Electrical machine with contra-rotating rotors

An electrical machine comprising:

• a first stator member having a field magnet;
• a second stator member forming an armature, the second stator member being spaced from the first stator member;
• and
• a pair of contra-rotatable rotors disposed between the first and second stator members,
• wherein at least a portion of each of the rotors is magnetisable,
• wherein each rotor comprises a plurality of pole pieces which are magnetisable,
• wherein at least one of the rotors is, in use, driven by a prime mover and the rotors transmit magnetic flux from the field magnet to the armature thereby inducing an electromotive force, wherein a magnetic field produced by the plurality of pole pieces extends between the first stator member and the second stator member, such that the plurality of pole pieces of the first and second stator members act as flux linkage poles that transmit the magnetic flux from the field magnet of the first stator to the armature of the second stator member, and
• wherein the first and second stator members and the rotors are arranged concentrically.