No abstract

This paper presents a case study conducted to find out the reasons of rupture/failure at bends of water cooled stator bar in a 210 MW generator. The bars containing hollow and solid subconductors were cleaned to remove the insulation. The failed portions were examined under scanning electron microscope, optical microscope and the corrosion products by X-ray analysis. The investigation revealed the presence of intergranular brittle cracks, cuprous oxide tarnish film, ammonia, and moisture. All these showed the characteristic features of SCC in copper metal in ammonical solution. The ultimate rupture by SCC of solid and hollow conductors took place in three stages: 1) water leaked from inside the hollow conductor, at the lug braze; 2) the water reacted with the insulation and produced ammonia; 3) the ammonia caused SCC and led to heavy leakage of water and hydrogen in the generator. Each stage involved in the failure process has been described.

India is the third largest road network which is used by one percent of the world’s total vehicle population. On this road network six percent of the total of global road traffic accidents occur. India is the sixth-largest car market in the world but is still the only country amongst the global top 10 car markets to not have a testing program. To reduce the number of road traffic accidents, many countries have come up with safety programmes such as Euro NCAP (New Car Assessment Program), US NCAP, Latin NCAP, etc. In 2014, Indian government proposed a similar safety assessment program called as Bharat New Vehicle Safety Assessment Program (BNVSAP) but it is since delayed in its implementation due to a number of reasons. The aim of this study is to compare existing NCAPS and the new BNVSAP and propose some improvements in it by studying the experiences gained by the older NCAPS and observing the difference in the situation of road traffic in India and in other countries by analysing real world accident data.