Análise de causa raiz em alternador veicular

Abstract

The intention of this work is to present the root cause analysis for field failures of combustion engine’s alternator. The two failure modes evaluated are low voltage supplied by alternator or no voltage supplied by alternator. This work also presents the results of life data analysis, 5 whys analysis and Ishikawa diagram. 192 alternators were evaluated and the root cause for the field reported failures is tension rectifying bridge diode welding process variation. Life data analysis presented a cumulated probability of failure at 100.000km of 5,5%. It is known that this failure does not present risk to the driver or vehicle occupants and it of easy detection to the driver. The results here presented supports the car builder company to increase the alternator spare parts stock in order to avoid customer complaint related to lack of parts to repair the vehicle at the dealership network. The results also support the organization high management on the decision process on the most appropriate repair procedure towards vehicle population, which the engines’ alternator may present the reported failure.