Running 12v Fan @ 24 Volts?

[vicwang]

Does anyone have experience with running 12v case fans at 24v for extended periods of time?

The only thing I was able to find on the subject was this article, which shows that it can be done, but doesn't say anything about long-term repercussions:

http://www.afrotechmods.com/fanmod.htm

Basically I have a 120mm H1A Panaflo fan (12v) with a 3-pin connector, and a mosquito trap which uses a 120 mm case fan (24v) and a 2-pin connector. If I get a 3-pin to 2-pin adapter, would it work (and be safe) to replace the fan in the trap with the Panaflo?

 

[aigomorla]

why?

push/pull config > push or pull config alone.

get a push/pull config and lower your votlage on the fan. It will save your ears!

 

[vicwang]

Well, the mosquito trap will be outdoors, so noise won't really be issue.

And the fan in the trap died, and I just happen to have a spare Panaflo H1A, so if it will work (and possibly be more powerful than the old fan) I'd like to replace it with the Panaflo.

My main concern is making sure it won't destroy the fan, the trap, or both, and that it won't be a safety hazard if running 24/7.

 

[aigomorla]

Originally posted by: vicwang
Well, the mosquito trap will be outdoors, so noise won't really be issue.

And the fan in the trap died, and I just happen to have a spare Panaflo H1A, so if it will work (and possibly be more powerful than the old fan) I'd like to replace it with the Panaflo.

My main concern is making sure it won't destroy the fan, the trap, or both, and that it won't be a safety hazard if running 24/7.

the best person to ask this would be zepper.

Im sure he will spot in. If not PM him directly.

 

[Modelworks]

I would use either a voltage divider, or if you want to do it really easily buy a LM7812 regulator.
Cost under $1.00 and only has 3 pins, in , out, ground. Will convert the 24v to 12v . No heatsink needed on the regulator. just place it where it can get part of the airflow.
http://www.fairchildsemi.com/ds/LM/LM7812.pdf

 

[Rubycon]

It will die very quickly or damage the power supply for the original fan. Undervolting a fan is one thing but overvolting is VERY bad. These aren't universal motors!

 

[F1shF4t]

Haven't run one at extended periods of time but I did play with an old cpu fan. Ran like a small jet engine at 24V, at higher volts it stoped and then at 48V it started smoking. Don't think it would be a good idea, not unless you want to destroy it.

 

[Zepper]

Most 12V fans are rated for up to 13.x volts so they are safe for many automotive applications, but I wouldn't go much above that as you'll be buying a proper one shortly. Places like bgmicro.com and allelectronics.com carry odd-lot (meaning the ones they have today may not be the ones they have tomorrow) 24V DC fans for cheap. Only thing is is their shipping can be high if only buying one piece (though it's hard for me to get away from those sites having bought only one item... ;-) ). Turns out those two have a skimpy stock of 24V - buyextras.com has quite a few and thermalfx.com has some. They can also be found on the big electronics distributor sites like Mouser or Digikey, but you are likely to have to pay a left nut for them. the idea of hooking two identical 12V fans in series might be a useful alternative.

.bh.

 

[mpilchfamily]

At 24V the fan may be able to run but will get fairly hot. Long term it will wear out the bearings and seize up. If it can't handle the power it will burn out the motor pretty fast.

 

[Biggerhammer]

I've not done this with fans, but my understanding is, doubling the voltage to a DC motor halves its lifetime, quadruples heat output, and gives (I think?) double power for the time that it lives.

This is a lot more common in Battlebots than it is in cooling fans.

 

[Modelworks]

Originally posted by: Biggerhammer
I've not done this with fans, but my understanding is, doubling the voltage to a DC motor halves its lifetime, quadruples heat output, and gives (I think?) double power for the time that it lives.

This is a lot more common in Battlebots than it is in cooling fans.

The problem is that fans like you see in computers are brushless dc and that makes them overheat in the controller section long before the windings overheat, so you end up with a burned circuit board. Motors like in old cassette decks, etc that are dc uses brushes where the biggest worry is the voltage burning out the brush or winding.

you can google commutator if your interested in the brush dc motors.

 

[vicwang]

Thanks for the great advice, guys. I will look into those options.