核电650MW机组励磁机轴颈晃度超标原因分析及处理

Analysis and treatment of diametral tolerance of exciter shaft of the 650 MW nuclear power plant

秦山二核的发电机与励磁机的连接为三支撑结构形式,即发电机转子有两个轴瓦,励磁机转子只有一个轴瓦支撑,这种结构致使励磁机的轴瓦的晃度在检修时难以达到标准要求的数值。在秦山二核2号机组的第5次检修中,检修完毕回装励磁机时其轴瓦晃度难以达标,影响励磁机晃度不能达标的因素很多,有发电机与励磁机联轴器的对中状态、发电机与励磁机联轴器的紧固螺栓的力矩、发电机联轴器和励磁机联轴器的端面状况、发电机联轴器和励磁机联轴器内孔中的剪切套筒与内孔的配合尺寸。通过对各个因素进行分析并一一排除,最终找出致使励磁机轴瓦晃度大的根本原因是发电机联轴器端面状况异常,对其进行机加工处理后,缺陷得以彻底处理。

The generator and exciter has three support connection in Qinshan II,i.e.there are two bearings for the generator rotor and one for the exciter.This structure results in difficulty to meet the standard when checking the exciter bearing＇s diametral tolerance.In the fifth outage of 2# turbo-generator in Qinshan II,the diametral tolerance failed to meet the standard.There were several reasons,such as the alignment of generator and exciter coupling,the angular moment of generator and exciter coupling bolt,the end surface condition of generator and exciter coupling,the fitting dimension of the coupling bolt hole and the sleeve in it.After analysis and screening of all factors,it was confirmed that the radical reason was the abnormal condition of the generator coupling end surface,and the problem was solved by machining the end surface.