The invention relates to an apparatus for determining the position of the rotor of an electrical machine in relation to the stator, wherein the electrical machine comprises at least three phase strands which each comprise at least one pole winding with a magnetizable core; with devices for determining a measurement signal which is characterized by the current degrees of magnetization of the pole winding cores which are dependent on the position of the rotor.
Apparatus for determining the position of the rotor of an electrical machine are known from EP 1 005 716 B and DE 10 2006 046 637 A1. Within each half magnetic period, a clear functional relationship exists between the measurement signal and the rotor position which can be utilized for the determination of the position. In these known apparatus, the measurement signal is picked up, inter alia, at the star point of phase strands switched in a star configuration.