fan controller capable of 24A

[ak47is1337]

Hey guys, I'm trying to have adjustable on the fly fans for my watercooling rig but was wondering if I had options outside of buying another 5.25" drive bay thing. Right now I use a Sunbeam Rheobus Extreme which is okay, but I would like to use it in one unit, and preferably just use a single knob to control them all. They are 24 fans that draw 1A each at 12v. Anyway I was wondering if any of these would be workable for what I need:

http://www.ebay.com/itm/191148955654?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
http://www.ebay.com/itm/400684644153?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
http://www.ebay.com/itm/171042626068?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
http://www.ebay.com/itm/271485835469?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
http://www.ebay.com/itm/261210380258?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT

I have a pretty enormous case so I think I could cut out a 5.25" drive bay or mount it in back.

I am a little concerned that some of these are PWM controllers and my fans are 3 pin. Does that matter?

Any suggestions would be appreciated, thanks.

 

[ak47is1337]

Bump dump

 

[DedEmbryonicCe11]

I am a little concerned that some of these are PWM controllers and my fans are 3 pin. Does that matter?

YES. PWM and voltage regulation are two different methods of slowing a fan. PWM sends a signal along the 4th wire and the fan itself has the circuitry to modulate the 12v input and reduce fan speed. Unless you are willing to replace all those 3pin fans with PWM fans you have to use the older voltage regulation method to control them. Generally, case fans have a wide range of voltages they can run at (below that point and they won't spin at all). Regulating the voltage with resistance (rheostats) releases heat as a byproduct and controlling 24x 1amp fans is going to be a serious project. I know that Sidewinder sells 25w and 50w rheostats for controlling fans. Beyond that the only things I could find meeting your requirements would be through electronics warehouses:

http://www.alltronics.com/cgi-bin/item/1RH300/RH300/1-Ohm-300-Watt-Rheostat

http://www.alliedelec.com/search/productdetail.aspx?SKU=70022537#tab=specs

http://www.alliedelec.com/search/productdetail.aspx?SKU=70022551#tab=specs

I would do all the math yourself though and get a second opinion. I think you need 288W+ to handle 24x 1amp 12v DC fans in a single circuit. All that heat has to go somewhere hence why these rheostats are so large and open.


More reading:
http://www.swiftech.com/pwmcontrollers.aspx

Selecting a Rheostat

Rheostats

 

[flak-spammer]

PWM fan controllers are not the same thing as PWM controllable fans. First PWM fans or fans with the fourth pin have extra hardware in them to permit the logic level signal to turn on and off the 12v supply on the fan. This doesn't mean you can't do the same with non-PWM fans. Instead it means you have to do all the extra work yourself, e.g. switching the 12v power on and off with a mosfet that can handle the current of the fans. So the if the fan controller is PWM and asking for four pin fans then it's a problem, if it's PWM and has only 3-pin fan connectors then it's a non-issue as it's switching the 12VDC power to the fans itself. Odds are one of those ebay links would work, but you might get some nasty harmonics coming from the fans.

 

[DedEmbryonicCe11]

I don't know how accurate that Swiftech write-up is but:

So, PWM speed control of a standard fan is indeed very different from PWM speed control of a PWM fan… Nidec even goes so far as to say that modulating the main supply voltage is not advisable:

"Pulse-width modulation of DC operating voltage to modify fan speed [edit: in PWM devices] is not recommended. Transients generated by that approach can irreversibly damage motor commutation and control electronics and dramatically shorten the life of a fan."

Sounds like something I wouldn't try on 24 expensive fans at once. Maybe 1 or 2 if the seller had a good return policy on the PWM controller. {edit} I think they are talking about using a standard PWM controller damaging a PWM fan's circuitry but I'm not sure with that wording. It sounds like the OP has a mix of 3 and 4 pin fans.