|Fault Diagnosis for Engineering Systems gives a complete presentation of basic essentials of fault diagnosis, and takes a look at the cutting-edge discipline of intelligent fault diagnosis for condition-based maintenance. The paper presents a defect detection system based on development the tree faults analysis for a power rectifier. The tree fault method is used for quantitative and qualitative analysis of system reliability. For the qualitative analysis of the faults, the tree of faults is developed, based on symptoms, considered to be the most frequent ones during the operation of the power rectifiers. The paper describes the steps of the diagnostics system and the results obtained after the quantitative and qualitative analysis with the tree fault method for the three phase power rectifier. For the quantitative analysis, the reliability of the drive system is determined based on the values of the operating probabilities of the component elements. The reliability of a product can be provided in the design stage, controlled during the manufacturing process, measured during the test and maintained during the operation. The life of a product is influenced by the characteristics of the working environment. Specific information about the product’s working environment includes temperature, vibration strains, chemically or inert aggressive environments, electromagnetic conditions.