An on-Line Technique to Monitor and Control the Performance of Plain Bearings in Large Installations
A properly designed hydrodynamic journal bearing should ideally operate smoothly through out its design life. However, they do fail prematurely due to a number of reasons including shaft misalignment, incorrect choice of lubricant and faulty assembly. A need therefore exists for an on-line monitoring and control of plain bearings particularly in larger installations such as a power plant. An alternative to widely used vibration monitoring is to use direct parameters such as film thickness.
The paper describes a feed back control strategy for such bearings using film thickness as the controlled and shaft speed as controlling parameters. An experimental arrangement is developed where the film thickness is continuously monitored while a computer-controlled feed back circuit assesses the parameter and adjusts the shaft speed accordingly. The procedure provides a continuous cheek on the performance of the bearing such that in the event of complete film breakdown pre-emptive measures may be taken to avoid seizure.
An analysis of the stability of the control system is also given. The analysis provides us with the necessary gain of the control module for stability.
KeywordsThrust Bearing Shaft Speed Loop Transfer Function Plain Bearing Bridge Rectifier
Unable to display preview. Download preview PDF.