Am I missing anything?



  • Digging in the thousands of motors we have at the FabLab, I came across about a dozen or so of these:

    https://www.micromo.com/am2224-v-12-75-10.html

    They are 22 steps per revolution (15°) stepper motors, however, the plant an hour north of me may be able to laser weld a spur gear and give me any gear ratio I want on it, I'm thinking anywhere between 100:1 and 800:1 depending on what axis and on what style machine.

    I do not like microstepping anymore because of what I learned about the torque drop off, however, I do like the ability to simply increase resolution quickly if too little torque is not a problem. I am thinking of using these with high gear ratios (because I don't have to pay for it) to try to nearly eliminate torque drop off due to microstepping. I want to microstep these no more than quarter step.

    These appeal to me because of the potential increase in torque at higher resolution as well as significantly reduced rotor inertia which hopefully will result in higher precision, as the mechanical tolerance of the gearheads is less than that of microstepping (or at least that is what I've been told).

    Either way, I get funding if I can use their motors practically…in nearly any capacity...so why not try to attract attention with something cool like a 3D Printer?

    Since these are pretty regular stepper motors, I figure they are pretty close to "drop in" replacements. The torque is a concern though, I am worried I may need to double or triple the gear ratio to get comparable torque to the Nema 17 style Steppers we are used to, as these are easily half the size, closer to a third the size or less. I'm simply expressing a concern I have with these, feel free to ignore this as I'll find out more about the torque when the application engineer responds to my question about bringing in the motors to put gearheads on them.

    I also am worried they won't fit the GT2 pulleys common with our printers, but that is a separate issue and is solely dependant on the output shaft. I imagine I can simply request one with the right diameter with a flat or two...I may even be able to get precision lead screws directly attached to gearheads! 🙂 which means I need crazy high precision on the other end of the screw as well...yay...

    Is there any reason someone can see why these stepper motors will not work? There are individuals far more educated and far more experienced that I, so if anyone sees I problem with that I intend to do before I go and wire these up to test them...please let me know 🙂

    I'm hoping the Faulhaber's will fund my research and development of a PolyJet (Polymer Inkjet by Objet Geometries) and maybe I can bring you guys a [build log] (not a build guide, that's illegal, a build log is frowned upon*, there's a difference ?) on what I did with a Duet…of course for legal purposes I would recommend not to do it yourself ?

    Any and all advice, criticism, support, etc, is appreciated!
    Thank you in advance!

    *I think a build log is frowned upon...I hope it's not illegal cuz I'm gunna do one haha



  • The inductance of that motor seems to be 65 mH, and the rated voltage is 96V which is way high for duet electronics (and most other reprap electronics).

    With those gear ratios, you'd be lucky to achieve 1 mm/s speeds.



  • @bot:

    The inductance of that motor seems to be 65 mH, and the rated voltage is 96V which is way high for duet electronics (and most other reprap electronics).

    With those gear ratios, you'd be lucky to achieve 1 mm/s speeds.

    96 volts??? Where do you see 96v?? Oh…I see where it says that. I must know less about this stuff that I thought I did.

    "FAULHABER® PRECIstep® Technology series AM2224-R3, 22 mm dia. 2 phase DC stepper motor, 12V coil with 3mm shaft. with FAULHABER® series 26/1, 26 mm dia. precision planetary gearhead, 43:1 reduction ratio and 5.0 mm dia. output shaft."

    12v coil...and yet
    "Stepper Drive Voltage, Min. 96 V"

    I must not understand anything about this! Okay, so the duet wiki for choosing stepper motors tells me to stay away from motors higher than 4mH...yeah...these exceed that greatly. Okay.

    By the way, I cannot believe I never really thought about mm/s...wow. Okay. You're right, not worth it at that speed.

    Thank you, I'll keep reading! 🙂



  • You are welcome. I had little knowledge of any of this at one point, too, and it was quite confusing. It still is, but I at least know what to look for. 😛


 

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