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<title>Cryogenic Testing Of Stepper Motors</title>

1982; SPIE; Volume: 0331; Linguagem: Inglês

10.1117/12.933437

1996-756X

Stephen M. Pompea, F. Bartko, J. R. Houck,

Particle Accelerators and Free-Electron Lasers

Stepper motors operating at temperatures below 16°K may be used extensively in high sensitivity infrared instruments. However, the behavior and reliability of Hators operating at cryogenic temperatures have not been extensively characterized. We summarize our experimental investigation of stepper motor performance in vacuum at LN 2 (76 o K) and LHe (4 o K) temperatures. Initial tests demonstrated that stepper motors fail at LN 2 temperatures due to differential thermal contraction arising from the use of different metals in the motor construction. The motors were then modified to compensate for thermal contraction differences and one of the modified motors was successfully tested at LHe temperatures. It ran normally for 112 hours without any significant degradation either in its voltage waveform pattern or with any significant differences between its pretest and post-test holding torques. These test results may aid cryogenic instrument designers who utilize electro-mechanical devices in planned facilities such as the Shuttle Infrared Telescope Facility (SIRTF).