View Full Version : New Machine Build PRO4848 with MENA34 - Electrical help

07-01-2014, 04:01 PM
Hi Everyone,
I am well into my CNCRouterParts (PRO484) build, all/most of the mechanicals are complete (no calibration or testing yet) and just started working on the electrical portion. I bought the DIY NEMA34 kit from CNCRouterParts but the documentation is a little light. Can anyone tell me the model no, or provide spec sheet for the NEMA34 motors? I have pulled the data sheets for each component in the kit, but I don't have anything on the motors. I am basically trying to draw up a wiring diagram for my complete electrical setup including the Ethernet Smoothstepper, PMDX-126, Gecko 201X, ESS, and motors so I can begin the electrical wiring portion.

Better yet, if someone has already done it, I have no need to reinvent the wheel.

BTW - The guys from CNCRP have been great to work with and extremely helpful. They just dont have a wiring diagram for the basic DIY NEMA 34 kit available.

Thanks, Craig

07-01-2014, 04:23 PM
This might help Its not for your BOB, but its about 95 %


Regarding the nema's, how many wires on the motors?

07-01-2014, 05:10 PM
Thanks Paul, this is helpful.

The motor cable has 5 leads, but I think one lead (black) may be a ground. but I am not sure.

07-01-2014, 08:34 PM
ok 5 wire can have a couple of configurations. Did the supplier give you a wire colour code / break-out?
is connecting the motors an issue for you?


07-01-2014, 11:59 PM
Are you aware of their wiring diagram? I don't have their kit but have studied it intently. It should have everything you're looking for.

Also make sure you read through the PMDX manuals.

07-02-2014, 03:12 PM
Thanks for the replies guys. I took a closer look the the pigtail connector and the black lead is a ground, so that leads me to believe these are four wire motors. I have looked at the above wiring diagram (thats where I started this process) and it identifies which motor leads/colors. So with that and the vendor docs (PMDX-126, Gecko 201X, ESS) I think I can figure it out from here.

Just FYI, the CNCRP document listed above is NOT the diagram for the DIY kit they sell. The diagram has several components that are not included in the kit and I found a few obvious errors with this document. I think this document is for their complete electronics system with the enclosure. With that said, I am still very much impressed with their system and support thus far and would recommend it to anyone.

07-02-2014, 08:30 PM
working on the principal of measure twice cut once, can you confirm that the black lead is open circuit to all the other leads. ie black is case ground and not common feild ground please.


07-03-2014, 01:15 AM
Great idea, I did a continuity test between all the leads and here are the results;
Blue/Yellow - ~0.8 ohms
Red/Green - ~1.0 ohms
All other combinations were open so I think these are the two coil pairs.

For the ground:
Black to any other lead - open
Black to case - ~ 0.4 ohms
**So I think this makes the black lead a case ground. Please let me know if I am correct.

07-03-2014, 01:41 AM
that sounds lgical and will work with the Gecko's . just a tip: to reverse the direction of a stepper you only need to swap one coil. eg the A coil is blue/yellow and B coil is red/gereen.
To reverse direction it will be yellow/blue for the A coil and no change to the B setup.
The 20% variance in coil resistance is a stand out. they are a usualy closer than your reading. might want to check the other motors.


07-03-2014, 02:51 AM
Thanks Paul,
Sounds good. I will recheck the motors and use a more controlled test setup. My previous test was pretty basic and I wasnt concerned with variance, but I see your point. Thanks for the tip on reverse direction, I didn't know that and would probably have spent extra time "learning" it in my workshop!


07-03-2014, 03:26 PM
Hi Craig,

Sorry I just found this thread -- feel free to contact us for direct support on this. As to the bulkhead connectors, the pinouts for these are listed here:

7A Bulkhead Enclosure Connector | CNCRouterParts (http://www.cncrouterparts.com/7a-bulkhead-enclosure-connector-p-114.html)

I would wire all of your motors the same, and reverse the direction of one in software by changing the active low box for the direction bit. This is what we do in our pre-configured Mach XML files.

Best regards,

CNCRouterParts (http://www.cncrouterparts.com)

07-03-2014, 03:36 PM
Thanks Ahren,
The additional information will help. Appreciate the support.