Wantai Stepper Motors 42BYGHW811 vs. 42BYGHM810



  • I thought I had made up my mind about what steppers to buy. I wanted to go with Wantai 42BYGHM810 but now stumbled upon 42BYGHW811 and now I am not sure anymore which ones would be better.

    Specs

    Common

    • Price
    • Weight: 370g
    • Length: 48mm
    • Rotor inertia: 68g

    42BYGHW811

    • Step Size: 1.8°
    • Rated Current: 2.5A
    • Rated Holding torque: 4800gcm
    • Resistance: 1.25Ω
    • Inductance: 1.8mH
    • Detent torque: 280gcm

    Results in EMF Calculator@12V:

    Approximate peak back EMF due to rotation per motor: 3.2 V at 120.0 mm/s
    Approximate peak back EMF due to inductance per motor: 1.0 V at 120.0 mm/s
    Step pulse frequency: 12.0 kHz at 120.0 mm/s
    Speed at which torque starts to drop (low slip angle): 191.9 mm/s @ 19.2 kHz
    Speed at which torque starts to drop (high slip angle): 255.4 mm/s @ 25.5 kHz
    

    42BYGHM810

    • Step Size: 0.9°
    • Rated Current: 2.4A
    • Rated Holding torque: 4200gcm
    • Resistance: 0.8Ω
    • Inductance: 1.8mH
    • Detent torque: 220gcm

    Results in EMF Calculator@12V:

    Approximate peak back EMF due to rotation per motor: 2.9 V at 120.0 mm/s
    Approximate peak back EMF due to inductance per motor: 2.0 V at 120.0 mm/s
    Step pulse frequency: 24.0 kHz at 120.0 mm/s
    Speed at which torque starts to drop (low slip angle): 130.8 mm/s @ 26.2 kHz
    Speed at which torque starts to drop (high slip angle): 163.7 mm/s @ 32.7 kHz
    

    Things I already know

    As one can see the 1.8° steppers run considerably faster before torque starts to drop, so they are a clear winner there even if the 0.9° steppers already exceed my current requirements.

    I know that on a Cartesian using 0.9° steppers does not really help in accuracy.

    Question

    1. Does detent torque make any difference because this is a little lower on the 0.9° version (220 vs. 280gcm)
    2. Can anyone predict which of these two motors will be more quiet?


  • @wilriker Can't answer your question - DC42 is the man.

    But for info, when I was looking at steppers, David pointed me to "StepperOnline". They have a huge selection, good data sheets, and a German site https://www.omc-stepperonline.com/de/nema-17-42mm-schrittmotor/



  • @deckingman Thanks, I know that site and basically all potential replacements for the extruder stepper (if the soon to be used pancake stepper is insufficient) on my list are from Stepper Online.

    For now my final candidates are the two steppers listed above.


  • administrators

    @wilriker said in Wantai Stepper Motors 42BYGHW811 vs. 42BYGHM810:

    1. Does detent torque make any difference because this is a little lower on the 0.9° version (220 vs. 280gcm)
    2. Can anyone predict which of these two motors will be more quiet?
    1. Not really, except (a) if you run them at very low currents then higher detent torque might reduce microstep accuracy; and (b) for a belt driven Z axis or a delta printer, where you may depend on the detent torque to stop the bed or effector dropping when you power the motors off.

    2. I can't.

    Two other comments:

    • 0.9deg stepper motors are best used with 24V power so that you can get high speeds;
    • Both of those motors are quite high current, although within the rating of what the Duet can drive. So you might find yourself wanting to run them at a current for which fan cooling of the Duet is needed, e.g. 2.0A.


  • @dc42 Thank you.

    Re noise: I just contact Wantai directly and asked them if they have any information on noise levels.

    Re current setting: I already have a cooling fan below my Duet and I plan to run these motors at 50-75% of their rated current, i.e. 1300-1800mA.


 

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