An electrical synchronous machine, in particular for use as a drive machine in motor vehicle applications. A stator has an electrical winding arrangement for generating a rotating field. A rotor has magnetic flux generating means for generating a rotor flux with which the rotating field interacts.The rotor has a first rotor section with first magnetic flux generating means and a second rotor section with magnetic flux influencing means. It is possible to move the two rotor sections relative to one another between at least a first and a second relative position in such a way that the rotor flux provided by the rotor has a different magnitude in the two relative positions.