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3. Governor ball head
Q
A
(woodward strap suspended type)
4. Governor ball head (pelton)
A
5. Electro-hydraulic transducer
A
(electronic or digital governors)
6. Woodward oil motor vibrator
A
7. Pilot valve
A
8. Main distributing and auxiliary valves
NS
B
A
9. Miscellaneous valves
A
10. Dashpot
A
11. Linkage and pins
M
A
12. Restoring cable and position transducers
A
13. Hydraulic system
D
W
M
A
14. Generator air brake valve
B
A
15. Permanent magnet generator (PMG)
NS
A
or speed signal generator (SSG)
16. Position and limit switches
A
17. Shutdown solenoids
A
18. Speed changer and gate limit motors
A
and remote position indicators
19. Governor inspection report
A
D - Daily
W - Weekly
M - Monthly
Q - Quarterly
A - Annual
B - Biannual (Every 2 years.)
NS - Not scheduled (extraordinary maintenance; usually 5-year or longer intervals)
W - Weekly
M - Monthly
Q - Quarterly
A - Annual
B - Biannual (Every 2 years.)
NS - Not scheduled (extraordinary maintenance; usually 5-year or longer intervals)
1. Governor Tests and Adjustments
Annual. Check wicket gate timing, speed droop calibration, speed changer adjustment, speed stability index,
and governor time constant as described in
and governor time constant as described in
FIST, volume 2-3, section IV.
These tests not only optimize a
governor's performance, but also can be very helpful in trouble shooting governor problems. The mechanical
alignment of the governor should also be checked as described in
alignment of the governor should also be checked as described in
section III in FIST, volume 2-3.
It is
important to recheck governor settings with these tests after any major maintenance to a governor.
2. Governor Ball Head (Woodward Vibrator Type)
Weekly. Oil ball head by applying a few drops of light machine oil to the top of the ball head motor shaft. See
if a discernible motion can be felt with a finger between the main valve and base. If no motion can be felt,
replace the vibrator and balls.
if a discernible motion can be felt with a finger between the main valve and base. If no motion can be felt,
replace the vibrator and balls.
Annual. After shutdown, remove ball head and disassemble. Clean and inspect the slide blocks, flyball rod,
and flyball rod bushings. Replace vibrators and vibrator balls if no discernible motion of the main valve was
and flyball rod bushings. Replace vibrators and vibrator balls if no discernible motion of the main valve was