Wicket Gate Bushings Grease vs' Greaseless

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Wicket Gate BushingsGrease vs. Greaseless
Where's the grease??
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Greaseless BushingApplications
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
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Types of Greaseless Bushings

• Metallic

• Non-metallic

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Experience Problems
MAIN PROBLEMS Stalling and Stiction
(stick-slipping)
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Why?
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Servomotor PressureMonitor

• WATERVIEW - 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 365
  days.

Data storage at Norris Lab
Wide area network
4-20 ma
Waterview at Plant
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
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X-Y, Gate - Pressure Chart (Wet)
DRY
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Future of Greaseless in TVA
Options considered

• Other greaseless materials
• Green grease and bronze
• Standard greased bronze

Policy install greased bronze for stem bushings
and pads, use greaseless for linkages.
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TVA Greaseless Installations

• 32 turbines were converted to fully
  greaseless.
• 22 have been re-bushed after an avg. 8 years in
  service.
• 10 remaining in service 11 years.

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THANK YOU
Questions ?
END
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X-Y, Gate - Pressure Chart (Dry)
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X-Y, Gate - Pressure Chart (Wet)
BACK
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Why?
Chatter Vibration
Threshold