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  1. #1
    Hi,
    The items in cause are Nema 34 motor 5.6A, 1200oz-in, and driver DQ860MA.
    Dip switches set as OFF OFF ON ON OFF ON ON OFF , which sets the thing to 4.9A Peak, 3.5A RMS, Full Current from SW4 (i don,t really know how to set this), and 2000 pulse/rev. The next current setting is 5.7A peak.

    In mach 3, in ports and pins, motor outputs, checking only the enabled column does nothing, as I,ve seen in some tutorials. Checking only step low active will get the motors running, and also checking both dir and step low active, seems to work.

    In config, motor tuning, I,ve set a few different speeds and acceleration just to see the difference. What exactly should I set in there?

    Now, I,m new to this, and I,ve surely missed something, as the motors get relatively warm after a 1-2 min of running a test gcode from the default mach3 folder.
    The motors are not connected to the ballscrews, so there isn,t any load to carry.

    What have I done wrong?


    Regards,
    Andrei

  2. #2
    I can not see any thing wrong with how the stepper driver is set up

    with stepper motors the motor current depends on what you set by the DIP switches - sw1 to sw3
    not the mechanical load on the motor
    so the current does not go up when you mechanically load the motor as you may of expected

    depending on which manufactures data sheet you look at
    the motor can safely run at 70 to 80 degrees C - too hot to touch !

    a quick look on line did not find clear instructions for the setting of sw4
    but going by a photo of your DQ860MA driver
    I expect sw4 sets the current reduction when the switch is set to OFF and the motor is idle ( not being stepped )

    set to ON the motor will run hotter but should be OK

    setting the motor current to 4.9A instead of 5.6A will do two things
    1) reduce the motors temperature
    2) reduce the motor torque

    if the room temperature is not too high
    then I expect you can safely set the motor current to 5.7A
    the extra 1.7% current should not be a problem
    especially with sw4 OFF


    John
    Last edited by john swift; 15-06-2018 at 10:54 PM.

  3. #3
    Hi John,
    Thank you for the reply.
    It seems the problem then is my lack of experience with how this equipment runs in normal conditions. Besides others which might come in the near future.
    I,ll adjust the settings a bit then, as you,ve recomended, and proceed to mount the motors on the machine.


    Regards,
    Andrei

  4. #4
    General recommendations for stepper motors on CNC routers - set the DIP switch to reduce current when motor is stopped. You do not need as much torque to keep the motor in position when not moving, so you can safely reduce the current and therefore motor heating. Then adjust the motor current based on the motor temperature. Select a current setting, and check the motor case temperature with your hand after, say, 30 minutes. If you can hold it comfortably, try increasing the current. If it is too hot to touch, reduce the current. Aim at a motor temperature of about 60degC, which is about the maximum you can hold. Stepper motors are designed to run at these kinds of temperatures. Current ratings, specification sheets, etc, give you a first guess, but in practice you just want as much current as possible without the motor becoming too hot.

  5. #5
    Hi Neale,
    Thank you for the info.
    As soon as I,ll get the machine going, I,ll post some photos, and some detailed info about it, to get some feedback and advice.
    For example, the gantry weighs apx 250 lbs (100 plus kilos), and even if the motors are capable of moving it fairly easy, and the ball screws 2005 seem ok, surely there is an ipm limit, to avoid any problems from the inertia. It,s a wood router design, 5x5 feet, steel tubing frame.
    I,m reading as much as I can online, but surely there will be some things which I.ll not be able to figure out and I,ll have *to contact someone who knows what he,s taking about* as someone from youtube nicely put it.

    All the best,
    Andrei

  6. #6
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 4 Days Ago Forum Superstar, has done so much to help others, they deserve a medal. Has been a member for 9-10 years. Has a total post count of 2,908. Received thanks 360 times, giving thanks to others 8 times.
    According to the photo of the drive at http://www.wantmotor.com/product/dq860ma.html SW4 changes between full current and half current.

    As has been said, stepper motors can run pretty hot. If they're getting too hot to touch within a couple minutes, something is wrong, but 80deg after an hour or so of running is perfectly acceptable.
    Avoiding the rubbish customer service from AluminiumWarehouse since July '13.

  7. #7
    Hi Rob. Regarding the clicking issue we talked about 4 months ago (sorry it took so long, I started an youtube channel which required so much more work than I imagined, and used the cnc very little since July).
    here is a link with the problem as it happens up to this day: https://www.youtube.com/watch?v=chFWGLZtExQ
    It does not bother me much as it goes away after pressing reset a few times in mach 3, and the cnc works just fine.

    I have a new project in mind, a lot smaller, and not sure if here is the place to start a new topic. It includes steppers/servos, drivers, receiver, remotes etc, arduino components I guess, but it is a small robot (like a toy thing) and not a cnc. Is this (mycncuk.com) the place for such a topic, or should I search for a robotics forum?

  8. #8
    Quote Originally Posted by Radu_Andrei View Post
    I have a new project in mind, a lot smaller, and not sure if here is the place to start a new topic. It includes steppers/servos, drivers, receiver, remotes etc, arduino components I guess, but it is a small robot (like a toy thing) and not a cnc. Is this (mycncuk.com) the place for such a topic, or should I search for a robotics forum?

    I would put it here: http://www.mycncuk.com/forums/333-Ot...hines-Building.

    If it is wrong Lee will move it for you.
    ..Clive
    The more you know, The better you know, How little you know

  9. #9
    Ok. Thank you.

  10. #10
    PM sent

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