Woodward UG-10 Dial, Installation And Operation Manual, Page: 35 / 62

Manual 03040 UG Dial Governor
Woodward 29
Problem Possible Cause Correction
1. The prime mover
hunts or surges.
(continued) J. Low oil pressure. Normal
operating pressure is 758 to
827 kPa (110 to 120 psi) for the
UG-5.7 and UG-8; 965 to 1034
kPa (140 to 150 psi) for the
UG-10. (See outline drawing,
Figure 1-3, for pressure test
point location.)
Pump check valves are not
seating or accumulator springs
weak. Return governor to factory for repair.
K. Power piston is sticking. Check for side play or binding of output shaft.
L. Voltage regulator not
operating properly. Check voltage regulator. Operate in voltage droop or
manual. Do not disconnect voltage regulator. Adjust,
repair, or replace voltage regulator.
M. Fuel linkage incorrectly set.
This might occur if the governor
has been changed or removed
and replaced. Relationship of
governor travel to power output
of engine should be linear. Rework or reset the linkage from governor to unit to
obtain the linear relationship.
N. Faulty linkage. Linkage should be free of binding and lost motion
throughout service life of unit. Check yield links,
shutdown arrangements, etc, to be sure that prime
mover torque changes for very small increments of
governor output shaft travel. Stability and good
steady-state performance will suffer unless this
condition is met.
O. Incorrect non-linear
relationship between governor
travel and power output of the
prime mover. Engine may hunt
with light loads and be stable
with a heavy load. Adjust linkage from governor to gas valve to obtain
linear relationship between governor travel and
engine output. See Figure 2-1. Also, see application
note 50516.
P. Gas or steam pressure too
high. Adjust gas or steam pressure.
Q. Engine misfiring (bad fuel
injector or low pilot fuel on dual-
fuel engine). Check pyrometer readings of each cylinder and
make necessary repairs or adjustments.
R. Load limit indicator binding
on nameplate or load limit shaft
bent. Damaged indicator disc or nameplate must be
corrected or replaced. Load limit shaft must be
replaced if bent.
S. Negative droop when speed
droop knob at zero. Droop calibration out of adjustment. Reset (see
Chapter 4, Governor Operation and Adjustments).
T. Governor worn. Return governor to factory for repairs.
2. Fuel racks do not
open quickly when
cranking prime mover. A. Low oil pressure in governor. See Item 1J.
B. Cranking speed too low. May be necessary to use a booster servomotor. See
manual 36684,
Booster Servomotor .
C. Booster servomotor (if used)
not functioning properly. Check action of automatic air starting valve. See
manual 36684,
Booster Servomotor .