Biopowered - vegetable oil and biodiesel forum
Biodiesel => Biodiesel equipment => Topic started by: Oilybloke on March 18, 2013, 05:35:27 AM
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Morning all, can anyone let me know how the heat sink should be wired to the thermocouple/pid?
Many thanks,
Nick.
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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.
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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!)
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Mine is just bolted (with thermal paste) to the aluminium box it's in, it only gets slightly warmer than ambient.
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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.
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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?
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Please use my photo of a cheap copy SSR that melted,
(http://i250.photobucket.com/albums/gg264/mark405td/IMGP0003.jpg)
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.
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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?
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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.
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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.
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Was it mounted in a box Mark ? can't quite work out from the picture.
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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 ?
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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.
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The files are all over 2MB, over the permissible size.
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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)
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The files are all over 2MB, over the permissible size.
Maybe the forum software re sizes them for faster loading ... not sure, all a little beyond me, but I can re size them for you. Can you send them to me by by email?
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Resizing thread.
http://www.biopowered.co.uk/forum/index.php/topic,271.15.html
i used MS paint, or PC paint brush. i don;t recall which. Not to sure how I did it either, just physically shrink the picture, I think.
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Guys, many thanks for the replies. So am I right in thinking that it doesn't actually need to be connected or wired to anything, it is merely a way of dissipating heat from the control box? A la fins on an air cooled motor?
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Guys, many thanks for the replies. So am I right in thinking that it doesn't actually need to be connected or wired to anything, it is merely a way of dissipating heat from the control box? A la fins on an air cooled motor?
Yes the heat sink is just that.
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Guys, many thanks for the replies. So am I right in thinking that it doesn't actually need to be connected or wired to anything, it is merely a way of dissipating heat from the control box? A la fins on an air cooled motor?
Exactly that. However, if it's in contact with a metal housing that you can touch then make sure it's earthed.
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Julian, I've sent them to your website email address.
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Julian, I've sent them to your website email address.
Got them, thanks.
I'm off down the pub for a curry and quiz, so I'll sort them out tomorrow.
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Guys, many thanks for the replies. So am I right in thinking that it doesn't actually need to be connected or wired to anything, it is merely a way of dissipating heat from the control box? A la fins on an air cooled motor?
Exactly that. However, if it's in contact with a metal housing that you can touch then make sure it's earthed.
Very good point, what that man said - if it's metal - earth it!
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The transfer paste we use at work is call Dow Corning, or if you want to pass electricity through it we use bicon X1.
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The transfer paste we use at work is call Dow Corning
Id like to think everyone knows this anyhow, but just in case...#
Dow Corning make loads of things, and not everything pasty would transfer the heat : )
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Guys, many thanks for the replies. So am I right in thinking that it doesn't actually need to be connected or wired to anything, it is merely a way of dissipating heat from the control box? A la fins on an air cooled motor?
If your control box is aluminium (which a lot are) then i (personally) would not bother with a heat sink, providing the aluminium section is reasonably large.
Most sinks are made of al and, whilst they have fins etc. the heat we're talking about isnt vast, and a decent area of al case would dissipate the heat also.
Or...
If you dont feel confident with that, look out for an old computer psu. Crack it open, and harvest the heat sinks from it.
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...here's the remains of some e-scrap i killed earlier -
(http://www.biopowered.co.uk/forum/index.php?action=dlattach;topic=1068.0;attach=32;image)
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