A Magnetic Gear Box for application with a Contra-rotating Tidal Turbine

This paper presents experimental results for the application of a magnetic gear (MG) box to a contra- rotating tidal turbine. The contra-rotating tidal turbine is a novel design comprising two sets of rotors placed axially: the upstream rotor rotates in a clockwise direction whilst the downstream rotor rotates in an anti-clockwise direction. The tidal turbine is a low speed mechanical system similar to a wind turbine, hence the use of a gearbox is considered to permit a standard 4 or 6 pole induction generator to be used. The magnetic gearbox magnetically combines the output of both contra-rotating shafts into a single high speed rotating shaft. A gear box has been designed using 3D Finite Element Analysis and experimentally tested.