Table of Contents
Advertisement
Surge Protection
Due to potentially high-current surges that occur when switching inductive
load devices, such as motor starters and solenoids, the use of some type of surge
suppression to help protect and extend the operating life of the relays is
recommended. By adding a suppression device directly across the coil of an
inductive device, you prolong the life of the outputs. You also reduce the effects
of voltage transients and electrical noise from radiating into adjacent systems.
Figure 36
shows an output with a suppression device. We recommend that you
locate the suppression device as close as possible to the load device.
For outputs that use 24V DC, we recommend 1N4001 (50V reverse voltage)
to 1N4007 (1000V reverse voltage) diodes for surge suppression for the OSSD
safety outputs
(Figure
the load coil.
For outputs that use 120V AC or 240V AC, we recommend metal oxide
varistors.
Figure 36 - Surge Protection Examples
Metal oxide varistors
for V AC supply
K1
K2
V common
Rockwell Automation Publication 440R-UM015C-EN-P - April 2018
31). The diode must be connected as close as possible to
Diodes
for V DC supply
K1
K2
V common
Power, Ground, and Wire
Chapter 4
47
Advertisement
Table of Contents
