Nema 23 stepper motor run slowly and stuck at high speed

Discussion in 'General Electronics Chat' started by burnley1, Nov 24, 2015.

  1. burnley1

    Thread Starter New Member

    Nov 24, 2015
    4
    0
    Hello everyone!
    I have a question about RPMs of stepper motors.


    I have a kit from Longs motor: Nema 23 425oz motors, 350W 36Vpower supply and DMA542A microstep driver
    [URL='http://www.longs-motor.com/pr...ww.longs-motor.com/productin...12_86_173.aspx[/url]


    I can get only like 240rpms with my Nema 23425oz, If i go faster (with Arduino), the motor just stops and produces strange noises (high pitch noises, but it doesnt move) and vibrations. What to do? All the thing is with no load on the motor shaft.,


    Can u please help me what to do?


    Best regards
    Matic[​IMG]
     
  2. nerdegutta

    Moderator

    Dec 15, 2009
    2,515
    785
    Sounds like you try to drive your motor at a higher step rate than it can handle.

    What have you done troubleshoot?

    What does your code look like?

    How about a schematic diagram, to show your connections?
     
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,515
    2,369
    The torque is reduced in the micro stepping mode, if you try to supply too high a step rate you run into loss of torque at high rpm.
    Max.
     
  4. MrSoftware

    Member

    Oct 29, 2013
    497
    122
    Check the stepper controller to see if you can adjust the ramp up speed. If you go from zero to full speed instantly on a stepper and the first step doesn't have enough torque to overcome the combined moment of inertia of the load and the motor itself, the stepper will just sit there and buzz. You have to start the steps slower and build up to full speed. The rate at which you can build speed depends on the combined inertia of the motor rotor and the load. For a motor by itself you will be able to speed up very quickly, but with some motors you cannot go from zero to full speed instantly.

    It also depends a lot on your motor driver. You might need a stepper controller that can output more power; higher voltage and more current. Steppers will have a maximum usable speed, but not enough power can move that limit lower.

    Microstepping can really smooth things out, but you have less and less torque as you step between full steps, with the least torque when you're half way between 2 steps. My advice is first get it working with full steps. It might be clunky and noisy, but get it working. Then add in microsteps to smooth it out and make it quiet. If you're moving something that has a lot of inertia, microsteps might help you get it moving.

    This controller is based on a chip that I've used before with success, and an arduino library is linked from the product description:

    http://www.kr4.us/Dual-L6470-Stepper-motor-controller.html

    Here's a HowTo with some example arduino source:

    http://play.karlssonrobotics.com/tutorials/stepper-motors/using-l6470-dual-stepper-controller/

    PS-> When you stop your stepper, be sure you're aware of which mode you put your stepper controller in. If you lock the stepper electrically, the stepper controller will be delivering a lot of current and will get hot. If you need to use this feature, you might need to heat sink the stepper controller chip.
     
    GopherT and RichardO like this.
  5. burnley1

    Thread Starter New Member

    Nov 24, 2015
    4
    0
    Thank you all for your time for answering.
    The code from Arduino is:

    void loop()
    {
    digitalWrite(steppin, LOW);
    delayMicroseconds(del);
    digitalWrite(steppin, HIGH);
    }

    I think i cant do a fullsteps, because of that table, check it out: [​IMG]
    I can only do a half steps right? I also tried the setting of ON ON ON ON switches but its really precious, much more than halfstep.

    The wiring picture is in attachment

    I will try it to accelerate the motor speed from 0 to something.
    But I got all the parts in kit complete from seller, that is so wrong eh?
     
  6. shortbus

    AAC Fanatic!

    Sep 30, 2009
    4,004
    1,525
    Do you have the driver set at the correct amperage setting for your motor?
    What switches are you setting to the "ON ON ON ON"?
     
  7. burnley1

    Thread Starter New Member

    Nov 24, 2015
    4
    0
    Yes, the motors current is 3A from specs. And the set current is 3A RMS so the setting is OFF OFF OFF on the SW1 SW2 and SW3.

    I tried to run the motor while set the last four switches (SW5, SW6, SW7, SW8) to ON ON ON ON because i though that would be maybe fullstep option but its not. I have set on the OFF ON ON ON (on last 4 switches) then for halfstep operation..
     
  8. MrSoftware

    Member

    Oct 29, 2013
    497
    122
    If it came as a kit, ask the seller for their recommended settings for that motor/controller pair, that's the easiest way to start. Figure out how many steps-per-revolution your motor is and set the controller to match as a starting point.
     
  9. shortbus

    AAC Fanatic!

    Sep 30, 2009
    4,004
    1,525
    What is switch 4 set at? This driver will only go as low as 1/2 steps. The pulse/rev table shows the number of pulses to make one revolution.
     
  10. burnley1

    Thread Starter New Member

    Nov 24, 2015
    4
    0
    I tried to set the SW4 to ON and OFF so there is no difference of rpm that the motor can handle if its ON of OFF the fourth switch..
     
  11. shortbus

    AAC Fanatic!

    Sep 30, 2009
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  12. BR-549

    Well-Known Member

    Sep 22, 2013
    1,981
    388
    I would give the motor something to do(load). Something for the controller to work against.

    Is the effect the same under moderate load?
     
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