Abstract: An electromagnetic rotating machine driven by an electromagnetic action between a stator and a rotor has drive windings fitted to the stator for generating a rotating magnetic field for rotatably driving the rotor, position control windings fitted to the stator for generating a magnetic field having a different number of poles than that of the drive windings, a magnetic force generation circuit for generating a magnetic force to act on the rotor by supplying the position control windings with an electric current effective to unbalance the magnetic field on the stator side, a circuit for detecting an induced voltage or current generated in the one or more position control windings in response to radial displacement of the rotor and the rotating magnetic field generated by the drive windings, a circuit for detecting radial displacement of the rotor based on the induced voltage or current and the magnitude and speed of the rotating magnetic field, and a position control circuit for controlling the radial positio