NASA G2 flywheel module.
NASA Glenn Research Center’s Flywheel Development Team designed, built, and successfully operated the new G2 flywheel to 41,000 rpm on September 2, 2004. This work was supported by the Aerospace Flywheel Technology Program--a NASA Office of Aerospace Technology ETC Program funded by the Energetics Project. The work was performed by a team of civil servants, contractors, and grantees managed by Glenn’s Electrical Systems Development Branch, Structural Mechanics and Dynamics Branch, and Space Power & Propulsion Test Engineering Branch. The G2 flywheel was designed to be a low-cost modular testbed for flywheel system integration and component demonstrations.
This is the first module designed by Glenn, and it reached rated speed in a fraction of the time required for all the previous modules. New redundant magnetic bearings designed by Texas A&M University were used to levitate the rotor, and a new type of resolver conceived at Glenn was used for angle feedback. The design was supported by analytical work in magnetic bearing control and motor control that reduced the time from final assembly to full-speed demonstration to 1 month--a factor of 4 faster than the time for the previous module. More careful attention to the vacuum system resulted in better operating pressures. New electrical connectors were used that are more reliable, meet military standards, and are easier to work with. The G2 spin losses were 30-percent lower than those for the D1 flywheel, and the rotor temperatures rose only 10 °F in 9 hr of testing. Total spin losses were measured by disconnecting the motor and recording the speed versus time as the flywheel spun down because of losses. It took about 5.5 hr to spin down from 41,000 to 12,000 rpm. The reduced spin losses are a result of the Texas A&M bearing design and the improved vacuum. The low rotor temperature indicates that the split between the rotor and stator losses has shifted mostly to the stator. This is exactly what we are aiming for because the stator can be conductivity-cooled, whereas the rotor is only radiatively cooled. We plan to use the G2 flywheel in conjunction with the D1 flywheel to demonstrate full-power integrated power and attitude control.
Glenn contact: James F. Soeder, 216-433-5328, James.F.Soeder@nasa.gov
University of Toledo contact: Ralph H. Jansen, 216-433-6038, Ralph.H.Jansen@grc.nasa.gov
Authors: Ralph H. Jansen and Kerry L. McLallin
Headquarters program office: Exploration Systems
Programs/Projects: Human & Robotic Technology, CEV, Human Lunar Return, Earth and Space Science
Last updated: July 21, 2005 2:47 PM
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