Matching stepper driver to motor (motor current equal to the driver maximum current)

I have a two-phase bipolar stepper motor rated on 4.2 amps per phase (parallel connection). The peak current draw for this motor: 4.2 A * sqrt(2) = 4.2 * 1,41 = 5,92 A.

I'm looking for a matching stepper motor driver and I'm considering two options:
a) 2DM556S - it is rated for maximum of 4.2 A (RMS) = 5.88 A (peak)
(manufacturer assumes that sqrt(2) = 1.4, so 4.2 * 1,4 = 5.88 A)
https://www.cnczone.com/forums/attac...d=460784&stc=1


b) 2DM860H - it is rated for maximum of 6.0 A (RMS) = 8.40 A (peak), so absolutely no problem running this motor, but the cost is twice as high, compared to the 2DM556S.
https://www.cnczone.com/forums/attac...d=460788&stc=1


On a first glance, this 2DM556S driver would match my motor (same peak current draw), but is it a good idea to run the motor on the maximum possible setting of a driver (is it safe for the driver itself or would I be risking its damage in the longer period of time)? Should I pick a driver with a higher maximum peak current?

Hi XA - The driver is current limited so you can't draw more then the driver can produce. So its safe to use the 556S. For best performance run it at 48V. The 860 can be run up to 80V so it should be able to run faster if you need speed, that's the main reason its dearer it has to have higher rated parts.... . cheers Peter