Structural analysis and wear behavior of different graphite-based brushes for aircraft starter generator application

This research project focuses on the interrelationship between the rigidity, wear rate, and heat generation of three carbon brushes within a 399-Amp starter generator. The suggested technique is intended to substitute the starter generator with both the starting and generating modes by running each carbon brush in the starter generator for a specified timeframe and recording the temperature level and extent of wear created. The rationale for conducting the study can be attributed to the case of starter-generator heating through standard usage. Earlier speculation held that the overheating was caused by additional carbon dust that initiated arcing, or secondly, the amount of energy required to form carbon sand liberating an excessively high temperature, which caused a hardening of the brushes. The three brushes selected for this analysis possessed the required rigidity properties necessary for this material type. The research has analyzed the carbon brush surface to coordinate hollows and dents from the frictional coefficient. For this analysis, optical microscopes (AFM and SEM) were used. The findings imply that as the brushes' rigidity increased, the wear rate, in turn, reduced, while the whole internal temperature from the starter generator increased. The outcomes suggest that brush stiffness is a determining factor in the starter generator's additional temperature. The energy released in the form of heat as the carbon brushes gradually wear directly corresponds to the operating temperature increase. This implies that enhanced rigidity will extend the brush's life, while increasing the functional heat to extents that the element cannot handle.

Automated summary

The research project focuses on the interrelationship between the rigidity, wear rate, and heat generation of three carbon brushes in a starter generator. The study found that increasing brush stiffness can reduce wear rate, but also lead to an increase in the internal temperature of the starter generator. The findings suggest that brush stiffness is a key factor in determining the additional temperature in the starter generator.