Reliability improvement and economic benefits of online monitoring systems for large induction machines

Microprocessor-based monitoring systems are being developed for the regular analysis of large induction machine variables and to predict possible fault conditions, so that preventive maintenance can be organized in a cost-effective manner. A method for the evaluation of the improvement of machine reliability made by such monitoring systems is presented. An economic and financial analysis to examine the viability of a condition monitoring system for a large machine using comprehensive rotor, stator, and other parameter measurements is developed. In two case studies, the costs of design, construction, mounting, and operation of condition monitoring systems are discussed, and estimates are made at current costs. These costs are balanced against the costs avoided in cases of unexpected machine failures, lost production, and repairs. Cost estimates for repairs and downtime are made using published information from previous reliability surveys on electrical machines. Information is presented for different machine sizes, which will indicate any relevance of the machine size when evaluating monitoring systems