Don't turn current up past 2.8A on XController (for Nema 23s)

I had servo current turned up one extra mark in my XController. Then on a long job (hours) I noticed that the steppers were quite hot, almost too hot to leave my palm in contact with them. I fear that if they got much hotter, steps would soon be lost.

I paused the long job and turned the stepper currents back down to 2.8A. They have been running warm but not hot for the last hour. Perhaps this is why some of my longer jobs had failed, many hours in, in the past.

Yes, the NEMA 23s that Inventables sells have a maximum current rating of 2.8A per phase.

1 Like

But ya gotta turn it up to “11” sometimes just to see what will happen, am I right?



Where does the 2.6 amps number come from?

Check this page:

Ok, yeah the gShield is limited to 2.5 amps per phase “with adequate cooling”. Which means you really can’t get the full 2.5 amps except in the lab.

The X-controller has more power and can overdrive the NEMA 23s.

For discussion:
Are lost steps due to thermal shutdown of the drivers?
Or are lost steps caused by hot motors?

I believe thermal shutdown of the drivers is usually what causes lost steps.
I think too hot motors will wear them sooner, but shouldn’t cause lost steps… Do they lose their torque? (Another method of losing steps)…
BTW Most motors are rated to over 50 degrees C; much to hot to touch but within their limits.

PS Getting the X-Controller to reach thermal shutdown will take max current (4Amps). GRBLShield easily reached thermal shutdown.