SLC 500™ Fixed Hardware Style Controllers
21
Publication 1747-IN008B-MU-P
If you connect an SLC 500 controller 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 V220
MA2A, 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.
As shown in the illustration below, these surge suppression circuits connect directly
across the load device. This reduces arcing of the output contacts. (High transient
can cause arcing that occurs when switching off an inductive device.)
See page 103 for the physical dimensions and wiring diagrams of the SLC 500 Fixed
Controllers.
!
ATTENTION
Damage could occur to SLC 500 triac outputs if you use
suppressors having RC networks. Allen-Bradley ac surge
suppressors not recommended for use with triacs include Catalog
Numbers 199-FSMA1, 199-FSMA2, 1401-N10, and 700-N24.
-
+
Surge Suppression for Inductive dc Load Devices
Diode (A surge suppressor can also be used.)
Output Device
Summary of Contents for SLC 500 1747-L20
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