Select power supply. who can help?



  • Hey
    I want to use the duet3 6hc with the duet3 expansion 3hc.
    4 nema 23 and 5 nema 17 motors should work on my big beast.
    At the moment it´s still difficult for me to do the hole electric things.
    Can anybody help me?
    KR
    Richard





  • Just go and get and ATX psu from a computer. theyre rad for printers!



  • @barbarossa-cologne, the link that dekingman@ provided is very good. You will need to make a few decisions

    1. Voltage. The typical choices are 12VDC and 24VDC. As the link says, 24VDC has a few advantages and I would choose it unless you have a strong reason not too.

    2. Heating bed, operating on mains voltage (110/200VAC) or from the DC power supply. There are pro and cons for each approach. Do you have a preference here?

    3. Power capacity of the DC power supply. The link explains how to calculate the minimum power requirements of the power supply.

    4. Power supply vendor. You can go with a cheapo or with more recognized brand (e.g. Mean Well) with proper safety certifications (e.g. UL). People use both approached.

    These are the key decisions that you will need to make. If you will have specific questions, just post them here and people will help you.



  • @barbarossa-cologne in addition to the other information let me add:

    • I have good experience with MeanWell PSUs, 24V based
      9 motors means high power requirement like in the range 500W (needed power will be lower)
    • I would separate bed heating to a separate power supply, controlling on/off/temperature by the Duet. There ares some threads here how to do it (e.g. with SSR), so the mainboard is not under high load and is releaved from heating by the current for bed heating
    • cooling of the Duet mainboards will be important
    • if using 24V, everything like hotends and fans must fit 24V also
    • a security concept like smoke detector is important if you plan to print unmonitored, as well as grounding (Schutzleiter) is important
    • cabling and crimping of the connectors is also important. You will find documentation and discussions here how to do it best and which crimping tools are good (I am used to solder everything, but learned here that crimping is more secure)


  • @JoergS5 said in Select power supply. who can help?:

    ........................- 9 motors means high power requirement like in the range 500W

    How do you arrive at that statement? 200 Watts is more than adequate for my machine (excluding the bed heater) which has 13 stepper motors.



  • @JoergS5 said in Select power supply. who can help?:

    I have good experience with MeanWell PSUs, 24V based

    Same here. I like their UHP series, it is fanless (that is quiet), compact, stays cool, and has safety certification I trust.

    https://www.mouser.com/new/meanwell/meanwell-uhp-power-supplies/



  • @deckingman said in Select power supply. who can help?:

    @JoergS5 said in Select power supply. who can help?:

    ........................- 9 motors means high power requirement like in the range 500W

    How do you arrive at that statement? 200 Watts is more than adequate for my machine (excluding the bed heater) which has 13 stepper motors.

    I calculated Nema 23 = 4 A * 24 V = 100 W * 9 = 900 W maximum (minus Nema 17, but some Nema 23 have more than 4 A., They will not be active at the same time, so half the value, but some reserve to be sure, because I don't know the application). But you have far more experience, so you will be right.

    => calculation is incorrect, see below. There is also a good thread here to explain which I found now: https://reprap.org/forum/read.php?160,628636



  • @JoergS5 said in Select power supply. who can help?:

    I calculated Nema 23 = 4 A * 24 V

    Steppers budget should be calculated by power not by current. A 4A stepper doesn't consume 4A from the power supply, only a small fraction of it.



  • @zapta Thanks for explaining, I will change my recommendation.



  • @JoergS5 Just to add that usually the rated current is also quoted at the rated voltage, which is typically something like 3.6 V. So in very simple terms, 4A at 3.6 V is 14.4 Watts ( multiplied by 9 motors =129.6 Watts) but in practice, the consumption is even less that this.



  • @deckingman Thank you for the correction. Stepper usage (= printing cost) is less expensive than I thought...



  • @JoergS5 No worries. By way of a bit of additional information, not long ago I fitted a 24V DC UPS with two small 12V 20AH "leisure" batteries wired in series to give 24V and which power just the printer motors, hot end heaters, and fans (but not the bed or any non-essential "accessories" such as lights). These are sufficient to run my beast of a printer for very many hours - possibly as much as a whole day and night or more.



  • @deckingman I saw the thread when you described what you did and it was interesting. I thought about a flywheel solution with energy from solar modules, but flywheels loose energy very quickly, so I postponed the realisation. I still search for a low cost energy storage.



  • @JoergS5
    I have a 85x85cm heatbed. That needs a lot of power.
    Also I have 4 nema 23 and 7 other motors (some of then will be a nema23 with 3a / maybe).

    After my calculation I think the following power supply is the right one.

    Now, I prefer Meanwell HRP-600-24.

    Can anybody just tell me if I have to connect the expansion board directly to the power supply or indirect via duet3 6h board?
    Thank you all!!!!



  • @barbarossa-cologne @deckingman is the better address to answer it, he has more experience. I would use one PSU for the printer itself with 200 W and a separate PSU for bed heater, controlled by a SSR. The heatbed is very big, so separation makes sense to not use current through the Duet, which must be cooled then, IMHO.

    An idea for construction: myself I design a printer where I use different print beds: if I want to print a small object, I need only a small print bed, for a big one a big bed. So if you design to exchange to use a small bed if you print something small, you could spare a lot of power.



  • @deckingman
    Thanks. I did my calculation like you said.
    Do you know to what I should give attention with the 2500 watt silicon heater?
    I'm new in this world of printing and building printers.
    Thanks for all answers!


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