Passive Electromagnetic Damper's Effects On Vibration Control Of Flexible Rotor-magnetic Bearing System

The flexible rotor's unbalance mass can cause a strong vibration which could lead to serious damage while the rotor runs at the critical speed in a rotor-magnetic bearing system. In order to reduce the vibration of the flexible rotor and increase the stability of the rotor system, a passive electromagnetic damper (PED) have been designed and applied to the rotor-magnetic bearing system. Its effects on vibration control of the system are also analyzed in this paper.We begin by introducing the basic theory of the Rotor system. This is followed by detailed modeling and analysis procedure of the rotor system using FEA software, PATRAN and Nastran. The model of the rotor-bearing system is performed in patran while the critical speeds as well as the unbalance response of the flexible rotor are calculated using NASTRAN. In addition, the influences of the stiffness and damping of the rotor-magnetic bearing system on the rotor's critical speeds are also involved in the theoretical analysis. Furthermore, an example is used in this paper to demonstrate the accuracy and reliability of the software NASTRAN with the new function of rotor dynamics.In view of the large amount of vibration of the flexible rotor, a PED has been used in the flexible rotor-magnetic bearing system, which formed a compound support system. The experimental modal analysis of the rotor has been performed on the system with and without the PED respectively. The result shows that the PED's damping increased the system's damping ratio when added to the ordinary rotor-bearing system. This indicates that the stability of the flexible rotor system has been improved. Finally, the response analysis of a rotating rotor-bearing system with PED has been successfully carried out in this work. PED has been found capable of effectively reducing the amplitude of the flexible rotor around the resonance region.