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  1. #1
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    Nema 23 stepper motors

    Hi,

    I have 3 x Nema 23 high torque motors (3nm), they are barely 2 months old and have been running on a lower voltage & current that what they need.

    The motors worked perfectly fine for 10mins, I then turned them off and came back to them 3 days later and now will not turn and just vibrate (regardless of what I do with Mach 3 motor tuning).

    They seem to be vibrating at different levels, 1 is very weak but another is very strong, they just don't turn and make loud noises while moving around the bench.

    Could they be broke, or is there another explanation?

    Thanks in advance.

  2. #2
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    I doubt it is the motors. The probability of all 3 motors failing at the same time seems rather low. More likely is something common to all, like the power supply or drive. Also check for broken connections like a common ground somewhere.

  3. #3
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    do u have decent drivers for the steppers? maybe you just don't have enough power?

  4. #4
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    disconnect 2 and see if 1 will work on the PS you have.

  5. #5
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    I've disconnected 2 of the motors but it hasn't made a noticable difference.

    When I have the motors connected it seems like it wants to turn, it moves about 2 or 3 steps each way but will then not move until I change the direction I want it to move and then it moves a back to where it started.

    They were all working perfectly fine a few days ago, moved everything really well.

  6. #6
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    It could be that you have loaded a different profile in Mach. I have done this before and things were really weird until I figured out what I had done.
    Set you acceleration really low and try. If that don't work, try swapping the active high or low settings.
    Lee

  7. #7
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    I've checked all the settings on Mach 3, checked all the current & amp settings on the Stepper Driver and everything is set as it was before when they worked.

    Its so weird, you wouldn't believe everything that has went wrong with me setting the machine up, its like someone is trying to tell me something.

  8. #8
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    I guess there are 2 paths
    - Self diagnosis
    - Vendor diagnosis

    To get help on a forum, you will need to describe each and every part, setting, wiring diagram, etc. It also assumes you have some tools to visualize electrical outputs - like an O scope.

    If you are missing these (like many of us), then it might be useful to see if there is someone you can send some of the parts to so that their individual performance can be tested.

    Example - maybe another forum member can test your motors on their system ? OR - send at least 1 back to the supplier and see what they thik. Same with the other parts.

    I would certainly take all of the load off of the motors (take them off the machine) to see if that helps.

    Check your grounding paths. Use braided cable and make sure something is not floating up the ground connections.

  9. #9
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    It really does sound like electrical or a setting issue.
    I would think if the drives went bad, you would not have any motion. Electrical noise could surely do this as well.
    Is there anything located near the controls that wasn't there before?
    Do a Control Alt Delete and check to see what all is using resources on your PC.
    Lee

  10. #10
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    The motors haven't been attached to the machine throughout the tests.

    I attached some old motors to the driver board and they worked fine, unfortunately they aren't powerful enough to move the machine.

    The motors I have are these ones

    The Driver board I have is this one

    I am supplying the board with 13.8v & 7amps, I know thats very low but its the best powersupply I could afford and find that was UK wired.

    I have the motors wired in series, I have sat for hours with 1 motor and tried a lot of different settings on Mach 3.

    I'm pretty much an amature at this, how would I check the ground connections?

    Thank you all for your replies, its greatly appreciated.

  11. #11
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    Quote Originally Posted by nenetwork View Post
    The motors haven't been attached to the machine throughout the tests.

    I attached some old motors to the driver board and they worked fine, unfortunately they aren't powerful enough to move the machine.

    The motors I have are these ones

    The Driver board I have is this one

    I am supplying the board with 13.8v & 7amps, I know thats very low but its the best powersupply I could afford and find that was UK wired.

    I have the motors wired in series, I have sat for hours with 1 motor and tried a lot of different settings on Mach 3.

    I'm pretty much an amature at this, how would I check the ground connections?

    Thank you all for your replies, its greatly appreciated.
    13.8V is V low.....24V would be a start. :rainfro:
    Keith

  12. #12
    Is the power supply regulated or unregulated? 13.8V is very border line, and the line voltage may have dropped and causing the driver not to start properly.
    The 12V min voltage will most likely have a +/-10% tolerance?
    As kipper said, try another power supply, with a min voltage of 24V DC.

    Quote Originally Posted by nenetwork View Post
    The motors haven't been attached to the machine throughout the tests.

    I attached some old motors to the driver board and they worked fine, unfortunately they aren't powerful enough to move the machine.

    The motors I have are these ones

    The Driver board I have is this one

    I am supplying the board with 13.8v & 7amps, I know thats very low but its the best powersupply I could afford and find that was UK wired.

    I have the motors wired in series, I have sat for hours with 1 motor and tried a lot of different settings on Mach 3.

    I'm pretty much an amature at this, how would I check the ground connections?

    Thank you all for your replies, its greatly appreciated.
    Zapp Automation Ltd
    www.slidesandballscrews.com

  13. #13
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    The power supply is Regulated.

    Do you think that it seems likely to be the problem?

    I don't suppose you know the best place to get a Powersupply in the UK, I've looked at a few places like Maplins but they didn't have anything near what I need.

    Thanks.

  14. #14
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    Would this powersupply be ok - PowerSupply

    Update

    A colleague took the motors to a shop in town and they tried to move them by hand, 1 of the motors turns ok, another turns but at the same point it makes a noise and the last motor will not turn regardless of how much force is being applied.

  15. #15
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    I can turn my steppers by hand. You can feel the magnetic indents when you do this. Not smooth like a typical motor. You can't spin it and expect it to keep spinning once you release it.
    Your last post does sound like something when wrong with the motors. At such low voltage, I have a hard time thinking it was current related.

    I have accidentally shorted a motor wire to ground before.
    While it killed the drive, it didn't hurt the motor.


    That PS looks okay.
    May be a little low on the amps, but I did run one similar at 48 VDC with 7.3 amps and no issues.
    Lee

  16. #16
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    If that 24 VDC supply gives you trouble, you can always tie it to 2 each 12 volt lead acid batteries in series. That will smooth it out and provide some peak capacity in case your steppers have moments of higher draw.

  17. #17
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    Make sure you have a good ground on your signal line and line from PC. You might have issues with the shield on the connecting wire due to bad ground.

  18. #18
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    I have been told to send them back by the company I bought them off.

    My friends motors (the same ones) worked fine for over 30mins before he had to get off.

    I don't know how this has happened, its really strange and with one of them not turning using pliers I think there must be a fault with the ones I have.

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