🔍 Key Concepts

• Main turbine jacking gear purpose (why we use it when the turbine is stopped) • Importance of lubrication to prevent damage to bearings and turning gear components • Which systems must be running any time the shaft is turning, even at very low speed

💭 Think About

• Ask yourself: when the shaft is rotated slowly by jacking gear, what component is most at risk of damage if it is not properly supplied? • Which of the listed systems directly protects the main bearings and gears during rotation, even at low speed? • Which systems in the options are important for normal steaming, but are not strictly required just to slowly turn the turbine/shaft while stopped?

✅ Before You Answer

• Identify which system provides oil film protection between rotating and stationary parts • Confirm which system must be online before any rotation of the main unit is started • Eliminate choices that are mainly for vacuum/condensation or cooling, rather than direct bearing protection