# Computer Case Fan for Motor Cooling



## Ziggythewiz (May 16, 2010)

Typically no. A big computer case fan is designed to dissipate a few thousand watts. A motor fan is dissipating 10-50 times that.

The biggest difference is that a PC fan is pushing air over cooling fins (which works for a motor controller) while a motor blower must have much more pressure to push the air through the brushes and tight motor workings.

It all depends on the pressure, you can always try it out and measure the difference.


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## jeremyjs (Sep 22, 2010)

Ziggythewiz said:


> Typically no. A big computer case fan is designed to dissipate a few thousand watts. A motor fan is dissipating 10-50 times that.
> 
> The biggest difference is that a PC fan is pushing air over cooling fins (which works for a motor controller) while a motor blower must have much more pressure to push the air through the brushes and tight motor workings.
> 
> It all depends on the pressure, you can always try it out and measure the difference.


I agree. Volume of flow is just one way to measure a fan. Blade fans like what are used in computer cooling generally don't have a very high static pressure. I have no idea what the modified turbo ones that evtv uses static pressure is, but you can bet it's much much higher than any standard bladed fan's is. No PC fan I've ever seen can push 2-3 atmospheres through an engine.


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## Yabert (Feb 7, 2010)

Hi Yukon

I think you need this blower: http://www.detmarcorp.com/blowers.htm
I use it with a conical air filter and it work great. They are cheap at 20-30$ on ebay.


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## Yukon_Shane (Jul 15, 2010)

Well that would explain it. 

Thanks guys


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## jeremyjs (Sep 22, 2010)

you'd be better off using a centrifugal blower of one type or another. they genarally have a much better static pressure.


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## Ziggythewiz (May 16, 2010)

Yabert said:


> Hi Yukon
> 
> I think you need this blower: http://www.detmarcorp.com/blowers.htm
> I use it with a conical air filter and it work great. They are cheap at 20-30$ on ebay.


That's the style I have. It won't push as much air as a a squirrel cage, but it's more than adequate for me. Obviously your cooling requirements depend on your usage and the weather. Total system cost was around $50. If I had gone with the 3" blower it would have been cheaper/easier and I think still adequate for me.


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## skooler (Mar 26, 2011)

Hi,

I am toying with just this at the moment, I'm not convinced by it but its worth a go!

The fallback if it doesnt work is a turbo blower or squirell cage.

I am using 6 x 60mm server fans. Each will push 40-60CFM straight onto the armature.

Will post a propper update once I have it installed nd know how it works.

Pictures below.


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## Ziggythewiz (May 16, 2010)

Armature or brushes?


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## skooler (Mar 26, 2011)

Ziggythewiz said:


> Armature or brushes?


sorry, commutator.

The fans will blow straight onto the brushes.

Cheers,

Mike


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## onegreenev (May 18, 2012)

Yes, I know of one who has successfully done this. Check out this Bug. It is an excellent build and he drives it daily and has done so for many many years. I got my first EV ride in this EV. 

http://public.fotki.com/WAYNEWANG/electric-car-beetle-ev-/


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## Ziggythewiz (May 16, 2010)

I think weak fans on the brushes are likely adequate since thats where the real cooling is necessary. However, don't you have 4 sets of brushes? Also, you may find power and noise to be similar to a single, larger blower.


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## skooler (Mar 26, 2011)

Ziggythewiz said:


> I think weak fans on the brushes are likely adequate since thats where the real cooling is necessary. However, don't you have 4 sets of brushes? Also, you may find power and noise to be similar to a single, larger blower.


Sorry, was this question aimed at me?

I think It'll work, like you said, its the brushes that need the most cooling so forcing 'cold' air into the motor, past the brushes and through the motor should work. 

I do have 4 sets of brushes, I dont have clearance all the way around the motor so unfortunately the top brush misses out! The access hole will be covered up, i dont see this s any different to using a blower.

I will see how it goes. I'm by no means 100% confident with it but its worth a shout.

Cheers,

Mike


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## Ziggythewiz (May 16, 2010)

Ok. Are you able to get a laser thermometer pointed at it, or is there no clearance for that?


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## skooler (Mar 26, 2011)

Ziggythewiz said:


> Ok. Are you able to get a laser thermometer pointed at it, or is there no clearance for that?


Do you mean a temperature gun like

http://www.ebay.co.uk/itm/Digital-I..._Measurement_Equipment_ET&hash=item4ab4fae8cd

If so - Yeah, could do....

There is plenty of clearance on all sides of the motor except for the top as this is where the component shelf is. I have about 40mm of clearance.


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## Ziggythewiz (May 16, 2010)

Yes, it would be good to check that brush compared to the others a few times to compare the temps. Before the shelf is permanently affixed you'll want to see if you can see the high temps by shooting around it. Basically you want to point it at the brushes and move it around to observe the highest temp. Of course, this requires whatever you have covering the access hole to be easily removeable.


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## skooler (Mar 26, 2011)

Ziggythewiz said:


> Yes, it would be good to check that brush compared to the others a few times to compare the temps. Before the shelf is permanently affixed you'll want to see if you can see the high temps by shooting around it. Basically you want to point it at the brushes and move it around to observe the highest temp. Of course, this requires whatever you have covering the access hole to be easily removeable.


Yeah I agree, I'llgo and purchase the temp sensor...

Cheers,

Mike


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