Hey guys! New to the forum but long-time reader (I especially liked the G15 carbon fiber mod, looked awesome, but too scared of taking my beloved, £50 G15 apart hehe). I recently came into 2 great condition indutrial 12cm 11 watt muffin fans. They go at a huge 3000rpm. I want these bad boys in my PC, 1 in and 1 out. I tried them on my shorted PSU on the 12v rails of the 4-pin molex but this wasn't enough power. I am assuming that these are 24volt fans. How do I get them hooked up to my PSU? Thanks, SilverStream

You can try using the -12v rail to replace ground.

24V Cooler Overvolting

Personally, I would steer away from this method.

That guy at OC seemed to be umping into the idea a bit. Power supplies general have extremely low handling capabilities on the - rails. I personally wouldn't want to chane it.



A safer idea (On your power supply that is), would be to rig up a circuit with some capacitors. However, this is where my help ends, as the knowhow to build the inverter is out of my league.

Perhaps someone like Twiztid can help you out here.

Quote: Originally Posted by FireDemon666 Personally, I would steer away from this method. That guy at OC seemed to be umping into the idea a bit. Power supplies general have extremely low handling capabilities on the - rails. I personally wouldn't want to chane it. A safer idea (On your power supply that is), would be to rig up a circuit with some capacitors. However, this is where my help ends, as the knowhow to build the inverter is out of my league. Perhaps someone like Twiztid can help you out here.

True - but I've never seen a 24 120 rated to use more than .35 amps. Since your neg rails are mostly legacy - it's rather safe.

I am curious why you would want 3000 RPM in a 120mm fan. That sucker would be LOUD! When you can push a conventional 120mm fan over 100 CFM with relative quietness, why drive one up so high?

Of course, if it falls in the category of "just cause", I completely understand.

Yeh it pretty much is 'just cause'. They look pretty beastly for starters and I am wandering what overally effects it'll have on the PC's perfomance. The airflow shift would be bigger than my comparitively puny 1200rpm 120mm fans. I'd still keep the intake on the side panel to keep the pressure higher inside and dust out.
Damir Lukic's plan seems dangerous, I like it when my house doesn't burn down, I've already been through 3 OCZ PSUs lost via various lightning storms and general tinkering and most of the time they smelt like burning plastic.
This porbably won't happen any time soon I guess, I think I probably assumed too much. On the noise side of things, I'd cover the exterior of the fan in sheet bitumen. I love that stuff and I'd definatly craft some dampeners to screw between the fan and the case.
Just the voltage thing I'd like the sort out. Cheers!

It's going to be tricky to wire it up as it will have a realitivly high current draw. If it had a lower curent draw I would recomend a colepits oscilator and a voltage doubler circuit. you may have to use a seperate 24v supply or convert 12v DC into AC (using some kind of oscilator citcuit, although it will need to be able to handle at least 2A current I think, as fans have a higher starting power and the current will be twice what the fan would draw through 24v) and then use a transformer to converter it to 24v and then use a bridge rectifier to get DC again.


So:
12vDC>oscilator>12v AC>transformer>24vAC>bridge rectifier>24VDC

as it's only a fan it dosen't have to be regulated or filtered partiularly.

wouldn't THIS work pretty well, might have to do a few mod to get a few molex's, so you can hook up too. Plus you can steath the wire alittel better since its longer and you'll be stripping it.

Just a suggestion, many many laptops have 24vDC PSUs

Quote: Originally Posted by Iateronmly True - but I've never seen a 24 120 rated to use more than .35 amps. Since your neg rails are mostly legacy - it's rather safe.

Yes, I thought of that. The part that really worries me is that I don't think power supply manufacturers would still be using these negative rails if they weren't powering something somewhere. Qould be like putting AT connectors on, pointless.

I wouldn't want to add anything such as that to the loop to drive it over the edge.




And yes, meanwell makes a 600 watt 24v power supply that fits into a 5 1/4 bay, but if your not planning on getting a peltier or anything to go along with that fan, it would be complete overkill.

The capacitor circuit is what I'd use. Though it will take a bit of research.