Z-axis dual motor wiring

I'm commissioning a RepRapPro Tricolor (currently in mono mode) printer runningffg with an Azteeg X3 Pro board. I'm using the Arduino 1.0.5 r2, Marlin firmware and Repetier Host software. It has dual stepper motors for the z-axis. I can run each motor individually but when I wire them in series as shown on the schematic, they just chatter. I've tried different options other than the recommended diagram, hoping to hit on a successful scheme but can't find anything that works. Any suggestions? I have extra motor controllers on the board if needed. Any suggestions? Thanks, Gonetotx

I am not familiar with the Azteeg board, but on my ramps, the Z motors are wired in parallel.

Interesting. If I do this, should I crank up the voltage setting on my motor controller to about double the normal setting to handle both motors? The recommended setting for my NEMA 17 motors is .6 to .8 volts. The board and motor controller can handle twice this easily. Do you think there is any issue with accuracy (both motors rotating the same amount) if run in parallel vs. series? Thanks for your thoughts.

Gonetotx

I don't know the answer. If you consider the motors solely as impedance on the circuit, then doubling the voltage would make sense, but there's a timing aspect to this circuit, and I'm not sure how that would work out.

they should be wired in parallel. reasoning is that z axis is slow enough that change in impedance between motors is negligible. also the voltage driver is low enough (12v) that this is the only way to ensure enough voltage exists for the chopper circuit to control current.

if motors are wired in series then about only half of the voltage makes it thru the winding. current is still regulated by driver, but there may not be enough voltage to push more current when impedance increases. so only wire in series if you are using more than 12v.

Thanks Jamesdanielv,

I have the z-axis motors now wired in parallel and they work fine. I appreciate the advice.

The next stop in my commissioning phase is with an error in the hotbed. Since this is a new topic, I'll post it separately. Cheers,

Gonetotx