24v power supply with 5 nema 17



  • Hi all,
    I have a good 24V power supply with 10 amps dc output current that I would like to use for my duet project. In particular, I am using a Duet 2 Wifi with 3 NEMA17 (amps per phase: 2, ohms per phase: 2, mH per phase: 3.3) plus 2 NEMA17 (amps per phase: 2.1, ohms per phase: 1.6, mH per phase: 3). Sorry my incompetence on the argument, but I would like to know if it is safe to wire and run such a system or, if there are some further safe measurement to take like wiring some resistors in series with the motor phases or similar. Any help will be very much appreciated. Thank you!



  • Just connect the supply to diet, and duet to steppers.
    Why do you want more complicated ?



  • @pipersw I am just worried that I will meltdown the board with all the drivers... 24V power supply and all those nema17 (60 mm long cases.. the biggest ones) will all work fine ??



  • Yes, don't worry. If the drivers are too hot thez will shutdown, depend what current you defined for each steppers. 65% to 85% rated current for steppers are recommended.
    10A will be sufficient for steppers, fans and hotends, but with a main supply bed.



  • You can compute the total power needed, see https://duet3d.dozuki.com/Wiki/Choosing_the_power_supply#Section_Total_power_needed

    2A steppers are no problem on a duet2 board.



  • The bed is typically a much larger draw than the motors. Will this printer have a 24V bed? Or a mains (110V or 220V) bed with an SSR?

    If 24V, what wattage?



  • @Danal thank you for the reply. It doesn't have a hot bed and actually it is not a 3d printer... It is a filament winder for carbon fibres. I am using the duet because it is very practical and cost effective!



  • Fantastic! Post pics if you can... and, of course, that means there are no amps to calculate for the bed!



  • @Danal As soon as I publish something I will be incredibly happy to share! I am sure that I will receive some good hints for the next stage!



  • @fm16055, due to some electronic magic, when you set your stepper motor for 2A it will take from the 24V power supply only about 0.2A and will generate very little heat on the duet board.

    That's why people budget stepper by power (coil current x coil voltage specified by the stepper manufacturer) rather than by current.



  • @zapta ... perhaps I have no such competence to fully understand why and what it will means for my machine. I understand that 0.2 amps won't heat up the drivers, but what about torque? are there some settings that you suggest?



  • @fm16055 said in 24v power supply with 5 nema 17:

    are there some settings that you suggest?

    Your best bet would be to post your config.g and ask for feedback. There are some great gcode experts here.



  • @fm16055 the stepper drivers are 'choppers' which turn off the supply to a coil as the current hits a specific value. The current then drops (not sure if this is to zero or for a set time) and the process repeats. Very quickly! The net result is the loading on the stepper coils is similar to the power that would be consumed by appling the continuous rated voltage to the motor from the spec sheet.

    As torque is related to coil current if the stepper is moving it takes a period of time for the current to reach target current. This delay reduces the speed at which the motor can run, and you still get good torque. Higher voltage = faster current increase in coil = better torque at higher speeds & higher max stepper speed.



  • thank you all. As soon as I have access to the lab and I manage to build it I will post pictures for some further help. Thank you again. Cheers


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