Guess this is the layers fan week Mine won't work either



  • I've a Maestro on a CR-10S.

    My previous setup (Marlin) had this fan as the parts cooler:
    Blower Fan

    It was noisy and it was suggested on the CR-10 group that a 1ufd cap be placed across it to reduce the noise, I did and it did. Ran for a year like that, never giving any thought to it on my new Maestro.

    My initial test it ran fine but suddenly it stopped working. Now reading on here:
    RC low pass filter for Blower Fan
    I see the Maestro doesn't like a cap across the output, so I removed it. The 12v fan is well within the amperage range but I suspect I may have blown the MOSFET for the 1st PMW fan output. Close exam doesn't SHOW anything, MOSFET looks OK visually but no fan.

    What fan SHOULD I be using? It's a 5015 sized fan on a Petsfang cooler:
    https://www.thingiverse.com/thing:2759439

    What load should I put across the fan terminals to check for output? I assume it's just 12vdc out. I DO have access to an OScope if needed...
    Thanks!

    EDIT: The fan works on the 3rd channel using the Fan Test Macro (minus the cap), but I don't want to possibly blow another port until I know this fan is OK to use long term.



  • I'm replying to my own post to upload the fan pic I inserted which doesn't show for some reason.

    0_1551041919102_CR-10S Blower Fan.jpg


  • administrators

    That fan is OK, but connecting a 1uf capacitor across the fan output will cause a current spike in the mosfet on very PWM pulse and also increased power dissipation in the mosfet. So remove the capacitor. If the fan is producing noise at the PWM frequency, try changing the PWM frequency using the F parameter of the M106 command.



  • @dc42 said in Guess this is the layers fan week Mine won't work either:

    try changing the PWM frequency using the F parameter of the M106 command.

    Thanks, thought so. Cap is already gone. Any suggestions for F?
    Thoughts on Fan 1 output not working? I'm pretty surprised that a fan that worked for years on a cheap ass Creality board would kill an such an expensive replacement...


  • administrators

    Some cheap boards such as RAMPS provide 2 large mosfets where the second one can be used to power a second extruder heater but is more often used to power a fan. The Duets provide 2 large mosfets and three smaller mosfets for powering fans. There isn't room to use large mosfets for all the fan outputs.

    That said, I'm a little surprised that a 1uf capacitor would damage the mosfet, although the current surges could easily exceed its peak current rating especially if it is a ceramic capacitor with low ESR.

    If you have only one extruder heater, then it's possible to re-purpose the second extruder heater output for a fan using the A parameter of the M106 command, which is supported in firmware 2.02 and later.

    Try different F parameters to see what works well. Some fans don't work with PWM at all unless you use very low values. Between 50Hz and 1kHz is a good range to try. A few people use high values such as 20kHz.



  • @dc42 said in Guess this is the layers fan week Mine won't work either:

    That said, I'm a little surprised that a 1uf capacitor would damage the mosfet, although the current surges could easily its peak current rating especially if it is a ceramic capacitor with low ESR.

    Yeah, that's what I was thinking. I'm pretty fastidious in doing wiring so it wasn't crossed neg/pos at any point. It actually worked at first then just stopped. Found the cap while checking wiring. Pretty small cap:

    0_1551111420293_1ufd cap.jpg

    Damn big pic for resized smallest on phone, LOL! Today's high rez cameras are something else.

    Well guess at some point I'll replace the MOSFET (I've got a rework station), but for now I'll run on Fan 3 output. What is the replacement MOSFET?

    Nice to know about the reassign to E1 but I'm running my second Z there, the Duet boards sure are amazingly flexible.

    I'll play with the PMW freq. Now off to fire it up for my first print test, wish me luck!
    Thx as always.


  • administrators

    @puterpro said in Guess this is the layers fan week Mine won't work either:

    Nice to know about the reassign to E1 but I'm running my second Z there, the Duet boards sure are amazingly flexible.

    I was referring to the E1 heater output, not the E1 motor output. They are independent of each other.

    The mosfet part number is PMV40UN2 with or without an R on the end.



  • I was referring to the E1 heater output, not the E1 motor output. They are independent of each other.

    Read too fast since I knew it wasn't currently a problem, noted.

    MOSFET - Thx.

    I was just about to edit to add this:0_1551114763466_Fan MOSFET.jpg

    Doesn't LOOK blown, but I haven't metered it out. Non issue for now tho', if I ever go dual extruder I'll fix it.


 

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