Because of the action of strong magnetic forces, it's difficult to avoid end winding vibration in the large turbo-generator stator. Sometimes it leads to the occurrence of accidents and affects the normal operatio...Because of the action of strong magnetic forces, it's difficult to avoid end winding vibration in the large turbo-generator stator. Sometimes it leads to the occurrence of accidents and affects the normal operation of the generator. This paper firstly lays out the calculation method for end winding magnetic force. Second, based on the structure of large machines, the natural vibration frequency equation and forced oscillation equation is set up. Third, through the analysis of magnetic force calculation and vibration on the end winding of turbo-generator, it will be shown that the end winding vibration is related to the magnetic force and the position of winding binds as well as binding tightness. We can ease the winding vibration by distributing binding position appropriately or add more bindings, and test the concept through experimental data.展开更多
Through the Fourier-Bessel series expansion of wave functions,the analytical solution to the two-dimensional scattering problem of incidental plane P waves by circular-arc canyon topography with different depth-to-wid...Through the Fourier-Bessel series expansion of wave functions,the analytical solution to the two-dimensional scattering problem of incidental plane P waves by circular-arc canyon topography with different depth-to-width ratio is deduced.Unlike other existing analytical solutions,in order to ensure that the analytical solution is valid for higher frequency incident waves,the asymptotic properties of cylindrical functions are in this paper introduced to directly determine the unknown coefficients of scattering waves,avoiding the solution of linear equation systems and corresponding numerical issues,which in turn expand the frequency band in which the analytical solution is valid.Comparison with other existing analytical solutions demonstrates that the proposed analytical solution is correct.Furthermore,the scattering effects of a circular-arc canyon on the incident plane P wave are analyzed in a comparatively broad frequency band.展开更多
基金This work is supported by the National Natural Science Foun- dation of China under Grant 51105261.
文摘Because of the action of strong magnetic forces, it's difficult to avoid end winding vibration in the large turbo-generator stator. Sometimes it leads to the occurrence of accidents and affects the normal operation of the generator. This paper firstly lays out the calculation method for end winding magnetic force. Second, based on the structure of large machines, the natural vibration frequency equation and forced oscillation equation is set up. Third, through the analysis of magnetic force calculation and vibration on the end winding of turbo-generator, it will be shown that the end winding vibration is related to the magnetic force and the position of winding binds as well as binding tightness. We can ease the winding vibration by distributing binding position appropriately or add more bindings, and test the concept through experimental data.
基金sponsored by the National Key Technology R&D Program (Grant No. 2006BAC13B02)the National Natural Science Foundation (Grant No.50608066)the Joint Earthquake Science Foundaton (Grant No. A07045),China
文摘Through the Fourier-Bessel series expansion of wave functions,the analytical solution to the two-dimensional scattering problem of incidental plane P waves by circular-arc canyon topography with different depth-to-width ratio is deduced.Unlike other existing analytical solutions,in order to ensure that the analytical solution is valid for higher frequency incident waves,the asymptotic properties of cylindrical functions are in this paper introduced to directly determine the unknown coefficients of scattering waves,avoiding the solution of linear equation systems and corresponding numerical issues,which in turn expand the frequency band in which the analytical solution is valid.Comparison with other existing analytical solutions demonstrates that the proposed analytical solution is correct.Furthermore,the scattering effects of a circular-arc canyon on the incident plane P wave are analyzed in a comparatively broad frequency band.
