A Dewar is the key structure of motors with high temperature superconducting (HTS) armature windings. Traditional Dewars use total immersion cooling, which can cause additional mechanical losses and challenges for rotary sealing. To avoid these problems, a novel Dewar structure was developed with partial immersion cooling. A 15 kW cryogenic induction motor with the designed Dewar was then developed. Its stator core and the coil were cooled with liquid nitrogen through partial immersion cooling. We studied the thermal insulation performance of the Dewar, and the running performance of the cryogenic induction motor. The temperature characteristics of the stator core were measured by PT-100 temperature sensors. Results show that the stable temperature of the stator is 76.5 K. Under no-load conditions, the slip rate of the motor is 0.02 with the no-load current being 30 A at 350 V of the stator voltage. The no-load loss power at low temperature is much larger than that at room temperature. These results suggest that the partial immersion cooling is effective, which validates the reliability of the designed Dewar structure, and that running performance of the motor designed is desirable.

杜瓦瓶是具有高温超导（HTS）电枢绕组的电动机的关键结构。传统的杜瓦瓶使用全浸式冷却，这可能会导致额外的机械损耗，并给旋转密封带来挑战。为了避免这些问题，开发了一种具有部分浸没冷却的新型杜瓦瓶结构。然后开发了具有设计杜瓦瓶的15 kW低温感应电动机。通过部分浸没冷却，用液氮冷却其定子铁心和线圈。我们研究了杜瓦瓶的隔热性能以及低温感应电动机的运行性能。定子铁心的温度特性是通过PT-100温度传感器测量的。结果表明，定子的稳定温度为76.5K。在空载条件下，电动机的滑差率为0。02，空载电流为定子电压350 V时的30A。低温下的空载损耗功率远大于室温下的空载损耗功率。这些结果表明，部分浸没冷却是有效的，这验证了设计的杜瓦瓶结构的可靠性，并且所设计的电动机的运行性能是理想的。