Quote
NoobMan
... The 4 motors in series would make a 6.68ohms coil and the inductance would be 4 times of a single motor, so you probably "really" need 24v to make the Z axis able to move practically, even with a low speed, depending on load too. You could try maybe find a construction solution with a very lightweight Z and only 3 motors, imo that should be better than four.
I agree that he needs 24V to run 4 motors in series - he was intending to use 24V anyway. As to whether 3 or 4 Z motors are better, I think it depends on size. For a small to medium size bed that can be made rigid enough over the whole area so as not to deflect more than about 0.03mm at the unsupported corners, three Z motors would be enough, and 3-point support is easier to set up. For large beds where it may be difficult to make the bed rigid enough for 3-point support, 4 motors might be a better option. Or perhaps 3 motors supporting a truss, which in turn supports the bed.
Ideally, the 3 or 4 motors would be drive independently, so that in conjunction with a Z probe the bed could be levelled automatically.