Correct wire size for servo/stepper motors ? Dummy question

[dazp1976]

Yes, 1mm will be more than enough.



No that's not correct, Dir and Step are low current INPUT signals, they don't send anything out. This is the same for steppers or Servos.

It's the Drive OUTPUTS, usually marked A+ A- B+ B- on a stepper or U V W on a servo that are the high current wires. Wire size will depend on motor size and cable length but for a typical 3nm stepper with 3 to 5Mtr cable lengths then 0.75mm/2 to 1mm/2 works fine, don't need anything larger than that.

For smaller servo's 200w to 600w then 1mm/2 to 1.5mm/2 will work, again depending on cable length. For larger servo's it will be anywhere between 1.5mm/2 to 4mm/2.

There are no driver to motor cables. It's all built in.
There's just:
3 wires for main DC power incl gnd.
10 Wires for controls (step/dir) etc.
5 wires for RS232.
That's it.

So 14AWG 3 or 4 core for main and a DB15 for the rest. That'll do

https://www.ebay.co.uk/itm/180W-3000...yABEgLdtvD_BwE

I would NOT fancy running these with flood cooling that's for sure :)

[JAZZCNC]

There are no driver to motor cables. It's all built in.
There's just:
3 wires for main DC power incl gnd.
10 Wires for controls (step/dir) etc.
5 wires for RS232.
That's it.

Yes, I knew this but Andrew may also go the Closed-loop route if these don't work out which is why I answered like I did, it also doesn't hurt for anyone else who's watching in the background and might be unsure.!

Personally, I'm not a fan of drivers attached to motors for a number of reasons, vibration, dust, or fluid ingress and heat that will shorten electronics life are some.

Then you have the fact that unless you mount the controller close to the motors you are running sensitive low voltage signal wires around the machine on long wire runs which can basically become an aerial antenna for picking up electrical noise causing all kinds of brain curdling frustrations!
Also, with very long cable runs then you could experience voltage drop and signal loss, etc not good for a stable machine!

Andrew, if running control wires around the machine and through cable chains etc my suggestion is to buy a good quality shielded cable 22Awg (0.35mm) and keep the wire runs short as possible and keep signal cables away from high power cables like mains voltage or high-frequency cables like the spindle. An obviously good grounding in the control box is a must.