Controlling 3 pin fans?

Discussion in 'Overclocking & Hardware' started by Timcyn7, Feb 3, 2020.

  1. Timcyn7

    Timcyn7 Member

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    Hi ,

    Im currently building myself a server. I have about 10 fans that i need to control individually ... Im currently running a 6ch fan controller i found on ebay. It works but theres only 3 speeds, slow, tiny bit faster than slow, and then BAM! 100%.
    If there anything out there that can handle all my fans and control them individually? most controllers i see do 4ch/5ch and are around $70 and ill need 2... i see "fan hubs" but the ones i found are only for pwm fans...
    Any ideas?
    Thanks heaps
     
  2. power

    power Member

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    tried software?
     
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    Timcyn7

    Timcyn7 Member

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    No, wasnt sure software could control 3 pin fans? if so what software? Thought it was all to do with increasing and decreasing the voltage going to the fan?
     
  4. power

    power Member

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    check your BIOS for a start, if they are being detected there and showing RPM that's half the battle from there I think speefan is a good option. I personally on my current PC let the BIOS control ramping up and down based on temps.

    hardware wise you'd be looking something with a variable resitstor nob - unsure what's in the market these days as tbh i haven't needed to control fans for some time. just set and forget.
     
  5. DSTM (Dougie)

    DSTM (Dougie) Member

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  6. terrastrife

    terrastrife Member

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    Just splitters so run 2-5 fans off a single header depending on max amps.
     
  7. power

    power Member

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    Timcyn7

    Timcyn7 Member

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    Only 1 header on m/b

    Yeah pccg have a thermaltake one thats 6ch, guess i could group the fans (max 2-3) off of one header?
     
  9. power

    power Member

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    does use the header for multiple fans you risk overloading it.

    go with molex to 3 pin instead.
     
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    Timcyn7

    Timcyn7 Member

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    yeah but i want to control certain fans.... i have 4 200mm fans that can go 100%, its the 120 and 140mm fans that need backing back a bit
     
  11. power

    power Member

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  12. walker_2003

    walker_2003 Member

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    3 pin fans (DC) have very limited speeds you can run them at its just different voltages, where as a PWM fan has a range you can tweak nicely.
     
  13. mike-s

    mike-s Member

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    Slightly digging this up. But as walker mentioned 4 pin is going to be significantly better for this than 3 pin. But if you have only 3 pin fans and want to control them you could use a simple circuit like this and control up to around 30w of fans (don't forget the heatsink though).

    A PWM solution is something like this. They even recommend that if you want to run higher than 3a, directly connect the power to the psu and only run the pwm from the board. a 4A version is this one.
     
  14. Butcher9_9

    Butcher9_9 Member

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    Do you need to Dynamically set the speed or just set and forget on a per fan basis?
     
  15. terrastrife

    terrastrife Member

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    Unless you use a fan controller that can set your fan speed based on RPM (Like a Corsair Commander) instead of setting a voltage, that way the controller regulates the voltage to get the desired RPM including the requirement for a higher startup voltage compared to a lower steady state low RPM voltage. :p
     
  16. juzz86

    juzz86 Member

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    Good control of 3-pin fans is easy, it's just older, so not many people have do it anymore.

    You need linear voltage control - a pot. This gives you the wide control range, rather than just L M H.

    Linear controllers have knobs or sliders. Here's a Tt one, Here's an NZXT one. Five channels each, so just use splitters to get your ten fans. The NZXT one I use myself, it will take twenty fans okay.

    You can also do it on PCI slot backplanes if space is an issue. Here's Molex ones, here's a SATA one.

    You can also do it from a channel on your motherboard, using something like this. In this example you connect your fans, connect SATA power and then connect the weird cable to a CHA_FAN header on your motherboard. Then, you use BIOS fan control to set your usual silent / standard / turbo / full speed, and they'll all do that. You are limited by the granularity of your motherboard in this case.
     
  17. Wacko02

    Wacko02 Member

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    Back in the day, i'd just modify the molex power pins by swapping the cables to give 12V, 7V or 5V, Like This One although not all fans would start up at the lowest voltage. Some fans come with an adaptor that has a resistor in to limit the Voltage, but if you're after on the fly control, then one of the linked controllers will work.
    3 Pin fans can always be plugged into 4pin mobo headers and some software (MSI Dragon does) will give you a choice of running it on PWM mode or DC mode with control over the voltage and dynamic profiles.
     
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  18. juzz86

    juzz86 Member

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    I still do this mate. 7V on a 12V fan is pretty much the perfect balance when you're chasing quiet.

    If not that, inline resistors.
     
  19. terrastrife

    terrastrife Member

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    Most boards can still control DC fans with full range customisation.
     
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  20. juzz86

    juzz86 Member

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    That's good to know mate. My ASUS board detects whether fans are DC or PWM and goes from there, wasn't sure whether it was ubiquitous or not :thumbup:
     

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