Description: Future hybrid and hydrogen-powered zero carbon-emission electric aircraft require high temperature superconducting (HTS) electric motors to achieve power densities above 10 kW/kg while operating at temperatures above 25 K. However, the AC modes of stator coils in these motors makes it impossible to use available HTS tapes due to their large AC losses, requiring instead fine HTS wires made with the HTS-2212 material with advanced loss reducing features. The Phase I program established the feasibility of a low loss HTS-2212 cable with commercial-level operating current densities, losses and racetrack coilability. It built on our recent breakthrough development of low-loss HTS-2212 wire and cable features. Subscale and a full build (30 turn) racetrack test coil were fabricated and tested to establish and demonstrate coil ability of this cable type. This coil was also the Phase I deliverable, with test data showing in-coil operating current meeting required levels, namely, current density >200 A/mm2 at above 25K in 0.5 T field. In Phase II, by building on the 16-wire cable design, higher winding current cable with up to 96 wires will be developed and optimized for full stator coil functionality and loss. Loss and other critical properties will be validated by coil tests, providing vital specifications to HTS motor developers, including guidance for cost-effective stator cooling. A 1 MW motor-scale prototype HTS-2212-based stator saddle coil with end region knuckle bends that enable required nesting will be developed, with performance, loss, and cool-ability validated by testing, and with this coil provided to NASA as a deliverable. By the end of the program all the design features for motor-useable HTS stators will be established, with validation of low losses, performance at operating conditions and inclusion into at least one large-scale electric plane development initiative, with the groundwork for a collaboration already established in Phase I program.

Benefits: - Magnetic energy storage - Actuators - Power cables - Ultra compact, higher power density, more efficient motors for a variety of specialty applications, for example for cryogenic liquid pumps

- Much higher power density electric plane motors enabling zero carbon emission airplanes powered by hydrogen-oxidation in fuel cells - Lighter-weight, lower cost, easier to site, and more efficient wind generators - Magnetic energy storage systems - Particle accelerator magnets - Fusion reactor magnets, specifically the central solenoid of Tokamak designs