Rockwell Automation 1764-xxxx MICROLOGIX 1500 PROGRAMMABLE CONTROLLERS User Manual
Page 55
Publication 1764-UM001B-EN-P - April 2002
Wiring Your Controller 3-5
If you connect an expansion I/O triac output to control an inductive
load, we recommend that you use varistors to suppress noise. Choose
a varistor that is appropriate for the application. The suppressors we
recommend for triac outputs when switching 120V ac inductive loads
are a Harris MOV, part number V175 LA10A, or an Allen-Bradley MOV,
catalog number 599-K04 or 599-KA04. Consult the varistor
manufacturer’s data sheet when selecting a varistor for your
application
For inductive dc load devices, a diode is suitable. A 1N4004 diode is
acceptable for most applications. A surge suppressor can also be used.
See the table on page 3-6 for recommended suppressors.
As shown in the illustration below, these surge suppression circuits
connect directly across the load device.
Surge Suppression for Inductive ac Load Devices
Output Device
Output Device
Output Device
Varistor
RC Network
Surge
Suppressor
Surge Suppression for Inductive dc Load Devices
Output Device
Diode
_
+
(A surge suppressor can also be used.)