24v cooling fans and 5v always on fan



  • Is possible to use 24v fans pwm and 5v always on?

    On the help I find the exact opposite option

    "If you want to run your other fans on a Duet WiFi from 5V but your always-on fans from 12/24V, you can wire them directly across the power supply pins and ignore the Duet's connectors."

    Ofc I could use the expansion 5v or the panel 5v pins to power it, or a lower v of 3€, but was wondering if is possible or not 🙂

    Trying to connect a full umo+ with um2 hotend (basically all my printer is like a um2). So the hotend has a 5V fan always on, or regulated by the firmware. I could use a V lower thingy to connect it to the fan2 and adjust the firmware, but was wondering if there's a faster solution for now.


  • administrators

    Yes. You can connect the black fan wire to the FANx- pin on the fan connector, and connect the red fan wire to whatever voltage you want up to 25V. Or, as you suggest, connect your 5V always on-fans to the expansion connector +5V and GND pins. Or connect them to the 5V and GND pins on the PanelDue connector.



  • @dc42:

    Yes. You can connect the black fan wire to the FANx- pin on the fan connector, and connect the red fan wire to whatever voltage you want up to 25V. Or, as you suggest, connect your 5V always on-fans to the expansion connector +5V and GND pins. Or connect them to the 5V and GND pins on the PanelDue connector.

    Hi again,

    Sorry that I ask this, on the electronics/wiring area I'm still a noob, so I ask before assuming…

    Does that mean that I could connect the 5V fan to two different plugs? Can I connect the Red + Positive cable to the 5V of the expansion pins and the Black GRD to the PWM FAN2- negative/black ? Maybe I didn't understood (my English is so&so). It's that possible? And if so, does that mean that I could PWM this 5V fan so it starts when the hotend reaches X degrees with the easy gcode/firmware changes?


  • administrators

    @Neotko:

    Does that mean that I could connect the 5V fan to two different plugs? Can I connect the Red + Positive cable to the 5V of the expansion pins and the Black GRD to the PWM FAN2- negative/black ? Maybe I didn't understood (my English is so&so). It's that possible? And if so, does that mean that I could PWM this 5V fan so it starts when the hotend reaches X degrees with the easy gcode/firmware changes?

    Yes.



  • Oh, that's awesome!!! Thanks!!


  • administrators

    One thing I should mention for the benefit of future users. When the new Duet WiFi 1.02 boards arrive, they will have flyback diodes to V_FAN included. Then you will need to ensure that V_FAN is the highest voltage that any fan will be connected to. So your scheme of setting the V_FAN jumper to VIN connecting a fan between +5V and a PWM FAN- output would still work. But the reverse scheme of setting V_FAN to 5V and connecting a fan between +12V or +24V and a PWM FAN- output would not.


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