Are you concerned about rotor ground faults on your generators or motors with brushless exciters? A field ground fault can occur when insulation damage creates an electrically conductive path from anywhere on the field winding (or elsewhere on the excitation circuit) to the rotor forging. If two faults occur at different locations along the winding, excitation current is diverted through the forging, and severe burning of both insulation and rotor steel can occur rather quickly.
Do you wish you understood more about why ground faults occur, what damage they can cause, and how you can detect their onset in time to save your rotor from catastrophic damage? Watch this short presentation introducing ground faults and methods of detection.