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inverting cooling fan connections

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expert87

Member
Joined
Feb 8, 2009
Location
Middle East
Hi;
My case has a total of 4 cooling fans....the thing is that they all kick the air out of the case....and i was thinking of making some variety....
Any how would it change the flow of air if i inverted the wires of the cooling fan? i mean if i change the black wire with the red wire?
or would it just burn my fans??
 
Correct, just flip the fans you want to change. The most common scenario is have the front/side fans as intake and rear/top as exhaust.
 
well that won't work in my case.....if i put the fan on the other side the small engine well be in direct contact with the case which will prevent the fan from working
case%20fan.jpg
 
Most fan cowling designs have the fan itself set back enough into the cowling such that it can be mounted flush against things. What your saying is that your fans are such that the fan is either sticking out from the cowling or is pretty much flush with the cowling.

That in itself is rather odd...and not to doubt your word here but that pic does not really support what your saying. We can't really see if what I described above is indeed the case.

However provided what you say is all true you could try reversing the voltage though the fan. If you have a spare wall-wart that could provide a suitable voltage (5v - 12v) to test that out 1st before you wire it to your mobo/PSU I would suggest that.
 
Reversing the fan voltage or wiring is bad.

The fan blades are designed to blow in only one direction, the efficiency of the fan will be crap, probably blow very little air if you reverse the rotation.

On the side of a fan is an arrow showing the direction of air flow. At least on all the fans I have ever bought.
 
Most fan cowling designs have the fan itself set back enough into the cowling such that it can be mounted flush against things. What your saying is that your fans are such that the fan is either sticking out from the cowling or is pretty much flush with the cowling.
yep....thats what is hapenning
 
Post pics of the inside of your case. There shouldnt be a problem with making the front fan blow into the case.

yep....thats what is hapenning

If thats the case, you could use a few small plastic washers between the fan housing and the screw holes. They need to be the thick ones though.
 
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The fan blades are designed to blow in only one direction, the efficiency of the fan will be crap, probably blow very little air if you reverse the rotation.
I would tend to agree. However if expert87 wants to try they are his fans.

If thats the case, you could use a few small plastic washers between the fan housing and the screw holes. They need to be the thick ones though.
I thought about mentioning this but of course I thought it might not even be worth it depending on how much the fan is sticking out of the cowling. Such that the gap you need to introduce to offset that would negate a lot of the flow. But shrug, might be better than nothing if the fan spin can't be reversed and or such a spin gives very poor results.
 
I thought about mentioning this but of course I thought it might not even be worth it depending on how much the fan is sticking out of the cowling. Such that the gap you need to introduce to offset that would negate a lot of the flow. But shrug, might be better than nothing if the fan spin can't be reversed and or such a spin gives very poor results.

If the gap was too much, I would agree that you may lose pressure, however we are only talking a few mm so it shouldnt affect performance.

Reversing the rotation would definitely hurt performance.
 
well that won't work in my case.....if i put the fan on the other side the small engine well be in direct contact with the case which will prevent the fan from working
case%20fan.jpg
I cant see how that would be possible....not with any fan I have ever seen anyway..
 
Ummm, they're brushless DC motors, you cannot get them to run backwards by switching polarity. They will just sit there doing nothing until the IC burns out, (few are built with reverse polarity protection) at which point they will just sit there doing nothing.
They will continue this madness for eternity in the landfill. :eek:


Instead of using washers to bring the fan away from the case's fan holes, I just give the center of the fan location a quick rap with a hammer to dent the center of it away from the fan motor.
That's if I don't just snip that useless bit of metal off completely and quiet the fans down while I'm at it.

*edit*
Oh, and that bit with the label on the fan hub does not turn expert87, however if it is in contact with the case it will increase noise. That's why I just smack the metal center of the cases fan guard with a hammer.
 
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thanks for the replies (especially Diggrr)
i will try the hammer method...just hope these cheap fans survive the impact
(ur personal pic show a lot of potential in hammering things:santa:)
 
he didn't mean hit the fans with the hammer >.<
He means to hit the Case with the hammer, and dent the case outwards to make room for the motor, so that its not making contact with the case.
 
You could also get a sheet of some gasket making material (either cork or paper) at an auto parts store and offset it that way for some clearance. That would also have a noised dampening effect.
 
Yes you could, there's also those silicone fan silencer gaskets made for the job. But given a choice between waiting a few days and hitting something with a hammer, you can guess which one I'm up to. :D
 
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