Lube oil at 12# is primarily supplied by which system component?

Lube oil at a pressure of 12# is primarily supplied by turbine bearings. In a turbine system, the bearings require proper lubrication to reduce friction, wear, and to ensure efficient operation. The lube oil system is designed to provide sufficient oil flow to these bearings, as they are critical components that support the rotating elements of the turbine.

Each turbine bearing relies on a continuous supply of lubricating oil to function correctly. This lubrication not only protects the bearings but also helps in cooling them down during operation. By maintaining the right oil pressure and flow, the turbine bearings can operate smoothly and efficiently.

While pumps are essential for circulating the lube oil throughout the system, their primary role is to deliver oil to the turbine bearings and other components rather than being the direct supplier of lube oil at specific pressures. Manual valves control the flow direction and can help isolate parts of the system but do not supply oil themselves. Heat exchangers can help regulate the temperature of the lube oil but are not the primary source of the oil pressure required at 12#. Therefore, the correct answer highlights the critical function of turbine bearings in the lubrication system.