At what point does the over-speed trip mechanism activate?

The over-speed trip mechanism is crucial for the safety and operational integrity of turbines, particularly in power generation systems. This mechanism is designed to prevent damage to the equipment that could occur if the turbine exceeds its designated operational speed. The correct activation point of this mechanism occurs when turbine speeds exceed 10-12% above standard operating speeds. This threshold is established to provide a safety margin that activates before potential mechanical failures or catastrophic events can occur due to excessive speeds.

When the turbine operates above its maximum safe speed, there can be increased stresses on the rotor, supports, and other critical components. This can lead to mechanical failure, loss of control, or even explosive ruptures. By setting the trip mechanism to activate at this higher speed, it ensures that operators have a failsafe to mitigate these risks, promoting safe and reliable turbine operation.

The other options do not accurately reflect the point of activation for the over-speed trip mechanism. For instance, if the turbine speeds fall below a certain percentage of the standard, this scenario typically does not trigger an over-speed response but rather may indicate an operational issue that needs addressing without immediate danger. Overheating, while a critical aspect of turbine operation management, does not directly correlate with over-speed conditions, and the trip is