CHAPTER 1
INTRODUCTION
Today’s industry uses increasingly complex rotating machines, some with extremely demanding performance criteria. Attempting to diagnose faults in these systems is often difficult and daunting task for operators and plant maintainers. Machine failure can lead to economy loss and safety problems due to unexpected and sudden production stoppages.
Rotating machinery is a common class of machinery in industry. The root cause of faults in rotating machinery is often due to faulty bearing. One way to increase operational reliability and thereby increase machine availability is to monitor faults in these bearings.
Fault diagnosis techniques are crucial for monitoring condition in bearings. Current fault diagnosis techniques have variety of limitations. Thus the Bearing and Balancing Simulator (BBS) is specifically designed to demonstrate and support the study of bearing faults and unbalance under controlled conditions. The BBS is a variable speedmachine that can be used to generate each type of fault individually or in combinations, providing a stable platform for study. Since bearing related problems are very common, it is essential to have a thorough understanding of the associated fault signatures that occur under a variety of operating conditions. The same can be said for unbalance, where a properly balanced machine will save a factory on machine down time, replacement parts, inventory, and energy consumption.
And also portable, robust, cost-effective balance and bearing vibration trainer.It develop signal processing techniques to identify bearing fault frequencies in the presence of defects, at multiples of shaft RPM, without using high-resolution spectra.
CHAPTER 2
LITERATURE SURVEY
HISTORY
During course of the last 50 years, rotating machinery has been studied in more detail. A thorough understanding of the principles of rotor dynamics is essential for engineers and scientists involved in transportation and power generation industries, as well as many other fields, on which we find ourselves relying to an increasing extent.
Since the analysis and design of rotating machinery is extremely critical in terms of the cost of both production and machinery, it is not surprising that the fault diagnosis of rotating machinery is crucial aspect of the subject, receiving even more attention. As the design of rotating machinery become increasingly complex, due to rapid progress being made in technology ,so must machinery condition monitoring strategies become more advanced to cope with the physical burdens being placed on the individual component of a machine. Modern condition monitoring technique encompass many different themes, one of the most important and informative being the vibration analysis of rotating machinery.
Vibration condition monitoring as an aid to fault diagnosis has been examined by Stwart(1976) in much the same way as Smith(1980) and Taylor(1995). Smith covered the general kinds of faults listed above and described qualitatively how they may be recognised from their vibration characteristics, and included effects caused by non-linearity. Stewart and Taylor also included information on the actual data analysis process – how measured data should be processed in order for a diagnosis to be performed. Downham (1976) gave a broad but comprehensive coverage of recent advances in malfunction diagnosis in rotating machinery by vibration analysis, including a brief history of main development in the area over the previous 50 years.
2.1 Bearing
A bearing is a device to allow constrained relative motion between two or more parts, typically rotation or linear movement. Bearings may be classified broadly according to the motions they allow and according to their principle of operation as well as by the directions of applied loads they can handle.
2.2 Functionsofbearing
The purpose of a bearing is to reduce friction, most often on a rotating shaft. It may be made of many different materials including sintered bronze, which holds oil to reduce friction, and various metals which are cast in place to make a soft slippery surface for really heavy shafts. A bearing can also use balls or rods between two hardened metal surfaces, the balls or rollers convert what would be a sliding contact to a rolling point contact.
It permits relative motion between two machine members while minimizing frictional resistance. It consists of an inner and outer member separated either by a thin film of lubricant, or a rolling element