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DIY Fan Controller for PWM Fans

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Naah... not necessary, no need to buy another psu just to prove this, just any pwm fans like two that monsters plus your xigmatek and maybe intel fan from stock hs will be fine too.

But again, just take your time, no hurry, thanks in advance.
 
Thanks for the write up. Having a PWM signal generator that leaves the 12 volt line alone is exactly what I was looking for.

The only issue is that the parts you suggested come up with many hits in digikey and I'm not sure which to get.

Can anyone provide digikey part numbers for the components?

Also, since this fan controller is for a fan that will not be in my computer, I wanted to make it temperature regulated. As for setting a thermistor in series or parallel, does anyone have a circuit diagram for that? Which thermistor and potentiometer set would work for that?
 
this is awesome...
I google search for "diy pwm fan controller", and I always got this thread on the 1st page :thup:
 
12v or 5v

hi guys,

i just recently bought 6x Coolermaster xtraflo 120mm pwm fans for a 360 radiator (wanting to do a push pull setup)
my problem is i need to make a 4 pin pwm fan controller, do i need to use a 5v or 12v controller.
i have an existing Cooler Master Aerogate II Fan Controller is there a way to modify this to be compatiable with the 6 pwm fans .
i like this unit as it has the temps and rpm displayed.

if anyone could help this would be appreciated.

regards
zerocoolzmax
 
my problem is i need to make a 4 pin pwm fan controller, do i need to use a 5v or 12v controller.
x

The controller itself works on 5V; the fans get 12V from the PSU and the PWM signal from the controller for speed regulation.


i have an existing Cooler Master Aerogate II Fan Controller is there a way to modify this to be compatiable with the 6 pwm fans .

Unless you're relatively good with electronics and quite handy with a soldering iron; modding that controller to send PWM out will be kind of hard. You do have an option though... The fans you bought; though PWM, can still be connected/controlled by that Aerogate II. The controller has 4 channels rated for 18W each; the fans take a max of 8.4W so you could connect two fans per channel and control them via voltage adjustment like normal fans and not lose any functionality on the controller.
 
How many W?

I'm just wondering how much W they can handle? Mostly I need to know single 555 timer output but it could nice if you could tell other two outputs.
 
I'm just wondering how much W they can handle? Mostly I need to know single 555 timer output but it could nice if you could tell other two outputs.

One million Watts... :)

Now; for the serious answer.

The PWM controllers that this article refers to don't actually power the fans. The fans are powered straight from the PSU (12V) all the time and the controller simply sends ON/OFF signals to a circuit on the fan that switches power ON/OFF very fast (the standard is 25KHz, but some fans work on other frequencies).

So since the fans are not being powered from the controller; the answer to your question is that you can run whatever fans you want (no watts limitation); provided your PSU can power them.
 
Very nice article!! - Still need help though :)

Hi there,
Excellent write up! - I read a good portion of the original thread last night. Very informative.

But I still have a few questions - Yes I'm a noob :thup:
I know this is an old thread now, but I hope it's okay to revive it again.

Here goes...

1) IF I where to build my own PWM-controller and (don't know the correct word) power-module??? - Would "PWMing" a 3-pin fan wreck the "fan tach" signal from the third wire?

2) "Nidec" states that modulating the 12V main supply isn't a good thing to do.
But isn't that exactly what a PWM-fan does? chops up the 12V supply with it's OWN built-in circuitry (with help from an external PWN-controller) in order to control the speed??

The thing is that I have a bunch of 3-wire fans that I would like to run slower. I'm not interested in soldering a resister on one of the wires in order to reduce the speed. Well that would be the easy way to do it, but not a very efficient way.. I'm also worried about the tach-signal..

3) Would using the 556 Dual Timer boost the PWM-signal up to a level where it will damage the circuitry on my 4-wire fans if only ONE fan is connected to the controller?? (yes, I also have a bunch of 4-wire fans) :bday: - Nidec UltraFlo V12E12BS1B5-07 - Very nice (discontinued) fan, I think.

Well these are just some of my thought's - I'll spare you the rest, for now :D

Kind regards!
 
MuHcOw, :welcome: to OcF !

Trying my best to answer your questions here.

1) IF I where to build my own PWM-controller and (don't know the correct word) power-module??? - Would "PWMing" a 3-pin fan wreck the "fan tach" signal from the third wire?

Yes, PWM-ing 3 wires fan is really crude method to control the fan speed, this simply turning the whole fan power on and off at very high speed.

Since tach signal is also in pulses (common standard is 2 "pulses" per rotation), definitely this signal will be wrecked so badly that it is useless.

There is other alternative that use this method called pulse skipping, but still this is a really lame method, and also will create even annoying noise from the fan, cause its sort of stopping the pulsing momentarily, then there is a circuit will monitor the tach signal for certain period, and then continue the pulsing again. :-/ This process is repeated again and again that sometimes the fan will create a funny tone. :bang head

Simply put, forget about power pulsing PWM on 3 or 2 wires fan, its not worth the effort and troubles.

2) "Nidec" states that modulating the 12V main supply isn't a good thing to do.
But isn't that exactly what a PWM-fan does? chops up the 12V supply with it's OWN built-in circuitry (with help from an external PWN-controller) in order to control the speed??

Yes, in principal they're "almost" the same, but again, as the olde says "the devil is in the detail" :sn: , as you see, on PWM 4 wires fan, the power is supplied "constantly" to the fan circuit, so the fan circuit is never turned off, also PWM fan circuit is much-much more complicated than ordinary 3 wires fan.

An example, here I made a tear-down of an industrial PWM fan, click -> Pictures of A Dead Delta Fan and It's Internal Parts, you can see it has complicated circuit with many more tons of components compared to common 3 wires fan.

Now, about the chopping, yes, its using the same principal, but ... it has a dedicated circuit to handle this situation ("smarter") in chopping the power "at the right & precise timing and moment" that this method will be effective. Again, remember, PWM fan has a dedicated circuit and this smart circuit is "constantly" powered on by a dedicated 12 volt line to do this work. 3 wires fan doesn't have this luxury, hence fan with PWM feature will be much more expensive than it's 3 wires brethren or exact same model.

Randomly chopping the power as in pulses to the fan stators definitely will wreck the fan rotation, torque power and reduce the fan efficiency. Combining these disadvantages, usually this method will create annoying weird noise since the pulsating pulse is not fired at the right precise timing and moment.

Made a short explanation here, read it carefully and also recommending to stare at the pic in that post while imagine the overall over process as I explained there, click -> HERE, trust me, speed it up in your brain, its dizzying. :screwy: ... LOL ... :D

The thing is that I have a bunch of 3-wire fans that I would like to run slower. I'm not interested in soldering a resister on one of the wires in order to reduce the speed. Well that would be the easy way to do it, but not a very efficient way.. I'm also worried about the tach-signal..

The only safest & better way to control the speed of 2 or 3 wires fan is by using voltage control (aka reducing voltage supplied to the fan), which is most commercial fan controllers do out there.

Also this old but proven method is the best in controlling and reducing the fan noise effectively.


3) Would using the 556 Dual Timer boost the PWM-signal up to a level where it will damage the circuitry on my 4-wire fans if only ONE fan is connected to the controller?? (yes, I also have a bunch of 4-wire fans) :bday: - Nidec UltraFlo V12E12BS1B5-07 - Very nice (discontinued) fan, I think.

Nope, don't worry, it doesn't work like that. Think of the booster like your PSU, even though it has beefy power, it will only supply the "needed" power which is your fan either single or more safely.

It is like computer with single or multiple hard-disks, you never heard of that a psu was toasting the hardisk if only one was used compared multiple harddisks, right ? ;)


Hope this helps.
 
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MuHcOw, :welcome: to OcF !

Thank you :)

Hope this helps.

It helps A LOT !!! Thank you very very much! :D

I was just worried that the "boosted" controller meant higher voltage in the PWM signal which could burn out the circuitry in the fan.
But now that I'm thinking about it... - Well.. I should have known :facepalm:. The PWM-wires to the fans aren't connected in series but parallel, if you know what I mean. Same voltage level but more amps, when needed..

Then again I may be wrong - Wouldn't be the first time, and probably not the last :blah:

Well, looks like "good" old voltage control for my 3-wire fans then.. Just have to make sure the controller (resistor) can handle the load.
Do you know if the lower voltage will have an effect on the tach-signal??

My only concern regarding the PWM controller is that "frequency-thing". But I think that could be fixed by using another capacitor or something like that, right?... I'll read the thread again - I know the answer is in there somewhere :)

Again - Thank you very much!!

Kind regards
 
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please help

I made this circuit and connected it to the pwm pin on a 12v 1.6a delta fan and it didn't work

the fan was connected to 12v molex power and the circuit was connected to 5v molex power
 
Help me :D

hey men great work there.
im noob in this feild and im trying to do the pwm control setup using the 556.
but when i tried it im only getting to values in the PWM output.
first the potentiometer is at the lowest position, the fan is turing 1250 Rpm then when i turn the potentiometer just a little bit the fun runs to 3150 Rpm :-/. and ive tried throttling the potentiometer to the max and tha fun is nut speeding up just upto 3150 Rpm. help me :confused::confused::confused:
 
Can you post a pic of the circuit? There could be a bad connection or an unwanted extra connection.

When I built my most recent controller, one of the channels was stuck at low duty cycle because two pins on one of the ICs were bridged unintentionally. Took me HOURS to find it, and I'm used to doing this sort of thing! :)
 
its okay now! i discovered that the Potentiometer is busted. so i just put a working one and its done. well thanks anyway :):):) and by the way love your work. :clap:
 
I'm going to build 25 of these, everything is SMT but for the connectors and potentiometer

PWM.jpg

PM me if you want 1.
 
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Depending on what application you plan for that controller, it'll probably need a fatter ground track. Looks nice though. :)
 
Depending on what application you plan for that controller, it'll probably need a fatter ground track. Looks nice though. :)

:rofl: I saw that and made the change.

edit: the board is about 58mm (2.3 in) x 31.5mm (1.24 in), and I re-posted a new pic in above post.
 
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Well, it's done, here is the schematic I used:
PWM-circuit.png

And here is the finished board:

DSCN0595.JPG

DSCN0596.JPG

DSCN0598.JPG

DSCN0599.JPG

The layout looks a lot like the schematic :)
Just 1 last step and that is to wire the pot and box it.
 
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