PE) ground.