Thesis (M.S.)--University of Michigan, Ann Arbor, 1980. / Typescript (photocopy). Includes bibliographical references (leaves 57-59). Also issued in print.

Thesis (M.S.)--University of Michigan, Ann Arbor, 1980. / Typescript (photocopy). eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 57-59).

Magnet wires find many applications in modern world. Magnet wires used for the electrical insulation in fly-back transformers, solenoids, sensors, adjustable speed drives etc. are subjected to multistress aging factors such as electrical (high voltage, high frequency), thermal and other environmental stresses. Due to the action of these aging factors degradation and aging of the insulation will occur and thereby lead to reduced life-time or premature failure. In order to identify the most important factors affecting the life-time of the electrical insulation, the insulation must be evaluated under simulated service conditions. This study is done by performing accelerated aging tests at high electrical stresses, elevated temperatures, and often at combined electrical and thermal stresses, and at high frequencies. The electrical phenomena behind the breakdown of the insulation have been studied. In this study accelerated life tests are performed on AWG 40 magnet wire. Life-time characteristics, probability of failures, and life-time percentiles are determined.

Using electron beam lithography fine Au<SUB>60</SUB>Pd<SUB>40</SUB> wire samples have been made, which were then used to investigate size effects in disordered systems. The wires made had widths from 140nm to 36nm, and lengths from 125nm to 100μm. The thickness was varied from 10nm to 50nm. Using gas etching techniques it was possible to make these wires free-standing with lengths of over 100μm and thicknesses of 10nm. At first some of the important electrical and mechanical properties of the free-standing wires were investigated. The tensile strength was found to be much larger than that found in bulk gold, and a simple model was developed to predict at what voltage the wires would melt. At low temperatures localisation and interaction contributions to the resistance were seen both in wires on a substrate and when free-standing. Electric field heating of the wires on a substrate was used to find the electron-phonon scattering time, which was seen to be proportional to T<SUP>-2</SUP>. The resistance rise for the free-standing wires was less than for the same wires on a substrate. Magnetoresistance measurements revealed this to be due to an increased negative localisation term in the presence of strong spin orbit scattering. The inelastic lengths were consistent with strong magnetic scattering which was reduced on being made free-standing. Electric field heating of the free-standing wires revealed that the thermal conduction of the wire is dominated by the electron contribution. At 1K the phonons in the wires should be one dimensional, but no contribution to the heat conduction was observed from these phonons. Below 800mK conductance fluctuations were observed in the magnetoresistance of the short samples. Below 125 K the amplitude of the fluctuations saturated which is consistent with both the interaction and the inelastic lengths being longer than the wire.

No description available.

No description available.

No description available.

Thesis (doctoral)--Friedrich-Wilhelms-Universität zu Berlin, 1924. / Vita.

No description available.

No description available.