Hotend fans replacement ?

[DzzD]

I have upgrade an A20m with TMC2208, it is really much quieter, but now I have a problem with the noise of those two 30mm fans on the hotend, anyone managed to replace them with quieter one or with 40mm ? If so could you point me which one you use and if it require a new hotend support where can I found a STL for this ?

[William]

Hi, you can try to replace it.
But you need to pay attention to the corresponding use voltage.

[DzzD]

i just rewired them in series to reduce them to 12V each.

Nice idea !, I should have read your comment earlier ... I unwired both and use a 4020 mm 12v fan on front (I modelised and printed a cover for that), I will share it when will be completly finished.

For now I use a voltage regulator that down the voltage from 24v to 12v (LM2596) but I am thinking of replacing it with a simple resistor (with appropriate power 0.5W) equals to the fan resistance, it will be smaller and will require less space.

I choose a 20mm thick fan as it flow more air with a lower speed (and so less noisy).

Now I need to redisign a fan duct for cooling parts, because all those I have found do not work with the A20m original fan I have (I suppose they changed it, as they also change a lot of other things... https://www.geeetech.com/forum/viewtopi ... 08&t=69516)

[DzzD]

i just rewired them in series to reduce them to 12V each.

I think now that it is a better solution and I will rewire those fan that way, as they are not really noisy with 12v but do you think they still blow sufficient air ? did you have any issues when printing for a long time ?

I will not completly throw away my design but rather use it for replacing the fan that is cooling parts.

[DzzD]

been using my printer like that for a year no issues.

So it is perfect solution, everything is rewired now and it is printing silently, cool.

[Jarda3d]

Did not rewire 2x12V fans to 24V supply! It is very bad idea! Fans are not resistors!

If you want to use 24V supply for 12V fan, buy step-down DC/DC power module

https://www.aliexpress.com/item/33010669409.html
https://www.aliexpress.com/item/4000333580671.html

DzzD, it is nice, would you like to share STL file, please? My fans at A10M are very weak now. I have 30mm, but 40mm will be better. I have 4020 fan blower for better cooling here too, but still does not changed.

[Jarda3d]

Fans are not linear load. They should work, but you should get into flames. Use step-down module for safety reasons.

[DzzD]

Fans are not linear load. They should work, but you should get into flames. Use step-down module for safety reasons.

My electronics studies are far... and english is not my natural language, but here is what I think : these fans are simple coils often 3 like DC motors, but as they are spinning coils receive something equivalent of an AC voltage with a frequency proportional to them rotating speed and then they produce an inductive reactance, so using two same fan they will produce the same inductive reactance and then they will probably receive each 12v same as two coils in serie under an AC voltage.

Once again my studies are far, so my apologies if I am wrong.

[Jarda3d]

BLDC motors in the fans are not plain "coils in series", nor asynchronous motor, they have some electronics. In reality, there are 2 different devices with 2 different loads.

Laboratory short tests and real usage in thousands hours per year in real enviroment are totally different.

EDIT: OK, if there are 2x24V in series, no problem