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Balance potentiometer for stepper drivers

Posted by liminal1 
Balance potentiometer for stepper drivers
May 04, 2019 09:12PM
Hey guys,

Strange issue with the stepper drivers on a ramps. Its like there is not enough power to drive all the steppers, turning up one potentiometer to get that stepper running smoothly, seems to make another motor start to judder. I cant seem to find anyone having the same issue, how do I get them balanced?
Re: Balance potentiometer for stepper drivers
May 04, 2019 10:06PM
Without more information this is difficult to diagnose.

I would venture to guess that the power supply / Supply wiring is not rated for the current.
This means that if you are pulling more power than the supply or wiring can handle something is going to be starving for energy.

When I assembled my first 3D Printer they gave me this tiny wire to run the controller, I used knowing it would not work.
While I was using the wire you could smell the heat, and when a multi-meter was used you could measure the voltage drop from the supply to the controller.
This voltage drop being almost 4 volts. Controller was tiring to function with 8 volts, this is not sufficient to operate the controller an caused printer to act incorrectly...


Electronics Technician / Computer Programmer
Re: Balance potentiometer for stepper drivers
May 04, 2019 11:30PM
Yeah that sounds plausible, but the wires are fine. They all came from either the original Anet A8 the printer is based off, or proper electrical cable:

[www.bunnings.com.au]

Like this.

The PSU is 12v 30amps so thats fine I think?

But I would have thought it was the cable or the PSU then Id have issues heating the bed or HE? I thought the steppers would be low draw?

But I'm happy to be corrected, I'm no expert hence why I'm here lol

What other info would help?
Re: Balance potentiometer for stepper drivers
May 05, 2019 01:43AM
Ok,

So I found this video

[www.youtube.com]

About tuning the steppers;

Ive put them all at about 5.5V they were a little all over the place. Maybe some were too high and thats what was causing the juddering? I dont know enough about it.

g28 seems to be ok right now... About to try a test print. wish me luck lol
Re: Balance potentiometer for stepper drivers
May 05, 2019 04:59AM
5.5V ?

I didn't know the vref's could go that high ??

You should normally have them around 0.5V to 1V'ish (depends what stepper current you want).
Re: Balance potentiometer for stepper drivers
May 05, 2019 07:25PM
Lol, sorry, I meant .55

[youtu.be]

So here is a video to my issue. The extruder stepper works for a while. Then just starts doing this.
Re: Balance potentiometer for stepper drivers
May 06, 2019 05:49AM
When the stepper starts doing that, maybe try holding the filament yourself by the extruder, release the extruder wheel pressure on the filament, and slowly push the filament through with your fingers, just to see if the filament path is not getting stuck somehow.

If not, then when it does that, just release the extruder's filament wheel pressure again and see if the stepper starts rotating normally.
Re: Balance potentiometer for stepper drivers
May 07, 2019 11:27PM
Thanks all,

Ive created a new post more specific to this issue;

[reprap.org]
Re: Balance potentiometer for stepper drivers
May 08, 2019 04:19AM
Quote
liminal1
Thanks all,

Ive created a new post more specific to this issue;

[reprap.org]

Please try to keep it in one post ^_^ shall I remove this post so we can continue in the new one?


http://www.marinusdebeer.nl/
Re: Balance potentiometer for stepper drivers
May 11, 2019 12:02AM
Well this is now a different issue, I would have thought? I have balanced the power for the steppers. And then I opened a new post because, while its the same problem, cant extrude, its a new issue, its nothing to do with balancing the stepper drivers.

What do you think?
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