Spin Commisionning And Drop Tests Of A 130 kW-hr Composite Flywheel

The Center for Electromechanics at the University of Texas at Austin is developing a power averaging flywheel battery for use on high speed passenger trains as part of the Federal Railroad Administration’s Next Generation High Speed Rail Program. The flywheel rotor, which weighs 5100 lb, is designed to store 130 kW-hr of energy at a peak design speed of 15,000 rpm. The graphite-epoxy composite rotor, which runs in a vacuum, is supported by a 5 axis active magnetic bearing system. A high speed 2 MW motor-generator, which is outside the vacuum, is directly coupled to the flywheel with an industrial disk pack coupling, through a custom integral rotary vacuum seal. This paper begins with a brief description of the design of the vertically oriented flywheel rotor/housing system. The partially complete rotor (currently 3000 lb mass) has recently been undergoing system level laboratory commissioning. Test results are presented demonstrating the performance of the magnetic bearings. Since flywheel system safety is such a critical issue at this energy level, satisfactory performance of the backup bearings was demonstrated experimentally. Delevitation “drop” tests have been performed onto rolling element backup bearings, and behavior is reported and compared to related flywheels discussed in the literature. Finally, testing of a semi-passive whirl arresting scheme is presented.