Failure analysis of mechanical and electrical components

• Main Author: Wang, Jianhong
• Other Authors: Tan Ming Jen
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/60917
• Institution: Nanyang Technological University

In today’s world, every product has its modes of failure as they do not perform at the expected performance level forever. It is important for the engineer to insure the product’s life or if not, conduct an accurate and thorough failure analysis of the product that underwent failure so as to determine the mode of failure and to take measures to mitigate the problem. This report discusses the causes of failure on copper conductors and lugs which are some of the various mechanical and electrical components of an automatic transfer switch. Furthermore, a set of copper wires were investigated to find out what caused the malfunction. To find out the possible modes of failure, application of failure analysis methods such as fractography and metallography were used to investigate the failure mechanisms involved. Metallographic testing is applied to observe and examine the microstructure of the copper conductors and lugs samples. All these analytical findings will be attributed to the conclusion of the report. From the experimental results showed, there are presence of the coarse grains in the microstructure of the three copper conductors (Red, Yellow and Blue) and the copper lugs, this showed an indication that they experienced localised overheating. It was concluded the failure was due to the mismatch in the current rating between the automatic transfer switch and the utility power source. The conductors and lugs were unable to cope with the excess current flow from the utility power source as the current overload from the utility power source is significantly more than the current capacity of the components. The excess heat generated led to localized overheating at the point of contacts of both conductors and lugs and ultimately caused the failure of the machine. Suggestions for future work were also included in this report to improve the findings which were obtained for these failure analyses.