This proposed project will demonstrate the potential for a 15kW magnetically geared drivetrain (MGD) to radically improve the cost, reliability and efficiency of an electric aircraft. The MGD is made up of a series connected magnetic gear (MG) connected to a high-speed motor. The Phase 1 portion of this SBIR proposed project aims to design, fabricate and conduct preliminary testing of a 12.1:1 ratio coaxial magnetic gear for use in an electrified aircraft propulsion system.
Unlike a mechanical gearbox a MG creates speed change without any physical contact, eliminates gear lubrication and can operate at high efficiency. A MG also has inherent overload protection, as excessive torque will simply cause the poles to slip, whereas a mechanical gearbox would fail. The MG also has the potential to have a lower applied starting torque than mechanical geared systems and does not have backlash. The inherent axial re-centering forces in a MG could also help to alleviate axially induced bearing wear. The successful performance demonstration of the MGD within the framework of this NASA SBIR program will enable the scalability and performance benefits of the MG technology to be clearly demonstrated for the first time within the context of an aircraft application.
For target improvement purposes this proposed project seeks to design, build and test a 15kW coaxial magnetic gear with a volumetric torque density greater than 300 N·m/L and with a mass torque density greater than 53 N·m/kg.
Gearing is highly useful for providing a mechanical advantage to reduce the overall mass and size of drivetrains. Gearing enables the high-speed, low torque prime movers, to drive low-speed, high torque loads, such as propellers. Magnetic gears have a high potential for use in NASA aerospace applications because they can operate at cryogenic temperatures and don’t require lubrication.Magnetic geared drivetrains eliminate the concerns associated with loss of lubrication in failure critical task.
Magnetically geared motors and generators offer a new way of improving the performance of existing generator and drive motor technology in a myriad of high-torque applications. Magnetic gears could find benefical use in traction motor applications, ship propulsion, wind turbines, marine hydrokinetic generators as well as in robotic and food processing clean room industries.