[Bamball95]

Ok guys. sorry no pictures yet but I promise they are on their way. I just finished my electronics and decided to do some testing with my steppers. At first it seemed they worked great, however, I soon realized that wasn't the case. About 20% of the time they stop spinning and stall out. They still sound like they are running but they don't spin. It seems like (but I am not sure on this) it occurs more when they get hot. Could this be that case? Any ideas? I have the hobbycnc EZ board and three nema 23's.
Thanks all, Beau

[RomanLini]

What is your power supply voltage and what are your motor specs (ie voltage, current, photos etc)?

[Bamball95]

My motors are size 23 steppers. They they run at 3.6 volts and draw 2.3 amps. Here is a link to them.
1.8DEG. 3.6V SIZE 23 STEPMOTOR-MPJA, Inc.
My power supply is a 24 volts 14.5 amps and is regulated.

Here are a few pics of my controller box(almost finished.)
Sorry for the bad quality. It was just my phone. I will try to use my camera for the next pics.










Happy cncing, Beau

[Bamball95]

I just found a video on youtube in which the guy has the same problem.
[nomedia="http://www.youtube.com/watch?v=vg1p99FGUXA"]YouTube - CNC stepper motors stalling[/nomedia]
Best regards, Beau

[beamsjr]

Play with the motor tuning, you may have the steps per wrong or the speed is set too high. I remember having this problem when I was setting my first machine up. I have the hobby cnc 4axis board.

[Bamball95]

Its weird thought because it will even do it at slow speeds like 20 ipm. I can't seem to figure out what causes this.

[ger21]

Resonance. It actually can be worse when the motors are not attached to the machine.

See this thread.

http://www.cnczone.com/forums/steppe...tml#post256639

[RomanLini]

I have used a similar PSU voltage to your 24v and have similar unipolar IC drivers, and similar unipolar steppers (mine are 3v 2A) and mine gets excellent low-med and high speed performance although I never have a need to run it over 12 revs per second.

Check you have the right current adjustment, you can even run a little over the rated current with unipolar like using 2.5A instead of 2.3A.

After that it might be an issue with the wrong acceleration ramps or sometimes a PC issue where an interrupt or something is causing pauses in your step signal.

And like Ger21 said you can't judge it when the motors are not attached. I have a foam pad that I sit the motors on when testing them with no load, and sit them sideways which helps a little with the resonance.