No abstract

A simplified analytical approach for modeling the synchronous instability phenomenon known as the Morton effect is presented.The analysis is straight forward and easily applied to any rotor supported on fluid film bearings. The analysis clarifies the interaction of three distinct machine characteristics which combine to create a case of the Morton effect. Some example calculations are shown illustrating the possible types of spiral vibration.In addition, an analytical approach is described for estimating the magnitude of the shaft temperature difference in a journal bearing as a direct function of the shaft orbit. It is significant that this method can readily be applied to any type of journal bearing, from plain sleeve bearings to tilting pad bearings. Example calculations using the method are shown.

Abstract-This paper presents work that was performed to design a compact flywheel energy storage solution for a fuel cell powered transit bus with a focus on commercialization requirements. For hybrid vehicle applications, flywheels offer much higher power densities than conventional batteries. The presented design attempts to maximize the use of lower-cost technologies. The rotor relies primarily on steel for the flywheel structure, and emphasis is placed on size reduction for vehicle packaging advantages Simulations of bus configurations on measured routes was performed using PSAT to correctly size the flywheel energy storage system.

The design and initial testing of a five axis magnetic bearing system in an energy storage flywheel is presented. The flywheel is under development at the University of Texas Center for Electromechanics (UT-CEM) for application in a transit bus. The bearing system for the prototype features homopolar permanent magnet bias magnetic bearings. The system has been successfully tested to the maximum design speed of 42,000 rpm. A gain-scheduled, MIMO control algorithm was required to control the system modes affected by rotor gyroscopics. The implementation and basis for this control scheme is discussed. The cross-axis forces produced by this approach are described in terms of circumferential cross-coupled stiffness and damping to explain the effect on system stability. Dynamic test results are discussed relative to the rotordynamic and control system design.

No abstract