794 resultados para Durant Motors, Inc.


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This paper is believed to be the first documented account of a full adoption of lean by a software company. Lean techniques were devised by Toyota and other manufacturers over the last 50 years. The techniques are termed lean because they require less resource to produce more product and exceptional quality. Lean ideas have also been successful in service industries and product development. Applying lean to software has been advocated for over 10 years. Timberline, Inc started their lean initiative in Spring 2001 and this paper records their journey, results and lessons learned up to Fall 2003. This case study demonstrates that lean thinking can work successfully for software developers. It also indicates that the extensive lean literature is a valuable source of new ideas for software engineering.

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Current high temperature superconducting (HTS) wires exhibit high current densities enabling their use in electrical rotating machinery. The possibility of designing high power density superconducting motors operating at reasonable temperatures allows for new applications in mobile systems in which size and weight represent key design parameters. Thus, all-electric aircrafts represent a promising application for HTS motors. The design of such a complex system as an aircraft consists of a multi-variable optimization that requires computer models and advanced design procedures. This paper presents a specific sizing model of superconducting propulsion motors to be used in aircraft design. The model also takes into account the cooling system. The requirements for this application are presented in terms of power and dynamics as well as a load profile corresponding to a typical mission. We discuss the design implications of using a superconducting motor on an aircraft as well as the integration of the electrical propulsion in the aircraft, and the scaling laws derived from physics-based modeling of HTS motors.

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This paper presents a novel detection method for broken rotor bar fault (BRB) in induction motors based on Estimation of Signal Parameters via Rotational Invariance Technique (ESPRIT) and Simulated Annealing Algorithm (SAA). The performance of ESPRIT is tested with simulated stator current signal of an induction motor with BRB. It shows that even with a short-time measurement data, the technique is capable of correctly identifying the frequencies of the BRB characteristic components but with a low accuracy on the amplitudes and initial phases of those components. SAA is then used to determine their amplitudes and initial phases and shows satisfactory results. Finally, experiments on a 3kW, 380V, 50Hz induction motor are conducted to demonstrate the effectiveness of the ESPRIT-SAA-based method in detecting BRB with short-time measurement data. It proves that the proposed method is a promising choice for BRB detection in induction motors operating with small slip and fluctuant load.

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Ce mémoire présente l’étude numérique d’un emballement de turbine hydraulique axiale à échelle modèle. Cet état transitoire est simulé du point de meilleur rendement jusqu’à l’atteinte de 95% de la vitesse d’emballement. Pour ce faire, une méthodologie numérique est développée à l’aide du logiciel commercial ANSYS CFX en utilisant une approche "Unsteady Reynolds Averaged Navier-Stokes" avec modèle de turbulence k-ε. Cette méthodologie numérique a été validée grâce à des mesures expérimentales de pression acquises en situation d’emballement sur les aubes d’une roue de turbine axiale étudiée au Laboratoire de Machines Hydrauliques de l’Université Laval. La validation des simulations numériques a été réalisée grâce à des comparaisons dans les domaines temporel et fréquentiel entre les pressions mesurées expérimentalement et calculées numériquement. Les analyses fréquentielles en transitoire ont été effectuées à l’aide de transformées en ondelettes afin de représenter l’évolution temporelle du spectre de fréquence. Des analyses qualitatives de phénomènes hydrauliques prenant place dans la turbine sont aussi présentées. Les analyses effectuées ont permis de confirmer le développement d’un tourbillon en précession par rapport à la roue dans l’aspirateur provocant les fluctuations de pression dominantes à des fréquences subsynchrones. La comparaison entre les données expérimentales et numériques a permis de valider une stratégie de simulation transitoire et d’en définir les limites en vue de prochaines simulations d’emballement. Des tests supplémentaires sont suggérés pour améliorer la précision ou le niveau de confiance de la méthode.

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Dissertation to obtain the degree of Master in Electrical and Computer Engineering