| abstract |
An energy conversion and storage device (1) which comprises a magnetic rotor (5) and a stator (7) comprising one or more electric coils whereby electrical energy may be applied to and extracted from the device (1) when the rotor (5) is rotating relative to the stator (7) and means (13, 14, 15, 17) for electromagnetically suspending the rotor (5) whilst rotating relative to the stator (7), wherein the rotor (5) comprises a tubular body portion formed of a composite of fibre reinforced material and magnetic material embedded within the fibre reinforced material and the stator (7) is disposed inside the rotor (5) co-axially with the rotor (5) and extends along at least a major part of the length of the said body portion of the rotor (5). |