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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Problematika rychlé automatické výměny nástrojů u obráběcích strojů / Problematic of Fast Automatic Tool Change by Working Machinery

Pavlík, Jan January 2011 (has links)
This dissertation thesis is focused on the problem of the Automatic Tool Change for milling centers, which is recently shown as a very current topic. The content of this work is to conduct a comprehensive research of various types of ATC depending on the type of machine, as well as research of the current tool interface relating closely with these problems. There was made a comprehensive analysis on the basis of data obtained by comprehensive research, from which both the main factors affecting this topic and the area dealed and developed by this work resulted. The most problematic area of machinery used nowdays for the Atomatic Tool Change was detected as manipulator provided the exchange between spindle and tool storage. Kinematic structure and design of individual elements affects very significantly the dynamics of the whole process of exchange of tools. Therefore, the work is focused on problematic of the manipulator. The main results of this thesis are constructional design of several types of manipulators, which were partly realized within the project 1.2.4 of Brno department of RCMT in the form of the testing stands. There was developed simulation models for selected types of manipulators which were verificated by measuring on the real stand. On the basis of abovementioned problem there was identified another key issue related not only to the exchange process but also with complex problem of service life of spindle. It is a grab force in the process of picking tools. The work outlines the possibilities for further research of these forces on the service file of spindle (especially on service life of bering groups of spindle).
12

Distribution On Load Tap Changer Control Using IEC61850 Client/Server Architecture

Maneikis, Andrius January 2016 (has links)
Distributed generation is transforming the power system grid to decentralized system where separate units like wind power generators or solar panel shall coexist and operate in tandem in order to supplement each other and make one extensive system as a whole so called smart grid. It is utmost important to have a control ability over such units not only on a field level but on a system level as well. To be able to communicate with numerous devices and maintain interoperability universal standard is a must. Therefore, one of the core standards relevant to smart grids is IEC 61850 – Power Utility Automation which comes into assistance and tackles aforementioned challenges. This project uses IEC61850 architecture to implement client/server windows applications for on-load tap changer remote control. The proposed solution and designed applications are tested together with a real time simulator where simple power system is modelled to emulate the system response to control signals in a real time. In this way, the implemented applications can be tried and assessed as if performing in real environment. Consequently, a user of the client application is able to remotely control voltage on the power transformer's secondary side and manipulate the switching equipment simulated in the model. / Distribuerad generation håller på att förändra transmissionsnätet till decentraliserat system där separata enheter som vindkraftverk eller solpanel skall samexistera och fungera tillsammans för att komplettera varandra och att göra ett omfattande system som helhet så kallade smarta elnät. Det är ytterst viktigt att ha en kontroll förmåga över sådana enheter inte bara på ett fältnivå utan även på systemnivå. För att kunna kommunicera med många enheter och bibehålla interoperabiliten som universell standard är ett måste. En av de grundläggande normer som är relevanta för smarta nät är IEC 61850 - Skydd & Automation, som kommer in i bistånd och möter ovan nämnda utmaningar. Detta projekt använder IEC61850-struktur för att implementera klient/server windows applikation för lindningskopplarens fjärrkontroll. Den föreslagna lösningen och utformade applikationer testas tillsammans med en realtidssimulator där enkelt kraftsystem modelleras för att emulera systemets svar på de givna styrsignalerna i realtid. På detta sätt kan de implementerade programmen prövas och bedömas hur de utföras i verklig miljö. Följaktligen kan användare av klientapplikationen fjärrstyra spänningen på transformatorns sekundärsida och manipulera ställverk som simuleras i modellen.
13

Contribution méthodologique au changement organisationnel : facilitation par l'appropriation et l'accompagnement de l'Homme dans les projets. Application dans un grand groupe aéronautique.

Perotti, Clément 12 December 2011 (has links) (PDF)
Cette thèse Cifre, réalisée dans le domaine du génie industriel, traite de la prise en compte de l'Homme dans les projets de changement organisationnel d'un grand groupe aéronautique (Turbomeca, groupe Safran). La piste explorée dans ce travail est celle de l'élaboration d'une méthode d'accompagnement du changement individuel. Cette méthode est à destination des managers chargés de la gestion des projets, afin d'accompagner les personnels qu'ils impactent. Notre terrain de recherche se situe au niveau de : * l'appropriation des changements organisationnels par les employés, * la capacité organisationnelle à changer de l'entreprise. Nous recherchons ainsi : * une évolution des pratiques relatives à la prise en compte des individus tout au long des projets, * une amélioration de la gestion globale de l'accompagnement du changement réalisé dans le cadre des différents projets de l'entreprise. Notre méthode, structurée par rapport au séquencement des projets et par rapport à la logique d'appropriation d'une nouveauté, est basée sur une augmentation des coopérations entre managers en charge des changements et populations impactées par ces changements. A partir d'un ensemble d'outils d'analyse et de planification, nous proposons d'élaborer puis de mettre en œuvre une stratégie de communication, de formation et d'accompagnement de terrain. La conception de cette méthode s'est inscrite dans l'activité d'une nouvelle équipe, dédiée à la gestion globale de l'accompagnement du changement dans les projets de l'entreprise. Nos travaux traitent également des stratégies utilisées par cette équipe pour la diffusion de la méthode dans l'entreprise, et par la structuration de ses activités vis-à-vis des autres services concernés par les projets. Nos résultats démontrent une diminution de la durée d'appropriation d'une nouveauté, et que les chefs de projets comme les personnels impactés ont perçu l'utilisation de notre méthode comme une amélioration de l'accompagnement réalisé dans le cadre des projets. Nous présentons également un ensemble d'éléments relatifs à l'amélioration de la capacité à changer de l'entreprise dans laquelle nous sommes intervenus.
14

Μελέτη σφαλμάτων σε μετασχηματιστές υψηλής τάσης με αυτόματο μεταγωγέα τάσης (TAP changer)

Παππά, Αγγελική 19 January 2011 (has links)
Στην παρούσα διπλωματική εργασία γίνεται αναλυτική περιγραφή της λειτουργίας της διάταξης του Μεταγωγέα Τάσης Υπό Φορτίο ενός μετασχηματιστή υψηλής τάσης 150 kV/ 21 kV. Επίσης, περιγράφονται και αναλύονται σφάλματα που εμφανίζονται σε μετασχηματιστές με Μεταγωγέα Τάσης Υπό Φορτίο με χρήση εμπειρικών δεδομένων από την εταιρεία Δ.Ε.Η. Α.Ε. και τη θεωρητική ανάλυση και εξήγησή τους μέσα από βιβλιογραφική μελέτη . Συγκεκριμένα, περιγράφονται τα αίτια που δημιουργούν αυτά τα σφάλματα, τα συμπτώματα που εμφανίζονται στο μετασχηματιστή και το μεταγωγέα τάσης , οι επιπτώσεις των σφαλμάτων αυτών στο μετασχηματιστή και τη διάταξη του μεταγωγέα τάσης . Επιπλέον, γίνεται αναφορά στα συστήματα προστασίας που διαθέτει ο μετασχηματιστής και ο μεταγωγέας τάσης προκειμένου να προστατευθεί από τις επιπτώσεις αυτών των σφαλμάτων. Στη συνέχεια, μελετάται συγκεκριμένο σφάλμα, που παρουσιάστηκε στο Μ/Σ 150 kV/21 kV Νο1 του Υ/Σ 150 kV/21 kV των Ελληνικών Ναυπηγείων Σκαραμαγκά, και καταγράφεται η αντιμετώπισή του βήμα προς βήμα σε συνεργασία με την εταιρεία ΠΑΡΑΛΟΣ ΤΕΧΝΙΚΗ Α.Ε., στην οποία ανατέθηκε η επίλυση του σφάλματος. Τέλος, μέσα από την προσομοίωση ενός Μ/Σ υψηλής τάσης με μεταγωγέα τάσης υπό φορτίο με χρήση του λογισμικού πακέτου MatLab/SimuLink κατανοούμε σε βάθος τη λειτουργία του μεταγωγέα τάσης υπό φορτίο. Η προσομοίωση περιλαμβάνει την εφαρμογή διαταραχών της τάσης του δικτύου στο Μ/Σ στην περίπτωση ορθής και εσφαλμένης λειτουργίας του οργάνου του ρυθμιστή τάσης, καθώς η εσφαλμένη λειτουργία του ρυθμιστή τάσης ήταν και η αιτία του σφάλματος στο Μ/Σ του Υ/Σ 150 kV/21 kV των Ελληνικών Ναυπηγείων Σκαραμαγκά. / The particular project deals with the detailed description of the layout and the operation of the on load tap changer belonging to a transformer of high tension 150kV/21 kV. Furthermore, it describes and analyzes faults that occurs to transformers with on load tap changer using empirical data from DEI S.A. (Public Power Corporation) as well as theoretical analysis and explanation based on bibliography. In particular, there are described the reasons behind these faults , the symptoms that appear to the transformer and the tap changer and the consequences to the transformer and the layout of the tap changer. Moreover, there is reference to the protection systems that the transformer and the tap changer have in order to be protected from the consequences of the faults. Further on, a particular troubleshooting is studied that occurred at the transformer 150 kV/21 kV no1 of the high voltage substation 150 kV/21 kV at the Hellenic Shipyards of Skaramagas and its handling is reported step by step in association with PARALOS TECHNICAL S.A. , the company which was assigned to solve the troubleshooting. Finally, the operation of the on load tap changer is studied in depth through simulation of a high voltage transformer with on load tap changer using MatLab/SimuLink software package. The simulation includes the application of voltage variations at the transformer, occurred to the high voltage network in the case of orderly or disorderly operation of the voltage regulator, as the faulty operation of the voltage regulator was the reason behind the troubleshooting of the transformer of the substation of 150 kV/ 21 kV at the Hellenic Shipyards of Skaramagas.
15

Probabilistische Modellierung dezentraler Energieanlagen und Sekundärtechnik für die Verteilnetzplanung

Dallmer-Zerbe, Kilian 29 January 2018 (has links) (PDF)
Der Ausbau dezentraler Energieanlagen wie fotovoltaischen Anlagen beeinflusst die Netzzustände signifikant. Dabei ist unsicher, wo und in welchem Maße deren Ausbau zukünftig erfolgt. Es ist nun an den Netzbetreibern gleichzeitig die aktuellen Herausforderungen zu meistern und die Netzplanung und -regelung für die Zukunft zu aktualisieren. Eine statistische Methode wird entwickelt, die Verteilnetzplanung unter Einsatz von quasi-stationär modellierten ”Smart Grid”-Lösungen wie Blindleistungsreglern und regelbaren Ortsnetztransformatoren ermöglicht. Durch Stichprobenverfahren werden Unsicherheiten wie Ort, Größe und Leistungsprofile der Energieanlagen in das Netzmodell eingebunden. Diese als probabilistischer Lastfluss bekannte Methode wird durch Gütemaße im Bereich geringer Kombination evaluiert. Beispiele probabilistischer Netzplanung werden an Netztopologien präsentiert. / Development of distributed energy units such as photovoltaic systems affects grid states significantly. It is uncertain, where and to what extent the development of these units is carried out in the future. It is now up to the distribution system operator to cope with todays grid challenges and to update grid planning and control for the future. A statistical method is developed, which incorporates quasi-stationary modeled ”smart grid” solutions such as reactive power controllers and on-load tap-changers. Uncertainties such as location, size and power profiles of energy systems are integrated into the grid model by sampling. This method is known as probabilistic load flow and is evaluated by quality measures at low combinations. Examples on probabilistic grid planning of different grid topologies are presented.
16

Comutador eletrônico de taps aplicado a um transformador de distribuição monofásico / Electronic on load tap changer applied to a singlephase distribution transformer

Quevedo, Josemar de Oliveira 27 February 2014 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Voltage regulation still is a problem faced by power utilities currently. In addition to the series impedance and the significant load variation of the distribution grids, the main causes of voltage regulation problems, the requirements for the enhancement of power quality by the electricity regulatory agencies, increasing energy consumption, the inclusion of distributed generation and the development of the smart grids tends to increase the complexity of the distribution systems. One of the most used methods for voltage regulation in alternating current systems is the employment of tap changer on transformers, this method allows voltage regulation by varying the transformation ratio, modifying the value of the secondary voltage. The application of these devices is primarily performed by manual commutation mechanical devices in distribution systems, and by automatic electromechanical on load tap changers in substations. In the case of manual devices, operating costs and the impossibility of automatic voltage regulation are limiting factors, while in the case of electromechanical devices the limitations are mainly related to the costs of employment and maintenance. Currently, the increase of voltage and current operating levels of semiconductor devices has allowed envision the application of semiconductor switches instead of the mechanical switches employed nowadays. However, due to the operating characteristics of these devices, a detailed analysis of the commutation process is necessary, in order to allow the proper design of the devices involved in the commutation and protection process of the electronic tap changer. In this context, this work presents the analysis, design and implementation of an electronic on load tap changer applied to a single-phase distribution transformer, proposed as an alternative to the existing mechanical and electromechanical tap changers. Such a system enables the automatic voltage regulation, avoiding the insulation oil degradation, resulting from the commutation process, and also the elimination of movable parts, the main cause of defects in current automatic commutation devices. In addition to allowing steady state voltage regulation, the system allows the regulation for momentary voltage sags, since they occur in the transformer operating range. The analysis of the commutation process is presented, allowing the design of the electronic switches, as well as the protection system to be employed. Experimental results show the correct voltage regulation for different kinds of load, demonstrating the potential application of electronic on load tap changers in the current distribution systems and in future smart grids. / A regulação dos níveis de tensão é um problema ainda enfrentado pelas companhias concessionárias de energia elétrica atualmente. Além da impedância série e da significativa variação de carga das linhas de distribuição, principais causas dos problemas de regulação, a maior exigência dos agentes reguladores do sistema elétrico para a melhoria da qualidade de energia, o aumento do consumo de energia, a inclusão de geração distribuída e o desenvolvimento das redes inteligentes (smart grids), tendem a aumentar a complexidade dos sistemas de distribuição. Um dos métodos mais empregados na regulação de tensão em sistemas de corrente alternada é a aplicação de comutadores de taps em transformadores. Este método permite a regulação da tensão através da variação da relação de transformação, modificando o valor da tensão secundária. A aplicação desta solução é feita, majoritariamente, através de dispositivos mecânicos de comutação manual nos sistemas de distribuição e de dispositivos automáticos eletromecânicos de comutação sob carga em subestações. No caso dos dispositivos manuais, os custos operacionais e a impossibilidade da regulação automática de tensão são fatores limitantes, enquanto que no caso dos dispositivos eletromecânicos, os limitantes estão relacionados principalmente aos custos de implantação e de manutenção. Atualmente, o aumento dos níveis de tensão e corrente de operação dos dispositivos semicondutores tem permitido vislumbrar a aplicação de chaves semicondutoras em substituição às chaves mecânicas empregadas. Entretanto, devido às características de funcionamento destes dispositivos, uma análise detalhada do processo de comutação do sistema é necessária, de modo a permitir um adequado projeto dos dispositivos envolvidos no processo de comutação e proteção dos comutadores eletrônicos de taps. Neste contexto, o presente trabalho apresenta a análise, projeto e implementação de um comutador eletrônico de taps aplicado a um transformador de distribuição monofásico, proposto como alternativa aos comutadores mecânicos ou eletromecânicos existentes. Tal sistema permite a regulação automática da tensão, eliminando o desgaste do óleo isolante, resultante do processo de comutação sob carga e também a eliminação de partes móveis, principal causa de defeitos nos comutadores automáticos atuais. Além de permitir a regulação da tensão em regime permanente, o sistema possibilita a regulação para afundamentos de tensão momentâneos, desde que estejam na faixa de operação do transformador. A análise do processo de comutação do dispositivo estudado é apresentada, permitindo o projeto das chaves eletrônicas, bem como do sistema de proteção a ser empregado. Resultados experimentais demonstram a correta regulação de tensão do sistema desenvolvido, dentro dos limites de operação do transformador, para diferentes tipos de carga, evidenciando a potencialidade dos comutadores eletrônicos de taps em aplicações nas atuais redes de distribuição e nas futuras redes inteligentes.
17

Technologie znovuvyužití odpadních vod / Technology of wastewater reuse

Velikovská, Kristýna January 2019 (has links)
This diploma thesis presents the knowledge of wastewater reuse. The theoretical part of the thesis describes types of wastewater (greywater, brownwater, and yellow-water) and their characteristics. Further, the theoretical part describes the possibilities of re-use of wastewater as a source of water in detail, including treatment technology, and the heat recuperation from wastewater. The practical part of the thesis uses gained knowledge for designing a greywater treatment and heat recovery technology of grey water in an apartment complex.
18

Paletizace frézovací multifunkčního obráběcího centra s vodorovnou osou vřetena / PřekladačVypnout okamžitý překladPalletizing of the tilting head of a milling multi-purpose machining center with a horizontal spindle axis

Hynšt, Tomáš January 2019 (has links)
This diploma thesis deals with palletization of heavy workpieces that are used by multi-purpose machining centers. The final outcome introduces a suitable option for palletization heavy workpieces of multi-purpose machining centers. In the first part of the thesis is draft of machining centers with parameters which were chosen by exploration of market for selecting suitable solution. The second part of thesis is dealing with a detailed draft palletization made by parts of exploration of market then design palletization system and design pallet changer. The designed construction of pallet changer is dimensioned with help of analytical calculating methods and numerical simulations methods. Outcome palletization system allows automatic change of twenty tons workpieces including pallet between two storage places.
19

Automatická výměna nástrojů - napichovací rameno / Automatic tool changer

Rydlo, Andrej January 2020 (has links)
Adressed topic of the thesis is automatic tool change in industrial machining. Core work is done on construction design of automatic tool changer. Designed manipulator grabs the tool by linear movement and is meant to be used with unspecified horizontal machining centre. Individual working cells include design of grippers, extending motion of the arm, rotary motion of the arm and linear motion of the whole manipulator. Essential part of the thesis are technical calculations and simulations.
20

Regulátor pohonu opony / Curtain Drive Control

Večerník, Jan January 2008 (has links)
Master's thesis describes and proposes solutions for a given problem of a drive in theater curtain DS Krakonoš - Vysoké nad Jizerou using modern microcontroller with voltage transducer.. There is given a detailed analysis of the problem, including the mathematical description of the entire system, then design and its subsequent implementation. The goal of this work is designed to apply a device designed to the engine, which moves theater curtain.

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