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Random Motor Stalling

Discussion in 'Motors' started by barnett chenault, Jan 14, 2017.

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  1. barnett chenault

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    Hello everyone, I'm looking for some direction on a base c-beam build that I'm trying to maximize for projects.

    The issue I am getting is that it seems to randomly stall at high speeds.
    Here's my current setup:

    Power Supply - 36V @ 8.3amps
    Drivers - CW230 @ 24-40V - 3.0 amps
    - Set to 1/32 microstepping
    Motors - Nema 23 high torque
    Motion Controller - CNC4PC - C32S w/ MACH 4

    I notice it the most when it is rapid planing in two directs, almost like it is pulling too much amperage.
    I'm open to any suggestions as to what the weakest link in this chain is.

    Thank you,
     
  2. snokid

    snokid Master
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    Could try to turn the current down to 2.7A and see if that helps....

    Bob
     
  3. David the swarfer

    David the swarfer OpenBuilds Team
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    Turn your microstepping down to 1/16 (and don't forget to reset steps/mm in Mach to half the current value).

    This increases the available power. more microsteps = less power.

    If the stalling stops it means that the mechanism is jamming somewhere, sometimes.
    If it continues to stall, it means one or more of the drivers is overheating and cutting out to self-protect (or even the main power supply).
     
  4. Joe Santarsiero

    Joe Santarsiero OB addict
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    Also, your acceleration rates may be too high.
     
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  5. barnett chenault

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    Thank you Bob, are you suggesting 3.0A down to 2.7A on the drivers themselves or somewhere else?
    I'll try that, but im wondering what the theory is, and if it wouldn't be better to find a power supply that
    could keep the amperage at 3.0A?

    David - Right I read about that, and perhaps 1/16" is better, but the problem has still demonstrated in the past even
    at 1/2" stepping. It only becomes apparent when the machine is rapid planing in two directions, such as when homing to Zero. I
    know its not a mechanical issue as it is completely random as to where/when it happens, and it doesn't exist at other times.

    Joe - I agree it may be; however, my hope is to get the maximum performance out this machine. So im hoping to
    find a way to improve things overall to maintain higher accel and velocity speeds.

    I'm really very happy with the machine, but i'm have projects lining up that will require fast repeatability, and so I'm looking
    to see how far I can push the machine.
     
  6. David the swarfer

    David the swarfer OpenBuilds Team
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    so only during rapids with 2 axes in motion? (do both stop or just one?)
    then either you have electical interference between the wires, or your max speed is just a little too high.

    Don't forget you can get the same overall speed with several combinations of acceleration and max speed.
    a slightly lower max speed with higher acceleration is just as fast as a higher max speed but lower acceleration.
    This applies especially to the Z axis, it does a lot of short movements so very high acceleration is better than a very high max speed.

    I would first prove that it never happens when the max speed is lower than it is now. So reduce by 10 or 20% and do a lot of testing. IF that solves it, then it is not electrical interference.

    To obviate electrical interference just separate all the signal wires from the power wires (and from each other) as much as possible and test, test, test.

    I understand you are trying for as fast as possible, but if it is not 100% reliable then the speed is useless.
     
  7. snokid

    snokid Master
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    yes on the drivers....
    Bob
     
  8. Joe Santarsiero

    Joe Santarsiero OB addict
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    Does the problem occur during the rapid or at the beginning of movement?
     
  9. snokid

    snokid Master
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    he says its random....
     
  10. Joe Santarsiero

    Joe Santarsiero OB addict
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    Does one axis stall or both?
     

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