Hello,

I have two motors for Z axis on my printer (Prusa i3), and they are connected tot he same Pololu driver - basically the wires are Y split.

These motors are identical. I'm just wondering, if one of them went bad for some reason and I had replace one of them, should I replace it with the same kind of motor? I know that will be ideal thing to do, but the motor may no longer be available, or I may have another motor (of a different type) sitting around and want to use that.

My question can be restated as - what would be the requirements for two motors to share the same Pololu driver? In other words, what are the specs which I need to make sure to be the same or compatible?

Quick answer: get the same one. I'll bet the $20 or so you pay for it would be far cheaper than the time it would take you to modify the circuitry and firmware.

Long answer:

You'd want the same wattage, torque ratings, and step size, I'd imagine.

A wrong wattage would be hard to compensate for.

Most other things could be finagled if you dare. Wrong torque or speed could be compensated for with a gearbox, or even with firmware. The firmware just sends 3 signals to the stepper for every step. If you modified the code to send those signals slower or faster, I would think you could effectively modify the rpm of the motor, and thus the torque.

Keep in mind though, if the second motor is different, you'll have to wire it in separately, and probably add some resistors to balance out the current going to each, plus write a separate code for the second one.

has to be the same, dont even wire different motors up,