🔍 Key Concepts
• Function of main and standby lube oil pumps in steam turbine propulsion systems
• What loss of lube oil pressure immediately affects first: bearings, reduction gears, throttles, vacuum, or sump level
• Sequence of protective devices and trips on a geared main propulsion steam turbine
💭 Think About
• If lube oil flow to the turbine and reduction gears suddenly stops at full sea speed, which component or system would react FIRST, before any others?
• Which of the listed options (vacuum, ahead throttle, shaft brake, sump level) is directly and immediately dependent on lube oil pressure rather than on speed, temperature, or condensate conditions?
• Think about what automatic safety or interlock would be designed to protect the most critical, quickly damaged component when lubrication is lost.
✅ Before You Answer
• Identify which listed event is normally controlled by a low lube oil pressure trip or interlock.
• Ask yourself: does a shaft brake ever engage while the turbine is still turning at full speed, or is it used only at very low/zero speed?
• Consider whether vacuum in the condenser or sump level would change instantly, or only after some time, when lube oil pumps stop.