Stochastic Behavior of 2-Unit Standby Redundant Systems with Imperfect Switchover

We discuss two models of 2-unit standby redundant systems with imperfect switchover. In Model I the switch assumes up and down states repeatedly, independently of the behavior of the main unit. We obtain the stochastic behavior of the system, i.e., the first-passage time distributions, the expected numbers of visits to a certain state, and the transition probabilities. In Model II the failure of the switch can be detected only when it is used.