During what operational state is a separate electric lube oil pump primarily used?

A separate electric lube oil pump is primarily utilized during the startup phase of an engine or machinery. This is crucial because, during startup, the main engines or pumps may not be running yet, and they do not generate sufficient oil pressure on their own. The separate electric lube oil pump ensures that the bearings and other critical components receive proper lubrication, preventing wear or damage that could occur if the oil system relied solely on the engine-driven pump.

In normal operation, continuous running, or during shutdown, the main oil pump is typically capable of maintaining sufficient lubrication by circulating oil as designed. The additional electric lube oil pump specifically supports lubrication during the startup, addressing the critical need for lubrication when the system is at lower speeds or not yet fully operational.