Screened or not screened a question of cables

[bladehunter]

Hi guys, just going through the electronics phase and I have a question or two regarding screening of cables from control box to steppers and wire gauge size.

I'm running 570oz steppers as per Hoss's recommendation on my BF20 and was wondering what is the wire size needed from control box to the stepper. From what I've read 22 awg will handle 7 amps as chassis wirining (not bundled) and most catalogues quote 22awg 4 core bundles at 4.5amps or so. Will this be ok ? I can't see the longest cable being more than 5 odd feet long, ok maybe 6.

As for screening, is this absolutley neccessary ? I can see the pluses or screening, but has\is\does anyone use unscreened ?

Cheers
Rob

[Robin Hewitt]

I use unscreened and it doesn't seem to interfere with anything, even driving the steppers at 240 Volts.

I used the 4 individual wires per motor and ran them through flexi-conduit. I used the fattest cable that would fit in the controller, (assuming the controller could do a better job controlling the current in the windings if I minimalised the losses).

[hoss2006]

I've run stepper motors with unshielded cable no problem but there are pretty good deals these
days on shielded cable so what the heck.
Go for 20 or 18 awg for the 570's.
I tried 22 awg and though it didn't fail, the wire definitely got warm and extra "pliable".
Hoss

[keebler303]

Its best to shield wire which may emit EM noise and to shield wire which may be susceptible to EM noise. Can you get by without it? Probably so, but it depends on a lot of variables and best practices should be used whenever possible (shielded wire, star ground, etc. etc.).

Matt

[photomankc]

I definitely like 18 gauge or 20 gauge. It's not so thick that it won't fit in connectors but it leaves a huge margin above what you need in capacity and resistance. I used 18ga and they will sit there all day long running and never get above room temp.

[hoss2006]

Probably not worth it to you in Australia Rob, but Keling has the cable I recommend on my site.
CNC Stepper Motor and Components
4 wire 18 awg shielded.
Hoss

[bladehunter]

Probably not worth it to you in Australia Rob, but Keling has the cable I recommend on my site.
CNC Stepper Motor and Components
4 wire 18 awg shielded.
Hoss

Nah it's fine, living Down Under you get used to buying stuff from O\S. Just out of interest you don't happen to know the OD of the Keling wire ? Dunno why I didn't see that lol

[denz]

bladehunter,
Try Wire & Accessories : AusXmods
Or Cables : Homann Designs!, The preferred CNC Component Supplier

[wizard]

That is motors or steppers driven by any sort of PWM or switched driver. It is good practice and can prevent interference in un expected ways. In some locals it would be a requirement anyways to meet emission standards.

As to wire size I can't see a good reason to ever use 22awg wire to provide power to a motor or stepper, even if it technically works. There are mechanical considerations beyond the "will it burn up" question. 18ga would pretty much be the minimal size, just from the durability standpoint.

As a side note funky cabling is hard to track down in servo or stepper systems. If suitably intermittent nailing a fault to a Cable can take months. This is especially the case in cables that move.

Hi guys, just going through the electronics phase and I have a question or two regarding screening of cables from control box to steppers and wire gauge size.

I'm running 570oz steppers as per Hoss's recommendation on my BF20 and was wondering what is the wire size needed from control box to the stepper. From what I've read 22 awg will handle 7 amps as chassis wirining (not bundled) and most catalogues quote 22awg 4 core bundles at 4.5amps or so. Will this be ok ? I can't see the longest cable being more than 5 odd feet long, ok maybe 6.

As for screening, is this absolutley neccessary ? I can see the pluses or screening, but has\is\does anyone use unscreened ?

Cheers
Rob