A rotating electrical machine includes a stator and a rotor arranged to rotate inside the stator. The rotor includes a plurality of permanent magnets arranged to produce a radial magnetic flux in an airgap between the rotor and the stator. The machine also includes a stationary excitation coil. The rotor also includes a plurality of low reluctance elements. A current through the stationary excitation coil causes a magnetic flux to be established in a magnetic flux path which passes into the rotor through a first low reluctance element and out of the rotor through a second low reluctance element, which magnetic flux combines with the radial magnetic flux produced by the permanent magnets in the airgap. This arrangement can allow control of the field within a permanent magnet radial flux machine.