PWM fan suggestions

[MrSpiffy]

I'm finishing up an LED fixture that will be dimmed via Meanwell LDD's and an Arduino. The code that I found has a section for fan control, but the fans I purchased (Arctic F8 PWM) are not powering up both with and without the PWM signal. I was under the impression that PWM fans should run without a PWM signal, as long as they receive power, but the Arctic F8's don't to anything. So, at this point I'm not sure what fans will work with an Arduino's PWM output.

Does anyone have suggestions about some good fans to implement with the Arduino's PWM signal without messing with the built-in timers?

 

[perkint]

You are right. If you supply most fans (including the artic pros) with 12V they should spin, even with no PWM. You didn't connect the +ve and -ve the wrong way round, did you?

Tim

 

[MrSpiffy]

I tried reversing the wires, but no dice.

I checked with a multimeter to ensure the proper voltage was being produced. It came up with around 12.7V. I've connected one fan, both fans, parallel, series. Nothing.

 

[perkint]

I have killed more than a few cheap fans by connecting +ve and -ve the wrong way round! If you do this, it can kill the fan. Swapping them back round the right way will not help, if you had got it wrong

Tim

 

[MrSpiffy]

That's good to know. It's entirely possible I've fried my fans. I'll see if I can get another set.

I've also found that these fans typically operate with a much higher PWM frequency (25kHz) than the Arduino is set to by default. I'll look into adjusting the frequency and try again. Hopefully that helps.

 

[perkint]

Yeah, the default PWM from the arduino is very low for fans. But it is easy to adjust And, with a capacitor in the right place, the default should actually work without the fan buzzing anyway LDDs will not work with a PWM set to 25KHz.

Tim

 

[karimwassef]

Have you tried just connecting straight DC power from the adapter to one fan?