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Thread: Problem with cranking up the current for steppers

  1. #13
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    Default Re: Problem with cranking up the current for steppers

    Hi Tangi - This seems to point at a wiring problem. No matter what the current setting is or the voltage, when the system is turned on the motors should lock if wired correctly. Going from 24V to 28V will not change things significantly. You do need to find out why the system is faulting before you do anything. Often 24V is not enough to overcome the motors back EMF when they go fast. The highest voltage the controller can take 30V is best if your game seems 40V is OK. But first check that everything is wired correctly. At low speeds if the motor is getting its correct current then that means the motor is providing its full torque. if you have a switch in the wrong place this can create a surge that trips the controllers. Check the wiring diagram and ensure all switches are where they should be. Plus you can put a limiting resistor into circuit to limit the amperage. This should be explained in the manual/wiring diagram. You can disconnect a motor at a time and turn the system on to see if this isolates which circuit is at fault. A 10A supply should be heaps for this system. Check your set velocities or accelerations are not ridiculous (bring them way down while you are sorting this) as if they are trying to take off like a rocket that will trip the system, sometimes you can be a factor of 10 out somewhere and this is all it takes...

    If your axis is working somewhere along it then it doesn't work somewhere else this maybe mechanical alignment. Should move the same everywhere along an axis. Do not daisy chain the drives ie do not use in series or parallel. Each drive should be supplied via an individual wire otherwise you will get different voltages across each driver... Cheers Peter

    Last edited by peteeng; 06-01-2019 at 07:05 PM.


  2. #14
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    Default Re: Problem with cranking up the current for steppers

    Quote Originally Posted by rodw View Post
    Your drivers are undersized re voltage for NEMA23
    24 volts is not enough for good performance. I've been there and done that.
    Somewhere on Gecko's site I read 2 things:
    1. If you double the voltage you quadruple the torque
    2. The total amperage draw of your steppers can safely exceed your power supply output by 40%

    I drive my NEMA 23's with a 48 Volt power supply with drivers that are good for 50 volts.
    With 4 x 2.5 amp steppers, you will be fine with a 7 amp 48v power supply.
    You will never get satisfactory performance at 24 volts. Bite the bullet and upgrade and you will be amazed at what the difference you will get from your machine.
    Okay thanks for the reply rodw, it seems that I must upgrade my drivers, to get full performance then.

    I been looking around. Would something like this be good for a setup like mine?

    https://www.omc-stepperonline.com/st...er/dm542s.html

    Or this, but it's a little bit more expensive

    https://www.omc-stepperonline.com/st...42t-m542t.html

    Or can you recommend any?

    Quote Originally Posted by peteeng View Post
    Hi Tangi - This seems to point at a wiring problem. No matter what the current setting is or the voltage, when the system is turned on the motors should lock if wired correctly. Going from 24V to 28V will not change things significantly. You do need to find out why the system is faulting before you do anything. Often 24V is not enough to overcome the motors back EMF when they go fast. The highest voltage the controller can take 30V is best if your game seems 40V is OK. But first check that everything is wired correctly. At low speeds if the motor is getting its correct current then that means the motor is providing its full torque. if you have a switch in the wrong place this can create a surge that trips the controllers. Check the wiring diagram and ensure all switches are where they should be. Plus you can put a limiting resistor into circuit to limit the amperage. This should be explained in the manual/wiring diagram. You can disconnect a motor at a time and turn the system on to see if this isolates which circuit is at fault. A 10A supply should be heaps for this system. Check your set velocities or accelerations are not ridiculous (bring them way down while you are sorting this) as if they are trying to take off like a rocket that will trip the system, sometimes you can be a factor of 10 out somewhere and this is all it takes...

    If your axis is working somewhere along it then it doesn't work somewhere else this maybe mechanical alignment. Should move the same everywhere along an axis. Do not daisy chain the drives ie do not use in series or parallel. Each drive should be supplied via an individual wire otherwise you will get different voltages across each driver... Cheers Peter

    Hi and thanks for your reply too. The motors are seperately connected to the PSU and is not looped, if that is what you mean? I have been playing a lot around with the velocity and accelerations. The Y-axis moves really slow and accelerates really slow (do not have the numbers here unfortunately), and still it can't move to the bottom of the y-axis without missing steps. I haven't tried disconnecting motors, to like trying to isolate the problem, so that's one more thing I can try out, next time I have time to play around with it. Thanks again.



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    Default Re: Problem with cranking up the current for steppers

    I have bought from Stepper on line and they give good service and I did get a power supply replaced under warranty after I returned it to a local Aussie address.

    I think you are on the right track. I use Longs Motor DM542A controllers and are very happy with them. A friend also has them on a Syill CNC mill based on a Seig SX3 mill and he does good work. Look for the Elephant on ebay. I bought these a few years ago and I know the A was significant at the time
    stepper motor driver-DM542A - China Changzhou Longs Motor

    FOr the few extra dollars

    Rod Webster
    www.vehiclemods.net.au


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    Default Re: Problem with cranking up the current for steppers

    Quote Originally Posted by rodw View Post
    I have bought from Stepper on line and they give good service and I did get a power supply replaced under warranty after I returned it to a local Aussie address.

    I think you are on the right track. I use Longs Motor DM542A controllers and are very happy with them. A friend also has them on a Syill CNC mill based on a Seig SX3 mill and he does good work. Look for the Elephant on ebay. I bought these a few years ago and I know the A was significant at the time
    stepper motor driver-DM542A - China Changzhou Longs Motor

    FOr the few extra dollars
    Okay cool, and thanks for a fast reply. If ebay it has to be an european one, I live in Europe and I see that stepper online ships from within europe, so it shouldn't be a problem with them



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    Default Re: Problem with cranking up the current for steppers

    YEEEES! It worked, it is working so nicely now! Thank you all for your inputs. The setup is now as follow:

    PoKeys57CNC
    3 * NEMA 23 - 0.7Nm - 1/4" shaft (1=Z, 2=Y)
    NEMA 23 - 1.3Nm - 1/4" shaft (X)
    Power Supply - 24V 10A (Noname)
    Power Supply - 36V 10A (Noname)
    4 * DM542A,4.2A, 18-50VDC

    And it sounds better and runs smoother and faster. The 36V psu is powering the four motors and the 24V psu is now only powering the PoKeys57CNC, but I think I will add some proximity swithches to the setup and power them with the 24V psu too. Thank you all again!



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Problem with cranking up the current for steppers

Problem with cranking up the current for steppers

Problem with cranking up the current for steppers