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Electromagnetic Redesign of NASA’s High Efficiency Megawatt MotorNASA’s High Efficiency Megawatt Motor (HEMM) is being developed to achieve the performance needed by single aisle class electrified aircraft. It is a 1.4 MW electric machine designed as a generator for NASA’s STARC-ABL concept vehicle. It has performance objectives of greater than 16 kW/kg electromagnetic specific power and efficiency of greater than 98%. A significant flaw in the preliminary electromagnetic design of HEMM was recently discovered. The stator teeth in the preliminary design cause the magnetic flux in the rotating components of HEMM to oscillate at a very high frequency (12,240 Hz). Two independent energy loss analyses are presented to show that the frequency is high enough to cause eddy current losses that significantly exceed the rotor’s loss limit (50 W), despite the very small magnitude of this flux oscillation (<0.01 T). To eliminate these rotor losses, while continuing to meet the target performance, it was determined that the stator teeth needed to be removed and the electromagnetic geometry of the motor needed to be revised. The revised, slotless HEMM motor design is summarized. Sensitivity of the new design to key unknown variables such as the temperature of and number of turns in the superconducting rotor coils and the stator winding’s average temperature.
Document ID
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Thomas T Tallerico
(Glenn Research Center Cleveland, Ohio, United States)
Justin J Scheidler
(Glenn Research Center Cleveland, Ohio, United States)
Dongsu Lee
(University of Illinois at Urbana Champaign Urbana, Illinois, United States)
Kiruba Haran
(University of Illinois at Urbana Champaign Urbana, Illinois, United States)
Date Acquired
July 16, 2020
Subject Category
Electronics And Electrical Engineering
Meeting Information
Meeting: AIAA/IEEE Electric Aircraft Technologies Symposium (EATS)
Location: Virtual
Country: US
Start Date: August 26, 2020
End Date: August 28, 2020
Sponsors: American Institute of Aeronautics and Astronautics, Institute of Electrical and Electronics Engineers
Funding Number(s)
WBS: 081876.
Distribution Limits
Portions of document may include copyright protected material.
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