Z stepper getting VERY hot!

As the title says my Z stepper motor is getting VERY VERY hot when sitting idle.
I know that stepper motors use more power when not moving to keep it steady, but for some reason this one gets just WAY to hot. Hot enough that it will burn my fingers if I touch it after only a few min.
If I turn the XC on and it just sits there while I’m tweaking some cut setting or something on the computer after a min or two if I touch each of the motors they are all cool or maybe warm at the most except the Z, its scalding. I try to keep the XC turned off unless its currently being used to cut, but I’m afraid its going to burn up or something. If nothing else I would like to be able to start a cut and be able to let it sit for a little bit after its done before I get back to it without worrying if its gonna catch fire or something.
I have adjusted the voltage for that motor to the lowest I can turn the POT down to and it still be able to move the 611 and dust shoe up and down without missing steps.
Any suggestions?!

X controller or shield?

You could try swapping steppers around and see if the one from the Z axis behaves the same elsewhere. The result from that should leave two exits:

-Dying stepper should it heat up when acting as e.g X axis motor
-Something is messed up in front of the Z motor.

I have not had this happen to me so just thinking out loud…

Nema17 or Nema23?
Do you have the steppers engaged 100% or do they go to idle (IIRC check if $7=255, try setting it to 50)

As Ebr suggest, try connecting the Z-stepper to X or Y stepper driver, do the same motor heat up or is it the new Z-motor?

I did have the thought of swapping it out with one of the others, but honestly I seams to always be running it and falls into the category of if it ain’t broke…
I’m just really worried that it will be sooner or later.
They are NEMA 17 motors, and I also don’t know what language this is–>> “(IIRC check if $7=255, try setting it to 50)” lol
but having them go idle sounds great.
From what I’ve read the motors are fully engaged when not moving because it’s forceably holding itself still if that makes since.

I had Nema17 running my Z-axis before, spindle is Makita RT0700 which is about same weight as the Dewalt 611 - mine got sizzling hot aswell. Water would boil on its surface. It worked fine though…
The weight of my Z-axis lift plate/spindle was high enough (or friction low enough) for it to slide down by its own weight when unpowered.

I changed to Nema23 and it is just baaaarely noticably warm, rest of the system is unchanged.

GRBL code (v0.8) for value 7 ($7) relate to the amount of time the stepper motor driver will give power, when value = 255 it is ON 100% of the time. Any value below that mean that the motor will go to idle after xxx milliseconds. (So $7=50 mean motor will go idle 50ms after last command) It is GRBL-speak :wink:

Stepper motor will due to its two coils have a holding torque even without power (this is the cogging you feel when rotating the shaft by hand)

My suggestion:
Get a Nema23 in the 140-270oz/in range and leave the rest untouched :slight_smile:
(Edit, the 56mm Nema23 140oz is a drop-in replacement, longer cases need change of motor position on the xcarve)


I think you are talking about $1.

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I think I’ll try getting a NEMA 23 when I have a few extra $$(and I mean cash money not GRBLE haha).
The Z doesn’t fall down when unpowered. Though I do have the POT turned up pretty far and it still doesn’t that really like my z axis knob I made. So I’m really feeling like the 23 would be a good fix. If not it wouldn’t hurt!

I’m not at the house right now, what’s the max height size stepper motor that will fit in the z axis spot? Inventables’ site says they don’t recommend the 262 Oz motor for the x carve.

That is correct. The 262 oz/in motor is 76mm deep it will not fit the standard Z axis configuration. If you want to use a larger motor you can invert the design and mount the motor on the top with spacers.

The standard 140 oz/in NEMA 23 motors are 51mm deep.

You can go up to 56mm in depth and that will fit the standard design and mounting position.

If you are using the gShield you are limited to approximately 2.2 amps/phase unless you provide extra cooling and then you can go to 2.5 amps/phase.

If you use the X-controller you can go up to about 4amps/phase.

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Exactly what I was looking for! Thanks! Trying to shop eBay while kids are reading book in library. Haha

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Forgive my ignorance but I just wanted to make sure I had picked the right one before I order it.
this is the one I am looking at…
thanks again.

I just bought a zyltech nema 23 to run on my x axis. Seems decent enough quality and hasn’t had any issues thus.

I run a makita currently and my nema 17 on the z axis has plenty of power and doesn’t get overly hot.

I am currently running a gshield/arduino combo.

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“Product Description
shaft diameter 6.35 mm; Shaft length 20 mm. Step Angle 1.8° Step Accuracy 5% Holding Torque 1.3N·m (184oz·in) Rated Current/phase 2.5 A Phase Resistance 1.6 ohms Rated Voltage (≠driving voltage) 4 V Inductance 3.8 mH ±20% Weight 720 g”

6.35mm is equal to .25inch so it should be good right?!

Well I’ll get that one when the $$ is freed up and see how it goes.
Thanks for all the help

The motors that came with my XCarve are Automation Technology KL23H251-28-4AP If you search that in google you can buy them from Automation Technology for $20.

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