Jacking Oil Pump


Since jacking (or "lift") oil is pumped into the bearing where lubricating oil is also being pumped, it comes from the Lube Oil system.

Please review the L.O. P&ID for the turbine at your site for details.
@CSA, yess I know the jacking oil pump gets its source of oil from the lube oil system. But what am asking is, is the source from the Auxiliary lube oil pump, Main lube oil pump or from the lube oil tank directly???

Thank u.

The answer to your question is clearly shown on the P&ID for the oil system that the jacking oil pump is shown; it's not the same for every turbine, and we don't know what kind of turbine you are referring to. Just that it has a jacking oil pump motor (88QB is the motor for the jacking oil pump).
Every single heavy duty frame turbine I have seen with jacking oil installed get it's supply from the lube oil header. Physically the jacking oil tapping off point is just before the generator bearing lube oil header supply.

Is the tap for the jacking oil pump suction ahead of or after the L.O. Bearing Header Pressure Regulating Valve? Is the lube oil at Aux. Pump discharge pressure or bearing header pressure?

I have seen it done both ways--before and after the bearing header pressure regulator. Some Frame 7EAs with Brush generators had the tap after the regulating valve, and most late-model F-class turbines have the tap after the pressure regulating valve. But some early F-class machines had the tap before the pressure regulating valve. That's why--without more information about the specific turbine in question--the answer can always be found on the L.O. P&ID (Piping Schematic) for the unit in question.

In all the years I've worked on GE-design heavy duty gas turbines I've only encountered two (2) occasions when the Piping Schematic (P&ID) drawings have been wrong--and both of those instances were involved vendor-supplied equipment that was found not to have met the purchase specification. The Piping Schematics (P&IDs) are very critical to understanding how GE-design heavy duty gas turbines operate and people should refer to them always with questions like this--because there can be slight differences even in the same line of turbines over time.
Always on the header after VPR2. Never from the lube oil tank. It is pointless to jack the shaft if there is no lube oil to the bearings, as it shouldn't be rotated.
hello MCA..

currently i have issues for GE gas turbine.
After rehab by contractor, during shutdown it requires DC JOP to support AC JOP. After we test AC JOP, its can go around 70 bar. But during first commissioning, It can go up to 140 bar. The lifting around 0.06mm. we try to blank before the inlet bearing, the pressure shows 250 bar. We checked and found the AC JOP pump, they used pressure relief valve instead regulator valve to control the oil. I don't know how its happened.

Another issues is, oil ingress inside generator compartment.

Any idea??