Novel Sensor for Determining the Aging Condition of Insulation Paper in a Transformer

Author(s):  
T. Munster ◽  
T. Kinkeldey ◽  
P. Werle ◽  
K. Hamel ◽  
J. Preusel
Keyword(s):  
1982 ◽  
Vol 68 (6) ◽  
pp. 649-657 ◽  
Author(s):  
Kiyohiko NOHARA ◽  
Kenji WATANABE ◽  
Yutaka ONO ◽  
Nobuo OHASHI

2021 ◽  
Vol 11 (9) ◽  
pp. 4029
Author(s):  
Jian Wang ◽  
Pui-Lam Ng ◽  
Yuhua Gong ◽  
Han Su ◽  
Jinsheng Du

Porous asphalt mixture can be used as a road surface paving material with the remarkable advantage to prevent water accumulation and ponding. However, the performance of porous asphalt mixture in low temperature environment has not been thoroughly investigated, and this forms the subject of research in the present study. The mineral aggregate gradation of porous asphalt mixture was designed based on Bailey method, and the low temperature performance of porous asphalt mixture was studied by means of the low temperature bending test. The factors affecting the low temperature performance of porous asphalt mixture were analyzed through the orthogonal experimental design method, and the effects of porosity, modifier content, aging condition, and test temperature on the low temperature performance of porous asphalt mixture were evaluated. The results showed that the modifier content was the most important factor affecting the low temperature performance of porous asphalt mixture, followed by the test temperature, while the porosity and the aging condition were the least. Among the three performance evaluation indicators, namely the flexural tensile strength, maximum bending strain, and bending stiffness modulus, the maximum bending strain had the highest sensitivity to the porosity. It can be seen from the single factor influence test of porosity that there existed an approximately linear relationship between the maximum bending strain and the porosity of porous asphalt mixture, and the maximum bending strain decreased with increasing porosity. Furthermore, in order to ensure the good working performance of porous asphalt mixture in low temperature environment, the porosity should also satisfy the required limits of the maximum bending strain.


2013 ◽  
Vol 813 ◽  
pp. 43-46
Author(s):  
Hob Yung Kim ◽  
Jae Sook Song ◽  
Sun Ig Hong

3-ply Cu-Ni-Zn/Cu-Cr/Cu-Ni-Zn clad composite plates were prepared by roll bonding at 823K and their properties were characterized. No intermetallic compounds were observed at Cu-Ni-Zn/Cu-Cr interfaces in the as-rolled and heat-treated Cu/Ni-Zn/Cu-Cr/Cu-Ni-Zn clad plates. The strength of as-rolled clad plate reached up to 420MPa with the ductility of 13%. After heat treatment at 723K for 1.5 hours, the strength of Cu-Ni-Zn/Cu-Cr/Cu-Ni-Zn clad composite plate dropped to 340 MPa and the ductility increased to 20%. With annealing at 723K, there is no drastic drop of the stress before final fracture, meaning three plates were bonded together until the last part of the stress-strain curve. The peak of the conductivity (>70% of IACS) was attained after aging for 1.5 hrs, compatible with the typical peak aging condition of Cu-Cr alloy.


2021 ◽  
Author(s):  
Mohammad Ashraful Haq ◽  
Mohd Aminul Hoque ◽  
Jeffrey C. Suhling ◽  
Pradeep Lall

Abstract A major problem faced by electronic packaging industries is the poor reliability of lead free solder joints. One of the most common methods utilized to tackle this problem is by doping the alloy with other elements, especially bismuth. Researches have shown Bismuth doped solder joints to mostly fail near the Intermetallic (IMC) layer rather than the bulk of the solder joint as commonly observed in traditional SAC305 solder joints. An understanding of the properties of this IMC layer would thus provide better solutions on improving the reliability of bismuth doped solder joints. In this study, the authors have used three different lead free solders doped with 1%, 2% and 3% bismuth. Joints of these alloys were created on copper substrates. The joints were then polished to clearly expose the IMC layers. These joints were then aged at 125 °C for 0, 1, 2, 5 and 10 days. For each aging condition, the elastic modulus and the hardness of the IMC layers were evaluated using a nanoindenter. The IMC layer thickness and the chemical composition of the IMC layers were also determined for each alloy at every aging condition using Scanning Electron Microscopy (SEM) and EDS. The results from this study will give a better idea on how the percentage of bismuth content in lead free solder affects the IMC layer properties and the overall reliability of the solder joints.


2019 ◽  
Vol 972 ◽  
pp. 118-122
Author(s):  
Yan Nian Zhang ◽  
Jun Xie

The present study was conducted to obtain a better understanding of the variation rule of mechanical properties of laminated neoprene bridge bearing pads under thermal aging condition using compression tests. A total of 5 specimens were processed in a high-temperature chamber. After that, the specimens were tested subjected to axial load. The parameter mainly considered time of thermal aging processing for specimens. The results of compression tests show that the specimens after thermal aging processing are more probably brittle failure than the standard specimen. Moreover, the exposure of steel plate, cracks and other failure phenomena are more serious than the standard specimen. The compressive capacity, ultimate compressive strength, compressive elastic modulus of the laminated neoprene bridge bearing pads decreased dramatically with the increasing in the aging time of thermal aging processing. The attenuation trends of ultimate compressive strength, compressive elastic modulus of laminated neoprene bridge bearing pads under thermal aging condition accord with power function. The attenuation models are acquired by regressing data of experiment with the least square method. The attenuation models conform to reality well which shows that this model is applicable and has vast prospect in assessing the performance of laminated neoprene bridge bearing pads under thermal aging condition.


2012 ◽  
pp. 1107-1112
Author(s):  
Yasuo Takaki ◽  
Tetsuya Masuda ◽  
Equo Kobayashi ◽  
Tatsuo Sato

2014 ◽  
Vol 986-987 ◽  
pp. 106-109
Author(s):  
Chun Fang Yi ◽  
Yi Xin Chen ◽  
Pei Song Liang

The HTV SIR provided the superior hydrophobicity for the composite insulator. But it faces the aging problem more than the inorganics. Corona, as an inevitable influence factor in insulator’s operation, its effect to the material could not be ignored. The paper developed a multi needles to plate corona aging equipment, 1000 hours’ corona aging to the HTV SIR was done. The duration of corona aging effect was study by FTIR, SEM and volume resistivity-temperature character testing. Three testing methods from the aspect of material’s chemical, physical and electrical characters to evaluate the aging effect with time went on. It had good consistency in all three methods for HTV SIR’s corona aging evaluation.


Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4240
Author(s):  
Qingfeng Wang ◽  
Hong Chen ◽  
Fengjiang Wang

Excessive growth of intermetallic compounds (IMCs) during service affects the reliability of solder joints, so how to suppress the growth of IMC thickness at the interface in solder joints becomes a widespread concern. In this work, the interfacial reaction between Sn-10Bi solder and Cu substrate after thermal aging was investigated. Moreover, to depress the IMC growth at the interface, trace amounts of Zn was added into the Sn-10Bi solder, and the interfacial reactions of Sn-10Bi-xZn solders (x = 0.2, 0.5) and Cu substrate after thermal aging were studied in this paper. Compounds such as Cu6(Sn, Zn)5 and Cu5Zn8 were formed at the interface after adding trace amounts of Zn. The addition of 0.2 and 0.5 wt% Zn significantly inhibited the thickness growth of IMCs and the formation of Cu3Sn IMC at the interface of Sn-10Bi-0.2Zn/Cu and Sn-10Bi-0.5Zn/Cu during thermal aging. Therefore, the addition of trace Zn had an obvious effect on the interfacial reaction of Sn-10Bi/Cu solder joint. Interestingly, the evolution of IMC thickness in Sn-10Bi-0.5Zn/Cu solder joints was completely different from that in Sn-10Bi or Sn-10Bi-0.2Zn solder joints, in which the spalling of IMCs occurred. In order to explore the mechanisms on the depressing effect from the addition of trace Zn, the activation energy Q in solder joints during aging was calculated.


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