1. Wicket Gate Bushings Grease vs. Greaseless
Where's the grease??

2. Greaseless Bushing Applications
1. Linkage bushings
2. Bearing
3. Wear pads
4. Wicket gate bushings
5. Wicket gate bushings
6. Packing wear strips
7. Wicket gate bushings
1. Bearing
2. Linkage bushings
3. Wicket gate bushings
4. Wicket gate bushings
5. Wear pads
6. Trunnion bushings
7. Trunnion bushings
8. Wicket gate bushings
Bushings, bearings, and wear pads will be known as “bushings”.
Shift ring radial and thrust pads + wicket gate linkages and stem bushings.

3. Types of Greaseless Bushings
Metallic
Non-metallic
Oiles 500sp1-sl403(for hydro) does not contain graphite (PTFE/wax plugs with a little lead).

4. MAIN PROBLEMS: Stalling and Stiction (stick-slipping)
Experience & Problems
Delamination
Plug swell
Slip-sticking from Lubron AQ30 on 6 units. 4 units have had gate stalling at high heads.
Delamination of Thordon Traxl on 2 units. COE Hartwell plant and Ontario Hydro Canyon plant , too.
Tight Thordon Traxl on 1 unit.
MAIN PROBLEMS: Stalling and Stiction (stick-slipping)

5. Why?
Slip-sticking from Lubron AQ30 on 6 units. 4 units have had gate stalling at high heads.
Delamination of Thordon Traxl on 2 units. COE Hartwell plant and Ontario Hydro Canyon plant , too.
Tight Thordon Traxl on 1 unit.

6. Why? Chatter Vibration Threshold
Slip-sticking from Lubron AQ30 on 6 units. 4 units have had gate stalling at high heads.
Delamination of Thordon Traxl on 2 units. COE Hartwell plant and Ontario Hydro Canyon plant , too.
Tight Thordon Traxl on 1 unit.

7. Servomotor Pressure Monitor
DISPLAY
Realtime pressure (5 sec. update)
Max. pressure in last 24 hour period
Graph of max. pressure per day for last 365 days.
Graph of max. head per day for last days.
Data storage
Wide area network
4-20 ma
Installed on 22 suspect units .
View data at office or any location on WAN
Rosemount mounted on wheel pit wall and connected to wicket gate servomotors’ existing taps in most units or in governor cabinet of some units.
Rosemount Differential pressure transmitter

8. X-Y, Gate - Pressure Chart (Wet)
AFTER
Before and after rebush.

9. X-Y, Gate - Pressure Chart (dry)
Head and thermal considerations may change output slightly.

10. Future of Greaseless Options to consider: Greaseless materials
“Green” grease and bronze*
Standard greased bronze*
*Hybrid: install greased bronze for stem bushings and pads, use greaseless for linkages.

11. Consider for greaseless installation:
Things to
Consider for greaseless installation:
Force – servomotors
Friction – coeff. of friction & head
Fatigue – will the material last?
Is the friction (from the bushings and max. hydraulic head force) less than the sum of the servomotor’s force?
Beware of pump-turbines!
1.      Pick a material that is strong and will hold together under harsh conditions.
2.      Material should have a low coefficient of friction. Ideally, the static and dynamic coefficients of friction should be close together to avoid “stick-slipping”.
3.      Material should have a low wear rate. Note, a material that is good in the wet may not be so good in the dry.
4.      Material should have low or no swell. At the very least , the swell must be predictable and allowances made.
5.      Don’t skimp on bushing clearances. Follow manufacturer’s recommendations.
6.      If your water quality is poor, consider installing seals. Silt and debris will accelerate wear.
7.      Study your unit. Take dry differential pressure readings and wet running readings at maximum head. Assume the friction will increase regardless of manufacturer’s data or laboratory tests. Are the servomotors strong enough for a 25% increase in friction? If not, continue using greased bronze or consider installing stronger servomotors.
8.      Accept that the life of the greaseless bushings will be less than the greased bronze.

12. OTHER CHARTS OF INTEREST
APPENDIX
OTHER CHARTS OF INTEREST

13. 18 units with Thordon Traxl as stem and linkage bushings.
12 units with Lubron AQ30 as stem and linkage bushings.
25 units with Lubron AQ30 as shift ring wear pads.
2 units with Deva Glide as stem and linkage bushings.
4 units with Deva BM as shift ring wear pads.
2 units with Tenmat T814 feroform as shift ring wear pads.
4 units at RM use Slip-ease as linkage bushings.
29-72 month spread on re-bush.

14. X-Y, Gate - Pressure Chart (Dry)
“typical”

15. X-Y, Gate - Pressure Chart (Wet)
“Typical”. Head and thermal considerations may change output slightly.