[Al_The_Man]

Quite common to find that.
Just to bring a sense of reason, the gantry, mill head etc that is installed on the machine should have an earth ground/bonding conductor to it.
So the frame of the motor would be earth grounded through the mounting anyway, but it is not wise to rely solely on that method.
Most remove the 4pin receptacle and fit an earth GND from pin to motor frame. Then use a 4 conductor cable to the motor.

[Norkamus]

So the ground terminal on the VFD would have two wires on it, correct? --> One from the spindle ground that I create, and the other on the ground wire for the 220v supply into the VFD... Yeah, I'm pretty new at this..

I'd like to guess about the Chinese note on causing damage if the spindle is grounded. They refer to the problem being when cutting metal (pretend for a moment that is possible with this spindle). Would they be referring to creating a ground loop? When your cutter engages the material, it would be possible depending on your machine construction that the spindle ground and the chassis ground are connected?

What kind of damage are we talking about with a ground loop here? Death? Destroying the VFD or spinlde?

Nick

[mactec54]

So the ground terminal on the VFD would have two wires on it, correct? --> One from the spindle ground that I create, and the other on the ground wire for the 220v supply into the VFD... Yeah, I'm pretty new at this..

I'd like to guess about the Chinese note on causing damage if the spindle is grounded. They refer to the problem being when cutting metal (pretend for a moment that is possible with this spindle). Would they be referring to creating a ground loop? When your cutter engages the material, it would be possible depending on your machine construction that the spindle ground and the chassis ground are connected?

What kind of damage are we talking about with a ground loop here? Death? Destroying the VFD or spinlde?

Nick

Electrical shock is what you can expect to get with an un-Grounded spindle, the rotor voltage has to go somewhere and if it can't go through a Grounding conductor, then when you touch the spindle to change a cutter you will get Zapped.

Can this damage a spindle motor No not at all. it is an electrical code requirement to have it Grounded so don't run this until you have all the correct wiring in place that means from the VFD to the Spindle you need a 4-wire shielded cable and the shield correctly terminated at each end with 360 Degree clamp

You should use a Star-Point Ground stud or Bus in your cabinet all Grounds connect to this one point