If the bearings of a piece of machinery are fed by a gravity feed lubricating oil system, what statement is true?

Correct Answer: Option D — The lube oil pump draws a suction on the lube oil reservoir/sump and discharges to the lube oil gravity tank. The oil then gravity feeds the bearings and the return oil drains to the lube oil reservoir/sump.

Gravity feed systems utilize a pump to transfer oil from the sump to an elevated gravity tank. The tank provides a constant, reliable head pressure to the bearings, ensuring lubrication even during pump failure. Excess oil from the bearings returns to the sump, completing the closed-loop circulation cycle.