Heat sink.

[Oilybloke]

Morning all, can anyone let me know how the heat sink should be wired to the thermocouple/pid?

Many thanks,
Nick.

[therecklessengineer]

You need some sort of heat sink on the SSR. It doesn't need to be massive - I've just bolted mine to the metal cabinet that houses it.

[julianf]

If youre keen, sand both surfaces, so you know theyre flat, and then use thermal transfer paste to fill in the micro-holes (or whatever the term is!)

[Tony]

Mine is just bolted (with thermal paste) to the aluminium box it's in, it only gets slightly warmer than ambient.

[therecklessengineer]

A very quick back of envelope calculation puts the heat dissipated by the SSR at just under 10W with a 3kW load.

It's really not that much.

[Julian]

A very quick back of envelope calculation puts the heat dissipated by the SSR at just under 10W with a 3kW load.

It's really not that much.

That's useful info.

We don't yet have an SSR page, but do you mind if I start a WIP page with that info?

[Head Womble]

Please use my photo of a cheap copy SSR that melted,



This was mounted on a heat sink and thermal paste was used,
it's 20A rating so should have handled the load with any problems.

[Julian]

Would be good to use that, thanks Mark.

You're an expert in uploading photos now so you doing it would save me the trouble of saving it to my PC and up loading.

Was that the one I gave you?

[Head Womble]

Would be good to use that, thanks Mark.

You're an expert in uploading photos now so you doing it would save me the trouble of saving it to my PC and up loading.

Was that the one I gave you?

Ok I see if I can remember how to do it, I sure I can, I think.
I have three or four photos of it, I upload all of them so you can choose which ones you want.

No it's not the one you gave me (that one didn't work if you remember) as it was to replace the one that burnt out.

I'll see if I can find the thread I put on VOD to get more info on the unit it's self.

[Head Womble]

This is where I got it from

 http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=300...

At 99p I should have known better.

[1958steveflying]

Was it mounted in a box Mark ? can't quite work out from the picture.

[Head Womble]

Yes, it was mounted in a box, on a heat sink with heat transfer paste and hole drilled in the box for ventilation.

I can't upload the pics are the file is too large !
How do I reduce the file size ?

[Julian]

Yes, it was mounted in a box, on a heat sink with heat transfer paste and hole drilled in the box for ventilation.

I can't upload the pics are the file is too large !
How do I reduce the file size ?

Don't think they are too big.  If I'm not getting confused with my bytes, the one you posted above is less than 0.1 meg and the wiki will accept 2 meg files.

I sometimes have trouble uploading as the system appears to time out.  Give it another bash.

[Head Womble]

The files are all over 2MB, over the permissible size.

[julesandtash]

On my panel,  just cleaned the pain off of the steel enclosure down to bare metal then tightly bolted the (decent quality) SSR to it with some computer heatsink paste in between.

It then has a 600mm X 600mm X 150mm steel cabinet as the heatsink. Strangely enough it really doesn't get warm, even when carrying 3KW for three of four hours continuously (ie heating up 800litres of oil from current ambient temps to 70C)