[chbot] Matthias Wandel, and his amazing exploding SSR

[Richard Jones]

I'm planning some 10A resistive load switching based around moc3043 and
bta41 along the lines published by open energy monitor. I'll let you know
how I get on when the parts arrive. For PCB layout I'll be looking for 6mm
separation between mains and low voltage side, re-enforcing the current
carrying tracks with 1mm2 copper wire, and treating the low voltage side as
live for good measure.

Richard

On Thu, 23 Aug 2018 10:59 Volker Kuhlmann, <list0570 at paradise.net.nz> wrote:

> On Thu 23 Aug 2018 06:33:39 NZST +1200, Mark Atherton wrote:
>
> > https://www.youtube.com/watch?v=FV9t1GFVbhU
> >
> > What happens when you try and control a 22A electric water heater
> > (presumably 120+120V in Canada) using a cheap 25A solid state relay.
>
> Oops, thanks for posting that. I had similar plans, although with a bit
> more protection. I have 2 100A versions here... but got them from
> Aliexpress, so they must be good, right...? US$18/2.
>
> Digikey has Omron G3NA series for around US$100+, and they require a
> massive heat sink.
>
> The bipolar load switching creates a significant voltage drop. Another
> list member reported that the SSR got only lukewarm without heat sink
> when operated at 10A for the 40A version. Does anyone else have
> experience with this, and with which SSR model?
>
> The guy who took one apart is wrong on his electrical safety assessment
> though, there ain't 4mm clearance on that PCB...
>
> 25-40W power loss, big heat sink, 20mA permanent leakage (that's more
> than an old wirewound transformer), me thinks a mechanical relay might
> be better...
>
> Volker
>
> --
> Volker Kuhlmann
> http://volker.top.geek.nz/      Please do not CC list postings to me.
>
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