A motor driven synchronizing device, figure "D" shown in the illustration, operated from the generator switchboard, initiates fine adjustments to the steam turbine speed by directly __________. Illustration SE-0009

Correct Answer: Option B — changing the vertical location of the pilot valve bushing

Synchronizing devices on turbine governors alter the vertical position of the pilot valve bushing or control linkage. This adjustment changes the control oil pressure acting on the relay piston, finely tuning the turbine speed to match electrical grid frequency.