What should a technician do if they notice an unusual vibration in a steam turbine?

When a technician observes an unusual vibration in a steam turbine, the appropriate action is to immediately shut down the system. This is because unusual vibrations can indicate significant mechanical issues, such as misalignment, imbalance, or wear on components, which could lead to catastrophic failure if not addressed promptly. Shutting down the system allows for a thorough inspection to determine the cause of the vibration and to prevent damage to both the turbine and associated equipment, ensuring the safety of personnel and the operational integrity of the system.

Ignoring the vibration could lead to severe mechanical failure or accidents. Increasing the load on the turbine may exacerbate the problem and lead to further damage. Lowering cooling water temperatures does not address the underlying cause of the vibration and could lead to other problems, such as thermal stresses. Thus, immediate shutdown is a critical and responsible action when abnormal conditions are detected.