Electrical machine and method for setting the field and armature of a permanently excited electrical machine

An electrical machine, comprising:

• a stator which bears a winding;
• a rotatable rotor, situated at a distance from the stator via an air gap, the rotor including at least two coaxial rotor sections which are rotatable relative to one another, in which each rotor section bears a system of permanent magnets having polarities which point outward radially in alternation;
• and
• an actuating device for rotating the rotor sections relative to one another;
• wherein the actuating device has a controllable actuator configured to align the rotor sections with one another with a variable rotary offset which is independent of a rotational speed of the rotor;
• and
• wherein the rotor sections are provided on shaft sections of a main shaft designed as a hollow shaft, in which an inner shaft is supported in an axially displaceable manner, and the actuator is designed as a displacement element for axial displacement of the inner shaft which, in mechanical linkage with a mutually engaged guide situated on the shafts, provides a freely selectable rotation and alignment of the rotor sections with respect to one another.