Relay Contact Arc Preventer

KatyBri

It is common practice to put·something across the contacts of a mechanical relay to prevent them from arcing when they operate.

If you have a relay with contacts rated at 5A, and have a load of 120VAC with 3A current, what devices would "snub" the arcing?

Thanks

Beau Schwabe

Is this when the contacts come together or when they separate?

If it's when they come together, this indicates a large amount of inrush current. In this case, the arching can be minimized by
increasing the number of contacts (Several contacts that are in parallel).

If the arching happens when the contacts separate, this indicates a large inductive load, and can be minimized by placing a
reverse biased diode across the inductive source and/or a small (.047uF) capacitor across the relay contacts.

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Beau Schwabe

IC Layout Engineer
Parallax, Inc.

SteveD

I have some manufactered "snubbers" 10um cap with 330 ohm resistor to be place across the contacts. Let me know if you want them or you can make your own.
Steve