The 3Nm steppers we sell need 2.1A in series and 4.2A in parallel.
you can run them in series with a small driver like the MSD325, but due to the low volts of the driver the performance will be limited after about 250 RPM.

we suggest you run them in parallel with a min of 40V, they run best at about 70V with the MSD980, but that it a big driver and costs a lot more.

Quote Originally Posted by Smiler View Post
My 3Nm steppers pull 4.2A peak (so Zapp tell me).
Can you get 3Nm that can use a 3A driver? If so I have a spare here I could turn to good (4th axis) use :)