MAGNETIC BEARINGS FOR MINIATURE HIGH SPEED TURBOMACHINES

THIS PROGRAM IS AIMED AT THE DEVELOPMENT OF A NOVEL ELECTROMAGNETIC (E-M) BEARING SYSTEM SPECIFICALLY FOR MINIATURE HIGH-SPEED TURBOMACHINES USED IN SPACEBORNE TURBO-BRAYTON CRYOCOOLERS. COMPARED WITH GAS BEARINGS CURRENTLY IN USE, THE E-M BEARINGS PROVIDE GREATER RUGGEDNESS AND WILL ALLOW FOR OPERATION AT LOWER TEMPERATURES AND IN VACUUM ENVIRONMENTS. THESE ATTRIBUTES OFFER THE POTENTIAL FOR MAJOR IMPROVEMENTS IN CRYOCOOLER EFFICIENCY AND RELIABILITY, PARTICULARLY AT THE TEMPERATURESAND REFRIGERATION CAPACITIES ASSOCIATED WITH SURVEILLANCE SENSORS. IN THE PROPOSED PROGRAM, THE TECHNOLOGY OF ACTIVE E-M BEARINGS, WHICH IS RELATIVELY WELL DEVELOPED FOR LARGE SHAFTSIZES, WILL BE EXTENDED TO MINIATURE TURBOMACHINES. THE KEYCHALLENGE IN MINIATURIZING E-M BEARINGS IS THE DEVELOPMENT OF MINIATURE SHAFT POSITION SENSORS THAT ARE NEEDED TO CONTROL THE BEARING FORCE. IN PHASE I, AN E-M BEARING USING A NOVEL CAPACITIVE SENSOR WILL BE DEMONSTRATED. THE DETAILED DESIGN, DEVELOPMENT AND DEMONSTRATION OF A COMPLETEMINIATURE E-M BEARING SYSTEM IN A PROTOTYPE TURBOMACHINE IS PLANNED FOR PHASE II.