Quote Originally Posted by Evans View Post
I'm rebuilding a 60/40 CNC.
I'm using DM542T drivers and Nema 23HS45-4204S stepper motors
The amps/phase rating for the motors is 4.2 amps
The dip switches can be set at either 3.76 or 4.5 amps
Which should I use ?
Thanks Evans
The 4.5A is the peak value, so you can safely set it to the maximum. Also, the motor is rated at 4.2A, but that is not and absolute maximum +/- 10% is normal margin, so you can safely use it with the driver set to 4.5A. On the other hand, why set it to maximum unless you need the extra power? So set it to 3.8A full current, and if it is good and not losing steps then keep that setting.

Note that steppers operate at very high temperature, so don't panic if you burn your hand when touching it. 60°C -- 80°C is OK, and that's far more than what your hands tolerate. It can feel hot already around 40°C, which is pretty cool for a stepper.