Comparative analysis of two reliability models with regard to provision of assistant repairman and discussion time

A two-unit cold standby system with regular as well as visiting repairmen is studied. On failure of a unit, the repair is undertaken by the regular repairman who always remains with the system. The regular repairman while repairing the failed unit may get tired after some time and then the nature of the fault is discussed by an outside expert repairman telephonically and accordingly he himself comes or sends his assistant (an ordinary repairman). Various measures of system effectiveness are obtained. Profit is evaluated for a particular case.