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Unknown steppers?

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  • undefined
    antlestxp
    last edited by 23 Oct 2019, 23:02

    plug them in with low current and see what happens. you should be able to get them to move with 600mA. If you are curious about what they will handle you can slowly bump the current until you stop seeing shifted layers. I can't give any advice on running nema23. I don't believe the maestro can push them. The nice thing about these duets is you can make changes on the fly and not worry about having to burn firmware to the board with every thing you want to test.

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    • undefined
      MRob
      last edited by MRob 23 Oct 2019, 23:20

      Thanks for the reply, not a bad idea, go until layer shifts stop - and then I'll add some extra. Probably better than random guessing. Maybe I could monitor the stepper temperature for the top end. No advice needed on the nema23, and the DM542 is the driver. I'll hook it to the maestro via another chip to amp the stp/dir/en signals (ULN2003LVDR if anyone is interested!).

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      • ?
        A Former User
        last edited by 24 Oct 2019, 03:44

        in my experience - the temperature is the best way to do it.. start low and slowly increase current till you get steppers to reach ~50C operation temperature.. (not 50C immediately, they should safely operate at about 50C after few hours of print)

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        • undefined
          Veti
          last edited by 24 Oct 2019, 07:16

          look for steppers that are close to it and use that as a starting point.
          see
          https://www.omc-stepperonline.com/nema-17-unipolar-1-8deg-26ncm-36-8oz-in-1-2a-4v-42x42x39mm-6-wires

          undefined 1 Reply Last reply 24 Oct 2019, 07:30 Reply Quote 1
          • undefined
            dc42 administrators @Veti
            last edited by dc42 24 Oct 2019, 07:30

            @Veti said in Unknown steppers?:

            look for steppers that are close to it and use that as a starting point.
            see
            https://www.omc-stepperonline.com/nema-17-unipolar-1-8deg-26ncm-36-8oz-in-1-2a-4v-42x42x39mm-6-wires

            Are the motors in the Wanhao printer 4- or 6-wire?

            Duet WiFi hardware designer and firmware engineer
            Please do not ask me for Duet support via PM or email, use the forum
            http://www.escher3d.com, https://miscsolutions.wordpress.com

            undefined 1 Reply Last reply 24 Oct 2019, 09:08 Reply Quote 0
            • undefined
              Veti
              last edited by 24 Oct 2019, 08:38

              the 4 lead version has the same current rating
              https://www.ato.com/nema-17-stepper-motor-linear-actuator-2-phase-4v-1-2a

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              • undefined
                MRob @dc42
                last edited by MRob 24 Oct 2019, 09:08

                Thanks for the replies - very helpful!
                @dc42 - the X/Z/E steppers are 4 wire, the Y is 6 wire (plug) but with 4 wires going into it.

                undefined 1 Reply Last reply 24 Oct 2019, 09:20 Reply Quote 0
                • undefined
                  dc42 administrators @MRob
                  last edited by dc42 24 Oct 2019, 09:20

                  @MRob said in Unknown steppers?:

                  Thanks for the replies - very helpful!
                  @dc42 - the X/Z/E steppers are 4 wire, the Y is 6 wire but with 4 wires going into it.

                  That stepper motor has 3.3 ohms resistance (close!) and 1.2A rated current.

                  I looked up Nema 17 motors with 48mm body length (the closest they had to 46mm) at https://www.omc-stepperonline.com/nema-17-stepper-motor?mfp=149-step-angle[1.8],183-body-length-mm[48]. the closest they had in resistance were 6.2 ohms for the 0.85A motor, and 1.65 ohms for the 1.68A motor. To a first approximation, for constant body length the rated current should be inversely proportional to the square root of resistance. So a motor with 0.3 ohm phase resistance would have a rated current of 1.22A (based on the 0.85A motor) or 1.25A (based on the 1.68A motor). So I think it's safe to say that the 3 ohm 46mm long motor has a rated current of around 1.2A or a little higher. I suggest running them at between 0.8 and 1.0A.

                  Duet WiFi hardware designer and firmware engineer
                  Please do not ask me for Duet support via PM or email, use the forum
                  http://www.escher3d.com, https://miscsolutions.wordpress.com

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                  • undefined
                    MRob
                    last edited by MRob 24 Oct 2019, 10:54

                    Awesome, thanks for the detailed help! I'll try that, and leave a thermocouple on the steppers as well as previously suggested. Looking closer at them, I see I was actually wrong about the other ones (so FB poster was definitely incorrect), the Z are actually the same as the Y, and the X is 40mm body with 1.8Ohms (also 6 lead plug, 4 going in). So I guess they chose lower weight, and they compensated by using a higher current model... perhaps! Bit of a head scratcher. Anyway closest on the OMC site is then 42mm body, 1.65Ohms, rated current 1.68A. If I am calculating right they from what you said, mine should be 1.41A in that case. So I'll try it at 1.1A to begin with.

                    By the way, while I have you - I've gotten tired of naff, noisy 5015's and am thinking of using a 5v radial CPU fan from ebay on the hot end. One I am looking at claims 250ma in the listing but the sticker in the pic says 350ma <sigh> - looks like other CPU fans are all pretty high current, so should make for good part cooling. Would these current levels be OK for the internal 5v on the Maestro though, or would it be better to add in an external 5v supply?
                    Edited: Just need one fan, not two.
                    Edit again: For higher current fan, I could create an external circuit taking PWM signal from board, ULN2003LVDR should do the job again, but I'm not so familiar with PWM fans so be nice not to have to!

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                    • undefined
                      dc42 administrators
                      last edited by dc42 24 Oct 2019, 15:39

                      Are you not able to find a suitable radial fan that runs from your VIN voltage, which I presume is 12V or 24V?

                      The 5V regulator on the Maestro should be OK up to at least 1A.

                      Duet WiFi hardware designer and firmware engineer
                      Please do not ask me for Duet support via PM or email, use the forum
                      http://www.escher3d.com, https://miscsolutions.wordpress.com

                      undefined 1 Reply Last reply 24 Oct 2019, 16:29 Reply Quote 0
                      • undefined
                        MRob @dc42
                        last edited by 24 Oct 2019, 16:29

                        I could find them, sure, but I'm thinking good quality CPU fans would be better - if I can get 1A out of the on board regulator, that is great and they should be perfect for the job. Long lasting, quiet, high flow.

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                        • undefined
                          Veti
                          last edited by 24 Oct 2019, 17:42

                          get a noctua fan for the hotend.
                          https://noctua.at/en/products/fan/nf-a4x10-5v-pwm
                          its 0,07 A

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                          • undefined
                            MRob
                            last edited by MRob 24 Oct 2019, 18:45

                            Nice but all axial, really needs to be centrifugal for part cooling. I'm curious about dropping a CPU fan in anyway, lots of options there to play with.

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                            • undefined
                              MRob
                              last edited by 30 Nov 2019, 12:33

                              Just writing this to add to the knowledge base, in case anyone else wants to try using a CPU fan....

                              So I tried 25k Hz and it didnt work at all, although I had already tested with an arduino PWM output so knew the fan was good. Hooked up to a 50% duty variable frequency signal generator and it turns out that very low frequencies work best. I settled on just 30Hz. Much above this, maybe 50+hz and the fan starts to make audible tones, getting worst as you get higher, higher still and the airflow will reduce down to nothing. Below 15ish Hz and the airflow starts to oscillate. Now its up and running though, it is perfect for the job - high power, quiet and hopefully extremely reliable. I used one with a part number GC055510VH-A, fits lenovo ideapad B450 etc.

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                              • undefined
                                MRob
                                last edited by MRob 12 Mar 2019, 00:30 2 Dec 2019, 23:31

                                Addendum: My CPU fan seems to have some sort of onboard power management, and reduces its speed either based on time or sensing "blockage" not sure yet. Requires power off/on again to reset back to previous high flow. Most annoying! Not sure why it does this, but others may with to avoid going down this route...
                                On the other hand, my above PN for the fan is actually wrong, I nearly bought it but then went with ZC0560120VH-6A, which is 4 pin and therefore tacho controlled. Perhaps a 3 pin fan wouldnt be so picky? Assuming it is for PWM and not tacho again... I'll test one. Also possible is that adding a circuit to regularly reset the fan, would be a workaround, although that is probably more hassle than it is worth...

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                                • undefined
                                  dc42 administrators
                                  last edited by 3 Dec 2019, 07:53

                                  The safe and sure way of making a fan work with PWM when it really doesn't want to is to use an inductor in series with it and a very high PWM frequency. A flyback diode is also needed if the output doesn't have one built in.

                                  Duet WiFi hardware designer and firmware engineer
                                  Please do not ask me for Duet support via PM or email, use the forum
                                  http://www.escher3d.com, https://miscsolutions.wordpress.com

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                                  • undefined
                                    MRob
                                    last edited by 3 Dec 2019, 12:30

                                    Thanks, good to know - although I'm not sure it would work with a 4 pin, as the control circuit probably wants a certain voltage to function? But thinking more about 3 pin cpu fans, I think it should be good. I just bought one to test, at 400ma it pretty much has to be speed controllable, but also the laptop needs to know RPM to monitor for fault. So third wire must be tacho, therefore it "should" be PWM control like standard 5015 fans. If I can get it to work consistently, then it really is an excellent solution. Previous one (280mA) was seriously powerful before the control circuit kicked in, and they are not even expensive.

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