Why VFD Controlled spindle motor bearings damage?
As an electrical person I can say that I have seen these problems and helped with wiring. The VFD (variable frequency drive) capacitive couples electricity to 'where it wants to go'. It wants to get back to the VFD. Here is best practice: Shielded motor cable tied to frame with 360-degree bonds at both motor and VFD, uninterrupted. (VFD, not cabinet). AND a separate ground conductor in the motor cable that ties the motor frame to the VFD frame. Note: 2 pole motors (1 pole pair) are notorious for this so we avoid them whenever possible), May sound redundant but you are dealing with frequencies in the mega hertz range - you got to provide a low impedance back to the source or they will jump into the shaft and machine.
