No problem at all, if the shields are terminated correctly
12 AWG cable is ridiculous for a spindle that is only 8.5A, you should be using no more than 16 AWG, this is the cable you should have if your Spindle is 2.2Kw
CF6-15-04 you can get this from IGUS, they have some of the best cable to get for machine wiring like this
Mactec54
Grounded the spindle tonight. Model GDZ-80F-2.2B
Took a while but not having a good ground with 3 phase is not something I want to deal with.
The only safe way I could think of was to use an eye connector along with the back cover screw so that there was no chance of it coming off through vibration.
Had to notch the cover a little. So the cable would not migrate towards the spinning bits. Had to crimp it so that the wide part of the crimp was at 90 to the eye. Otherwise it stood to proud and interfered with the cover snapping back in.
In other words I crimped it the wrong way around. Seemed pretty tight though. Better than nothing, which is what I had before.
The connector is upside down in this image but if fits against the case nice and snug with the crimped part sitting inside the air vent.
Here is the other side.
Ohm'ed before and after assembly.
That's about it really. Thought someone might find it useful in the future.
I made a new aluminum cap, and will attach the ground screw to the cap. Here's some pics.
https://www.cnczone.com/forums/cnc-w...ml#post2096902
I'm also using a better plug than the stock version.
Gerry
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David
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It has very little to do with piece of mind, the Ground when the Spindle is running is dumping the Rotor current to Ground, without it doing this you would get a shock when you touch the Spindle or the frame around it, this can cause damage to Electronics also if the Spindle is not Grounded
Mactec54
Three phase motors do not need a ground wire except for the frame or equipment ground. According to the NEC a metal mounting frame or other metal properly bonded serves that purpose. Your spindle motor is grounded to the frame of the Z by means of attachment. Is your carriage grounded or bonded to the machine? My router motor is grounded by the means of the ground wire included in the 120 vac power cord.
1000x750 Workbee CNC - Mach4 - PMDX USB - Windows 10 Pro
You obvious have no understanding of what happens to a 3Ph VFD driven motor
His spindle motor is not Grounded to the Frame, when you have moving parts like a Z axes and a X and Y axes they are not Grounded, you also have to use a Shielded Cable which has to be Bonded at each end this is a VFD Drive requirement
Do you even understand what Bonding means, apparently not if you say no Ground is required, if you did this practice you would loose your license
Mactec54
That's exactly why I came here to post tonight. My wire arrived today and I got to thinking about the shield.
What do I do with it at the motor end? I only have four pins. Do I solder the shield to the ground pin? The connector is isolated from the spindle body. (plastic end cap)
I don't know what bonding is.
Thanks.
You need to get your thinking cap on and re-read my statement. Three phase motors do not need a ground wire except for the frame or equipment ground what part of that do you have trouble understanding?
The next is a little harder to understand.... of attachment to the machine? According to the NEC a metal mounting frame or other metal properly bonded serves that purpose. Your spindle motor is grounded to the frame of the Z by means . Is your carriage grounded or bonded?
I have been licensed and in the trade since 1962 and have a Masters license. The ground or bonding for a VFD driven motor is no different than the requirement for any 3 phase motor. It can be grounded through the frame or bonding jumper or a equipment ground wire. In this case both the motor and the Z carriage need to be bonded together and then grounded to the incoming power line grounding conductor. I do not think cable shielding qualifies as an equipment ground not for NEC anyway.
1000x750 Workbee CNC - Mach4 - PMDX USB - Windows 10 Pro
The metal part of your spindle motor needs to be attached to equipment grounding conductor by some means. Shielded wire does not qualify. It must be the same size as the wire feeding your motor, if that is #14 wire that is the size. It needs to be physically connected to the equipment grounding wire feeding the machine. That grounding conductor also needs to be connected to the metal of the frame. Most pre-wired except for the Chinese machines have this done for you. The shielded wire is only to prevent EMI or RFI interference to electronics elsewhere.
Going to add this, today I finished up my NEMA 34 build as posted elsewhere amd my router motor which is the same as my Spindle on my other machine has an aluminum frame. It mounts into the clamping type mount on my router Z carriage. If you were to run your equipment grounding wire as above and attach to this clamping mount it would qualify as a ground. No sense soldering a wire to a pin in a plug that does not attach to the metal frame of the motor in some way. Added a picture to make it clearer, the router mount is machined out of aluminum and makes full contact on the motor. Green wire is attached to mount and goes back to control panel and connected to machine ground.
Last edited by wmgeorge; 08-09-2018 at 08:06 AM.
1000x750 Workbee CNC - Mach4 - PMDX USB - Windows 10 Pro
Yes you have a problem with having the plastic cap, you did well to Ground the Ground wire, and the Shield will be a challenge, but can be done with a 360 degree clip something like this, no you must never solder a shield to terminate it, here are some method's, of how you can connect a Shield correctly
Mactec54
No it can not be just Grounded just through the Frame, it would not be electrical EMC compliant, which is a code requirement in most countries when using a VFD Drive
Every VFD Drive manufacture goes into great detail of how important it is to Ground the VFD and Motor and termination of the Shields
Last edited by ger21; 08-09-2018 at 07:49 PM.
Mactec54
I really like that last solution.(pictures with purple wire.) I can definitely come up with something like that and attach to the steel CNC frame. Or is it spindle? I know , or at least want, the frame grounded as well with a separate grounding wire placed elsewhere. The VFD case attachment should not be an issue as I think I may have to fabricate a metal box so I have some control of how it happens in there.
Thanks.
Last edited by PLJack; 08-09-2018 at 12:13 PM.
Yes your VFD needs to be in a metal box if you can. As far as termination of the shield, you can just rake out the strands on the end twist together and use a crimp lug on the end, sized to fit your screw used for attachment to your ground plane. Your grounding method looks good from what I could see.
1000x750 Workbee CNC - Mach4 - PMDX USB - Windows 10 Pro