Patent ID: 8729766

Claim:
An electric machine, comprising: a laminated stator ( 16 ) with a multi-phase stator winding ( 18 ); and a laminated rotor ( 20 ) with an exciter winding ( 29 ) which is arranged in grooves ( 40 ) on the rotor circumference and which supplies the excitation of the machine, characterized in that the rotor grooves ( 40 ) include respective groove openings ( 45 ) and groove bases ( 44 ) wherein the grooves widen in the direction from the openings ( 45 ) to the bases ( 44 ), characterized in that the rotor ( 20 ) has two-pole electrical excitation and has the grooves ( 40 ) on its circumference, the exciter winding ( 29 ) which is composed of two component coils ( 29 a, b ) which are arranged substantially symmetrically with respect to a rotor shaft ( 27 ) is located, in the grooves ( 40 ) and characterized in that a groove width (B) at the base ( 44 ) is larger than a diameter (d) of the rotor shaft ( 27 ) and smaller than 40% of a diameter (D) of the rotor.