Woodward UG-10 Dial, Installation And Operation Manual, Page: 25 / 62

Manual 03040 UG Dial Governor
Woodward 19
When the prime mover is started for the first time after the governor has been
filled with oil, the governor may be stable at constant speed, yet may need
adjustment. High overspeeds and underspeeds after load changes and slow
return to normal speed indicate the need for compensation adjustment.
Maximum compensation settings generally provide stable steady
state operation, but result in greater offspeeds on load changes.
After the oil in the governor has reached its normal operating temperature, make
the following compensation adjustments without load on the prime mover to be
certain that the governor gives optimum control. See Figure 1-1 for location of the
adjustment parts.
1.
To bleed trapped air from the governor oil passages, first loosen the nut
holding the compensation adjusting pointer and set the pointer at its
extreme upward position for maximum compensation. Tighten the nut.
Next, remove the needle valve access plug and open the needle valve two
turns counterclockwise. Use a Phillips screwdriver to avoid damage to the
threads inside the bore and to the needle valve.
Damage to the threads or to the needle valve will cause the governor to
change fuel rhythmically. This is called governor hunt. See Chapter 5 for
more information on hunting.
There are two screwdriver slots in the needle valve, a shallow and a deep
slot, located at right angles to each other. The deeper slot is used to expand
the head of the needle valve and increase friction to prevent vibrations from
changing the needle valve setting. If a plain screwdriver must be used, be
sure to use the shallow slot of the needle valve.
Allow the prime mover to hunt for approximately 30 seconds to bleed
trapped air from the governor oil passages.
2.
Loosen the nut holding the compensation pointer and set the pointer as far
as it will go towards minimum compensation. Tighten the nut.
3.
Gradually close the needle valve until hunting just stops. If hunting does not
stop, open the needle valve one turn and move the compensation pointer up
by one mark on the front panel indicator scale. Again gradually close the
needle valve until hunting stops.
If hunting does not stop, set the needle valve 1/4 turn open and repeat
setting the compensation pointer up by one mark. Retest the governor until
hunting stops.
The objective of the compensation adjustment procedure is to find
the particular settings for the compensation needle valve and
compensation adjustment pointer at which the prime mover will
return quickly to speed (needle valve adjustment) after a speed
disturbance with only a slight over- or undershoot (compensation
pointer adjustment).