Fans 1 & 2 only operate full speed?



  • Hi - converting my printer to use E3D Chimera. The main fan for cooling the block is set as P1 and I have a little part cooling fan as P2. I also have a fan near the Duet to cool the stepper drivers as P0.

    P0 can run at S0.3 very nicely (almost silent!). However, the fan supplied by E3D for the Chimera only works at S1 or 255, very far from silent! Any value less than that and it just stops. Same for P2.

    Anything obvious I'm missing here?

    Tried sending M106 P1 H-1 to change their defaults and then try some speed tests, but I can't get them to come on unless the S value is very high (over 250).



  • Some fans require more juice off the start to get spinning and can be reduced after the initial spin up.

    M106 has a B value to Blip full power to the fan initially to overcome the initial resistance. I think by default it's pretty low. 0.1. Try setting it to 1 for a full second of full power.

    However, some fans do not respond well to reduced speeds at all. I believe the Chimera has fairly heavy thermal needs, and E3D may have purposely chosen a fan that will only run at full speed, to ensure it is cooled properly.


  • administrators

    Yes as Phaedrux says some fans really do not like PWM and so not work properly at anything less.

    Quick check: Swap F0 and F1 (power down the board in between :D) that will prove its the fan and not some other issue if the ability for working PWM follows the fan you have fitted to P0.

    If it is the fan you need to see what the flow rate of the Chimera heatsink cooling fan is and then see if you can get a quieter fan that has a higher flow rate to swap out.


  • administrators

    Some fans can be made to work with PWM if you set the frequency (F parameter in M106) very low, e.g. 100 or even lower. But the 30mm ones that E3D supplies didn't work with PWM at all when I tried them.



  • @dc42:

    Some fans can be made to work with PWM if you set the frequency (F parameter in M106) very low, e.g. 100 or even lower. But the 30mm ones that E3D supplies didn't work with PWM at all when I tried them.

    Ah, that doesn't sound good! I'll try swapping them as suggested above just to check. The fan that throttles down is a 40mm Noctua that I bought.

    Shame that E3D fans have to be on full speed, suggests the cooling fins on the chimera aren't very effective. I had heard rumours to that effect prior to their new design coming out.


 

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