Which of the following is NOT one of the four safety devices on a gas turbine?

The correct choice indicates that excessive fuel pressure is not typically categorized as one of the four primary safety devices on a gas turbine. Gas turbines usually incorporate critical safety mechanisms to monitor and react to various operational conditions to ensure safe functionality.

Overspeed monitoring is an essential safety feature designed to detect situations where the turbine exceeds its designed rotational speed, which could lead to catastrophic mechanical failure. High vibration sensors serve as another critical safety measure, as they detect abnormal vibrations that may indicate misalignment, imbalance, or mechanical failures, prompting corrective action.

Low lube-oil pressure is another crucial safety device that ensures there is adequate lubrication within the turbine components to prevent overheating and wear, which could lead to severe damage or failure. Each of these safety devices plays a vital role in protecting the turbine and its surroundings from potential hazards related to operational anomalies.

In contrast, while managing fuel pressure is important for optimized combustion and efficient turbine operation, it does not typically fall into the category of primary safety devices in the same manner as the others listed. Fuel pressure management is more about operational efficiency and performance than direct safety monitoring. Therefore, excessive fuel pressure may not be directly addressed as a dedicated safety device within the context of turbine operations.