某水轮发电机磁极绕组连接片模态仿真和试验研究

The Modal Simulation and Experimental Study on Magnetic Pole Connecting Piece of One Hydraulic Generator

针对某水轮发电机正常运行时,磁极绕组连接片频繁断裂的现象,对连接片整体和单片分别建立有限元模型,求解得到前几阶固有频率和振型。同步开展模态测试,对整体振动和单片振动进行甄别。从结果上看:单片建模计算与试验结果一致性较好,即连接片振动以单片振动为主,振动前两阶频率分别为250 Hz和370 Hz左右。为防止产生共振破坏,应消除250~370 Hz的激励源或采取措施使其自振频率远离此范围。

In view of the frequent fracture of the magnetic pole connecting piece during the normal operation of a hydraulic generator,the finite element model of the whole and single connecting piece is built to obtain natural frequencies and modes of the first several sections.Meanwhile,the modal test is carried out on site to identify whether the connecting piece vibrates as a whole or a single piece.The results show that the single-piece modeling calculation results are better agree with the test results,and the vibration of the connecting piece is mainly single-piece vibration.During the first two section,the frequencies of vibration are about 250 Hz and 370 Hz respectively.In order to avoid resonance damage to the connecting piece,the excitation source of 250~370 Hz should be eliminated or other measures should be taken to keep the natural frequency away from this range.