Patent ID: 7646128

Claim:
An electric motor, comprising: an electric motor stator; an electric motor rotor having a substantially cylindrical core, made from a core material and having a plurality of longitudinal grooves extending substantially parallel to an axis of the cylinder; a plurality of conductive rods made from an electrically conductive material and arranged in the longitudinal grooves; two short-circuit rings that conductively connect axial ends of the conductive rods to one another; a diffusion layer extending between the conductive rods and the cylindrical core and comprising a diffusion material that is different from the core material and the electrically conductive material of the conductive rods; wherein the electric motor rotor forms a common rotor shaft with a compressor rotor; wherein the common rotor shaft is mounted on magnetic radial bearings; wherein the compressor rotor includes at least one impeller; wherein the electric motor rotor, compressor rotor, common rotor shaft, magnetic radial bearings, and at least one impeller are accommodated in a common gastight housing; wherein the electric motor stator is provided in a gastight housing area which includes a stator space surrounding the cylindrical core, the stator space being formed by a wall section of the gastight housing and a partition, the stator space being provided with a dedicated cooling circuit having a pump, a cooling medium, and a heat exchanger solely for use within the stator space, wherein the cooling medium circulates through the cooling circuit in direct contact with the stator, and wherein a separate cooling medium circulates through cooling system lines to cool the electric motor rotor, compressor rotor, common rotor shaft, and magnetic radial bearings.