Recommendations for 24v blower fans that play nice with the duet PWM?



  • Anyone have recommendations for 24v blower fans that play nice with the duet PWM. Ive tried a handful of <$10 from china and they all sound horrible unless they run at 100%. I'm happy to spend the money for the right one. I just dont want to add any more to my stack of noisy 24v blowers.

    thanks!



  • I second this request. I can find loads of cheap, and expensive, 24v blowers, but none seem to be designed to run quietly with the Duets PWM setup. The best I've found is a fan from Mechatronics (B5015E24B-BSR ), but it does make a lot of electronic noise below 100%.



  • Get a fan from a well known brand. I use Sunon and Ebm-Papst Fans.
    On my Aero extruders I use the 414F/2 model from Papst.



  • @whosrdaddy:

    Get a fan from a well known brand. I use Sunon and Ebm-Papst Fans.
    On my Aero extruders I use the 414F/2 model from Papst.

    I may be missing something, but that seems to be an axial fan. The issue Jason and I are having is finding a 24v blower fan.



  • Ah I see, yes that is a problem indeed. I use Sunon 12V Maglev blowers on 24V (noisy but works well :))



  • Not tested myself but have you guy tried changing the Frequency of the PWM? That might help reduce the noise if the default frequency does not play well with your specific fan.
    https://duet3d.dozuki.com/Wiki/Gcode#Section_M106_Fan_On



  • @Kezat:

    Not tested myself but have you guy tried changing the Frequency of the PWM? That might help reduce the noise if the default frequency does not play well with your specific fan.
    https://duet3d.dozuki.com/Wiki/Gcode#Section_M106_Fan_On

    I second that. Maybe I've just been lucky but I have a range of fans both 12 and 24v between 30 and 80 mm diameter. I've been able to make all of them work by messing with the frequency and blip. My 30mm 12v blowers run through a 12v converter for which I had to drop the frequency right down to 10hz but I get reasonable control out of it.



  • I just got an Prusa MK3 in the mail. I will try their 24v blower fan.

    Im a little confused when you say "Change the PWM frequncy". Isnt that what is happening when you go from 20% to 100% fan power?

    The fans all run fine at 100% but they do not like anything under S1.0. Sounds like a plane taking off. I print mostly petg so i like to keep my fan at like 20%ish. I just go no fan now because its SOOOOO noisy.



  • @Jason:

    Im a little confused when you say "Change the PWM frequncy". Isnt that what is happening when you go from 20% to 100% fan power?

    Er No. PWM is Pulse Width Modulation. Essentially when you vary it, you change the width of the pulse, or to put it another way, you change the "on time" compared to the "off time". If you could imagine a square wave form with a period of say 100ms, then with 50% PWM, you'd have a "high" lasting for 50ms followed by a "low" also lasting 50ms. The high and low cycle then repeats. With 90% PWM, the high would last 90ms and the low 10ms and conversely with 20% PWM, the high would last 20ms and the low 80ms. The 100ms in total is the frequency - in this case 10Hz. If we increase the frequency to say 100 hz, then the 100ms for the entire on-off cycle becomes 10ms but the ratio of on time to off time stays the same. In the above examples, 50% PWM would now be 5ms on and 5ms off, 90% PWM would be 9ms on and 1ms off and 20% PWM would become 2ms on and 8ms off.



  • UPDATE!!

    I was in the process of rebuilding my x axis carriage and I ended up rewiring everything. I recently came upon a load of fancy igus flex wiring (which is also shielded) so I decided to use that and replace all the crappy copper coated tin stuff that was there before.

    Long story short- the fans are quiet as can be now. Of All the things I thought the new wire would possibly improve that was on the bottom of my list.

    SO… if you have noisy blower fans when they are subject to PWM- get some nice wire.

    Does anyone have a good source for flexible stranded all copper wire? It always seems way to expensive or like the seller may be trying to push copper coated stuff as all copper.


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