Running the new E3d Hermera extruder on a 24v fed Duet Wifi



  • Hello all, I have a question so I don't harm my new Hermera extruder. I have the bowden version for my delta and it only comes with a 12 volt stepper motor. How can I run this with my version 1.0 Duet Wifi that is being fed 24 volts? Can I just run it at 24v (which I think would cause the stepper to heat up to much) or do I use a buck convertor and if I do, how would I wire that in? Thank you in advance for your expertise in answering this. I very much appreciate it.



  • Short answer: 24V is fine.

    Long answer: Voltage is almost un-important on a stepper that is driven by a current controlled driver chip. Set the initial current to about 1/2 the rating and adjust from there.



  • @Fishbyte , are you the 12V refers to the stepper motor and not the hotend? Where did you get the specification?

    https://e3d-online.com/e3d-hemera-175-kit

    Edit: the data you need is here, motor current 1.33A and fan voltage https://e3d-online.dozuki.com/Document/UBaWiCkBAAlCkZBG/Hemera-Datasheet-(Edition-1).pdf



  • @Danal . thanks for the quick answer. So just plug the 12v Hermera in the 24v Duet wifi and since the stepper is rated for 1.33 amps, then set extruder current starting at .65 to .7 amps? Does that sound right?



  • Correct.



  • @zapta This is the bowden version that does not have fan or hotend.



  • I'm curious re the 12V and where this number has come from since E3D don't actually publish a coil voltage for the extruder motor, at least they don't in any of the documentation that I have.

    Either way with steppers the volts doesn't matter so much - just pay attention to the current - you don't need to halve the current as these motors aren't voltage driven. The TMC stepper drivers monitor the rise of the coil current and ignore the coil voltage. think of this as a digital signal (it is kind of hard to explain but it doesn't behave like a DC motor where voltage would matter), energy is sent as pulses not continuous current. In fact a higher voltage is better, then inductance comes into play but things start to get complex real fast ....

    Chopper Drives

    Trinamic



  • @Garfield Makes sense.....I think I was on something magical when I thought about the stepper being 12v......Should have gotten more sleep. I forgot stuff I should have remembered since I have been away from 3d printing for awhile due to health issues. Thanks for explaining


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