NASA High Efficiency Megawatt Motor (HEMM)
Overview
Topology
- HEMM is a 1.4MW wound field synchronous motor with a stretch performance goal of 16 kW/kg and efficiency of 99 percent
- The motor combines a conductively self-cooled, DC superconducting rotor windings with a slotless stator, allowing the motor to achieve exceptional specific power and efficiency without inheriting the external cooling weight penalty commonly attributed to superconducting machines.
Aircraft Level Impact
- Fuel Burn: STARC-ABL studies have shown that increasing motor efficiency from 96% percent (state-of-the-art) to 99% will reduce fuel burn an additional 2 percent
- Thermal System: Improving from 96% efficiency to 99% will reduce the amount of waste heat and related thermal management systems by a factor of 4.
Key Features
- Uses standard aircraft cooling systems
- Direct drive at optimal turbomachinery speeds (no gearbox)
- Can be shut off if fault occurs (wound field)
