Hach-Lange SI794 D User Manual - Manual (Page 20)

Protective wiring of relay contacts
Relay contacts are subject to electrical erosion. Especially with
inductive and capacitive loads, the service life of the contacts will
be reduced. For suppression of sparks and arcing, components
such as RC combinations, nonlinear resistors, series resistors, and
diodes should be used.
1
2
3
1 2
3
Typical AC applications
with inductive load
1 Load
2 RC combination, e.g. RIFA PMR 209
Typical RC combinations
for 230 V AC:
Capacitor 0.1µF / 630V,
Resistor 100 ohms / 1 W
3 Contact
Protective wiring of relay outputs
20