Where to buy power cable for larger spindles?

[Goemon]

You do know you only need shielded for the VFD 3ph out (UVW).?
The options for the power in are several and cheaper. Also depending if you need rigid or flexible cable.
Al.

I didn't know that so thanks. You saved me wasting another $100 on cable. I have plenty of 10 and 8 gauge unshielded cable I can use for the power in and I already have a length of double shielded cable for the VFD out.

[Goemon]

It's only a problem if the Shields are not Grounded correctly, you should keep the unshielded terminal connecting wires as short as possible, there are more than one way to do it but direct Grounding of the Shield is best way to do it

The Best source for cable is IGUS https://www.igus.com/chainflex/control-cable, you can buy it by the foot

Maybe I have a different way of understanding things than other people but those CNC wiring diagrams just don't explain anything without additional words to clarify. The wiring diagrams I understand show wires going between devices I can identify with specific info on which screw terminals they connect to on each.

To me, that top image shows four seperate ground wires going out from four seperate points to four seperate ground screws that aren't on either the VFD, the spindle or any of the plugs. It doesn't seem to say what those ground screws are connected to.

It also seems to show 4 wires going in to the VFD from the wall outlet for power.

When I asked here about where the wires connect to, I was told:

- There are just two wires going into the VFD for power (two hot) and if there is a third wire on the cord, it should not be connected to anything
- There are four wires (shielded) going from the VFD to the spindle. 3 hot going from u, v, w to u, v, w and one going from ground on the VFD to ground on the spindle

and that is it (assuming the spindle will be controlled by the VFD and not by Mach3 or Linux CNC). Is this not correct? Do I need additional wires going from the cable shielding to a seperate device? Or is there more than one wire from ground on the spindle or ground on the VFD?

[Goemon]

A recent professional installation by VFD supply and installation professionals for American Chillers.
Al.

My eyesite is not good enough to extract any info from that pic. I also lack the requisite x-ray vision needed to see where the wires are connected to. Also, I can't see what distinguishes this installation from an amateur one. It just looks like they mounted two VFDs in an enclosure with some cable ties to make that spaghetti junction of wires look a little neater.

If there is something in this pic related to shielding or grounding that I need to replicate, please can you point it out to me?

[Goemon]

If the cable on Ebay does not have a flex rating then don't get it, your spindle cable being for your Z axes need a high flex rate, most normal regular shielded cable does not have a flex rate and won't last very long

The one I bought was sold specifically for CNC and robotics so hopefully it's fit for purpose. If it doesn't last, I'll replace it. I'll have to check the listing info to see if it included any flex rating. I can't remember off the top of my head.

[Goemon]

IMO, this is what a CNC spindle wiring diagram (for forum-level use) should look like:

https://www.buildyourcnc.com/images/...Wiring-800.JPG

It's simple and easy (at least for me) to see which wires go from which screw on which device and everything is labeled so I know if it's the ground wire or a coffee stain on the page.

It's consistent with what you guys told me except that it has 3 wires going from the power outlet to VFD instead of just two, so there is an extra ground wire. If this diagram is not correct or complete, what more needs to be added to properly ground the shield on the cable?

[Al_The_Man]

What you have to understand that many countries use a live (L1) and a neutral for 220/240v power, unlike N.A. that has a 120v-0-120v, this is why you often see VFD's etc labelled with (N) neutral, these cater to these other countries..
As you are in N.A. you can ignore the N label and just use the L1 - L2 ( 240v).
SO there are two power conductors and earth GND to the VFD.
Al.

[ger21]

IMO, this is what a CNC spindle wiring diagram (for forum-level use) should look like:

https://www.buildyourcnc.com/images/...Wiring-800.JPG

Not sure why they have that diagram, as they are a US company, and you can't wire it like that in the US.

I wouldn't put a lot of faith in anything from that site.

[Al_The_Man]

Not sure why they have that diagram, as they are a US company, and you can't wire it like that in the US.

I wouldn't put a lot of faith in anything from that site.

They seem a little mixed up, in another VFD hook up they label the live as L1 and N as L2, slightly better but still can be confusing to some.
Al.

[mactec54]

Not sure why they have that diagram, as they are a US company, and you can't wire it like that in the US.

I wouldn't put a lot of faith in anything from that site.

Going by the Parameters they have set, they are using a 1.5Kw spindle and a VFD with a 120v single Phase connection, Geomon needs to be more careful as to what he is looking at

So if there wiring is for 120v single phase input to the VFD, then this is correct if it was for 120v input

It's confusing at best, when someone posts something like this, without it having all the correct information

Ok just had a better look they are using the neutral white wire as a Hot wire, not correct for NA unless labeled or taped with a Black or Red Tape

This is correct for other countries but not for NA

[ger21]

So if there wiring is for 120v single phase input to the VFD, then this is correct

If you read the text right below the pic, it says:
Input to VFD.
240V Active (Black)
240V Neutral (White)

Which is not correct.

[mactec54]

If you read the text right below the pic, it says:
Input to VFD.
240V Active (Black)
240V Neutral (White)

Which is not correct.

It is correct if it is not for NA, this is where people get confused, if it is for NA then it is wrong

[Goemon]

Not sure why they have that diagram, as they are a US company, and you can't wire it like that in the US.

I wouldn't put a lot of faith in anything from that site.

I don't put any faith in that site. I spotted the obvious issue with their diagram straight away. I am just saying that their diagram is the clearest I have seen and I prefer how they lay it out. If the info was actually correct, it would be a diagram worth keeping.

I put my faith in a small handful of people on this forum (like you),who have offered consistently good advice.

I just wish there was a correct diagram (signed off on by you guys) in this style because it's easy to follow.

The problem (for me) with most of the other diagrams is that they have wires that don't seem to go to any particular device. I don't know what to do when a wire goes to a "ground" symbol that is floating in mid-air.

I can see now that this issue is further complicated in America by the variety of diffent styles of outlet as they are not wired in the same way.

The old style nema 10-30 and nema 10-50 outlets found in older places (like mine) use a 3 prong plug with no earth ground. From what I read, some devices have some kind of wiring work-around with ground tied to neutral in some way (that apparently isn't as unsafe as it sounds) but that doesn't apply to VFDs (or at least not my one).

I plan to get my electrician to replace my 3 prong outlets with the newer 4 prong design with earth ground next month but I need to test my spindle before then. I need to check it works before the warranty expires. So... I need to temporarily wire it up to a 3 prong outlet.

If I understood what you told me correctly, the way to use this kind of plug is to use the two hot power wires and not connecting the 3rd neutral wire to anything at all. The only ground wire I have goes from the VFD ground (E) to the ground screw on my spindle.

I was planning to check it is safe for testing by using my voltage tester to check there is nothing that will shock me on the outer casing of my spindle or VFD.

Is there something extra that you need to do with regard to grounding when using 3 prong outlets with no earth ground?

[ger21]

The old style nema 10-30 and nema 10-50 outlets found in older places (like mine) use a 3 prong plug with no earth ground. From what I read, some devices have some kind of wiring work-around with ground tied to neutral in some way (that apparently isn't as unsafe as it sounds) but that doesn't apply to VFDs (or at least not my one).

I plan to get my electrician to replace my 3 prong outlets with the newer 4 prong design with earth ground next month but I need to test my spindle before then. I need to check it works before the warranty expires. So... I need to temporarily wire it up to a 3 prong outlet.

You're 3 wire outlets most likely do have a ground.
There are basically 2 types of 240V single phase outlets in the US.
2 Hot wires + ground
or
2 Hot wires + Neutral + ground.

Plugs with a neutral are for appliances that use both 120V and 240V, like dryers and ovens.

Is there something extra that you need to do with regard to grounding when using 3 prong outlets with no earth ground?

Any outlets without a ground should be re-wired and replaced. But I don't think that's really what you have, unless your wiring is well over 50 years old.

[Goemon]

Going by the Parameters they have set, they are using a 1.5Kw spindle and a VFD with a 120v single Phase connection, Geomon needs to be more careful as to what he is looking at

So if there wiring is for 120v single phase input to the VFD, then this is correct if it was for 120v input

It's confusing at best, when someone posts something like this, without it having all the correct information

Ok just had a better look they are using the neutral white wire as a Hot wire, not correct for NA unless labeled or taped with a Black or Red Tape

This is correct for other countries but not for NA

Huh? It specifically states 240v over the wall outlet. I think they are just wrong. My guess is that whoever wrote it was not used to outlets with two black power wires with a third unused neutral in a different color so they got confused on the labels. Or they copied info from another country without realizing.

either way, none of that matters. I wasn't putting that diagram forward as being info that should be followed. I was just saying that I like the style of the diagram as it's easier to understand without additional explanation (which is the whole point of a diagram). Wiring diagrams that don't specify which device the wires go to are pointless.

If anyone is going to go to the trouble of drawing a diagram to help people that actually need a diagram, that is the way to do it imo.

Aside from the innacurate info, the main issue with this and most other diagrams is that it doesn't specifically state which country and style of outlet it is for. Just look at the mini tail spin it caused here among people who already know this stuff.... it's even more confusing for people who are new to CNC because there is no obvious reason why each diagram is different.

Nothing generates more confusion and duplicate threads than this topic because we don't have a simple (and correct) diagram like that for each country and plug style.

[Al_The_Man]

Huh? It specifically states 240v over the wall outlet. I think they are just wrong. My guess is that whoever wrote it was not used to outlets with two black power wires with a third unused neutral in a different color so they got confused on the labels. Or they copied info from another country without realizing.

Nothing generates more confusion and duplicate threads than this topic because we don't have a simple (and correct) diagram like that for each country and plug style.

One of the main problems is most of the equipment used here originates from China, they do not appear to be concerned as to what country they are shipping to and to the different standards that apply in each, there seems to be no enforcement by the local standards associations..
This makes it doubly hard for those that chose to help here attempt to explain the international differences. I have seen some horrible examples of equipment that originates from Asia that contravenes N.A. standards as laid out in the NEC/CEC and NFPA79, which is a standard for wiring Industrial machinery.
NFPA79 lays out all the requirements for wiring, grounding, fusing, conductor size, wire colours etc.
White for neutral is pretty much standard for most countries, in N.A. we have L1 & L2 for domestic 240v, where a 3 conductor cable (2 wire and GND) is used and one is white, and it is used for 240v, the white will be marked either Red or Black at each termination point.
Al.

[Goemon]

You're 3 wire outlets most likely do have a ground.
There are basically 2 types of 240V single phase outlets in the US.
2 Hot wires + ground
or
2 Hot wires + Neutral + ground.

Plugs with a neutral are for appliances that use both 120V and 240V, like dryers and ovens.



Any outlets without a ground should be re-wired and replaced. But I don't think that's really what you have, unless your wiring is well over 50 years old.

I didn't install any of the outlets that are currently there but my understanding is that they were installed to run appliances and they look like the old kind with 2 hot and a neutral that carries 120v. As I understand it, a nema 10-30 and a nema 10-50 outlet never has ground. That's why they replaced them with the newer style outlets. Hard to believe those old nema 10-30 outlets are still allowed.... espiecially as they sell replacement drier cables in Best Buy for diy installation...

I agree that they need replacing which is why I am getting them replaced with the newer 4 wire kind (with earth ground) but... I need to test my spindle before then. My intention is to test it without ground going in to the VFD (like how the Chinese wire their spindles).

I can't seem to find much info on this topic so I am in trial and error territory. Not a great place to be with electrical wiring so I have ordered a new heavier duty voltage tester to make sure there is nothing that will shock me on any of the surfaces I will touch on the spindle or VFD.

I suspect that I am not the first to encounter this issue. Based on what I have seen out there, I bet there are a lot of people who have used an old 220v drier outlet and connected a neutral with live current to their ground screw without realizing what they have done... the good news is that I haven't seen many threads entitled "I died and had to be revived after incorrect VFD wiring".

[ger21]

As I understand it, a nema 10-30 and a nema 10-50 outlet never has ground.

They most certainly do have a ground.
Two 120V hot lines + a ground. No neutral.

My intention is to test it without ground going in to the VFD (like how the Chinese wire their spindles).

That's wrong, and dangerous. The chinese manuals all show ground connections, and have ground terminals for a reason.

[Al_The_Man]

, I bet there are a lot of people who have used an old 220v drier outlet and connected a neutral with live current to their ground screw without realizing what they have done... the good news is that I haven't seen many threads entitled "I died and had to be revived after incorrect VFD wiring".

I agree it is not good, the saving grace is that in a L1/L2 balanced system where the current is identical in each such as a VFD. Dryer etc, there is zero current in the neutral.
Al.

[Goemon]

I agree it is not good, the saving grace is that in a L1/L2 balanced system where the current is identical in each such as a VFD. Dryer etc, there is zero current in the neutral.
Al.

I thought there was a current on neutral (which is why it can't be used even if tied to ground). I read that dryers use the 120v from neutral to power peripheral electronics like LCD displays.which don't use 220v.

[Al_The_Man]

If it has 120v circuitry then the unbalance or current difference in current between the two L1-L2 will be carried by the neutral.

An example is where a 120v 15a duplex receptacle has L1 on one outlet and L2 on the other and they share the same neutral as it was done in kitchen outlets at one time.
If a 120v 10a load is plugged into each receptacle what is the current in the shared neutral?
A: 10a
B: 0a
C: 20a
Ask your local electrician next time, see if he knows the answer?
Al.
.