The overspeed trip on a steam turbine should be tested:

Testing the overspeed trip on a steam turbine before putting the turbine on-line is crucial for ensuring the safety and operational integrity of the equipment. The overspeed trip is a safety mechanism designed to shut down the turbine if it exceeds its safe operating speed. This is vital because an overspeed condition can lead to catastrophic failure, resulting in severe damage to the turbine and potential hazards to personnel and equipment.

By verifying the functionality of the overspeed trip before the turbine is operational, engineers can confirm that the system is working correctly and that it will act as a reliable safeguard in the event of an abnormal condition. This proactive approach helps to prevent incidents that could arise from equipment malfunction and is an essential part of operational best practices.

While regular maintenance checks and inspections are important for overall turbine reliability and safety, the specific timing of the overspeed trip test is most critical just prior to operation to ensure immediate readiness and function under operating conditions.