Change bearings on spindle motor

The Bearings are quite easy to change, you will need to make the correct wrenches to undo the 2 main nuts on the Rotor the Top Nut will be left-hand thread so watch for this, what VFD Drive does your machine use, as the carrier frequency may be set to low also, check for spindle Grounding the 4th pin must be connected with a Ground wire, if not this will cause the Bearings to have a short life, so the Cable from the VFD Drive to the spindle needs to be 4-wire Shielded Cable