Sökning: "rotating magnetic field"

Visar resultat 16 - 20 av 31 avhandlingar innehållade orden rotating magnetic field.

1. 16. Core Loss Prediction in Hydroelectric Generators and Analysis of a Contra-Rotating Machine Topology

   Författare :Martin Ranlöf; Uppsala universitet; []
   Nyckelord :TECHNOLOGY; TEKNIKVETENSKAP;

   Sammanfattning : The call for increased accuracy in the process of design and analysis of electrical machines has encouraged the use of numerical methods to calculate the electric and magnetic field distributions within this type of apparatus. The finite element method is a numerical technique that has become specifically widespread and popular, due to the relative swiftness and accuracy with which it is possible to treat complex machine geometries and non-linear material characteristics. LÄS MER

3. 17. Interaction between Electromagnetic Waves and Localized Plasma Oscillations

   Författare :Jan-Ove Hall; Thomas Leyser; Jan Trulsen; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; space physics; plasma physics; radio waves; ionospheric modification; density depleations; field-aligned irregularities; lower hybrid solitary structures; lower hybrid cavities; Z mode waves; magnetosonic waves; scattering; mode conversion; Rymd- och plasmafysik; Space physics; Rymdfysik;

   Sammanfattning : This thesis treats interaction between electromagnetic waves and localized plasma oscillations. Two specific physical systems are considered, namely artificially excited magnetic field-aligned irregularities (striations) and naturally excited lower hybrid solitary structures (LHSS). LÄS MER

4. 18. Electromagnetic Analysis of Hydroelectric Generators

   Författare :Martin Ranlöf; Urban Lundin; Georg Traxler-Samek; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Contra-rotating rotors; damping torque; damper winding; finite element method; hydroelectric generators; permeance model; pole shoe shape; rotational losses; single machine infinite bus; slot ripple; synchronizing torque; synchronous machines; voltage waveform.; Engineering physics; Teknisk fysik; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

   Sammanfattning : Hydropower maintains its position as the most important source of renewable electric energy in the world. The efficiency of large hydropower plants is unsurpassed, and after more than hundred years of development, the technology is mature and highly reliable. LÄS MER

5. 19. Electromagnetic Fields in Moving and Inhomogeneous Media

   Författare :Paul Piwnicki; KTH; []
   Nyckelord :Moving Media; Light; Genaral Relativity;

   Sammanfattning : The present thesis deals with electromagnetic effectscreated by the motion or inhomogeneity of a dielectricmedium.In the first paper the quantum R\"ontgen effect isdiscussed. Here a rotating Bose-Einstein condensate -- oranother kind of quantum fluid -- is placed in a chargedcapacitor. The medium's rotation creates a magnetic field. LÄS MER

7. 20. Machine tool vibrations and violin sound fields studied using laser vibrometry

   Författare :Kourosh Tatar; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Experimental Mechanics; Experimentell mekanik;

   Sammanfattning : The knowledge of the dynamic behaviour of a milling process is very important for finding an optimum process window. In today's manufacturing industry the machining parameters are often predicted using experimental data from non-rotating spindles. LÄS MER