Stepper choices for Maestro.



  • @DC42, I have just a quick question about the recommended ratings for steppers for the Duet 2 Maestro.

    I have a printer that uses the Maestro and the CoreXY steppers have the following specs.

    • Rated Current = 0.7 A
    • Phase Resistance = 8.8 Ohms
    • Inductance = 18 mH

    The Extruder steppers are:

    • Rated Current = 0.45 A
    • Phase Resistance = 20 Ohms
    • Inductance = 24 mH

    Considering this recommendation in the Wiki:

    Avoid motors with rated voltage (or product of rated current and phase resistance) > 4V or inductance > 4mH.

    Is it possible these motors could damage the board over time?

    Thanks.




  • administrators

    Those motors won't damage the Maestro, as long as you avoid moving the motors rapidly by hand while they are connected. However, even with 24V power you may find that you can't achieve motion speeds as high as you want.



  • Thanks for the reply.

    There's a group of us that have this printer and a few of us have had components on the boards suddenly stop working. For me the extruder heater ports just stopped working out of the blue in between prints. For others one of the stepper drivers shows evidence of dying. One guy had a terrible issue with layer shifts and when he swapped boards they stopped.

    So we were just curious if that high inductance under normal use conditions might put enough of a strain on the driver to cause a failure.



  • What is the printer?



  • M3D Promega



  • @kenny66 I wonder howany of those issues are related to stealth chop configuration.



  • Not sure. I'm running 1/16 microstepping with Interpolation on and I think most are running the StealthChop with the setting D3 V0, because as soon as you leave StealthChop the steppers start squealing like crazy.



  • The extruder steppers (for various reasons) will stall because they don't have enough torque to push the filament. I was curious if running a stepper constantly at it's edge of torque before a stall could possibly harm the Maestro? No matter what speed you're extruding the motors get very warm. If you try and push the speed over 20mm/s (if it doesn't stall) the motors will get to hot to hold a finger on for more than a second or two and you start getting Phase Disconnected errors, which we know was (in that firmware version) a catchall error that in this case was indicating that the TMC driver was overheating and briefly shutting off to protect itself.


  • administrators

    @kenny66 said in Stepper choices for Maestro.:

    The extruder steppers (for various reasons) will stall because they don't have enough torque to push the filament. I was curious if running a stepper constantly at it's edge of torque before a stall could possibly harm the Maestro? No matter what speed you're extruding the motors get very warm. If you try and push the speed over 20mm/s (if it doesn't stall) the motors will get to hot to hold a finger on for more than a second or two and you start getting Phase Disconnected errors, which we know was (in that firmware version) a catchall error that in this case was indicating that the TMC driver was overheating and briefly shutting off to protect itself.

    StealthChop does not work at high speeds. Symptoms of running too fast for stealthChop include skipped steps, reports of short-to-ground, reports of phase disconnected, and drivers getting hotter than they do at lower speeds. Use the V parameter of M569 to restrict the maximum speed at which stealthChop is used.

    Motor noise with TMC2208/2224 drivers seems to be a problem when high inductance motors are used. The 1.33A motors in my Ormerod, which is powered from 12V, are quiet in spreadCycle mode.


 

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