[sploo]

You are Grounding the Shield just make sure the complete plug when assembled has continuity to the Spindle body

The complete plug is Grounded through the body to Ground wire this is normal , in your case because your spindle has a plastic cap you will need to add a Ground jumper from the Ground pin to the plug body ( Under the plug ) then the complete Plug will be Grounded so when you clamp the shield in the cable restraint it will be Grounded also

With the EMI Filter every bit that can be filtered is why I chose that part number and use them on all VFD Drive installs, this has to be mounted as close as you can to the VFD Drive Twist all your wires where ever you can, do not Twist any Ground wires with the power wires in your case Live and Negative

You will find the filters are High quality with a low cost compared to other EMI Filters which have exposed connections

Yes; this a good point: because the socket on the spindle is isolated from the can via the plastic cap it will not be grounded. I'll ensure that's fixed.

On the subject of the VFD earth points, a bit more investigation tells me that connecting the earth core on the VFD-to-spindle wire to the earth point for the incoming single phase mains is the way to go. At least, based on the wiring diagram at this site (which sells the same VFD): https://www.buildyourcnc.com/item/sp...-spindle-novfd

[mactec54]

Yes; this a good point: because the socket on the spindle is isolated from the can via the plastic cap it will not be grounded. I'll ensure that's fixed.

On the subject of the VFD earth points, a bit more investigation tells me that connecting the earth core on the VFD-to-spindle wire to the earth point for the incoming single phase mains is the way to go. At least, based on the wiring diagram at this site (which sells the same VFD): https://www.buildyourcnc.com/item/sp...-spindle-novfd

It can be done that way, if you only have one thing in you cabinet that needs a Ground / Earth connection that is why you need a Ground / Earth Bus so all the Grounds connect to that one point ( Star Ground )

[sploo]

It can be done that way, if you only have one thing in you cabinet that needs a Ground / Earth connection that is why you need a Ground / Earth Bus so all the Grounds connect to that one point ( Star Ground )

Ref the diagram in my original post in the thread... the CNC controller enclosure itself is grounded, but it's because it takes an IEC C13 connector (live, neutral, earth from the 240VAC mains). It would be possible to strip out the earth line from that incoming connector, and instead wire an earth cable from the CNC controller to the VFD earth terminal (or have all earth wires connected to a ground bus that sits between the CNC controller and the VFD). However, the CNC controller uses a transformer to convert the incoming 240VAC to 24VDC, and the only connections between it (the CNC controller) and the CNC machine are that 24VDC (via the Gecko G320 servo drivers), and a few wires that carry the limit switch and server encoder signals. As such, there's no AC mains connection from the CNC controller to the CNC machine; so I assume (perhaps incorrectly) that it's fine for the CNC controller earth to be separate? Probably the same question for the PC too.

[mactec54]

Ref the diagram in my original post in the thread..

Yes which is incorrect

First the Mains Power coming in to the cabinet needs a Disconnect at the cabinet and a Ground / Earth Bus connected to the Ground Plane

From the disconnect it has to go to Circuit Breakers for each device being connected to the Mains Power this would be your Transformer and the VFD Drive Etc.

For the VFD Drive connection

MCCB

EMI Power Filter

VFD connected to terminals R Live and T Neutral Plus Ground / Earth to the Ground Bus

No Ground / Earth connections can be separate if so you will have a Ground / Earth loop and lots of noise

If you don't understand this then you should consult with an industrial Electrician that has done VFD Drive installs

[sploo]

Yes which is incorrect

First the Mains Power coming in to the cabinet needs a Disconnect at the cabinet and a Ground / Earth Bus connected to the Ground Plane

From the disconnect it has to go to Circuit Breakers for each device being connected to the Mains Power this would be your Transformer and the VFD Drive Etc.

For the VFD Drive connection

MCCB

EMI Power Filter

VFD connected to terminals R Live and T Neutral Plus Ground / Earth to the Ground Bus

No Ground / Earth connections can be separate if so you will have a Ground / Earth loop and lots of noise

If you don't understand this then you should consult with an industrial Electrician that has done VFD Drive installs

I was referring to the original diagram more as context for the question, rather than a statement of correctness.

I suspect that for a home/hobbyist set up, an industrial electrician with VFD experience will be rather hard to find (and expensive); I'm just trying to learn, and get the best/safest wiring I can with the resources available.

EMI filters are on their way. Shielded cable has arrived today. I've no problem separating out the relevant earth cores in order to use a ground bus, so I'll look into doing that.

[Al_The_Man]

I was referring to the original diagram more as context for the question, rather than a statement of correctness.

.

Very few actually know what a ground loop is, it is a difference in potential that may exist on earth ground conductors or points of system ground at different points in the system.
Now in Industrial systems that mix low level and high level high frequency signals, it is advised to use something called equi-potential bonding.
This is use a dedicated conductor to ground bond each separate metallic parts of a system. Generally ending up at the earthed star ground point
If this is done properly, it virtually eliminates all chance of ground loops.

[mactec54]

I was referring to the original diagram more as context for the question, rather than a statement of correctness.

I suspect that for a home/hobbyist set up, an industrial electrician with VFD experience will be rather hard to find (and expensive); I'm just trying to learn, and get the best/safest wiring I can with the resources available.

EMI filters are on their way. Shielded cable has arrived today. I've no problem separating out the relevant earth cores in order to use a ground bus, so I'll look into doing that.

Yes I understand but we seem to be going around and around instead of forward, you are dealing with an industrial device VFD Drive and it has to be treated as such so all wiring must comply it does not matter if it is for a Hobby or a manufacturing plant all electrical wiring needs to comply for your own safety and everyone around you that may come in contact with your machine

Not all that you see on hobby sites and videos are correct, the basics don't change some are good to look at but not to copy !

[sploo]

Yes I understand but we seem to be going around and around instead of forward, you are dealing with an industrial device VFD Drive and it has to be treated as such so all wiring must comply it does not matter if it is for a Hobby or a manufacturing plant all electrical wiring needs to comply for your own safety and everyone around you that may come in contact with your machine

Not all that you see on hobby sites and videos are correct, the basics don't change some are good to look at but not to copy !

Two issues really; the first is that I don't have a cabinet/ground bar etc - the machine isn't of that scale, and indeed has been running without problems for ~16 years (albeit with a router rather than a VFD and spindle). Point is: I want to get things clear before I spend time and money; though I've every intention to "do the right thing" (and I appreciate the advice).

The second issue is mixed information; I mean, even in this thread there's been disagreements. Looking at information regarding the shield on shielded cable (from numerous forums, CNC vendor articles, blog posts, VFD manuals etc) I've learned that:

• The shield must be mechanically bonded at either end, but absolutely should not be grounded as that's not it's job and how do you expect it to work otherwise
• The shield absolutely must be grounded at both ends, otherwise how do you expect it to work properly as a shield
• The shield absolutely must be grounded at one end only, otherwise how do you expect it to work without creating ground loops

Obviously every source will tell you they're right; but dumb goobers like me have to sift through the "truths" and choose a path. If all the guidance were consistent it'd be easy to move forward.