A4988 Driver and motor

Hello everyone, I wanted to know if these drivers can operate these two stepper motors “103H7123-0140” “103-H5210-4240” are to 1A per phase.

Thanks for your help

Hi Lucamu,

The 103H7123-0140 appears to be a 1 A, 6.7 ohm/phase, 24 VDC, 2 phase unipolar (6 wire) stepper.
The 103-H5210-4240 appears to be a 1 A, 4.8 ohm, 24-48 VDC, 2 phase, NEMA 17 size. It’s unclear from the spec sheet if this is really unipolar (6 wire) stepper or bipolar (4 wire), but either way…

The A4988 will support 1 A/phase and 8-35VDC. It accepts 4-wire (bipolar), so the two additional center tap wires on the unipolar motors will simply be unused to operate them in bipolar fashion, as described in the FAQ page for the A4988. So, all looks good and typical.

The A4988 will chop the voltages, so an applied 24 VDC (or higher up to 35 VDC) divided by 4.8 ohm would suggest 5 A running through the motor, but the A4988 will chop the signal to give an average current similar to what you set (I can see this on a low cost oscilloscope). Even applying 12 VDC might might work depending performance needs…although too low and the chopping won’t even microstep. Just dial a 1 A setting (or lower if you wish to underpower) into the A4988’s variable resistor and verify nothing gets too hot.

ok, I get it, so it should work! however, I use one shield Arduino Arduino Nano CNC v4 and grbl code, but then setting the current limit to the maximum I can not make these two stepper! the shield is this …
what’s wrong? I have to set the maximum or minimum?


I see you posted this same post in another forum thread. You should continue the troubleshooting process on that thread instead of reposting the problem in multiple areas.