Quote Originally Posted by Al_The_Man View Post
Just another opinion! What basis?
There is a lot more likely hood of spurious signals being imposed on a conductor that is ran twisted with hi-current carrying ones.
The earth GND is best kept away from these if at all possible, this is what can and does cause ground loops!.
This is why when the 3 separate conductors are used ran as twisted motor power conductors, the earth is kept along side and non twisted, this is the preferred method.
This is not a 50 Hz 60Hz install which can work with what you are saying, and is definitely not a preferred method my be 50 years ago

You have not done many if any of these High frequency Spindle installs or you would not be posting this, while the spindle is running Rotor Voltage and Frequency, travels through the Ground conductor , unshielded Ground wire will cause unwanted noise if it is independent, So this is a No for all new installs of the High Frequency Spindles