How find maximun current of steppers drivers



  • Hi,

    the issue i have in the stepper motor of extruder... i dont know how find the current in config.g, M906.

    • If i put a low current in M906, as M906 E600, the extruder start ok, but in some moment in 3 or 4 layter cant push the filament, think cant push the filament when start to do retractions.... suppose.

    but

    • If i put a high curren in M906, as M906 E1200, the extruder start ok... but in some moment, by the hot suppose, loose steps, not printing during seconds..., in fact if in this moment touch the stepper, its VERY HOT...

    Questions:

    1º- There is some method to find the optimal current of steppers?
    2º- What its the maximun temperature, recommened, for a stepper dont loose steps?
    3º- Microstepping affects to the temperature of stepper? (A stepper with a microstepping of 256 and a M906 of 1000, work more hotter than a stepper with a low microstepping, for example 32 and a M906 of 1200)



  • @peirof said in How find maximun current of steppers drivers:

    1º- There is some method to find the optimal current of steppers?

    it should be between 70-80% of the rated current of the motor.
    please post the specification of the stepper.

    give us some more information. what extruder do you have. what hotend. what material are you printing. at what temperature.
    do you have the correct values for your thermistor.



  • ok,

    PSU: 24V
    Extruder Stepper: Nema 17 (Tevo Little Monster Stock 17HD4401-C5.18)
    Extruder: Bondtech BMG
    Hotend: Knoff off E3D v6 (no Volcano, 40w Heatcardrige, 0,4 nozzle)

    Setup as short fliying extruder, 20 cms, aprox

    I have, think, correct thermistor values, calibrated as try error, with a kitchen termometer



  • this one?
    https://tevo3dprinterstore.com/products/3d-printer-parts-titan-step-motor-tevo-black-widow

    then 600 is the correct current.

    if a bmg extruder can not push out filament, then that usually a sign of something else going on.
    either there is to much friction, a clogged nozzle or printing at the wrong temperature.

    please post your config.g



  • that is 1.7A current motor so at 600mA it has a very little torque hence can't extrude but it should not get too warm at 1200mA, it would run below 70C at 1700mA and I'd probbly run it at 1300-1400mA myself ...

    You are saying it gets very hot (you can't hold your hand on it or you can but it is hot? if you can but it is very hot that's for average folk ~50-60C and can't hold it too hot is ~70+C) at 1200mA and you have BMG+V6 (so you do not use your motor as heatsink like MK hotend) than it might be faulty or missmarked?!

    here they mention for TEVO motors that they should run at 1.3A and they are suggesting configuring drivers to run them at 1250mA so again your 1200mA settings should not have it run too hot and is kinda perfect for this motor..

    see if you can find a proper way to measure temp of the motor .. 50C is super safe temp for them to run, over 50C it depends on the motor, most can handle long time running at 70-80C (otside temperature) ... I personally tune current for my motors by temperature, I try to run motors at 50-60C



  • weird that datasheet for this states 17hs4401 is 1.7A .. this tevo store marks it at 0.7A so 600 should be ok but 700 will work too .. again I'd monitor temperature of the motor, if it is kept around 50C it runs at "max optimum"



  • @smece said in How find maximun current of steppers drivers:

    weird that datasheet for this states 17hs4401 is 1.7A

    He has the 17HD4401 not the 17hs4401



  • And... A good Nema 17 stepper for extruder....? Maybe 0.9 deg stepper? Or a pankaque nema 17?



  • @Veti said in How find maximun current of steppers drivers:

    @smece said in How find maximun current of steppers drivers:

    weird that datasheet for this states 17hs4401 is 1.7A

    He has the 17HD4401 not the 17hs4401

    I am bliiiiiiiiiiiiiiiiiiind thanks!!!! should stop posting before sleep


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