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629 Uppsatser om Voltage measuring - Sida 13 av 42
Mätning av träddelar och flis på Dåvamyran, Umeå energi :
The moisture content in 10 deliveries of tree parts and 10 deliveries of wood residues were measured with different methods to analyze the quality of procedure used at Dåvamyran today. At the same time a survey was made on the measure procedures used at heating plants in Sweden
The majority of the heating plants in Sweden use weight and moisture content as base for payment but at some plants only volume. The moisture content is usually estimated by drying wood chips in an oven but few plants a visual estimation is used. At few plants moisture content is estimated spectroscopicily. The techniques using near infra read light and other electromagnetic are still at a test stage.
The methods of measurement used today are quit unreliable for the individual deliveries and there is a risk for systematic mistakes.
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.
Elektronisk Handel : Framtagning av två implementeringsmodeller
This report is about helping Q-Med AB in Uppsala to start its implementation of uncertainty of measurements analyses in their manufacturing department. Prior to this, the company relied solely on personal experience or did not take this uncertainty into consideration at all during different kind of measurements, which means that some of the processes that the company previously believed were within specified acceptance limits, will actually fail when considering these sources of uncertainties.Q-Med AB needed some sort of instruction to help the company, in a systematic way, to investigate different types of disorders that are affecting all kinds of measurements. This instruction includes a short summary about measurements and uncertainty of measurements in general and a detailed procedure about how these uncertainties are going to be handled in their daily work.The goal was to be able to use this instruction to systematically locate, eliminate (when possible) and analyze all kinds of disorders when measuring. Q-Med is using a lot of different types of instruments when measuring different types of quantities, including temperature, mass, pressure and density. This instruction will hereafter be used for every instrument, regardless of quantity and type of instrument.The instruction is tested through 4 different kinds of measurements, for mass, temperature and humidity.
Impulsmätning medelst gradvis deflektion av alla sprayer från högtrycks common rail spridare
A method for measuring the total impulse from a multi hole diesel injector, introduced inprevious thesis work, ?Development of a method and a device for measuring the momentumrate of fuel sprays?, by Mikael Lindström, has been further developed and tested. The conceptis to simultaneously deflect all sprays from a multi hole diesel injector by using a bell shapeddeflector. The fuel sprays are deflected straight down from their initial umbrella angle, andthe resulting deflection force is measured in a thin strained section of the load cell. The strainis given by three strain gauges, with quarter-bridge circuitry for each gauge.
Rengöring på restauranger : Kontroll och utvärdering av olika rengöringsmetoder på restauranger i Södra Roslagen.
Control and comparison of various cleaning methods on restaurants in Södra RoslagenThe purpose of this report is to find out and analyze the efficiency of cleaning methods in restaurant kitchens. The investigation was carried out through unannounced inspections at 89 restaurants in Södra Roslagen (municipality of Danderyd, Täby and Vaxholm). ATP-measuring was done on a plate, a knife, a bench surface and a cutting board. The ATP-method measured the amount of food residue on equipment and working surfaces after cleaning, with a luminometer and swabs. Restaurant staffs were asked to describe in detail how and when the last cleaning was carried out on the surface.
Venezuela under Hugo Chávez - en mätning av demokrati
The present state of politics in contemporary Venezuela portrays a country of polarization, a chase for power and accusations of authoritarian and even undemocratic rule. The purpose of this bachelor thesis is to examine the democracy in Venezuela, in order to clarify the sometimes vauge perception of the political situation. By applying the theories of polyarchical democracy put forth by Robert Dahl, one of the most highly regarded theorists on the subject, accordingly the discussion will therefore follow a theoretical framework. Dahl requires seven nstitutions to be guaranteed in a democracy, amongst them the possibility to vote, run for public office and the practise of freedom of speech. Measuring Dahl's levels of institutions in Venezuela, it is made clear that the level of democracy vary in different areas.
Metoder för att fastställa begränsningsnivå vid hörapparatutprovning
Audionomprogrammet.
Att mäta generell skam : En analys baserad på Raschmodellen
The purpose of this paper was to investigate whether Suzanne Retzinger?s linguistic cues for shame and verbal behaviors for hiding shame could be used to measure shame in surveys based on Thomas Scheff?s theory of shame. I created a measurement instrument consisting of 30 statements, which were all meant to measure general shame.The instrument was administrated to 180 respondents studying at Karlstad University, of whom 4 respondents were removed from the data set due to lack of standardization. With the polytomous rasch model used for the analysis, data from 176 respondents were analyzed, of whom 124 respondents were female and 52 were male.The result showed that the measurement instrument?s statements should not be used together because the analysis indicated multidimensionality.
Utveckling av Mätmetoder för Färdmotstånd
The student project Elba at KTH started in 2011 and is a project where a battery driven prototype car is developed. The vehicle competes in Eco Shell Marathon in Rotterdam, Holland. In this competition the vehicle that travels a certain distance including several starts and stops with the lowest energy consumption wins. To minimize the consumption is therefore very important, which requires knowledge of the vehicles energy losses.A vehicle's energy losses depends on several factors and can be divided into the powertrain efficiency and the driving resistance. The driving resistance can then be divided in to rolling and air resistance, if smaller losses like vibrations are ignored.
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.
Avfyrnings-/relälåda
This is a report of our examination project in electronics carried out for Bofors Test Center in Karlskoga. The task was to construct an electronic devise for starting up different kinds of measuring systems in exact time during test sequences. The modules that are used today are old and unreliable. Our goal was to construct a prototype, which later on is supposed to be developed into a useful system..
Analys av PWM-mönster i Matlab
One of ABB Power Systems´s business areas is HVDC (High Voltage Direct Current) technology. HVDC is used for transmissions for both short and long distances. One of Power Systems?s products is called HVDC Light. HVDC Light is a relatively new technology for power transmission, but have before only been used for motor drives applications.
VSM och 16 förluster
With background in the rapidly growing need to find solutions for sustainable energy production and the increasing interest for wind power, this report was written. With take-off point from the wind power plant Big Glenn, which has been built in the harbour of Gothenburg, a model of the adjacent power grid has been created in Simulink/SimPowerSystems. Parameters for the power grid and its components has been provided by Göteborg Energi Nät, that has also been the supplier of measurement data of produced power, the power need from loads in the vicinity, voltage levels, current values and also the variation of power factor at the wind power plant.The SimPowerSystems model has been used to perform simulations of power flow in the grid. These simulated values have then been compared to the measured values to verify the functionality of the model. Further, the model has been used to perform simulations of a grid fault, which causes a voltage drop.
Ett flervariabelt feldetekteringssystem för övervakning av bärlagertemperaturen i vattenkraftturbiner
The purpose of this thesis work was to develop an automatic fault detection system for surveillance of bearing temperature in hydropower turbines. The parameters used except the bearing temperature were cooling water temperature and cooling water flow. A simple static model based on data sampled every minute was developed to estimate the bearing temperature. Then a detector for detection of change in bearing temperature based on the CUSUM-algorithm was designed. Since the amount of data was very small the developed model was too uncertain to be used in a working system.The designed fault detection system showed to work well for the available data.
Dimensionering av hjälptransformator
The aims of the following project has beento make a proposition how to create aspecific kind of transformer. Thefollowing report evaluates the differentimportant variables and contains asuggestion for a possible design. Intheory it's an ordinary transformer that'ssuppose to transform electrical effect toa high voltage line. The design of thetransformer is using an already existingcurrent transformer design and is adjustedto work for it's specific purpose. Theproject also contains the developing of atransformer simulation model that will beused to evaluate and optimize thedimensions of the resulting transformer..