Rockwell Automation 1336T Wiring and Grounding Guide, (PWM) AC Drives - Manual (Page 78)

78 Rockwell Automation Publication DRIVES-IN001M-EN-P - March 2014
Chapter 6 Electromagnetic Interference
Putting resistor-capacitor (RC) networks or voltage-dependant resistors
(varistors) across contacts can mitigate transient interference. Be sure to select
components rated to withstand the voltage, power, and frequency of switching
for your application.
A common method for mitigating transient interference is to put a diode in
parallel with an inductive DC load, or a suppressor in parallel with an inductive
AC load. Be sure to select components rated to withstand the voltage, power, and
frequency of switching for your application.
AC AC Load Load
IMPORTANT These methods are not totally effective at stopping transient interference,
because they do not entirely eliminate arcing at the contacts.
DC
+
-
AC AC
Load
Load Load