EVALUATION OF MEAN TIME TO SYSTEM FAILURE OF A SYSTEM OF RELAYS UNDER TESTING CONDITIONS.

This will work as a guideline for the design engineers for designing the system in order to make it a reliable (up to required level) one. The actual component failure rates (open type failure and closed type failure) and repair rates were not available. Discussions with concerned personnel led to assume certain failure rates for the relays. Mean time between failures (MTBF) values were calculated assuming values for the repair rate. Stochastic process model was used to evaluate MTBF with availability and nonavailability of service facility. These were found to be approximately 542. 29 and 512. 15 hours respectively. A methodology for estimation of MTBF for a given system of relays has been given. The different causes of failures were identified on the basis of feedback from actual users. These will help at the time of actual performance of life tests for relays.