An Innovative Integrated Starter Generator & Combination Magnetic/Foil Bearings for Oil-Free Support of Small Turbine Engines

Magnetic suspension for gas turbine engine applications has previously been limited to lower load capacity, low cycle life demonstrations. A complete oil-free bearing and integrated starter generator (ISG) system is proposed that is capable of supporting asmall turbine engine in the <15,000 lbs thrust class. In Phase I the preliminary design of an innovative ISG concept, and combination magnetic/foil bearings with high load capacity will be accomplished. The ISG magnetic structure is innovative andanticipated to demonstrate excellent control of ISG side-loading thus managing radial bearing requirements, low weight, and significant radial suspension capability. SatCon's experience in high temperature, high speed, and fault tolerant magnetic bearingswill be applied to design of combination magnetic/foil bearings to complete the rotor support system. In Phase II a complete, full scale, inline prototype demonstration is planned. Multiple paths (long-, mid-, and near -term) to commercializing theresults of the program are clear. A long-term application is in support of the VAATE initiative, which will carry on from the IHPTET More Electric Engine Initiative. The SatCon ISG and combination oil-free bearings could be applied to advanced versions oflarge (turbofan) engines, small (turboshaft and turboprop) engines, and expendable (cruise missile or UAV) engines. Such a solution is primarily targeted at next generation UAV/UCAV applications that will require oil-free bearing systems with thrust loadsup to 5,000 lbf for non-expendable first day/first strike missions. The IHPTET Phase III, Advanced Concepts demonstrators (ATEGG, JTAGG, and JTDE), and Joint Strike Fighter (JSF) programs will likely provide the basis for the next generation of commercialand military transport aircraft engine, which will be a More Electric Engine where the oil-free bearing and ISG components could be employed as part of the rotor support and electric power systems.In a mid-term time frame, SatCon sees a clear application for the technology in advanced-concept Auxiliary Power Unit and industrial stationary gas-turbine-driven power generation applications. In the near term, some of the innovations in the ISG designwill be incorporated by SatCon Power Systems business unit to expand the existing product line and possibly to provide cost reduction for the existing product by elimination of a set of costly permanent magnets.