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From: Don Kuenz <g@crcomp.net>
Newsgroups: sci.electronics.design
Subject: Re: AC switch fault current philosophy
Date: Wed, 3 Jan 2018 17:57:27 -0000 (UTC)
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Tim Williams <tiwill@seventransistorlabs.com> wrote:
> "Don Kuenz" <g@crcomp.net> wrote in message news:20171228b@crcomp.net...
>> You might limit the current and trip the mains breaker to cope with the
>> short. That way you simultaneously protect the shorted device and send
>> users a dramatic message that something's wrong.
>
> How does that work?
>
> If you have a shunt coil to trip the breaker separately (like a lot of
> UL1077 breakers do, or the guts of a GFCI receptacle), you can open the
> circuit without drawing fault current.  Though that still won't act fast
> enough to save a transistor (not without a switching mechanism like I
> described, anyway).

Is it possible to separate the current limit functionality from the
mains breaker trip? Limit the current first and always, sense an over
current state, and then leisurely use a low voltage to trip the mains
breaker a few cycles later?

Thank you,

--
Don Kuenz, KB7RPU