SLC 500™ Fixed Hardware Style Controllers
19
Publication 1747-IN008B-MU-P
Relay Contact Ratings
To calculate make and break ratings for other load voltages, divide the volt-ampere
rating by the load voltage. For example:
Using Surge Suppressors
Inductive load devices such as motor starters and solenoids require the use of some
type of surge suppression to protect the controller output contacts. Switching
inductive loads without surge suppression can
significantly
reduce the lifetime of
relay contacts. By adding a suppression device directly across the coil of an inductive
device, you will prolong the life of the switch contacts. You will also reduce the
effects of voltage transients caused by interrupting the current to that inductive
device, and will prevent electrical noise from radiating into system wiring.
Maximum
Volts
Amperes
Amperes
Continuous
Volt-amperes
Make
Break
Make
Break
240V ac
7.5A
0.75A
2.5A
1800 VA
180 VA
120V ac
15A
1.5A
125V dc
0.22A
1.0A
28 VA
24V dc
1.2A
2.0A
28 VA
28 VA
48V dc
-----------------
0.583 A
=
Summary of Contents for SLC 500 1747-L20
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