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Electric Machines

Electrified aircraft require motors and generators, also known as electric machines, to generate electrical power that drives fans and propulsors. These systems can open up new design possibilities for reducing fuel and energy use in the aviation industry.

Quick Facts

Researchers at NASA are developing an electric motor that is smaller and 10 times more powerful than a traditional car engine, with efficiency greater than 98%.

Researchers at NASA are developing an electric motor that is smaller and 10 times more powerful than a traditional car engine, with efficiency greater than 98%.

NASA sponsors work with industry and academia to advance electric machine development and achieve power densities 2-3 times greater than the state-of-the- art for machines in the megawatt or larger class.

NASA sponsors work with industry and academia to advance electric machine development and achieve power densities 2-3 times greater than the state-of-the- art for machines in the megawatt or larger class.

Overview

NASA’s research in the electrical power area focuses on building lightweight, high-efficiency motors and power converters in the megawatt (MW) class. MW-level components could help enable partially turboelectric and hybrid electric propulsion in aircraft up to the single-aisle class, transporting around 180 passengers per flight, and fully turboelectric or hybrid electric systems for smaller aircraft.

While specific power several times higher than industrial motors has been recognized as a key need for several years, the system benefits of combining high specific power with high efficiency have more recently become clear.  

A top-down view of a single-aisle aircraft rendering with dotted lines showing power distribution from the engines to the electric fan on the tail of the plane. The words “2.9 MW onboard power generation” and “2.6 MW power driving electric fan (after 10% power loss)” are written along the top half of the image. A small box in the lower right corner contains the words “challenge: minimize losses due to power conversion inefficiency and weight of added components.”
An artist’s rendering showing the power levels required for large-scale electrified aircraft.
NASA

Advanced Power Technology

Measuring electricity, 1 MW is enough energy to power roughly 500-800 U.S. homes. Future single-aisle electrified aircraft will require between 3-20 MW of power – enough to supply a small township. NASA is sponsoring work to achieve power densities that are 2-3 times the state-of-the art and higher efficiencies for electric machines in the MW-class or larger.

The three major electric machine configurations that are currently being developed include permanent magnet, induction, and wound field. These each offer a different way of using electrical current to create a magnetic field that enables the motor to rotate, with varying levels of performance and efficiency. Permanent magnet motors tend to have higher efficiency with less torque and speed, while induction and wound field motors are often more cost-effective with better control torque control. 

 

Electric Motor Development

High-Efficiency Megawatt Motor (HEMM)

Researchers at NASA are developing a 1.4 megawatt motor for future electrified aircraft.

NASA is investigating partially and fully superconducting motors for electrified aircraft. HEMM offers three times lower losses and weight than current aircraft motors and is being designed for a range of aircraft that require megawatt-levels of electrical power.  

Learn More about High-Efficiency Megawatt Motor (HEMM)
A cross section of an electric motor render showcasing the internal workings of the High-Efficiency Megawatt Motor (HEMM).
An artist’s rendering of the High-Efficiency Megawatt Motor (HEMM).
NASA

Academic Collaborations

Three different angles of an aircraft motor. The first two angles are artist’s renderings. The first view shows a close-up of the inside of the motor and the second view highlights the motor integration into a turbofan. The third view focuses on the exterior appearance of the motor. Credit: University of Illinois.

University of Illinois Air Cooled PM Machine

The University of Illinois developed a 1 MW permanent magnet synchronous motor with a performance goal of 13 kW/kg and efficiency of >96%. Extensive analysis and subcomponent testing have been done to optimize the electromagentic, structural, and thermal design of the system, as well as full-speed rotor validation testing to ensure the best possible permanent magnet/carbon fiber overwrap rotor design.

Three different views of an aircraft motor. The first two views on the left and upper right showcase an artist’s rendering of the inside of an electric machine with key components highlighted using bright colors. The lower right angle shows the exterior shot of a component in the physical motor.

Ohio State University Induction Machine

The Ohio State University developed a 2.7 MW ring induction motor with a performance goal of 13 kW/kg and efficiency of >96%. The design features Variable Cross-Section Wet Coil (VCSWC) technology which utilizes direct fluid cooling to maximize heat transfer and current density. Aircraft-level integration of the system consists of a 10 MW motor integrated with a turbofan.

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Materials Technology

Superconducting Wires

New materials research can help increase efficiency in future electrified aircraft systems.

NASA is collaborating with industry to advance research on superconducting wires for use in motors and generators on electrified aircraft. The materials used in superconducting wires eliminate electrical resistance when cooled below a critical temperature, which helps support higher current loads with minimal energy loss. 

Learn More about Superconducting Wires
Three different cross sections of a wire decreasing in size from left to right. The circular objects feature a honey-comb texture on the inside and are displayed against a black background. On top of each cross section from left to right reads “0.51 mm,” “0.35 mm,” and “0.20 mm.” In the bottom right corner reads “100 µm.
A cross section of the multifilament magnesium diboride (MgB2) superconducting wires produced by Hyper Tech in collaboration with NASA.
NASA

Explore More EAP

A rear-view rendering of a blended wing body aircraft with distributed fans across the top rear of the vehicle as it flies across a blue sky with white clouds in the background. The NASA insignia is displayed on the left wing, and the words “N3-X” are written on the right wing.

Aircraft Concepts

Learn more about NASA's conceptual aircraft design studies for future electrified aircraft.

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A white building surrounded by external equipment in front of a blue sky with clouds

EAP Labs and Testbeds

Learn about NASA's labs and testbeds enabling advanced electrified aircraft propulsion research.

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An artist rendering of a rectangular-shaped aircraft converter with various wires and circuiting systems displayed on the inside.

Technology

Discover the innovative systems and technologies that enable safe and efficient electrified propulsion.

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