Source for this or similar heatsink - Page 1
Forum section: electronics / general

author: HooRide
author_rank: Regular Contributor
timestamp: November 12, 2012, 12:02:20 am
content: I am looking to rebuild a 30A power supply I built when i was 15 into a nicer (and safer) enclosure. I really liked the wind tunnel heat sink design that the BK Precision e-load had that we saw in Dave's tear-down and looked for a source for them. Ironically, the only source was in Australia. Anything in the US so I don't have to forgo eating for a week just to pay for shipping?http://www.jaycar.com.au/productView.asp?ID=HH8530&form=CAT2&SUBCATID=980#1

author: notsob
author_rank: Frequent Contributor
timestamp: November 12, 2012, 01:22:46 am
content: Do a search for something like 'aluminium extrusion heat sink', a quick look & I found Ullrich.com in Australia, who seem to have a similar profile, or for you, possibly wakefield.com in USA

author: rsjsouza
author_rank: Super Contributor
timestamp: November 12, 2012, 06:35:02 pm
content: I am not sure how many transistors you have to "freeze", but I am designing a 20A 12V fixed output power supply that has two TIP36C and I am using thisCPU heatsinkthat I had lingering around. Given that this heatsink kept my 125W CPU at around 60°C, this will be enough in my design, considering the Vce voltage drop, the current and the thermal derating of the transistors (basically the last graph atthis datasheet.You can find similar stuff everywhere at several price points (checkthis example), but always watch out the parameters above and make sure you have a good thermal connection between the devices and the heatsink.Quote from: AcHmed99 on November 12, 2012, 12:25:01 pmVery nice score!

author: Monkeh
author_rank: Super Contributor
timestamp: November 12, 2012, 07:30:54 pm
content: Quote from: rsjsouza on November 12, 2012, 06:35:02 pmTDP != actual power dissipation, by a long shot.

author: rsjsouza
author_rank: Super Contributor
timestamp: November 13, 2012, 04:43:03 am
content: Quote from: Monkeh on November 12, 2012, 07:30:54 pmYou are correct thatTDPis not always equal to the maximum dissipated power of a CPU , but that depends on how the manufacturer defines it.In my case my processor was an AMD Athlon 64 3500+ and they define it in a more "real" way than Intel (reference 1,reference 2).One thing I noticed is that my older processor was 89W instead of 125W - that may bring me back to the drawing board...

author: free_electron
author_rank: Super Contributor
timestamp: November 13, 2012, 04:53:41 am
content: try fisher electronics. or aavid thermalloy. they have tunnels and will cut to length even for 1 piece

author: Harvs
author_rank: Super Contributor
timestamp: November 13, 2012, 06:25:47 am
content: Quote from: rsjsouza on November 13, 2012, 04:43:03 amI've put 120W into a very similar looking Thermaltake cooler, as a CC load. It handled it fine and kept the mosfet case temps (two of) at around 65oC. Just don't let the fan stop, I thought I'd see what happened... At that power level, it only took a few seconds for the temps to skyrocket.For me, it was just too difficult mounting them though.

author: rsjsouza
author_rank: Super Contributor
timestamp: November 13, 2012, 12:33:39 pm
content: Quote from: Harvs on November 13, 2012, 06:25:47 amYep, that is the annoying part. I intend to do a threaded hole instead of using a nut and a bolt.

author: Monkeh
author_rank: Super Contributor
timestamp: November 13, 2012, 01:45:14 pm
content: Quote from: rsjsouza on November 13, 2012, 12:33:39 pmMm, threaded hole into a heatpipe, that sounds like a good move.

author: SeanB
author_rank: Super Contributor
timestamp: November 13, 2012, 04:51:02 pm
content: Just miss the pipes, not exactly hard to look at the 2 ends and avoid the piece. I just use the non heatpiped versions, and with low power you do not need a fan, though it will be good at over 15W.

author: Monkeh
author_rank: Super Contributor
timestamp: November 13, 2012, 06:09:12 pm
content: Quote from: SeanB on November 13, 2012, 04:51:02 pmReally? These look kinda hard to avoid.Welcome to modern heatsinks.

author: Monkeh
author_rank: Super Contributor
timestamp: November 13, 2012, 09:37:47 pm
content: Quote from: wilfred on November 13, 2012, 09:35:30 pmThey don't charge more for it, the basic physics back the design up, and the performance backs it up too.QuoteYou must hate yourself.

author: Unknown
author_rank: Unknown
timestamp: November 13, 2012, 11:29:46 pm
content: Quote from: wilfred on November 13, 2012, 09:35:30 pmHeat pipes were first introduced in notebooks (and before that in non-electronics applications). But since these don't typically have transparent cases, you wouldn't normally see them.Quote from: wilfred on November 13, 2012, 09:35:30 pmWeight savings are a real thing. Ask a mechanical engineer about the difference between rotating mass and static mass and their effect on performance. From memory, 1 kg of extra mass on the wheels is equivalent to 5 kg of extra static mass due to rotational inertia (don't remember under which conditions). In the case of suspension, unsprung mass vs sprung mass enters into the picture.

author: Tube_Dude
author_rank: Regular Contributor
timestamp: November 14, 2012, 01:00:44 am
content: Quote from: alm on November 13, 2012, 11:29:46 pmSony used them (with freon) back in 1979/1980, in the TA-F55 amplifier...http://seventiesstereo.blogspot.pt/2010/09/sony-ta-f55-integrated-amp.html

author: Tube_Dude
author_rank: Regular Contributor
timestamp: November 14, 2012, 03:39:37 am
content: Quote from: wilfred on November 14, 2012, 03:14:53 amMaybe it was more expensive to make than the normal extruded heatsinks, and don't add nothing in the "sound quality" department.At the time some more brand marks have used it in one or two models, but almost all had let it down.At the end of the day, just another case of technological exercise, so well suited for the marketing department brochures...

author: T4P
author_rank: Super Contributor
timestamp: November 14, 2012, 10:01:26 am
content: Using freon is a good idea in heat piping, you know, a air-conditioner depends on the coolant's rapid evaporation to cool the surrounding air down and they use pipes to transfer the coolant, so in heatsinks they are called "heat pipes" because all they do is pipe heat with a coolant (What's the name? I can't remember it)But in most heatsinks that aren't too high power they just use a liquid that doesn't evaporate i thinkThe reason AMD was able to efficiently pipe 300W of heat around their dual-GPU monster is due to something called a "vapor-chamber" (which essentially is a heat pipe filled with very volatile liquid (I mean something like the stuff they use for aircons?) without going over 80C in such a form factor

author: SeanB
author_rank: Super Contributor
timestamp: November 14, 2012, 11:19:34 am
content: Depends on the temperature and the distance as to what you use. For a PC cooler you can use methanol and make sure the charge is put into the system after a deep vacuum is pulled. You can then run at up to 70C with good results. Otherwise you will need a high pressure and use R600 ( propane) or R134A as the liquid. All depends on how much pressure you are willing to have in the sealed system as to the refrigerant you use. If you use a steel block you can get good results with R717 ( anhydrous ammonia) as the transfer medium.Heat pipes are basically an equilibrium at the hot side, the pressure adjusting to keep the liquid there boiling, and the vapour condensing at the cold side, then wicking back along the internal wick material ( a mesh layer on the wall that holds liquid by capillary action) to be evaporated again.

author: Harvs
author_rank: Super Contributor
timestamp: November 15, 2012, 10:23:18 am
content: I was sceptical about using CPU coolers with heatpipes until I tried it.With a standard aluminium plate and fin heatsink roughly double the dimentions of the CPU cooler, the MOSFETs being driven at 60W each would quickly overheat. Even using arctic silver transfer compound. I found that even with the ~10mm plate on the heatsink, the thermal resistance of the aluminum caused significant localised heating around the mosfets.So with a few people on this forum's recommendation I tried the CPU cooler, very similar to the one in this post. The difference was night and day. The effective heat transfer away from a concentrated area is awesome.To this day I'm still thinking about easy ways to clamp the MOSFETs in place. Current idea having seen mikeselectricstuff's video would be to make up some PCB plates.