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370 Uppsatser om Voltage drop - Sida 12 av 25

Drop Dead Gorgeous: en analytisk studie av bilder i svenska modebloggar

En studie av vilka kroppsideal som råder i svenska modebloggar..

Dämplindningens inverkan på spänningens kurvform i en vattenkraftsgenerator

Harmonics are a well-known problem that has to be dealt with in the design of thegenerator. Internationally accepted standards limits the amount of harmonics allowedin the no-load voltage. These limits can be difficult to fulfill with integral slot winding,where the number of slots per pole and phase is an integer. The presence of thedamper winding often makes the problem with harmonics even worse and harmonicswith frequencies of order 6q±1 arise with significant amplitude. How the damperwinding is designed affect the content of harmonics in the no-load voltage and the aimwith these ? has been to investigate in which extent design of the damper windingaffects the contents of harmonics.Simulations with the 2-D finite element method have showed that if the damper barsis centered in the pole shoe, the amplitude of the harmonics of order 6q±1dependsboth on the ratio between the stator slot pitch and damper bars slot pitch and if thedamper bars are connected between the poles or not.If the damper bars is displaced with ¼ stator slot pitch alternately, the amplitude ofthe harmonics of order 6q±1 is reduced and the influence of the ratio between thestator slot pitch and the damper bars slot pitch will vanish.

Teknik och teknisk kompetens enligt förskolans pedagoger : En studie av pedagogernas syn på teknik

System Andersson AB is a company located in Jönköping that works with developing computer systems for the mechanical engineering industry. As of today, when this report is written, the company is working on the development of a new Manufacturing Planning and Control (MPC) system. This new system aims to create not only a user friendly interface but also a modern, stylish interface. To achieve this, the company has decided to work with a, for them, new application framework; Windows Presentation Foundation (WPF).System Andersson is well known for developing systems for different kinds of touch screens, this project is no exception. For this new user interface the company wishes to implement different types of Drag&Drop functionality.

Navigationstyper på webben

Internet och dess webbplatser är källa till mycket information. Ofta vet vi vilken information vi söker, problemet är bara att hitta den. Ett nyckelelement på webbplatser för att hitta den information som man söker är navigationen. Navigationen kan vara utformad på många olika sätt, vilka har olika för- och nackdelar. Denna studie ska undersöka vilken navigationstyp som är den mest effektiva för tredimensionella navigationsstrukturer. Först väljs de fem navigationstyperna som ska jämföras, detta genom att undersöka vilka de bästa webbplatserna i Sverige använder.

Analys av mätdata från nätstationer

Fortum has in a pilot project installed metering equipment with wireless communication in secondary substations in Stockholm. So far, the collected data are used only in specific projects.This master thesis was carried out at Fortum Distribution AB in Stockholm during 2013. The purpose of this study is to simplify and enhance the use of data in for example network planning process, by giving suggestions on how data can be managed and giving examples of analyzes that collected data can be used for.The electricity meter which Fortum has installed is a EDMI-Mk10A which is set to measure max/average/min values with a one hour time resolution of the following parameters: voltage (per phase), current (per phase) andactive power and active and reactive energy.In order to analyze the collected data an analysis tool is required. During this thesis two customized tools in Microsoft Excel have been developed, one for sorting data and one for analyzing.One aim of the thesis is to show examples of what collected measurement data can be used for. This work shows an example of analysis of active power, power factor, voltage, occurrence of interrupts and the relationship between outdoor temperature and power.This master thesis has among others resulted in the following advice: Expand the number of secondary substations with measuring equipment.

Konstruktion av elstyrt lås (drop-off) för telemetrihalsband

Sedan 60-talet har man inom viltforskningen märkt djur med radiosändarföredda halsband för att få kunskap om deras geografiska rörelser. I dag använder halsbanden GPS-teknik för att bestämma positionen. Dessa koordinater och annan insamlad information om t.ex. temperatur och djurets puls sparas i halsbandet men skickas även med UHF-, GSM- kommunikation eller via satellit till en mottagarstation. Halsbandets elektronik har med ny teknik kunnat göras mindre och lättare och därför kan även mindre djur studeras.

Analys av spänningsstabilitetsberäkningar i det svenska elsystemet

Numerical simulations play a vital role in both static and dynamic stability assessment of electric power systems and the foreseeing of voltage collapse. Simulations performed by Svenska Kraftnät(SvK) are mainly done in the specialized voltage collapse predicting software tool, SPICA and the more all?purpose software tool, ARISTO.The grid operators at SvK use SPICA to predict the maximum transfer limit at specified sections (in this report the section in concerns is the southern part of Sweden i.e. interface1 4). SPICA is mainly used as an online application by using actual states from the grid, these states update every quarter of an hour.This thesis is a continuation of the master thesis SPICA ? ARISTO JÄMFÖRELSE by Jakob Katzman and Johan Fält.

Utvärdering av laddningskoncept för lastbilsbatterier

When drivers overnight in the truck lots of electric energy is consumed by heaters, fans, lights and other extra equipment. If the engine is not running, this energy is taken from the lead/acid batteries of the truck which then needs to be recharged during operating hours. The fact that the charge acceptance of the lead/acid batteries is dependent on the temperature makes it hard to fully recharge the batteries at lower temperatures. A negative charge balance can lead to starting problems within a few days use in cold climate.In this thesis work, the effects of different battery charging concept are evaluated on the most common Scania battery (175Ah). A battery model is implemented in Matlab and some simulations of charging are made.

Kommunal krishanteringsförmåga : Uppsala kommuns beredskap inför en eventuell naturkatastrof

De senaste åren har det skett en nedprioritering av risk- och krisföreberedande arbete på kommunal nivå, främst gällande naturkatastrofer. En av anledningarna till detta är att de kommunala medlen prioriteras mot andra saker som exempelvis skola, vård och omsorg.Syftet med uppsatsen är att undersöka lärdomar och förmåga rörande hanteringen av naturkatastrofer på olika myndighetsnivåer i Sverige. Lärdomar studeras utifrån ett verkligt exempel: skogsbranden i Västmanland sommaren 2014. Huvudfokus för uppsatsen är att studera Uppsala kommuns förmåga att hantera en eventuell framtida naturkatastrof.För att undersöka syftet används två teoretiska modeller: Framgångsfaktorer för krishantering samt DROP-modellen. Framgångsfaktorerna används sedan för att se om lärdomar har inhämtats ur skogsbrandskatastrofen.

Colour a Symbol : Autentisering för smartphones

Under de senaste åren har den mobila tekniken i stort sett helt gått över till smartphones. Smartphones är i princip mer datorer än telefoner, som vi alltid bär med oss och som innehåller allt mer känslig information. Detta medför att kraven på säkerheten kring enheten ökar. Detta arbete undersöker om det är möjligt att finna en ny metod att låta användaren autentisera sig på, som är säkrare än de som är vedertagna idag, men samtidigt har liknande nivå av användbarhet. Vår idé, som vi arbetar med under namnet Colour a Symbol, baseras på att kombinera symboler och färger i par.

Åsktransienter och överspänningar : En spänningsfylld simulering av elkraftsystemet vid Forsmark 3

A power system will inevitably be subjected to transient overvoltages, most often produced by switching operations and lightning strikes. These transient overvoltages may harm sensitive equipment without sufficient protection, but it is not an easy task to predict what transients may occur or how they affect the system. A fault occurred in a low voltage system at Forsmark 2012 and overvoltages from lightning were concluded as the probable cause. The three aims with this thesis are to develop and test a model of the power system at Forsmark 3, analyse the transient behaviour of the system when subjected to lightning surges and identify critical parameters, and lastly to provide a tool for investigating the protection of the system. The modelling and simulations were performed in the freely available simulation program LT Spice.

Analys av fördelningssystem för bostadshus

The purpose of this project is to analyze earthing systems for houses. By practical measurements and theoretical analyzes consequences of possible faults, that can occur within the facility and in the low-voltage distribution network, is illustrated.  The reason for this project is that nowadays one has to arrange with a main equipotential bonding system for buildings. Apart from that, if necessary, bathrooms must be provided with a supplementary equipotential bonding system.The practical measurements verify that potential differences in facilities may be due to Voltage drops in the PEN conductor between the origin of the electrical installation and the power transformer.Based on the theoretical analyzes of possible faults, it is considered that the requirement for  supplementary equipotential bonding systems for bathrooms in most cases can be questioned, when basic insulation, fault protection, residual current devise and main equipotential bonding system already provides an adequate level of protection.A PEN conductor loss may result in a situation where metallic parts attached to the equipotential bonding system starts working as earth electrodes. Equipotential bonding system may also increase the incidence of stray currents. If TN-C-S systems is provided with a local connection to earth a redundant system against PEN conductor loss is obtained.

Föreningsidrotten-en hälsosam plats för vuxna människor? : Intervjustudie om drop in-aktiviteter för vuxna inom föreningsidrotten

This paper has it?s background in Physical Activity on Prescription, a projectwhich the Swedish sports movement is part of. The study refers to a limiteddivision of sports for adults, namely a phenomenon here by referred to as dropin-activity. This form of physical activity is characterized by an understandingthat the participant often lack experience and that it is possible to pay for eachoccasion. The purpose of the study was thus to take a closer look on organized,non-profit sports clubs which offer this type of exercise for adults.

Styrketräning för truppgymnaster : mer än bara kroppsvikt som belastning?

Syfte och frågeställning: Syftet med denna studie är att undersöka de eventuella fördelar styrketräning med yttre belastning kan ge kvinnliga truppgymnaster på juniornivå. Frågeställningar: Vilken effekt på explosivitet i nedre extremitet har sex veckors powerträning med yttre belastning på truppgymnaster? Skiljer resultaten sig från de som uppnås vid traditionell gymnastisk styrketräning?Metod: Två lag som representerar Sverige-eliten på damsidan i juniorklassen delades in i test- (n=7) och kontrollgrupp (n=8). Testgruppen genomförde under sex veckor ett specialdesignat träningsprogram riktat mot power medan kontrollgruppen genomförde traditionell gymnastisk styrketräning. För- och eftertester genomfördes för att utvärdera effekterna av programmen.

Trafikverkets effektstyrningssystem - EFS 132 kV : Bidraget till minskade förluster

The technological legacy from the early electrification of the Swedish railroads has resulted in a power grid with a lower grid frequency than the national power grid from which it is fed. Energy transfer between these power grids with different frequencies requires substations, adapting the grid frequency for the rail road power grid. For this purpose, a feeding power grid has been built, stretching across the country from Boden in the north to Tälle/Häggvik in the south.Power transfer in the Swedish power grid results in voltage angle differences which increase with increasing loads and transfer distance. These voltage angle differences are transferred from the power feeding substations to the rail road power grid, will in some extent cause loss of energy due to unwanted power flows from north to south.To minimize the losses due to this phenomenon, a power management system called EFS 132 kV has been developed and implemented. The system minimizes the unwanted power flows and controls the desired power flow for a good distribution of loads between the power feeding substations.This thesis investigates the extent of the transmission losses avoided due to the EFS 132 kV that coordinates the idling angles to a common reference point.The results indicate that EFS 132 kV affects the power flow, especially between the northern substations through an improved load distribution.

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