UK companies in $2.5M project to develop marine magnetically geared propulsion motor; potential 10% efficiency gain
Rolls Royce, magnetic gear company Magnomatics and electric motor company ATB Laurence Scott are partnering in a two-year, £1.7-million (US$2.5-million) project to develop an electric Magnetically Geared Propulsion Motor (MGPM) for marine applications. Innovate UK, the UK’s innovation agency, is providing £925,708 (US$1.3 million) in funding.
A magnetic gear uses permanent magnets to transmit torque between an input and output shaft without mechanical contact. The highly efficient (MGPM) may offer significant benefits for marine propulsion by increasing the electrical efficiency by up to 7% compared to existing state of the art electrical machines.
In the project, the three companies will design, manufacture and test a 2.5MW novel propulsion motor. They estimate that the use of this machine within a vessel propulsion system could increase the total vessel efficiency by up to 10% and deliver a very low maintenance and robust propulsion system, suitable for a range of new build vessels and retrofits.
The aggregated efficiency benefits and low operational maintenance advantages would allow more flexible propulsion systems to be used on many types of vessels leading to an improvement in average fleet efficiency and therefore emission reduction.
The project will also demonstrate that this type of motor is suitable for both naval and commercial applications.
Magnomatics. Magnomatics was established in 2006 as a spin-out from the University of Sheffield to commercialize research on magnetic transmission systems, originally conducted by Professor Kais Atallah and Professor David Howe in the Electrical Machines & Drives research group at the University.
Magnomatics has developed two derivative products based on magnetic gears: the Pseudo Direct Drive PDD and MAGSPLIT. The PDD is a high-torque low-speed motor/generator highly suited to actuation, rail traction, marine propulsion and wind power. PDD integrates a non-contact passive magnetic gear within a permanent magnet brushless machine.
MAGSPLIT is a power-split continuously variable transmission, suited to blended hybrid power trains. MAGSPLIT will also filter torsional vibrations.
The PDD, which will be used in the MGPM project, combines a magnetic gear with a standard wound stator. The outer arrays of magnets are fixed to the internal bore of the stator and the magnetic fields generated by the windings are used to drive the internal rotor.
The torque produced by this rotor is then geared up in the magnetic gear and transmitted out via the steel pole pieces. This results in an extremely compact, highly torque dense machine. The natural elasticity resulting from the magnetic gear means that the output torque has extremely low levels of ripple (<0.3%).