Sökning: "UMP"

Visar resultat 1 - 5 av 12 avhandlingar innehållade ordet UMP.

  1. 1. Measurement and modelling of unbalanced magnetic pull in hydropower generators

    Författare :Mattias Wallin; Urban Lundin; Antero Arkkio; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Damper winding; eddy currents; field winding short circuit; finite element method; hydropower generator; parallel circuits; rotor eccentricity; salient poles; synchronous generators; synchronous machines; UMP; unbalanced magnetic pull.; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

    Sammanfattning : Hydropower research is often perceived to be an old and exhausted field of study but with ageing equipment and the need for more intermittent operation caused by an increased share of other renewable energy sources new challenges lie ahead.The main focus of this dissertation are the electromagnetic forces resulting from nonuniform air gap flux, whether it be caused by rotor eccentricity or a faulty field winding. LÄS MER

  3. 2. Contributions to the electromechanics of unbalanced magnetic pull in a synchronous hydropower generator

    Författare :Yogeshwarsing Calleecharan; Timo Holopainen; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hållfasthetslära; Solid Mechanics;

    Sammanfattning : Misalignment between the rotor geometrical axis and the geometrical stator axis in a hydropower generator is usually present at standstill and when the machine is under operation. Now, rotor-stator eccentricity in a rotating electrical machine is a harbinger to abnormal operating conditions of the machine. LÄS MER

  4. 3. On the dynamics of an hydropower generator subjected to unbalanced magnetic pull : characterisation and analysis

    Författare :Yogeshwarsing Calleecharan; Rolf Gustavsson; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hållfasthetslära; Solid Mechanics;

    Sammanfattning : Eccentricity leading to unbalanced magnetic pull (UMP) in rotating electrical machines is a significant concern in industry. The UMP arises due to magnetic flux crossing the air-gap between the rotor and stator, and can be more intense than the useful peripheral force that the machine develops. LÄS MER

  5. 4. Dynamic consequences of shape deviations in hydropower generators

    Författare :Niklas Lundström; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Computer Aided Design; Datorstödd maskinkonstruktion;

    Sammanfattning : Earlier measurements on hydropower generators have indicated the existence of backward whirling motion, and, also relatively large shape deviations in both the rotor and the stator. These non-symmetric geometries produce an attraction force between the rotor and the stator, called unbalanced magnetic pull (UMP). LÄS MER

  7. 5. Identification and characterization of nucleoside and nucleotide kinases : pharmacological activation of anti-cancer and anti-viral nucleoside analogs

    Författare :An R Van Rompay; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :;

    Sammanfattning : Cells require deoxyribonucleotides to synthesize DNA. Structurally modified precursors of deoxyribonucleotides, i.e. nucleoside analogs, are used as anti-viral and anti-cancer compounds. LÄS MER