Lateral-torsional Coupling Vibration of Rotor System of Hydro-turbine Generator Unit in Electro-magnetic Transitional Condition

The lateral-torsional coupling vibration of rotor system of a hydro-turbine generator unit caused by transitional electro-magnetic force and moment is studied in this paper.A mathematical model on the lateral-torsional coupling vibration is established.The dynamic characteristics of the system are investigated on the numerical computations.The results show that the vibration of the system is chaotic and the lateral motion has a significant influence on the torsional vibration of the system.The maximum peak amplitude of the vibration takes place at the 1/2 fractal frequency.The influence of the rotating eccentricity on the torsional vibration has an extreme value range within which the vibration will strongly increase.The role of the rest initial eccentricity in the vibration is not important against the dynamic rotating eccentricity.Therefore,if the operation state of the system falls into the sensitive area of the mechanical and electromagnetic parameters,a strong vibration will be induced due to the parametric resonance.