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Savebase Drivers From Ebay, StepConf Help Please

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11 Aug 2016 18:46 #78638 by Curbfeeler
Hi guys. First post. I've been using LinuxCNC for almost 6 months and really loving it.

I bought an X-Carve back in January and decided to upgrade it in several ways. One upgrade was I decided not to go with the default arduino-based software. Instead I decided to build a PC for LinuxCNC and to use a BOB and drivers found on Ebay for cheap.

I bought from a China ebay'er called SAVEBASE. These appear to be the same as what I bought. I paid $112 for three drivers and a breakout board.

www.ebay.com/itm/3-Axis-DIY-CNC-Kit-For-...?hash=item5d5e74515b

I'm running NEMA 23 140oz-in stepper motors. I run 2 on the Y (5A) and one each on X and Z (3A). Motors show Steps/Rev as 200 and Current / Phase as 2.8A in the specs.

At first I had issues with these drivers, mostly that they ran pretty hot and would start to smell hot when I ran them. I've put computer fans on them and don't have this issue any longer.

Now my issue is that my X and Y motors are hot when in HOLD. During a complex job if I feel my Y they are cool to the touch. But X is pretty hot and Z is quite a bit hotter.

I assume my issue is that I've been guessing on the StepConf settings, just trying random stuff. But honestly, I'm not sure how to configure or calculate this. Here is what I am running now.

discuss-assets.s3.amazonaws.com/original...47697fc0b3c5edaf.jpg

Again, this allows me to cut, but can somebody please help me to understand the process for configuring these settings for real, based on, you know, science?

Thanks so much!
Dan

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11 Aug 2016 19:22 #78639 by PCW
Stepconf only sets timing parameters, it really has nothing
to do with motor heating (and step motors normally do run hot)

Motor heating is mainly dependent on the motor current setting in your drives
(and what heatsinking the motor mounts provide)

Fancier step motor drives have a Idle current option which will reduce motor heating
when not moving
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11 Aug 2016 19:45 #78642 by tommylight
On your drives, reduce the power going to motors ( values are in A for ampere).
Also those drives, open the covers and look under the board where the IC is mounted with 2 screws to the heat sink if there is any white paste, as normally they don't bother to put any thermal paste there ( i know i had to open all of mine to put some, otherwise they will not last long.)
Current settings should be at 2A for your motors or max 2.5A, drives are not calibrated at all so even this might be to much for the motors.
I had some weird experienced with them ( like max power to the motors is when setting current at 4A and microstepping at 16, anything else on both settings and they did loose a lot of power.......and it goes on, but they do work quite good after some fiddling and testing)
Regards,
Tom
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18 Aug 2016 16:27 #79016 by andypugh

Now my issue is that my X and Y motors are hot when in HOLD.


You might be surprised how hot is "normal" for a stepper motor. If you can touch it and still have skin left on your finger then the motor is happy.
forum.orientalmotor.com/viewtopic.php?t=7

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