Sökning: "No-load"
Visar resultat 1 - 5 av 24 avhandlingar innehållade ordet No-load.
1. Numerical investigation of the flow and instabilities at part-load and speed-no-load in an axial turbine
Sammanfattning : Global renewable energy requirements rapidly increase with the transition to a fossil-free society. As a result, intermittent energy resources, such as wind- and solar power, have become increasingly popular. However, their energy production varies over time, both in the short- and long term. LÄS MER
2. Magnetizing Currents in Power Transformers : Measurements, Simulations, and Diagnostic Methods
Sammanfattning : This thesis demonstrates a method for transformer core diagnostics. The method uses the no-load current of the transformer as an indicator, and gives different characteristic signatures for different types of faults or defects. Using the no-load current for the diagnostic gives high sensitivity. LÄS MER
3. On methods of measuring magnetic properties of power transformers
Sammanfattning : The core of a power transformer can weigh hundreds of tons, and represents a significant part of the total ownership cost of the transformer, in terms of both the construction cost and of the monetary cost of losses. It is therefore desirable to have a method of diagnosing the core to ensure optimal performance, and to enable the operator to plan repairs of damaged or defective cores. LÄS MER
4. Three-dimensional Finite Element Computation of Eddy Currents in Synchronous Machines
Sammanfattning : The thesis deals with the computation of eddy-current losses in the end regions of synchronous machines. Various magnetic and electric vector potential formulations of three-dimensional eddy-current problems are investigated. The equations are discretized by the finite element method with nodal or edge finite elements. LÄS MER
5. Design of Rare Earth Free Permanent Magnet Generators
Sammanfattning : Low speed permanent magnet (PM) synchronous generators (SGs) are commonly used in renewable energy. Rare earth (RE) PMs such as neodymium-iron-boron are a popular choice due to their high performance. LÄS MER