An electrical machine comprising at least two rotors

The electromagnetic machine comprises at least two rotors 101, 102, and means (103, 104) for establishing a magnetic field, including at least one magnet having first and second poles. Each pole of the or each magnet is disposed to generate a magnetic field across a different rotor. Preferably, each pole of each magnet is disposed to generate a magnetic field across a different run of the rotors so as to form a magnetic circuit.