Superconducting Rotor With Closed-Loop Rotor-Mounted-Cryocooler: Design, Analysis, Assembly Procedure, and Experimental Results

Hinetics is developing a megawatt-scale supercon ducting motor for high power density applications such as electric aviation propulsion, marine propulsion, and remote data center power generation. To de-risk the full-scale system, a scaled-down demonstrator rotor—nicknamed Baby Yoda—was designed, built, and tested. This prototype features no-insulation high-temperature superconducting (HTS) coils on the rotor and a conventional stator. The rotor is cryogenically cooled using an onboard closed-loop cryocooler. The superconducting rotor was retrofitted onto a commercial induction motor frame to enable rapid system integration and testing. Two test campaigns were conducted: (1) system-level performance testing and (2) extended operation for reliability assessment. Both campaigns were successfully completed, demonstrating stable operation and validating key design and integration risks for the full-scale system. This paper presents the design methodology, analytical approach, assembly process, and experimental results of the risk reduction motor.