Part cooling fan always on at low speed
Hello, I have an issue with my Rat rig C-Core 3.1 priter (400x400) cooling part fan. I changed the part cooling fan with this one "https://www.distrelec.ch/fr/ventilateur-axial-dc-bille-40x40x28mm-12v-48-6m-sanyo-denki-9ga0412p3k01/p/30154445". It seems to work quiet well. I can change the speed with PWM control correctly. The only problem is that when the value of the fan speed is set to 0 (when not printing or while first layer) it still blows some air. The speed is very slow but not at zero as expected. I have trouble understnding the issue...
This is my klipper config for part cooling (pretty standard configuration) :
[fan]
pin: !fan_part_cooling_pin
cycle_time: 0.00004
Did anyone have the same issue ?
16 Replies
Yup that is a known issue, see https://os.ratrig.com/docs/guides/4028#my-fan-doesnt-shut-off-at-0
Connecting a 4028 fan | RatOS
4028 server fans are becoming a popular option for part cooling because of their light weight and great pressure and flow rates. In this guide we'll go over how to connect one and use it for part cooling. 4-pin fans usually aren't used in 3d printers, and many boards only provide 2-pin ports, but fear not! There's always a way.
manual-pink•13mo ago
Oops, I will try that... I thought that issue was only at printer startup.
What pin would it be on the "BIGTREETECH Octopus v1.1" (PA9) ?
if you read the instructions, you must wire it differently to use the enable pin. Did you first do that?
manual-pink•13mo ago
Yes exactly, I was thinking of connecting the gnd cable of the fans power intpu to HE1 - pin but I am not sure if I should keep the + wire on the HE1 + pin or leave it at its current position..
Sorry for the stupid question
you can leave + wire where it is. Only gnd is controlled
no worries
manual-pink•13mo ago
Yeah it is the PWM that is put on HE1..
You can connect PWN cable to fan octopus gnd pin, and GND of fan to HE1 GND
Does that make sense? I am not the best in explaining, so don't be ashamed to ask. 8)
manual-pink•13mo ago
On this image, the blue wire would be connected to the HE1 Negative pin right ?
black to HE1
gnd is black
manual-pink•13mo ago
Oh okay
blue is PWN - you can leave it as on picture
manual-pink•13mo ago
Ahh I got confused..
PWN does not need a lot of current - that is why fan pin is good enogh, but ground of power full fan should be controlled by powerful transisor, as in HE1
That is basically the main reason of not using another fan header for gnd of the fan
manual-pink•13mo ago
Okay, but then I dont understand really why the red wire souhld not be connected to the HE1 positiv...
My electricity nowledge is not ideal ^^
You can connect red to HE1 + too, it just doesn't matter, transistor control only the GND(black, -) pin, +(red) is always on
manual-pink•13mo ago
Okay I get it 🙂
Just tested it out and it works perfectly ! Thanks a lot for your help 😄