Fans and powers

[lamborgini8]

What fans does everyone here use in scanner builds? I need to fit one in mine but I am limited to 40mm fans with a max of 10mm thick. It also has to run from a 15V supply instead of 12V, which should be ok if not somewhat noisier.

Anyone know if this is a good fan to use? It caught my eye because it looks very thin and is a 2 wire fan to keep it simple.
http://www.dealextreme.com/details.dx/sku.15564

Is running a 12V fan on 15V ok as well?

[danielbriggs]

40mm fans are horrible: poor airflow and a whiney sound...
Is there anyway you could bump up to 80mm? (even 60mm?)

I wouldn't run it at 15V, may burn out the motor after a bit. Stick in a 36 Ohm resistor, and that should give you the voltage drop needed for that particular fan (0.08A). If you choose a different fan, you'd need a different resistor obviously...

Dan

[andy_con]

i have to disagree.

i have 4x 80mm fans in mine, 12v each and my projetor sounds like a fooking jet taking off!!

if its a small projector then 40mm fans should be ok. my small projector has 40mm in it and its fine no heat issues at all

[realtime]

I have also 40mm fans,

first i had 12V -JustCooler- one of them began to squeak after 20 h.

Now I use 5V types (Sunon, 0.14A, 5800U/min, 27dB, 12m³/h) because I do without 12V power supply in my projector.

It's correct, 40mm are noisier than 60mm or 80mm.

They sounds like a turbine, but what an exciting feeling when the projector starts it sounds like a LearJet.

I would not run 12V types on 15V, but what about combining 2x12V serially on 15V, then they are not as noisy.

Another advantage for 40mm is the size. You can use more fans for the same area, this estabilshes redundancy.

Ask yourself why are the most manufacturers use 40mm ?

The big disadvantage is: one 40mm is as loud as one 80mm.

[Soulstorm]

40mm fans suck. Plenty of time spent building computers to tell ya that


I've seen a laserworld with a few 40mms in it and the guy had overheating problems. Go for an dual 80mm push pull config or single 120mm push pull. 120mm will pump about as much air as 2 80s with less noise. You can normally tell sound levels by thickness of fan and current rating. Higher current means bigger motor and bigger noise. My 2W has a single 120mm and it's more than sufficient.

[lamborgini8]

40mm fans are horrible: poor airflow and a whiney sound...
Is there anyway you could bump up to 80mm? (even 60mm?)

I wouldn't run it at 15V, may burn out the motor after a bit. Stick in a 36 Ohm resistor, and that should give you the voltage drop needed for that particular fan (0.08A). If you choose a different fan, you'd need a different resistor obviously...

Dan

I could get an 80mm in there but it will be a squeeze... The enclosure is only 90mm tall.

[danielbriggs]

I could get an 80mm in there but it will be a squeeze... The enclosure is only 90mm tall.

Even 60mm would be better than a 40mm if you can't squeeze an 80mm in.

[lamborgini8]

40mm fans are horrible: poor airflow and a whiney sound...
Is there anyway you could bump up to 80mm? (even 60mm?)

I wouldn't run it at 15V, may burn out the motor after a bit. Stick in a 36 Ohm resistor, and that should give you the voltage drop needed for that particular fan (0.08A). If you choose a different fan, you'd need a different resistor obviously...

Dan

Even 60mm would be better than a 40mm if you can't squeeze an 80mm in.

Hmm, I have measured it up and even 60mm will be tight. The enclosure is 90mm minus 10mm because of the base plate. Plus the fan is going on the front so I am trying to get it symmetrical without looking odd.

If I use 40mm I could even fit two of them side by side.

[danielbriggs]

Hmm, I have measured it up and even 60mm will be tight. The enclosure is 90mm minus 10mm because of the base plate. Plus the fan is going on the front so I am trying to get it symmetrical without looking odd.

If I use 40mm I could even fit two of them side by side.

How about drilling vent holes on the front in a geometric pattern, and then sticking a fan on the back that's out of the way.

I'm not saying don't use a 40mm fan, I'd just personally try and bend towards using a 60/80mm.
But I'm sure there are more important things to worry about in your projector than fan size

[lamborgini8]

How about drilling vent holes on the front in a geometric pattern, and then sticking a fan on the back that's out of the way.

I'm not saying don't use a 40mm fan, I'd just personally try and bend towards using a 60/80mm.
But I'm sure there are more important things to worry about in your projector than fan size

That's what I am doing, I don't want to make another huge hole in the front so I am doing a sort of circle made of circles haha. I have had it running for 4 hours straight with the top of the enclosure off and the only fans were what are already on the laser head and the laser PSU and even then it was cool to the touch.