Flexible Stepper Motor Cable
February 17, 2019 02:42AM
Hi all,

What is recommended for flexible, shielded stepper motor cable? Got two applications in mind, one upto 2A and the other 3A motor current limits.

Thanks.
Re: Flexible Stepper Motor Cable
February 17, 2019 10:34AM
I suggest twisted pair, one pair per phase, shielded if necessary (last time I did EMC testing using a Duet, shielded cable didn't seem to be necessary to meet CE EMC regulations, but that was in a bench setup not a real printer). Check the current rating vs. AWG of the conductors at [www.engineeringtoolbox.com]. Bear in mind that only one of the phases carries the full peak current at a time. So if the motor currents you mentioned are peak, then you can use the up-to-3 cores column instead of the 4-core column.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Flexible Stepper Motor Cable
February 17, 2019 01:37PM
If it's for cnc /subtractive manufacturing and if good emc performance is important I'd get 4 wire cable with shielding and made for using in a drag chain. Like this one:
ÖLFLEX® CHAIN 809 CY 4 G 0.75

I use this for my cnc router, with 3A motor current.

For my 3d printer i'm now using 0.75mm^2 loudspeaker cable, since the stepper motors remain stationary.


--
Kind regards
Imqqmi

NFAN CoreXY printer:
[reprap.org]
Re: Flexible Stepper Motor Cable
February 17, 2019 02:02PM
Thanks for the comments.

@dc42 Kind of answered my question posed on the duet forums here. I had been wondering if twisted pair for the main cable run and grounding the motors would be enough for EMC emissions as the case should act as a cage catching the emissions from the coils themselves. I thought perhaps the shielding grounded at the ormerod 2 case was mainly acting as a ground for the stepper case through the conmector shielding.
Re: Flexible Stepper Motor Cable
February 17, 2019 02:04PM
Yes I would be looking at drag chains, making sure the bend radius of the chain was larger than the bend radius of the cable spec. I'll have another look for cable life specs as I guess stating when cables should be replaced woild be a good thing to do.
Re: Flexible Stepper Motor Cable
February 19, 2019 07:35PM
You might want to check out the Alpha Wire EcoCable. The unshielded twisted-pair option looks ideal for this sort of application.
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