uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Influence on the stability of generator rotors due to radial and tangential magnetic pull force
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Division for Electricity and Lightning Research. (Elektricitetslära)
Luleå tekniska universitet.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Division for Electricity and Lightning Research. (Elektricitetslära)
Show others and affiliations
2007 (English)In: IET Electric Power Applications, ISSN 1751-8660, Vol. 1, no 1, 1-8 p.Article in journal (Refereed) Published
Abstract [en]

Forces due to nonuniform airgaps in rotating electrical machines have been a researchtopic for over 100 years. However, most research in the area of rotating electrical machines hasbeen performed on motors. Large forces in hydropower generators can lead to expensive damageand failures. Therefore, it is of interest to calculate the forces that arise in a large synchronousgenerator with an eccentric rotor and study the influence these forces have on the stability of thegenerator rotor. A 74 MVA synchronous hydropower generator was simulated with an eccentricrotor, using a time-stepping finite-element technique. The forces were calculated using Coulomb’svirtual-work method and simulations were performed for no-load and load cases. The resultingforce was found to be reduced significantly when a damper winding was taken into account. Aninteresting effect of the rotor damper winding was that it reduced the eccentricity force andintroduced a force component perpendicular to the direction of eccentricity. The results from thefinite-element simulations were used to determine how the forces affect the stability of the generatorrotor. Damped natural eigenfrequencies and damping ratio for load and no-load conditions arepresented. When applying the forces computed in the time-dependent model, the damped naturaleigenfrequencies were found to increase and the stability of the generator rotor was found to bereduced compared with when the forces were computed in a stationary model.

Place, publisher, year, edition, pages
2007. Vol. 1, no 1, 1-8 p.
Keyword [en]
generator rotor stability, radial magnetic pull force, tangential magnetic pull force, nonuniform air gaps, rotating electrical machines, large synchronous generator, eccentric rotor, synchronous hydropower generator, time-stepping finite-element technique, Coulomb's virtual-work method, damper winding, damped natural eigenfrequencies, damping ratio, load conditions, no-load conditions, electromagnetic forces, 74 MVA
National Category
Engineering and Technology
URN: urn:nbn:se:uu:diva-14002DOI: 10.1049/iet-epa:20050430ISI: 000245100000001OAI: oai:DiVA.org:uu-14002DiVA: diva2:41772
Available from: 2008-04-25 Created: 2008-04-25 Last updated: 2011-02-09Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Dahlbäck, NiklasLeijon, Mats
By organisation
Division for Electricity and Lightning Research
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 214 hits
ReferencesLink to record
Permanent link

Direct link