Control motors with rated current higher than Duet Max Current?



  • Is it possible to drive a larger stepper motor (a Nema 24 with 3.5A/Phase rated current in my case), with the onboard stepper drivers?
    I don't really want to risk to blow my driver when connecting the motor... I don't want to drive the steppers with the full 3.5A, about 2A (<duet rating) would be sufficient.
    So can the drives handle a motor with a rated current higher than the capabilities of the drive? I'd say yes, but asking just to be sure.

    Thanks.



  • you might want to wait for the duet 3. the drivers on it can handle 4A.

    also see
    https://duet3d.dozuki.com/Wiki/Choosing_and_connecting_stepper_motors

    Duet 2 WiFi and Duet 2 Ethernet (maximum motor current 2.4A) => Stepper motor rated current <= 3.0A



  • Thank you for your reply.

    Referring to https://duet3d.dozuki.com/Wiki/Choosing_and_connecting_stepper_motors , as stated above the line you quoted
    Therefore, to get maximum torque out of your motors without overheating them, you should choose motors with a current rating no more than 25% higher than the recommended maximum stepper driver current.
    It says nothing about harming the drivers when driving steppers with higher recommended currents. I know this from industrial Servo Drives: where you can hook up a larger motor than the drive can handle, it just won't get the max power out of the motor, but nothing gets damaged.

    I don't need the maximum torque of this stepper, so I would think that - if the drivers don't get too high peak currents (I'd guess that would have to be handled in the trinamics itself), they should be able to drive 2A through a 3.5A rated stepper?

    Are there experiences with the Duet2 on larger steppers at underrated currents?

    The reason I would like this to work: I'll be converting an existing 3D printer with a nema 24 driving a rather heavy Y-axis. The nema 24 is chosen more for mechanical -easy installation- than peak performance. All the other axis are driven by Nema17's (dual Z w/ two independant drives). And waiting for the duet3 would be annoying as I already have a duet2 that's currently unused.

    As always, alternative solutions do exist. But right now getting it to work like this, seems like the nicest/easiest solution.



  • you can power the the stepper with 2A. it might just skip steps.
    the trinamic drivers shut down when they get to hot.


  • administrators

    @wnica said in Control motors with rated current higher than Duet Max Current?:

    Is it possible to drive a larger stepper motor (a Nema 24 with 3.5A/Phase rated current in my case), with the onboard stepper drivers?
    I don't really want to risk to blow my driver when connecting the motor... I don't want to drive the steppers with the full 3.5A, about 2A (<duet rating) would be sufficient.
    So can the drives handle a motor with a rated current higher than the capabilities of the drive? I'd say yes, but asking just to be sure.

    It's safe unless the inductance of the motors is very low. Do you have a specification of the motors?


 

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