Hi all, i have a question re. Grounding/shielding a diy Cnc machine.
I hope this is the appropriate sub-forum
Ive been reading all I can get my hands on, particularly regarding the cable from the vfd to the spindle. Apparently its a very noisy link with lots of mhz level noise, which often causes problems for the stepper motors and limit switches and various other sensitive equipment in the vicinity. Both the earth connection and shield of the cable need treating in specific ways. (shield connected at both ends, braid straps used instead of cable etc..)
My issue is as follows:
Im following guidance on a star-earth setup, and both the vfd cable ground and shield (360 degree connection) are extended to the star earth block using 6mm tinned copper braid straps inside some thin rubber tubing.
My concern is what happens next.. From the star earth point i connect to mains using a standard 16 amp kettle lead, so from braided straps i go to normal 16awg cable.. My limited understanding sees this as a "choke point" for the high frequency stuff, if that makes sense.
Given the stepper cable shields and all other bits go to the same star earth, i imagine i need "the path of least resistance" to be to mains ground..? Is my setup problematic?
I could potentially run another braided strap from the star earth, or even just from vfd cable shield (seperate it entirely) a few metres to the house boiler, and strap it to a water or gas pipe (copper, and the gas pipe goes straight outside and underground)
Would that be better? Should i leave mains earth connected too?
As you can see all this shielding stuff goes over my head, and there is *tons* of contradictory info online, from people who maybe dont know more than me!
Any advice from the pro's most appreciated.
Thanks!
I hope this is the appropriate sub-forum
Ive been reading all I can get my hands on, particularly regarding the cable from the vfd to the spindle. Apparently its a very noisy link with lots of mhz level noise, which often causes problems for the stepper motors and limit switches and various other sensitive equipment in the vicinity. Both the earth connection and shield of the cable need treating in specific ways. (shield connected at both ends, braid straps used instead of cable etc..)
My issue is as follows:
Im following guidance on a star-earth setup, and both the vfd cable ground and shield (360 degree connection) are extended to the star earth block using 6mm tinned copper braid straps inside some thin rubber tubing.
My concern is what happens next.. From the star earth point i connect to mains using a standard 16 amp kettle lead, so from braided straps i go to normal 16awg cable.. My limited understanding sees this as a "choke point" for the high frequency stuff, if that makes sense.
Given the stepper cable shields and all other bits go to the same star earth, i imagine i need "the path of least resistance" to be to mains ground..? Is my setup problematic?
I could potentially run another braided strap from the star earth, or even just from vfd cable shield (seperate it entirely) a few metres to the house boiler, and strap it to a water or gas pipe (copper, and the gas pipe goes straight outside and underground)
Would that be better? Should i leave mains earth connected too?
As you can see all this shielding stuff goes over my head, and there is *tons* of contradictory info online, from people who maybe dont know more than me!
Any advice from the pro's most appreciated.
Thanks!