[simjim33]

The shield should be grounded at both ends from the vfd to the motor. depending on the nature of your machine its also good to ensure an extra ground path from the motor to the frame of the machine, that way in the case of an electrical failure you don't send substantial current through the linear bearings or the ballscrews.

The 3 phases from the vfd are square waves of continuously varying duty cycle, they average out to get a sine wave current in the motor. the sharp rising and falling edges (and the ringing that occurs) is as high as 400 volts per microsecond and the frequency is as high as 1Mhz. the 350 volt bus of the vfd means there can be substantial current flowing at that frequency, as that +/-170 vdc square wave at the pwm frequency of the drive charges up and discharges the parasitic capacitance of the motor windings to ground, and that's the reason you need to ground the motor.. otherwise you can shock yourself pretty good on an ungrounded motor driven by a vfd, or the current will flow through something else and cause problems.

even the voltage on the cable can radiate through near field capacitance into other signal wires and mess your machine up, shielding it solves that problem, but only if the shield is grounded to the vfd.

Square wave pattern. That makes sense.
Thanks.
So yeah go ahead and attach the shielding to the earth point on the VFD it can share the motor earth point.
Then connect the shielding at the other end to the chassis.
Got it thanks.

I wonder. Why the Chinese don’t Earth at all!