COMPARATIVE AND OPTIMUM ANALYSIS FOR NUMBER OF COLD STANDBY UNITS FOR A SYSTEM WORKING WITH ONE OPERATIVE UNIT AND TWO TYPES OF FAULTS

A system with a single functional unit and one or two cold standby units is studied by developing two Models. In one of the two models, there is a provision for one cold standby unit, whereas in the other, the provision is for two cold standby units. The operative unit, whenever it fails, may either fail due to a major fault or a minor fault, which is revealed by carrying out an inspection. When the operative unit fails, the cold standby becomes operational with an activation time between the operative unit failing and the standby operating state. Reliability and profit analysis have been carried out for both two models. A comparative study has also been made between the two models to decide whether one or two cold standby units should be used for such a system, as far as the profitability aspect is concerned. The models have been examined using the regenerating point method.