Air Cooling

[Jordan A.]

This being my first FIRST year I have been relying heavily on you guys for some info. However now that our team has gotten to the cooling stage of our design I figure I could help you guys out for a change (not all of you, perhaps not any of you, but I'll try)

I have been an avid "Overclocker" for a few years now (Overclocking is running your computer processor faster than it is rated.) Because overclocking makes your computer run hot you must know a bit about cooling in order to make it work well. Now watercooling is bar far the most fun and best way of cooling for the average person, but since the rules forbid it I will do my best to let you in on some air cooling info.

When thinking of cooling you have to think of it as a whole system. Everything works together to get the maximum air flow. Just sticking fans here or there will not give you the best results you actually have to plan.

Take an inventory on the fans, find out what you have, what CFM they provide (CFM=cubic feet per minute) and then plan accordingly.

Enclosure dynamics are great, you can use an enclosed area in order to direct the air flow in ways you want it. The key is to have as much CFM on intake as you do on outake. For example, say you have a 100cfm fan, a 50 and 2 25's you want to have the 100 going in our out and the other 3 doing the opposite.

Another concept I dont like but has been used is "brute forcing" the idea is you direct ALL your fans as intake and let holes in your enclosure act as the exaust based on the presure built up from the fans. While it works you dont get as high an air flow as you would like.

When designing your air flow take into account where the air goes after it cools a component. It will be hotter than it was comming in. You dont want air going over a really hot motor and then to a speed controller because the motor would heat it up faster than the vic would. Also blowing across something is alot better than down on it. If you blow down on something the exaust from that will generaly spin around into air streams you dont want it to. You can occasionaly get kinds of loops where air is pushed onto something spun back around back into the same stream just getting hotter. Not a good way to cool.

Final concept I'll subject you to is a pretty basic one. Hot air rises. Exausts on the top and intakes on the bottom tend to work the best.

I realize that most teams will be screaming "COOLING SYSTEM!!! We have to worry about our DRIVING system!" and I understand, I really dont think out team is going to have the time to impliment a good one. But its something to think about.

-Jordan Armstrong ~who can't wait for FIRST to legalize water cooling so he can design a cooling jacket for the chipuahs

[KennethToronto]

hehe...I've been an avid o/c for along time as well..

in fact..my favourite webpage is www.hardocp.com - home to a very very large community of computer enthusiasts.

Right now...I'm thinking how cool it would be to make a copper heatsink enclosure for our robot's drivetrain motor..mmmm....

[Jordan A.]

Funny you mention [H], im a '[H]ard|Gawd" on the [H]|F

[Matt Reiland]

I posted the info for Aluminum Heatsinks in another thread if you really need some cooling

[Andrew Dahl]

actually the easiest and most effiecent way to handle cooling is to have air being pulled into the enclosure and pulled out by the fans

inorder to have this work right without having hot air pulled over other devices is to have two fans ported on different faces of the enclosure

example:

a box
have one fan on the top and another on a side

you will get max aiorflow around all components and not hae to worry about heated air fouling the mix



dahl

[Wetzel]

OR you can just make your robot go really fast and air cool the entire thing...
But overheating the motors happens, and Radio Shack sells some componet colant in a spray can that you can use during driver training or in between matches.

[Scott358]

Anyone heard of "canned cooling" (between matches) doing damage to the motors?

Someone had mentioned this last year.

Scott358

[Joe Johnson]

... but we do it anyway!

We are huge consumers of cool in a can. We use it all the time on Saturdays of the competition.

It is probably very bad for the motors, but when have we every worried about the fate of these motors? If we really cared about them, we wouldn't heat them up in the first place, would we? ;-)

Joe J.

P.S. Our favorite brand is Chemtronics' Freez-IT



Chemtronics.com

[Adam Krajewski]

After three years of experimenting with cooling systems on the drill motors, I've found that a simple, passive heat sink in the form of an aluminum motor mount (then to an aluminum chasis/baseplate) provides the best 'bang for the buck'. Actively cooling the motor mount/heat sink with a muffin fan provides a small amount of heat reduction, but it is to a much smaller extent when compared with the addition of a passive heat sink. A good thermal grease would certainly help, but I've never used it on a robot motor (yet). I may try a little Arctic Silver in between the drill motors and their heat sinks to improve heat dissipation, but even without it, you'll feel all kinds of heat being shed off into a well-fitting mount (with the 'sleeve' removed, of course ;-) )

computer tangent:
[H]ard|Forum user from the beginning. I only use Alphas for air cooling (with AS and ASII) and am working on getting into water cooling once the Coldforge AA-15 cases are available (and I have the money).
Current rig:
Athlon XP 1700+ (1.43GHz) @ 1.66Ghz w/ Alpha PAL8045 and ASII
512MB Corsair PC2100
Soyo Dragon plus w/ FasTrak 100 'full' BIOS flash
Radeon 8500 OEM w/ retail BIOS flash

[Wetzel]

Is Artic Silver considered a fastener?

Love my Soyo Dragon and Athlon XP 1700...not overclocked but still plenty fast....

[Adam Krajewski]

The epoxy certainly would be... If I get the chance, I was planning on trying the normal AS thermal grease, if it cools down the motors enough, then use the epoxy. If not, it's easier to get off than the epoxy.

[James Crivellone]

Originally posted by Jordan A.
Funny you mention [H], im a '[H]ard|Gawd" on the [H]|F

wuts you SN? I bet that you know who I AM! haha\

name in sig =)

[Jnadke]

Is it just me or is it getting a bit geeky in here?

[Al Skierkiewicz]

We also have used "freeze spray" on over heated components but please remember that many of these products are freon based. As such, freon is an effective degreaser and should be applied with care near motor bearings and gearboxes. Also consider the thermal shock to sensitive components like plastics. Finally, using freeze spray in Florida (or other humid regions) will cause condensation on electrical parts for a short period of time. Let the parts reach ambient temps before applying power.
Good Luck,

[Jordan A.]

James, im J-Muff, your the crazy kid who took a picture with Kyle and then got nailed with a photochop right?