Li Jianfu, Zhou Guanghou, Liao Yigang, Xiao Jian, Liu Chuankun
Research & Development Center, Dongfang Electrical Machinery Co. Ltd

Abstract

After running for several years, in the maintenance of a tubular turbine, many through bolts melted, and fatigue fracture, insulation damage were found. First, an analysis is done. Then
simulation calculations are done to investigate the additional losses and the electromagnetic force acted on the through-bolts. Finally, the modal is analyzed. The results show that after
long-term operation, under the action of the electromagnetic force vibration, fatigue, deformation, short circuit to stator core is formed with key bars, and a lot of heat is generated. That’s the reason how the accidents occur. At last, treatment suggestions are proposed. A year after the treatment, the bolts condition are examined and it shows they running well.