Design and Analysis of a Direct-Drive Motor for Astronomical Telescopes in Extreme Antarctic Environments

Effective motors are crucial for driving astronomical telescopes, especially for those operating in Antarctica, where the harsh environment and operating conditions, including extreme low temperature, ice/snow accumulation, low power consumption, and unattended operation, introduce challenges to the design and development of motor drives. We present the design of a permanent magnet synchronous motor suitable for this environment, conducting a quantitative analysis on the impacts of cryogenic conditions on lubricant performance, differential thermal contraction of metallic components, and remanent flux density of neodymium iron boron (N52) permanent magnets. We also implement a labyrinth seal structure, combined with silicone sealing rings, to mitigate ice crystal intrusion risks. Finite element analysis and laboratory tests demonstrate a maximum torque output of 25~Nm. This kind of motor is used in Antarctic 15 cm Near Infrared Telescope at Dome~A, Antarctica. Operation data shows a total encoder feedback error of 0.0678′′ for the telescope control system with 15′′/s tracking speed at −56.79 °C. These results comprehensively validate the high reliability and precision of the motor under the extreme conditions of the polar environment.