Centroid Community CNC Support Forum

A good read on VFDs, cabling and noise.
https://www.motioncontroltips.com/probl ... elp-solve/

It too recommends good cable designed for VFDs (automationdirect.com sells it) and grounding the shield at both the motor and the drive. Also a best practice recommended by Belden wire and cable.
https://www.belden.com/Blogs/tips-for-p ... -vfd-cable

Something I always try and follow.

Marty

Marty, you'll start a flame war with brave talk like that! Whether to ground the shield at only one end or both seems to really polarise opinion. Personally I have used both methods to good effect - to me there is no right or wrong, just options.

I think the bigger question is should the left end of the cable go to the motor or should it go to the VFD?

The Belden article touches on the issue of single ended grounding vs double ended grounding. As I recall, it's been couple of months ago that I read it, they justify the double grounding because of the size of the currents involved. Most of my experience has been with small to super small signals and with them you want single ended grounding. I followed the Belden recommendation and double ended my armor shields.

Thanks Marty. That's an excellent article. As far as grounding a cable on both ends goes, I just measure the resistance of the shield on the cable. If there is measurable resistance, then I only ground the controller side of the cable. If there is no measurable resistance, then I ground both ends of the cable. On my 5' X 10' Shopbot, that had over 30 feet of VFD cable, I could not measure an resistance on the cable so I grounded both ends. (I also tried grounding just the VFD side of the cable. Either way worked the same as far as I could tell.)

I ground both ends as stated in the Articles. I ALSO use the VFD cable from Automationdirect.com.
No noise issues for me so far.

The information is for the user to digest. I found them very interesting. Bottom line, its up to the user to use GOOD wiring practices in order to avoid ground loops and EMI issues.

I think its good to share this information with the group when found from reputable sources.

Marty

+1 for grounding both ends. I use twist and flex rated double-shielded PU insulated servo cable from McMaster. No problems in my 4 installations.

It looks like Belden "improved" their website and moved things around. I was getting a 404 error on the above URL, I found the article here:
https://www.belden.com/Blogs/tips-for-p ... -vfd-cable
At least I think it's the same article

GBCues wrote: ↑Mon Dec 28, 2020 1:28 pm It looks like Belden "improved" their website and moved things around. I was getting a 404 error on the above URL, I found the article here:
https://www.belden.com/Blogs/tips-for-p ... -vfd-cable
At least I think it's the same article

Looks like it. I updated my post too.
Thanks!

MecTecMike demonstrates EMI radiating from unshielded motor cable
Good to watch