In series, parallel or unipolar

I am having trouble understanding (in series, parallel or unipolar) for the stepper motors, I have the X Controller and as far as I can understand it outputs a max of 4 amps to each motor, the steppers I have are Nema 3.1Nm 439 which are 4 wire, and the technical data is that they can handle 4.2 amps wired in parallel 2.1 in series, and 3 amp in unipolar, I want to know if I am wired in series, parallel or unipolar, as I would like to get 4 amps to each motor, Inventables says I can set the potentiometers in the XController to 4 amps without overheating

I don’t believe you can have a unipolar option without at least 5 wires… unless these have a built on driver mounted onto the motor itself??
It would need at least 5 (usually 6 or 8) leads to accomplish unipolar use.

However Unipolar motors have very low torque output, so I wouldn’t use it that way, the benefit of a unipolar stepper is that the drivers used can be made much cheaper, but if you’re already using the X-Controller then this is not an issue as the proper controller is present for a Bi-Polar stepper configuration.

I would run these as Bi-polar Parallel because it’s just stronger than Bi-Polar Series. There is more current used, sure but the torque available at higher speed is greater when it’s Parallel than when it’s Series.
In fact most “Standard” steppers that don’t clarify how they are wired are generally Bi-Polar Parallel for this reason, it provides the most power and the most speed.

Sure a Bi-Polar Series wiring provides the same Torque at low speed, but as speed increases, the torque output of the Series wired drops drastically when compared to the Parallel version…

Although your Drivers will only output 4A when the Stepper Could take 4.2A it won’t hurt to only send the stepper 4A. It will have a little less torque than it could if there were stronger drivers, but it will still be stronger than the series wiring (except for at the very slow speed, if you’re only running these very slowly, than the Series wiring could be the better option, BUT only at that very slow speed…

Wire then as Bi-Polar Parallel and consider a stronger controller that outputs the full 4.2A as a future upgrade if you want that extra little bit of torque output…

Thanks, Seth, you have explained that very well, the motors I have came with 8 wires but I am only using 4, sorry I should have explained that better, I would like to run them in Bi-Polar Parallel but don’t know how to wire them, is there something I could read on this subject, and yes a stronger controller is definitely on the list, I would get one tomorrow if I knew which one to get, I have been looking and will continue to look

I actually had this pulled up and was going to link to it before, but didnt’.
About 3/4 down the page is the different wiring configurations. Determining which wire is which if they didn’t include a diagram can be a bit of a pain on an 8 wire though.

Here’s the source site:
Wiring Basics: Unipolar vs Bipolar.

And the wiring image:

Your steppers have four wires. You can’t do anything but connect them to the drivers. Everything else is irrelevant given your motors and your controller…just connect them.
Got a link to your motors or the datasheet?

Edit: Oops…read your second post and now your motors have 8 wires. Wire them in parallel… Always better unless you can’t supply the current.

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Thank you, Seth and Neil, for your help, and the wiring diagram, I will wire them in parallel tomorrow and increase the amps to 4 on the X- Controller, I will see if that improves things. The Buildbotics CNC Controller is something I have been looking at, but I am in the UK and postage would be ridiculous,

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I wired it in parallel and set the X-Controller to 4amps, it homed on the first attempt but the homing switches did not pull off entirely, so I had to switch off and move it away manually, and now when I try to home the Z-axis goes to the top, hits the switch and starts to come down again, and the homing cycle does not finish, do I have to make changes in GRBL

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To increase the pull off distance you can change the $27 setting.

Heres a list of the grbl settings and a long explanation of each.

Thanks, again Seth, I found that GRBL leaflet/book is very interesting and will keep it for future reference, all seems to be working well now, after some adjustments in GRBL, the Y axis is much faster now which is what I wanted, I am still fine-tuning it but I am happy at how it is working.

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