🔍 Key Concepts

• Pressure-compensated governor operation and what “pressure-compensated” actually refers to • Flow path from the oil inlet through the pump gears, relief valve, and internal passages in the Woodward PSG governor • Difference between using oil as a control/hydraulic medium versus using oil pressure as a speed or safety signal

💭 Think About

• Look at the color/texture legend in the illustration: what pressures and functions are associated with the oil that enters at the oil inlet and passes the pump gears? • Ask yourself whether the governor relies on changing engine lube oil pressure to detect speed, or whether it creates and regulates its own internal control pressure. • Consider what components in the drawing (pump gears, relief valve, buffer piston, power piston) actually move because of this oil and what that tells you about the oil’s role.

✅ Before You Answer

• Verify whether engine speed sensing in this governor is done mechanically (flyweights/speeder spring) or by varying oil pressure from the engine. • Check if there is any linkage from low lube oil pressure to a shutdown or alarm device in the drawing, or if those features are completely absent. • Confirm from the schematic that the incoming oil is distributed throughout the governor to lubricate moving parts and provide hydraulic force to pistons and plungers.