Dual z-axis stepper motors on a Prusa I3

(electronlove_SW) #1

I understand that the max. current for the stepper drivers on the smoothieboard is 2A. I am building a Prusa I3 which uses two NEMA 17 stepper motors on the Z-axis. The stepper motors that I am going to use are 1.5 A each (3A total). How can I wire up the board so that the two steppers are able to work. All of the other stepper drivers are going to be used, e.g. X and Y, and an extruder (and a 2nd extruder at some point later). I am new to this platform and any advice is appreciated

Imported from wikidot

(Arthur Wolf) #2

Hi there !

Please take a look here : http://smoothieware.org/3d-printer-guide#toc20

Tell me if you need anything else.

Cheers !

(GrnDragon_SW) #3

I am in the process of setting up a smoothie board on my Prusa i3 as well, so far I am using a max current of 1.25A on the dual Z steppers, without missed steps at a max speed of 200mm/min. also limiting the X and Y Nema 17 steppers to 0.75 A. The steppers I have are Kysan 1124090 rated at a max current of 1.5A. These are the same vaules I was using on a sanguinololu board and successfully printed 32 hour long prints.

Have a fan blowing across the drivers to keep them from going into themal shutdown, the smoothie board has very good thermal transferr characteristics.


(Josephfr346_SW) #4

It is easy to have dual head in prusa i3. Recently purchased one from 3dprintersonlinestore

(GrnDragon_SW) #5

Forgot to say I have both steppers wired to one Z-axis driver.

(electronlove_SW) #6

Thanks. I was also looking into getting heatsinks (Ebay has tiny heatsinks listed) to place across the stepper drivers in addition to a cooling fan. Do you think that this may be overkill?

(Arthur Wolf) #7

It would most probably be overkill.
If you choose to use those, put them on the bottom of the board, bellow the drivers. That’s how they are supposed to be cooled.

(SteveRWright_SW) #8

You can also wire the 2 steppers in series. I don’t know that much about it but was told that you lose top end speed, but the current will be 1.5 A. Z-axis shouldn’t need too much speed anyway. That is how I am building my Ord Bot Hadron, if I ever get it done.

(Tiago Torre Do Vale_SW) #9


Did anyone succeed in connecting the two Z motors into one driver ? Parallel or in Series?
I’m about to buy a smoothieboard since it seems to be the best board in the market, but I want to be sure if it is compatible with Prusa I3 with double head (e3d cyclops)

thank you

(Arthur Wolf) #10


Both parralel and series will work ( Parralel is recommended in most setups ).

Many users do this, it works fine.

It is definitely compatible with a prusa i3 with double head.

Cheers :slight_smile:

(dckerrigan_SW) #11

We’d like to wire the z-axis steppers in parallel. We have the Smoothieboard 5XC and we also have NEMA 17 stepper motors that are already nicely pre-wired into molex connectors (with four wires). Do you know of any type of molex connector / adapter we can get that merges the two molex’s into something that plugs into the Smoothieboard? Or some type of Molex that has two rows of wire inputs and one row of output? Or do we just need to cut the wires and re-crimp, in which case, are there special 2.54mm crimps that accept two wires into one female terminal?
Thank you for your help.

(Arthur Wolf) #12


You’ll probably need to solder two wires into one, and then crimp the output wire.

Robotseed has some pcbs with 3 molex connectors on them, but they are not in the shop. You can contact stephane@robotseed.com and ask him to send you one for free via snailmail.