Woodward 3161 LIO 3161 EGB Governor/Actuator

In general, the oil used in the prime mover will be satisfactory for use in the
governor.
Fill the governor with clean, non-corrosive, oxidation and rust inhibiting oil that
has minimum foaming or air retention qualities, and a viscosity of 100–300 SUS
(Saybolt Universal Seconds) at operating temperature (typically 140–200 °F/
60–93 °C). Fill to the line on the sight glass (approximately 2.3 US quart/2.2 L).
After start-up, and when the oil is at operating temperature, again check the oil
level and add more oil if necessary. Oil should be visible in the sight glass at all
times.
Oil Viscosities
Table 2-1 shows the viscosity of oil at the different operating temperatures. The
pour point (low temperature) is shown on the left and the temperature at which
the performance of the oil begins to decrease is on the right side.
The governor will operate at temperatures near the pour point of the oil, but
governor operation will be slow, and may be unstable. Do not operate the
governor at a temperature less than the pour point of the oil.
Operating the governor at temperatures greater than the high limit (50 SUS), will
decrease the stability of the governor, and may result in an inability to restart hot.
Operating the governor at a temperature greater than the point at which the
performance of the oil decreases can cause governor failure.
For specific oil recommendations, see manual 25071, Oils for Hydraulic Controls.

Woodward 3161 LIO

Gerotor Oil Pump—The gerotor oil pump is located in the base of the governor.
The inner rotor of the pump is driven by a pin in the drive shaft, and carries the
outer rotor around in mesh, pumping oil to the accumulator piston.
Accumulator—A single accumulator, consisting of a piston and spring, acts as a
relief valve for the oil pump and provides a reservoir of high pressure oil for quick
servo movement. Oil is pumped to the accumulator by the governor pump, with
pressure increasing as the accumulator spring is compressed. When the
pressure builds to the predetermined level, oil is released back to sump through
relief ports in the piston wall.
Power Piston—The power piston is attached to the output shaft by a link and
lever assembly. The power piston is designed with a large area on the bottom
and a small area on top (differential piston). A small pressure increase on the
large area of the piston will move the piston up, causing the output shaft to rotate
in the “increase” direction. The piston can move down only when oil under the
piston is released to sump. Oil to or from the bottom of the power piston is
regulated by the ballhead pilot valve and ballhead pilot valve bushing.