ABSTRACT
Machines, equipment, and structural components of any industrial plant need to be functional to meet plant objectives. Extended availability of all such objects is essential for productivity. However, it is a known fact that degradation in all objects takes place with time and may lead to catastrophic failures. Such failures are not healthy for plant safety, often result in huge financial losses, and sometimes claim the life of plant personnel as well. Considering these known facts, the plant is always equipped with a maintenance unit that looks into the health of machines and other components on a regular basis. The unit is mainly responsible for identifying health degradation or developing faults and the repair or replacement in a planned shutdown of the plant. The identification of such degradation/ faults is perhaps the most difficult task. Take, for example, a turbogenerator (TG) set; it requires the knowledge of several parameters, including condenser pressure, bearing fluid pressure, and temperature during the machine’s normal operation, and maybe material properties as well. Vibration-based condition monitoring (Sinha, 2002) is perhaps the most popular and well-recognized tool used in plants to meet the objective of predicting the faults in a cheaper manner. Vibration-based condition monitoring negates the need for monitoring of a large number of other parameters, because vibration response is more sensitive to any small structural or process parameter change. Hence, only vibration-based condition monitoring is discussed here. A few important issues need to be addressed before installation of a vibration-based condition monitoring system, such as:
1. Identification of critical machines and structural components related to safety and production
2. Types of transducers (sensors) that need to be used 3. Measurement locations, data processing, and storage
Apart from the above-mentioned items, the information gathered from the measured vibration data needs to be classified into different categories to address the needs of the different kinds of plant personnel. Different groups in a plant may not be familiar with the machines, equipment, and structural components (other than their functional use) and the vibration-based diagnostic techniques being used. However, their primary objective is to achieve optimum productivity without affecting the safety of the plant. So, the coordination or sharing of information among them is very important. To meet these requirements, vibration-based information is generally divided into the following three categories.
