1. Improper mechanical installation, misplaced parts and large preload.
2、轴系对中不良。
2. Poor alignment of shafting.
3、机器几何参数(如配合间隙、过盈量及相对位置)调整不当。
3. The geometric parameters of the machine (such as fit clearance, interference and relative position) are not adjusted properly.
4、管道应力大，机器在工作状态下改变了动态特性和安装精度 。
4. The pipeline stress is large, and the dynamic characteristics and installation accuracy of the machine are changed under the working condition.
5、转子长期放置不当，改变了动平衡精度未按规程检修，破坏了机器原有的配合性质和精度。
5. The rotor has been placed improperly for a long time, which has changed the dynamic balance accuracy and failed to be maintained according to the regulations, thus damaging the original matching property and accuracy of the machine