Accurate assessment of the electromagnetic excitation forces and the vibration behaviour of stators is essential to arrive at a suitable design for quiet operation of an electrical machine. These electromagnetic forces are produced on the surfaces of the stator and rotor along the air-gap periphery. The physical mechanisms underlying the production of the electromagnetic forces, and the characteristics of the ensuing vibrations are described in this thesis. <p>In this thesis, comprehensive analytical methods are developed for the determination of the radial electromagnetic forces in squirrel-cage and wound-rotor induction machines. Various magnetic fields are generated due to the distribution of the windings in slots, the slotting of the stator and rotor surfaces, and the magnetic saturation of the iron. The air-gap fields are determined using the permeance method by expressing the MMF and the air-gap permeance as waves. <p>In the analyses, the mutual interactions between the stator and rotor are incorporated. Asthe load increases, these interactions become prominent and influence significantly the nature of the air-gap field. Their effects on the electromagnetic forces are discussed from the perspective of the production of vibrations. Extensive investigations were conducted on a 7.5 kW squirrel-cage induction motor and a 70 kW wound-rotor induction motor to verify the validity of the analyses. The comparisons made between the experimental and the analytical results prove the general validity of the analytical methods. <p>Conclusions are drawn with a view to determine the actual role played by the harmonic air-gap fields on the production of the electromagnetic forces and the ensuing vibrations. In the course of these investigations, an experimental set-up which is particularly suited for the measurement of magnetic fields, magnetic forces, resonant frequencies, vibrations and noise was developed. A fundamental study on the vibration behaviour of electrical machine stators using an experimental modal-analysis is presented in the thesis. Modal-analysis is a process of forcing a structure to vibrate predominantly at a selected resonance. In order to achieve this, distributed electromagnetic forces are used.<p>Detailed investigations were conducted on the stator models of a 120 hp induction motor to study their vibration behaviour, and to critically examine the damping present in them. The physical interpretations of the results given in the thesis would help in acquiring a better understanding of the vibration behaviour of stators in relation to the problem of electromagnetic acoustic noise in electrical machines. This work was supported by the National Sciences and Engineering Research Council of Canada through grant no. OGP0004324.

A superimposed steering system is the combination of a conventional steering system with an electric motor which is used to alter the steering angle imposed by the driver. The potential benefits are increased agility, automatic compensation for lateral wind forces and decreased braking distance (in combination with an electronic stability program). In this thesis we implement a model and a controller for a superimposed steering system thus achieving the first of these potential benefits. The vehicle model is based on the single-track or bicycle model. Unlike most other publications, the motor model in this thesis goes down to the level of the electrical dynamics of the motor. The model is divided into three main modules (vehicle module, steering module and friction module) as well as several submodules to ensure easy adaptability. The overall control objective consists of increasing vehicle agility by achieving a variable ratio between the steering wheel angle and the actual road wheel angle as a function vehicle velocity. We divide the controller into a torque and a current controller. The actual controller is derived in three steps starting from an analog torque controller as well as an analog current controller then moving to a digital torque controller. In doing so we use the model matching, feedback linearization and state feedback control techniques. The model and the controller are evaluated using the parameters of a small truck and different road scenarios. Finally, the Validation Square technique is applied to assess the validity of the results.

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Resources limitation in corporation renders the need for open innovation to advance their competence. Open innovation suggests utilization of outside resources can improve internal innovation and the internal IP¡¦s shall extend their usage beyond the boundary of firm to reach maximum benefit. The most remarkable open innovation paradigm in the history was IBM¡¦s release of its PC core software to give impetus to information revolution. Recently, Proctor and Gamble adapts the open innovation model and seek for external ideas which account for more than 50% of innovation of the company. Despite its phenomenal success in several cases, open innovation is not rooted in many industries. This study would investigate on the feasibility of the application of open innovation model to the electrical steel (ES) industry chain. Electrical steel is one of the most dedicated products in the steel industry. It¡¦s the crucial material in motors and transformers. China Steel holds more than 7% of the market share of ES of the world and influences the local motor markets greatly. Taiwan was once recognized the most important manufacturing base of small motors in the world. Nevertheless, motor industries in Taiwan have suffered huge decline in the past 20 years due to migrating to China whose economy reform provides much more attractive investment environment by lower wages and other operation costs. Until recently, soaring energy prices and tighter environment protection measures recently create growing worldwide need of high efficiency motors and provide new opportunity for the motor industry in Taiwan. Being the sole supplier of high quality ES in Taiwan, how China Steel takes advantage of this opportunity and enhances its competiveness is the main interest of this study. This study focuses on the industry chain of ES in Taiwan by systematic survey on its market, technology, and man power to understand its strength, weakness, facing threat and opportunity. An open innovation model is proposed and implemented in the ES industry chain by establishing a new platform, introducing new management paradigm and creating new efficacy indices. The model potentially allows continuous technology support to the chain and creates a sustainable business environment. Its feasibility is further discussed as to forming a healthy industry chain. The fast growing trend of global production volume of ES indicates the ever-increasing demand in the motor industry. The consumption rate of ES in Taiwan however did not appear the same order of growing rate as the rest of the world. This may imply the motor industry in Taiwan still faces tough challenge from China. Advancing and upgrading in design and analytical capability along with the competitive manufacturing bandwidth is the only solution to regain the competiveness. The proposed open innovation model is anticipated to promote the value of the ES industry chain, which in turn will increase China Steel¡¦s domestic market share for high quality ES.

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references (leaves 55-56). Also available on the Internet.

Thesis (doctoral)--Helsinki University of Technology, 2009. / Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references (leaves 55-56). Also available on the Internet.

Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains xiv, 132 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 108-112).

Thesis--M. Sc.(Eng.), University of Hong Kong. / Mimeographed.

Thesis (M.Eng.)--Memorial University of Newfoundland, 2001. / Bibliography: leaves 113-117.