Optimum Inspection Polic][es for a Standby Unit

An inspection policy for a standby unit is considered by taking a standby electric generator as an example. The expected cost by the time of the electric power supply failure is derived by rising renewal-type equations. We discuss an optimum checking time which minimizes the expected cost. We further obtain a checking time such that the probability that a standby generator has failed at the tim(~ of the electric power supply failure is not greater than a prespecified value. Two cases where the failure rate is not disturbed by any inspection and a standby generator may fail during the time of the electric power supply failure arc considered. Numerical examples are fmally presented.