Re: Relay and the surge current

In article <24TSg.6808$vJ2.5643@xxxxxxxxxxxxxxxxxxxxxxxxxx>,
Vladimir Vassilevsky <antispam_bogus@xxxxxxxxxxx> wrote:

Hello All,

I need to run non-repetitive high current pulses (~1kA, ~100us) through
the contacts of the conventional electromagnetic relay.

How can I estimate the safe limit (t*I^2 or something else) for the
relay contacts?

The contacts are closed during the surge. No switching at that time.

In the datasheets for the relays, they always provide only the maximum
current limited by arching when switching.

Can we suggest that a relay rated at 10A, 220V will sustain eventual
pulses of 1kA x 100us ?

Any ideas?

Vladimir Vassilevsky

DSP and Mixed Signal Design Consultant

http://www.abvolt.com

It's the surface contact area that is important. You have to know what
the current density is. If it's high enough, it will melt the contact
metals at the contact points. If this fused area is large enough, the
contacts may not separate when you want them to.

Al
.

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