🔍 Key Concepts

• Mechanical vs. hydraulic (oil) overspeed trips in steam turbines • How centrifugal force is used to detect overspeed • Role of relay valves and oil pressure in closing steam throttle/control valves

💭 Think About

• Think about what part of the system actually moves the throttle/control valve toward the closed position in most marine steam turbines: is it direct mechanical linkage or a hydraulic/oil relay? • Consider which options describe a primary speed governor versus a separate overspeed safety trip device. • Ask yourself: when overspeed happens, what kind of change (mechanical movement, oil pressure, temperature) is the most immediate and reliable signal to shut steam off quickly?

✅ Before You Answer

• Identify which choices involve a direct mechanical flyball governor used mainly for speed control, not necessarily as the emergency overspeed trip. • Check which answer uses oil pressure acting on a relay valve to move the steam control or throttle valve toward shut. • Eliminate any option that relies on temperature change as the triggering factor for overspeed protection.