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Nema 23 issues

Discussion in 'General Electronics' started by Garrett Groll, Aug 28, 2017.

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  1. Garrett Groll

    Garrett Groll Journeyman
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    I’m building a vertical cnc machine for a polishing application, and I’m having problems with the y axis motor lifting my polisher. I’m using the nema 23 (NEMA 23 Stepper Motor) connected to the CNC xPRO V3 Controller (CNC xPRO V3 Controller Stepper Driver) powered by the meanwell power supply (24V /14.6A Meanwell Power Supply)

    The polisher weighs about 5lbs, and I’m using a belt and pinion for linear movement. From what I’ve read, a nema 23 should be plenty capable of lifting 5lbs.

    My question: does the xpro v3 have a limit on how much power goes to the motor? Could it be that the Nema23 motor isn’t getting enough power from the xpro, and that’s why it’s not able to lift the polisher?
     
  2. Jonathon Duerig

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    You can adjust the potentiometers on the board by gently using a screwdriver to rotate them. That might help. You should also double check that your wiring is correct and that the motor moves when it is unloaded.

    Aside from that, the weight that a motor can move depends on how much torque you are generating. So if you are using a belt, you might struggle lifting a weight that a lead screw setup would handle just fine. Belt and pinion setups tend to work best when you want something that can move at high speeds but don't need as much torque.

    -D
     
  3. Garrett Groll

    Garrett Groll Journeyman
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    Looks like I'm going to have to completely change my design to make a lead screw work instead of belt and pinion :( That's disappointing, but at least I know now rather than later as I get further along with the build. Thanks for the help Jonathon! :thumbsup:
     
  4. Gary Caruso

    Gary Caruso Veteran
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    could always do a counter weight with a pulley or a linear spring
     
  5. Garrett Groll

    Garrett Groll Journeyman
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    I actually am already, I just didn't want to complicate things while trying to explain my situation. The real weight of the polisher/gantry that I'm needing to lift is 12lbs. I have a tool balancer (https://www.amazon.com/gp/product/B002SR08A0/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1) positioned at the top which should theoretically cancel out all of the weight of the polisher/gantry. It does this just fine until the polisher gantry reaches the far max and far min travel on the yaxis. As it nears the max travel on the y axis, the tension from the tool balancer is greater than the weight of the gantry. The motor stutters as soon as it hits that point. The same is true as it's approaching the minimum travel (or the top) of the y axis, only at that point...the tension drops dramatically. The weight of the gantry is then too much for the motor to overcome. I estimate that the gantry probably weighs around 5lbs at both of those points. Does that make sense?
     
  6. Garrett Groll

    Garrett Groll Journeyman
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    Well...the gantry doesn't "weigh" 5lbs at the max travel point, per say... but that is the amount of resistance I imagine the motor is experiencing.
     
  7. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    Upgrade your balance system to a constant force spring. Should run you about 1/3 what you paid for the tool balancer.

    As for the steppers losing value, yes the xPro only puts out 2.5A rather than the 2.8A the steppers desire but I don't know enough about electronics to even guess as to the full extent of the loss. You could always go with an external driver that will give you full value but I can't specifically say that will solve your problem.
     
  8. Gary Caruso

    Gary Caruso Veteran
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    did you try less microsteps? do you have the 16 tooth or 20 tooth pulley on the stepper?
    16 tooth will get you some more force..
    Powge on Ebay
    a screw is the best way to do this however..
     
  9. Garrett Groll

    Garrett Groll Journeyman
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  10. Garrett Groll

    Garrett Groll Journeyman
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    I'll have to research constant force springs. I've never heard of one up till this point. I'm with you on "don't know enough about electronics". I just don't understand amperage/voltage and how that all affects the motors. Up till this point, I have just plugged n' played. If it worked, great. If it didn't, I just tried something else. It's an expensive strategy for sure :banghead:
     
    #10 Garrett Groll, Aug 28, 2017
    Last edited: Aug 28, 2017
  11. phil from seattle

    phil from seattle Journeyman
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    I second the fewer microsteps suggestion. You'll get less torque at higher microsteps. I would use the lowest microstep setting your application can tolerate. it's an easy thing to try and may get you there without having to rebuild.

    Also, I hate to say it but the drivers on the xPro are marginally suited for those steppers. I'd follow Rick's advice on external drivers.
     
  12. Garrett Groll

    Garrett Groll Journeyman
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    So I redesigned my machine and 3d printed a crap ton of custom adapters and plates in order to incorporate a threaded rod. I just finished assembling it all and it worked! Exact same motor, same xPro v3 driver/controller, much different result! I'm amazed. I had no idea a threaded rod provided so much more torque than belt and pinion. Thanks for your help everyone.
     
    #12 Garrett Groll, Sep 2, 2017
    Last edited: Sep 2, 2017

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