Failure Analysis and Investigation of Electrical Insulation of 10 MVA Oil-Type Transformers Damaged due to Direct Lightning Strikes

Author(s):  
C. Boonseng ◽  
D. Kammaroeng ◽  
K. Kularbphettong
2021 ◽  
Author(s):  
P. Watté ◽  
G. van Hees ◽  
R. Engelen ◽  
W. D. van Driel

Abstract Reliability of electronic drivers, or systems, is crucial for the business of Signify. We manufacture and sell more than a million drivers per year. Field returns taught us what failure modes are important, but this is not sufficient to provide lifetime claims for our products. Being in this business for almost a century, in order to provide detailed lifetime claims, we have established an internal reliability tool. This tool provides our designers the correct information for flawless driver development. The specially developed Electronics Reliability Tool (ERT) uses on the one hand FIT tables provided by handbooks like e.g., Telcordia and on the other hand also considers wear-out mechanisms due to e.g., lightning strikes. Validation and verification of our predictions is performed by collecting sold quantities, field returns, do extensive failure analysis and compare these values with calculated ones. Each internally designed driver is subjected to an ERT calculation. The forecasted lifetime is used as a yard stick to witness the drivers’ targeted lifetime. In our presentation we will demonstrate the tool. In this paper, we describe details of how ERT calculates failure rates. We will also present the comparison between field performance and calculated values of our electronic drivers.


Author(s):  
John R. Devaney

Occasionally in history, an event may occur which has a profound influence on a technology. Such an event occurred when the scanning electron microscope became commercially available to industry in the mid 60's. Semiconductors were being increasingly used in high-reliability space and military applications both because of their small volume but, also, because of their inherent reliability. However, they did fail, both early in life and sometimes in middle or old age. Why they failed and how to prevent failure or prolong “useful life” was a worry which resulted in a blossoming of sophisticated failure analysis laboratories across the country. By 1966, the ability to build small structure integrated circuits was forging well ahead of techniques available to dissect and analyze these same failures. The arrival of the scanning electron microscope gave these analysts a new insight into failure mechanisms.


Author(s):  
Evelyn R. Ackerman ◽  
Gary D. Burnett

Advancements in state of the art high density Head/Disk retrieval systems has increased the demand for sophisticated failure analysis methods. From 1968 to 1974 the emphasis was on the number of tracks per inch. (TPI) ranging from 100 to 400 as summarized in Table 1. This emphasis shifted with the increase in densities to include the number of bits per inch (BPI). A bit is formed by magnetizing the Fe203 particles of the media in one direction and allowing magnetic heads to recognize specific data patterns. From 1977 to 1986 the tracks per inch increased from 470 to 1400 corresponding to an increase from 6300 to 10,800 bits per inch respectively. Due to the reduction in the bit and track sizes, build and operating environments of systems have become critical factors in media reliability.Using the Ferrofluid pattern developing technique, the scanning electron microscope can be a valuable diagnostic tool in the examination of failure sites on disks.


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