Thesis (M.S.)--California Polytechnic State University, 2009. / Title from PDF title page; viewed on August 21, 2009. "July 2009." "In partial fulfillment of the requirements for the degree [of] Master of Science in Engineering." "Presented to the faculty of California Polytechnic State University, San Luis Obispo." Major professor: Linda Vanasupa, Ph.D. Includes bibliographical references (p. 100-101).

Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1923. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed June 1, 2010) Includes bibliographical references (p. 22) and index (p. 37-38).

Thesis (M.S.)--Tennessee Technological University, 2009. / Title from title page screen (viewed on June 29, 2010). Bibliography: leaves 127-131.

Thesis (M.S. in electrical engineering)--Washington State University, August 2006. / Includes bibliographical references (p. 64-65).

Thesis (Ph. D.)--University of Canterbury, 2007. / Typescript (photocopy). "March 2007." Includes bibliographical references (p. 241-256). Also available via the World Wide Web.

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Fault diagnosis is gaining more attention for electric machines running critical loads, whose sudden breakdown can result in unpredictable revenue losses. Consequently the motor drive systems with fault diagnostic and prediction features are of great concern and are becoming almost indispensable. Among all kinds of common faults, quite a few have relationship with unequal air-gap. So far, work on detection of eccentricity related faults in synchronous and induction machines have been well documented. However, few are reported on faults resulting fiom axial non-uniform air-gap. This thesis investigates the performance of a three-phase induction machine with non-uniform static eccentricity along axial direction or inclined static eccentricity. A variant of Modified Winding Function Approach (MWFA) is applied to study this fault. The relationship between the number of rotor bars, poles and the existence of fault related current harmonics is discussed. It is shown that inclined eccentricity also demonstrates similar characteristics as circumferential non-uniform air-gap (Static Eccentricity or Dynamic Eccentricity). The case that demands special attention is inclined eccentricity symmetric to the mid-point of machine shaft, which cannot be detected directly from current spectrum. These results will be useful reference to the designers of online tools for machine condition monitoring. Finite Element results to verify the inductance values used in simulation are also presented. The analysis is supplemented by the stator current spectra obtained fkom simulated results for different load and fault conditions. Finally a four-pole, 45 rotor bar, 2 kW induction motor is used to validate the theoretical and simulation results experimentally.

M.Ing. / The study looks into the impact of harmonic distortion on power-plant equipment in general, and then focuses on the impact it has on power transformers operating near the thermal limit. The feasibility of the study is firstly evaluated and then the theory on harmonics and transformer losses is analysed. The study had been narrowed down to power transformers due to the high numbers of failures nationally and internationally attributed to unknown causes. A transformer model is then developed through theoretical considerations. Finally, a case study is done on the capability of a fully loaded transformer under harmonics conditions evaluated through transformer capability calculations and the proposed transformer model. Thereafter the transformer model developed is verified with measured results. The main impact of harmonic current distortion on power transformers is an increase in the rated power losses that results in a temperature rise inside the power transformer. The heat build-up can lead to degradation of insulation, which can shorten the transformer’s life and lead to eventual breakdown. The harmonic current distortion impacts transformer losses – namely, ohmic losses, the winding eddy current losses and other stray losses. All of these harmonic effects on transformer losses are verified theoretically, mathematically and practically. The harmonic impact on the transformer capability is then evaluated through a numerical example of a transformer feeding a harmonic load. The transformer capability is determined via two methods – namely, harmonic capability calculations in the standard “IEEE Recommended Practice for Establishing Transformer Capability when Supplying Nonsinusoidal Load Currents”, [11] and a proposed transformer model derived from theoretical and mathematical analysis. The results show that an increase in the winding eddy current losses can decrease the maximum permissible nonsinusoidal load current substantially. If the load current of the transformer is derated accordingly it translates into a loss of the output power capacity of the power transformer. The standard recommended capability calculations for winding eddy current losses are conservative and not satisfactorily accurate. This results in a large loss of power capacity. The proposed transformer model includes a parameter that estimates the winding eddy current loss in the transformer that results in a smaller loss in power capacity. Furthermore, it was shown that the harmonic current distortion levels could exceed the permissible levels although the harmonic voltage distortion levels are within acceptable levels. The proposed transformer equivalent model is thereafter practically verified with experimental results of papers published by M.A.S. Masoum, E.F. Fuchs and D.J. Roesler, [19], [20] and [29].

In the drive towards power electronic integration, planar structures are widely used. Applications for the use of these structures are varied. These have been shown to have potential advantages with regard to reduction in size and cost. Much work has been done with regard to integration, but generally from an intuitive perspective, and without a general approach. An important part of power electronic integration is EMI filtering. One way in which this is achieved is through dissipative filtering. It is demonstrated that this can be done for planar structures through the use of multi-layered conductors. Planar conductors have a particularly distinct advantage in that they are low profile and can be miniaturised. The resulting focus of this dissertation is an investigation into the characterisation of two-layer conductors in terms of how the properties of the two layers contribute to the frequency dependent resistance of the conductor. This is done with a direct view towards dissipative filtering. This investigation begins with a description of the method of characterisation of two-layered conductors, and the construction of a parametric study around this. A contribution of this dissertation is the demonstration that the parametric space can be reduced without loss of generality of the characterisation. The results of this characterisation are used to demonstrate the importance of the total conductivity and total permeability as concepts. This concept provides flexibility in the design of two-layer dissipative filters. The concept of a single-layer approximation is presented and investigated. It is shown to even further simplify the model used for multi-layered conductors, and presents a good first level understanding of what the frequency dependent resistance of the structure will be. This concept is shown to be useful in the design of two-layered conductors, and may be generalisable to multiple layers. A second contribution of this work is the presentation of design equations based upon this approximation for five different scenarios. This contribution includes the limits to the dimensions of the two-layer structure, with the conclusion that some specifications do not have physically realisable forms. The final, major contribution that this work presents is as follows. In terms of dissipative filtering, it is shown under differential-mode excitation that the desired properties of the inner layer of the conductor should be: less conductive than the outer layer, and more permeable than the outer layer. These conditions are shown to provide a steeper gradient of resistance increase with respect to frequency. This conclusion is verified experimentally, which provides confidence in the modelling technique this dissertation is based upon.