Rolls-Royce Marine is leading a three-year, £1.7 million project investigating propulsion applications of a magnetically geared motor developed by UK company Magnomatics.
The tripartite cooperation, with high-voltage induction motor specialist ATB Laurence Scott also involved, will see the partners design, manufacture and test a new 2.5MW marine propulsion motor, based on Magnomatics’ magnetically geared propulsion motor.
The motor features inner and outer rings of permanent magnets, with a static outer ring and rotating inner ring. A middle rotating ring of steel segments alters the magnetic field between the two rings of permanent magnets, causing the middle steel ring and the inner magnet ring to rotate at difference speeds and creating a gearing effect. A stator around the stationary outer ring enables even greater magnetic force.
As torque is transferred non-mechanically and parts do not touch, there is no need for lubrication. According to Magnomatics, the system – known as the pseudo direct drive (PDD) gear – is more than 99% efficient at full load and highly efficient at part loads. It is said to require little maintenance and boasts low noise and vibration.
In its abstract submission to funding partner Innovate UK (which is contributing £926,000 to the project), Rolls-Royce noted that the motor “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”.
The company added: “It is estimated 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 runs from January 2016 to March 2018, and will aim to demonstrate the motor’s suitability for both naval and commercial marine applications.
As reported, Rolls-Royce launched its first permanent magnet azimuth thrusters into commercial production in June last year, and has already rolled out a range of permanent magnet motor driven deck equipment.
