6.2.3 AC and DC motor-driven auxiliary oil pumps
AC and DC auxiliary oil pumps which supply oil bearings under start-up and normal shutdown, or an emergency shutdown respectively, are centrifugal pumps with a submerged suction.
The AC pump delivers oil to the lubricating oil pipework feeding the oil filters and coolers at around 3 bar, and primes the main oil pump. The DC pump feeds either the same pipework system as the AC pump, or the pipework which feeds oil directly to the bearings at around 1.5 bar. Each pump has a capacity of around 70-120 litres/s.