Is active cooling required in "Standby"?



  • The Duet Wifi is capable of switching off an ATX power supply … If i understood correctly doing so disables the stepper drivers and heater control...

    So, my question is, with no power to those components, does the duet still need significant cooling or is it fine to switch the electronics fan off with the power supply?

    (I'm going to mount the board in a large enclosure, with the bottom of the board facing upwards and a 60mm fan blowing down onto it, which is the fan i would like to switch off in standby to make the printer silent)

    Thank you in advance for any answers 🙂



  • Well I don't use much cooling on my duet wifi machines on one the board is not enclosed, and is mounted vertically on the side, with 30mm standoffs, so a 40mm fan comes on blowing upwards over the front and back of the side of the board, where the driver chips are.

    On the other machine, the duet is under the bed, I have 50mm fans one push one pull, for the electronics compartment, but they only come on when the bed is over 45 deg C. When sat idle (with PSU on) no fans are on. I think there is practically zero risk of overheating when not printing.



  • @WarriorMe.

    Quick answer to the question posed by the title - No.

    Longer answer - I stuck thermistors on some of my stepper drivers and have cooling fans that blow air on to the back of the board if these thermistors read higher than 45 deg C. At idle (holding current set to 30% of my normal 1800 mA) all fans are off. That is to say, none of the chips get anywhere near 45 deg (at normal ambient temperatures up to the mid 30s). The CPU temperature is always lower than the driver chips. So yes, at idle the machine can be completely silent.



  • Do you have more than one power supply? Or are you running your Duet Wifi off USB?

    Otherwise I would think shutting off the AT power supply would shut down the entire system.

    Please correct me if this is wrong.



  • @knabo:

    Do you have more than one power supply? Or are you running your Duet Wifi off USB?

    Otherwise I would think shutting off the AT power supply would shut down the entire system.

    Please correct me if this is wrong.

    ATX power supplies are the ones used in computers, and to keep wifi and ethernet etc. running they have a 5v rail that is on as long as the main switch on the power supply itself is on. You don't usually notice because this standby rail doesn't need the power supply fan to spin, so it will look like it is completely off, but you will notice that the ethernet LEDs stay on (at least with most PCs)…


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