One of the most important issues when dealing with PHM developments is the availability of adequate sensors to provide measures that indicate the health state of a component or system. Installation of additional sensors for such purpose usually implies increments in costs and weight and reduction of reliability and availability. Sometimes equivalent information can be inferred from other available sources, allowing the design of PHM solutions with no need for additional sensors. The power consumed by a set of components may provide information concerning their health states.

Fatigue damage prognosis and diagnosis is of critical importance for the structural health management and is still a challenging problem despite extensive progresses during the last few decades. Traditional fatigue prognosis methods are cycle-based and have some inherent difficulties in the fatigue damage analysis. For example, cycle-based approach requires that the realistic load history needs to be transformed to the cycle history, which makes it impossible to perform the concurrent fatigue damage prognosis at the material and structure level.

Time Synchronous Average (TSA) is an essential algorithmic tool for determining the condition of rotating equipment. Given its significance to diagnostics, it is important to understand the algorithms performance characteristics. This paper addresses four topics in relation to the TSA performance characteristics. The first topic is the evaluation of the performance (measured against gear fault detection) of 6 different TSA algorithms.