I’m building my first CNC. I bought 3 stepper motors, an arduino and a cnc shield from ebay. I connected everything, set the current limit. I started the software Universal G-Code sender, but the motor didn’t spin at all. After some tries the arduino slowly shut down. I removed the stepper driver that was causing this and everything worked fine. But the motor still didn’t spin. Now another A4988 broke and I have only 1 left.
I’m using these stepper motors:
http://r.ebay.com/L1Eghm
And this arduino + CNC shield and drivers:
http://r.ebay.com/lqTMBl
I already contacted the seller about this issue, and asked him kindly to send me a new one. But the question is, what is causing this. Am I doing something wrong, or is it a bad manufacturing issue.
This is my setup:
Gescand_20160325-1040 (1).pdf (621.0 KB)
Gescand_20160325-1040.pdf (499.2 KB)
I set the current limit to about 600mV, which makes 2.5 x 600mV = 1.5 A which is the max current my steppers can handle.
What am I doing wrong? I am prepared to buy 3 new DRV8825 drivers.
It sounds like you set the current limit to 1.5A, which is higher than our A4988 carriers can handle, as noted on its product page; that might have been what damaged them. The eBay links you posted are not working correctly (e.g. the item has been removed or is no longer available). However, from your pictures, it looks like you are not using our drivers (we do not have a red version of the A4988 carrier), so I cannot say with any certainty what might have happened in your case or if your current limit setting looks correct, since it will likely be different for that board.
If you want to run the stepper motors at 1.5A per phase, I would recommend the DRV8825 Stepper Motor Driver Carrier you mentioned. I am not familiar with the CNC shield you are using, but if it was intended to use the A4988 carrier, you might want to read through the “Key differences between the DRV8825 and A4988” heading of the DRV8825 carrier’s product page if you are not familiar with it.
-Brandon
Dear Brandon,
Thanks for your fast answer! I updated the links, and they should work now. Do you recommend setting the current limit to 1 A max, or is it wisely to set it to 0.75 A?
Juul
Thank you for correcting your links. It looks like the stepper motors are rated for 1.5A per phase (as you mentioned). If you do not need to run them at their rated torque and speed, you could use a lower current limit (that your driver can handle).
As I said before, the drivers that come with that kit are not ours, so I cannot say what they are capable of. If you are switching to our DRV8825 carriers, you should be able to set the current limit near the 1.5A rating; although, it would not hurt to have a small margin of safety by setting it slightly lower than this.
Brandon
