Machine with two co-axial rotors

An electromechanical machine having two co-axial and relatively rotatable rotors and a coaxial stator or housing with respect to which both rotors are rotatable about an axis of rotation and wherein rotational movement of one of the rotors relative to the other or relative to the stator or both generates electrical energy. Two bearing arrangements mutually support the two rotors with respect to each other and also support the two rotors with respect to the stator or housing. One of the bearing arrangements comprises multiple support bearings angularly spaced apart with respect to the axis of rotation of the rotors relative to each other and relative to the stator with the support bearings each having an axle or shaft that is fixed relative to one of the rotors or the stator. Each support bearing cooperates with a raceway provided on a concentric adjacent rotor or stator wherein a diameter of the raceway and angular arrangement of the multiple support bearings is greater than the diameter of the other of the two bearing arrangements.