Analysis of the repairing technology of the guide bearing of Hydro Power Plant
During the operation of the Hydro Power Plant, radial centrifugal force will be generated due to the static imbalance of the runner. The uneven opening of the blade and the uneven clearance of the leakage ring will produce radial water thrust. The main role of the turbine guide bearing is to withstand the shaft. Radial force and oscillating force fix the axis position of the unit to ensure the stability of the axis. The guide bearing is an important part of the turbine. Its working quality directly affects the operation of the turbine. If the process requirements of the guide bearing adjustment are not met during the maintenance process, it will have a direct impact on the safe and stable operation of the unit, resulting in the swing of the unit during operation. If the temperature is too large, the temperature of the bearing bush is too high, and the bearing bush is seriously worn out. In severe cases, the bush may even burn.
2 Condition of water guide bearing adjustment
After the unit's cranking and thrust force adjustment are qualified, the installation and adjustment of the guide bearings of each part can be carried out. Before adjusting the clearance of the guide bearing, the center of the entire rotating part should be adjusted first so that the air gap between the turbine leakage stop ring and the generator is uniform, and the main shaft is at the center of the unit. When adjusting the clearance of the guide bearing, the center position should be the center of rotation of the unit, which should be based on the design clearance, cranking degree and spindle position. The guide bearing should be adjusted so that the double-sided clearance meets the design value, and the guide bearings must be coaxial with the center of rotation. In general, the order of the guide bearing adjustment is to adjust the water guide first, and then adjust the guide bearing.
3 Influencing factors
3.1 Impact of bearing bush cleaning inspection
In addition to checking for defects, the main task of guide bearing maintenance is to clean the bearings as a whole to ensure the safety of the bearing operating environment. It is also one of the prerequisites that must be guaranteed for the accuracy of bearing clearance adjustment, which affects the adjustment of bearing clearance. The reasons for accuracy include impurities, metal burrs, the flatness of the joint surface and the installation position of the top block, which will affect the clearance adjustment results. During the inspection and cleaning process, it must not be sloppy, otherwise, it will also affect the adjustment quality of the bearing clearance.
3.2 The effect of the large axis centering
After the shaft body and bearing pad are cleaned and trimmed, installation and adjustment are started, but after reinstallation, before adjusting the bearing pad clearance, it is first necessary to determine whether the bearing body is in the center of the unit, that is, the large shaft is centered. In the process of centering the large shaft, the reference point is selected first. Secondly, whether the bearing bush has been tightened and the bearing body is in the deformation range during the center shift process will affect the effect of the unit's bearing adjustment.
