3. Conclusions
Proper operation of turbine-generator bearings in hydroelectric power plants is of great importance for the unit to continue energy production. Therefore, it is necessary to periodically inspect the sliding bearings during the energy production by predictive maintenance methods and to measure and evaluate the factors such as vibration, balance and temperature. In this study, the causes of the fracture formed in the generator guide bearing shell of a hydroelectric power plant are investigated metallographically. When we examine the metallographic sample taken in the region near the fractured area near sliding bearing with the help of optical microscope, SEM images and EDS analysis, Ferrite and Perlite structures found in low carbon steels in the sample are seen and these structures have the least risk of fractures in the steel materials due to the formation of fractures So other factors that will affect the structure of this material have been focused. Variable loads and oil temperature changes as a result of this material working together with the shaft can cause fracture formation due to fatigue strength in the material. Not being able to apply necessary heat treatment in order to remove internal stresses that appear in the production stage of the ring when it becomes a cylinder due to the large size of ring causes fractures. Such fractures can occur frequently in the sliding bearing shells of hydroelectric power plants. The only way to prevent these fractures from damaging the sliding bearing is to follow the vibration changes in the bed well and to be interpreted by the experienced technical staff. Because vibration changes in sliding bearings can be caused by many reasons such as magnetic, dynamic and hydraulic imbalances.