The stepper motor cables have very little slack outside the machine.
The cable sold by Inventables is a AWG 18 7/26 shielded 4 strand cable. This would compare to a 0.9mm2 metric cable according to this conversion table:
This cable type is very hard to find here in Norway. What other dimensions would work with the Nema 23?
Eg. 0.2mm2, 0.5mm2, 0.75mm2, 1.0mm2…?
I guess shielded is important?
Should the area go up if longer cable?
Is the standard cable over dimensioned?
If you don’t have 18 gauge or equivalent available, you can go with something larger (lower gauge) like 1.0mm2 or greater, just make sure it’s stranded so it’s flexible. As long as you’re not planning to add a ridiculous amount of length (across the room), adding a few more feet to each piece will work just as well.
The shielding is highly recommended, since it’ll help capture and drain electromagnetic interference to ground (assuming you attach the shields to ground…), which will minimize the chance of stray signals either to or from the steppers.
So the wire instructions for the XC just removes the shielding of the cable, because they just tear the shielding foil off. It is not grounded.
Could just have been an unshielded cable then?
The instructions don’t address shielding the cables, but it’s a good practice. I took the metal drain wire and foil at the power supply end and combined them all together, then ran a wire from them to GND on the shield. It may be an unnecessary extra step, but I think it’s better to do that instead of waiting for some random interference to mess up a carving.
How do you shield the cable?
One end only?
Only the small ground wire?
Both ground wire and foil?
The foil is very thin and breaks and tears easily.
A picture of a good grounding would be nice
@RobertA_Rieke You combine the foil and ground wire. Do you have a picture of how you did your grounding?
What do you think of this cable offer:
I did it upside down and inside the CNC cart, so the picture would be more useless than usual.
You can always just connect the drain wires together and skip the foil, but if you do that I’d recommend using a little electrical tape to make sure you have good contact between the foil and the wire. Odds are that you do, but that’s just one of my many methods of overengineering.
$27.50 US for 50’ of 18/4 shielded wire, I think that’s a good deal. You can always use leftover wire for other applications, like wiring up speakers around the workshop.
So the shielding on my stepper motor wires are actually dead weight as I did what the instructions said and nothing more?
I did the same. No shielding.
Basically. The shielding provides very little protection unless it’s grounded. I don’t think they anticipated any noise/interference problems with their original spindle, which is why they never addressed it in the instructions.
…which could explain the complete lack of wierd things ruining my carves after replacing the original 24V spindle with a Makita.
These days every problem I encounter leads back to something mechanical or user error…
Redoing cabling to actually run shielding to ground might be a waste of time until the day I replace the makerslides to get a bigger machine. At that point I have to do it anyway…
If you had the 24V spindle, there’s the issue. I don’t think re-wiring would be necessary, I ended up stripping back another couple inches of insulation after everything was wired just to get to the drain wire and foil. If necessary, I’m sure an interim solution like that can be found.
The cables can be extended by using 5 pin aviation xlr plugs like these:
4 pins for colored wires and 1 pin for shielding.
Do you think this cable will be ok? It’s a 18 AWG 4 strand shielded cable 0.75mm2?
The standard Xcarve cable is also 18 AWG but 0.82mm2
I have problems finding contacts for my controller box that accepts larger wire sizes than 0.75mm2 for each pin. Eg. XLR aviation plugs 12mm or 16mm both like max 0.75mm2 wires.
I used the 12mm XLR connectors with the stock wire from Invetables with the Nema 23 motors. It seems to be working fine. Mine are not shielded.
Do you think it’s ok to step down a little on the cables.
0.75mm2 AWG 18 shielded cables should work ok?
Probably won’t be an issue…but I am by no means an expert on this.
as a marine electrician I’d say you’re fine. Every cable has a bit of a safety factor built in and the difference of the numbers you are looking at are miniscule. If you do hook up your sheild to ground, you do one end only. I wired all my connections on the X-Carve with Duetsch connectors instead of the terminals provided, as I didn’t like the idea of the exposed terminations Inventables supplies around dust and debris.
Here’s a place I used to work where I purchased them. They ship worldwide also.