Rockwell Automation 1398-DDM-xxx ULTRA 100 Series Drives Installation Manual - Manual (Page 277)

Publication 1398-5.2 – PDF 1997
Electromagnetic Compatibility Guidelines for Machine Design E-4
AC Line Filter Selection
Selection of the proper filter is only the first step in reducing
conducted emissions. Correct filter installation is crucial to achieving
both EMI attenuation and to ensure safety. All of the following
guidelines should be met for effective filter use.
1. The filter should be mounted to a grounded conductive surface.
2. The filter must be mounted close to the drive input terminals, par-
ticularly with higher frequency emissions (5-30 MHz). If the dis-
tance exceeds 600mm (2 feet), a strap should be used to connect
the drive and filter, rather than a wire.
3. The wires connecting the AC source to the filter should be
shielded from, or at least separated from the wires (or strap) con-
necting the drive to the filter. If the connections are not segregated
from each other, then the EMI on the drive side of the filter can
couple over to the source side of the filter, thereby reducing, or
eliminating the filter effectiveness. The coupling mechanism can
be radiation, or stray capacitance between the wires. The best
method of achieving this is to mount the filter where the AC
power enters the enclosure. “AC Line Filter Installation” shows a
good installation and a poor installation.
Figure E.2 AC Line Filter Installation
Intro
AC
LINE
RADIATED
EMI
DRIVE
RADIATED
EMI
FILTER
CONDUCTED EMI
CONDUCTED EMI
POOR
AC
LINE
DRIVE
RADIATED
EMI
FILTER CONDUCTED EMI
GOOD