Strange Movement

[martyscncgarage]

Note, inductance changes depending on how the motor is wired.
I think your Z axis motor is running very inefficiently.
If its inductance is 15 wired parallel, then the optimal DC power supply would be approaching 120VDC

Change the Z axis motor, as Mike suggested, find a NEMA 34 motor whose inductance rating is between 2.5 and 3 for a 48VDC power supply.

[Richards]

Let's turn the equation around and start with the power supply. Say that you have a power supply and you want to know how much motor inductance is ideal for that power supply, what do you do? Divide the power supply voltage by 32. Square the quotient. That's your ideal inductance is millihenrys. Example. 48VDC power supply / 32 = 1.5. 1.5 X 1.5 = 2.25mH. So, just like Marty suggested, a motor with 2.5mH to 3mH works very well with a 48VDC power supply. The equation gave us 2.25mH. When full performance is needed, that's the motor to use; however, it will run hotter than a 2.5mH to 3mH motor and, in reality, it won't give you much more performance. Another example: 36VDC power supply / 32 = 1.125. 1.125 X 1.125 = 1.265mH. A 1.5mH to 2mH motor matches a 36VDC power supply.

Make sure that the conductors in the cable going to the motor are at least as heavy as the motor's lead wires. If the motor has 22 gauge wires, use a cable with at least 22 gauge conductors. 20 gauge would be even better. I use shielded cable with stepper motors, with the shield tied to ground on one end only, usually the end nearest the controller.

[tuffduck]

Thanks for the help. I see how much the motors that were supplied are so out of whack.