Development of Pivoted-Pad Journal Bearings for Potassium Lubricated Space Electric Power Generators

An experimental program to select and develop the journal bearing configuration for use in a 24,000 rpm liquid potassium cooled space electric power generator is described. A preliminary study identified the pivoted-pad bearing as most nearly meeting the requirements of the proposed application. Initial tests, using water as the lubricant, revealed the formation of an unusual wear pattern on the pad corners at high speeds (8000-24,000 rpm). The problem was solved with the development of a method of relieving the pad edges to introduce and maintain the lubricant film. Thereafter, extended tests at speeds up to 26,000 rpm proved the bearing could be operated under the proposed conditions. The bearing configuration was then operated successfully to 12,000 rpm in potassium.