New heatsinks for my upcoming Aleph 5

[elizard]

Oh yes, before I can do a rough sketch, question.
Do I use 4x33,000uF caps? or 6? or 8?
6 i can fit great, that gives 198,000uF of capacitance for the PS .. should be just fine, right?

 

[roddyama]

I would use either 4 or 8. Rt ch +/- and Lt ch +/-. Do a search on PSU and CLC. There's a lot of info on powersupplies.

 

[mbroker]

You could <gasp> cut the sinks in half. Ok, maybe not.

Somewhere on this site I vividly remember (but cannot locate) the recommendation to place devices towards the top of a heat sink. The rationale is that the air is heated less at the bottom of the sink if the devices are near the top, allowing for more effective use of the long sinks. I'm not sure it would make more than a degree or two of difference, though.

www.rtheta.com has a nice online heatsink simulator in their "R-Tools" section. You can find a similar extrusion in their catalog, I'm sure, though I think you can input the specs for non-cataloged items (like yours).

Best regards,

Mark Broker

 

[elizard]

Heh, doesn't work for me at work. Stupid firewall, I'll do it at home.

Also, where can I get feet like Pedro's?

An externally hosted image should be here but it was not working when we last tested it.

Something along those lines anyaway?

 

[vsr123]

Heatsink Rating

Elizard and others - I tried rating the heatsink that was posted here by inputting the dimensions into Rod Elliots Heatsink calculator and I am just not coming up with a rating of anywhere close to 0.25 C/W. Can anyone tell me how they calcuated the rating of this heatsink?

thanks
vsr

 

[elizard]

20 fins, fin length is 13.25", fin depth 1.25", length 13", width 7", emissivity 0.85, ambient 25, max heatsink temp 50

i don't think i mixed up the dimensions, i don't have the diagram in front of me though

 

[elizard]

Well, i'm feeble, and don't know how to properly simulate it. So if someone is kind enough to give it a try.

When I try, all the temperatures are 25C. Strange

 

[faustian bargin]

try the heatsink selector worksheet thingie on aavid thermalloy's site. they have a lot of profiles, you'll probably find one that matches.

/andrew

 

[trigon]

If it is not to much work you can try this way to mount the IRFs


Trigon

 

[elizard]

i like your way of mounting trigon, i saw it in a post somewhere earlier too

btw, these heatsinks are available, the guy has some 80ish available, and they're $15/each, $3 extra for him to pick out the best ones (they are used heatsinks, and do have holes drilled in them. the final verdict will be when i receive them)

 

[elizard]

can someone suggest a good program that i can make a 3-d model of the chassis? Something not super hard to learn.

I've never used 3-d studio max, that's a possibility, any suggestions?

 

[JOE DIRT®]

autocad desktop mechanical maybe>???

 

[faustian bargin]

here's what i found on aavid thermalloy (LINK) - it looks almost exactly like your heatsink. 0.56°C/W rating, but with a distributed load they say you get a 10% improvement in performance, so figure about 0.50.

Here's another shot of it:

 

[elizard]

here's what i found on aavid thermalloy (LINK) - it looks almost exactly like your heatsink. 0.56°C/W rating, but with a distributed load they say you get a 10% improvement in performance, so figure about 0.50.

0.56 .. eeep!
that's a little too much .. i figured i'd need about 0.4 each heatsink, so 0.1 in total (4 sinks) .. hmmz, i guess we'll wait and see

 

[faustian bargin]

if all you want is a model, vanilla autocad will do the job. if you want to do a little barter , i can model it for you. (i'm an architect so i'm CAD-competent.)

/andrew

 

[elizard]

mmm bartering .. well, i've little to offer, so i'm not sure what i'd offer you

how about .. i'll be very thankful .. heh

 

[faustian bargin]

well...since we're talking about heatsinks, i've had my eye on the extrusions at MECI for a long time, just never got around to making a purchase...i need 4 of the $10 ones for my zenV4 project...

of course it doesn't really count as a 'barter' if you don't already have them on hand to offer, so you could just pay me 50 bucks or so...

but if you have access to any decent cad software with 3d capability, i say give it a shot yourself. it's not THAT hard to learn on your own, just takes time.

/andrew - wheelin and dealin

 

[elizard]

well, time i have .. access to software i can get .. patience, well its about as short as the money!!!

i'll try it myself though, see what i can get out of it