June 1, 1996
Technical Notes from Dr. Mel Giberson, P.E. - TRI President
The facts about Babbitt Bearings:
- Babbitted bearings are expected to serve for years and years without significant problems
In contrast, rolling element bearings have expected lifetime usually requiring continued replacement.
- Rotor Vibration: Bearing design usually has a significant influence on rotor vibration.
To change rotor vibration characteristics, consider changing bearing design. A good bearing design can solve problems caused by an unbalanced rotor, sub-synchronous rotor vibration, critical speeds, or vibration problems during start up.
Recent TRI Project Achievements: Rotor vibrations of 200 MW GE Turbine-Generator are tamed!!!
The problem: A series of 200 MW GE steam turbine-generators has had rotor vibration problems for years. The HP turbine rotor vibration was particularly susceptible to changes of load, steam conditions and valve position.
The solution: TRI evaluated the problem using TRI proprietary software. The software analyzed the rotor-bearing dynamics. The analysis showed that rotor vibrations were a result of changes in bearing film stiffness during operation. It also indicated that three bearings were most influential.
A new design using three TRI Align-A-Pad bearings in place of the existing tilting pad bearing and two elliptical bearings was implemented. The new bearings were specifically designed with the proper film stiffness.
The result: Low amplitude and steady vibrations over the entire load range
- TRI Consulting Engineering Services - to solve vibration and bearing problems and to design upgrade
- Rotor-bearing performance analysis by computer simulation
- Babbitted journal bearings
- Align-A-Pad bearings
- Fluid drives: 1,000 to 30,000+ hp.
- Full machine shop with 5-Axis CNC capabilities
- Oil systems for fluid drives, turbines and related equipment
- Seminars on bearing design and fluid drives
- Arrange a visit to your plant of TRI’s new Product and Service Display Van
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