Analysis On Magnetic Pull Characteristics Of Coupling Faults Composed By Eccentricity And Rotor Inter-turn Short Circuit Of Generator

Generator is the necessary equipment for electric power production. Practically, air gap eccentricity fault and rotor inter-turn short circuit fault frequently occur, and sometimes they even happen at the same time, causing abnormal vibrations and threatening the security of the generator set. Therefore, it is significant to study the unbalanced magnetic pull under the coupling faults.In this thesis, the fault simulation generator MJF-30-6 is used as the research object to analyze the characteristics of magnetic pull of per unit area(MPPUA) of the stator under normal condition, air gap eccentricity fault, rotor inter-turn short circuit fault, and coupling fault. Firstly, the formula of magnetic flux density(MFD) and MPPUA are obtained, but also the variation trend, the main frequency components and the amplitude variation of MPPUA of the stator are got by theoretical analysis. Then, the different conditions are modeled by using the finite element software Ansoft, and the distribution of MPPUA of the stator as well the time domain waveforms and the amplitude variation of its main frequency are obtained. The simulation result is basically consistent with the theoretical analysis. Finally, the experiment is done on the MJF-30-6 to study the regularity for change of amplitude of main frequency of the stator vibration under different conditions. As the result shows that is in agreement with the theoretical derivation and the simulation analysis.The achievements obtained in this thesis offer a reference for the diagnosis for the air-gap eccentricity and rotor short circuit composite fault and therefore have active meaning.