Patent ID: 8278795

Claim:
An electromotive machine comprising: a rotor; a stator operatively coupled to the rotor, the stator including at least one high voltage stator coil comprising: a plurality of coil strands arranged to form a stack of coil strands; a plurality of vent tubes arranged to pass a cooling gas to cool the stack of coil strands; a filler material disposed on a top surface and a bottom surface of the stack of coil strands; a voltage grading structure comprising a first voltage grading structure arranged by the top surface of the stack of coil strands, the voltage grading structure further comprising a second voltage grading structure arranged by the bottom surface of the stack of coil strands, wherein the first and second voltage grading structures comprise spaced-apart structures relative to one another, each voltage grading structure comprising: an electrical isolation layer on the filler material; an electrically conductive layer on the electrical isolation layer; and an electrically conductive bar positioned on the electrically conductive layer, the conductive bar electrically connected to at least one of the coil strands to shunt a capacitance effect between the conductive layer and the stack of coil strands and force the conductive layer to be substantially at a common voltage level relative to the stack of coil strands and thereby avoid an overvoltage condition.