Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
The effects of inter-bar currents in cast aluminium and cast copper rotors
KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
2009 (English)In: ICEM: 2008 INTERNATIONAL CONFERENCE ON ELECTRICAL MACHINES, NEW YORK: IEEE , 2009, 2381-2385 p.Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, a study of the influence of inter-bar currents on induction machines with aluminium and copper casted rotors is presented. The resistance between the rotor bars and the iron core is measured on five different rotors. An analytical model to predict the influence of inter-bar currents on machine performance is developed, and the results are verified by measurements. It is found that the measured inter-bar resistance is lower in cast copper rotors than in cast aluminium rotors. This leads to a reduced pull-out torque and increased stray-load losses.

Place, publisher, year, edition, pages
NEW YORK: IEEE , 2009. 2381-2385 p.
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
URN: urn:nbn:se:kth:diva-30704DOI: 10.1109/ICELMACH.2008.4800258ISI: 000269315000440ISBN: 978-1-4244-1735-3 (print)OAI: oai:DiVA.org:kth-30704DiVA: diva2:402875
Conference
International Conferece on Electrical Machines, Vilamoura, PORTUGAL, SEP 06-09, 2008
Note
QC 20110310Available from: 2011-03-10 Created: 2011-03-04 Last updated: 2013-03-20Bibliographically approved
In thesis
1. Analysis and Reduction of Parasitic Effects in Induction Motors With Die-Cast Rotors
Open this publication in new window or tab >>Analysis and Reduction of Parasitic Effects in Induction Motors With Die-Cast Rotors
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis presents a study of inter-bar current effects on induction motors with die-cast aluminium and die-cast copper rotors. The parasitic effects introduced by these currents are analyzed and possible solutions to these problems are presented. This is realized by developing analytical tools for the simulation of inter-bar current effects. The methods used are verified by measurements on prototype machines. It is shown that the inter-bar currents can have a considerable effect on the motor starting performance, which can result in a reduced pull-out torque. At rated operation, this is seen as increased harmonic rotor currents, having a negative effect on the motor performance.

Results from calorimetric measurements show, that the efficiency gained when substituting a skewed die-cast aluminium rotor with a skewed die-cast copper rotor, is less than the theoretical expectation. It is shown that this is a result of a reduced power factor for the copper rotor. High inter-bar currents are believed to be the origin of this effect, increasing the harmonic content in the rotor magnetomotive force. This would be seen as an increased rotor leakage reactance. Results from locked-rotor tests, and simulations using measured values of inter-bar resistance, support this theory.

It is shown, that these negative effects are suppressed to a negligible level by the use of an unskewed rotor, but to the expense of a large synchronous torque at a low speed. By using a modulated rotor concept, having an asymmetrical rotor slot distribution, an unskewed rotor is designed to reduce this parasitic torque. Measurements on a prototype machine show that the modulated rotor suppresses both the inter-bar currents and the synchronous torque, resulting in an improved starting performance, without any significant change of the motor efficiency. The presented results strengthen the potential of the modulated rotor concept, introducing new possibilities for the reduction of negative effects appearing in induction machines.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2013. x, 47 p.
Series
Trita-EE, ISSN 1653-5146 ; 2013:011
Keyword
Aluminium rotors, asynchronous torques, copper rotors, die-cast rotors, induction machines, inter-bar currents, modulated rotors, starting torque, stray losses, synchronous torques
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-119603 (URN)978-91-7501-682-5 (ISBN)
Public defence
2013-04-04, F3, Lindstedsvägen 26, KTH, Stockholm, 14:00 (English)
Opponent
Supervisors
Note

QC 20130320

Available from: 2013-03-20 Created: 2013-03-18 Last updated: 2013-03-20Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Stening, AlexanderSadarangani, Chandur
By organisation
Electrical Machines and Power Electronics
Electrical Engineering, Electronic Engineering, Information Engineering

Search outside of DiVA

GoogleGoogle Scholar

doi
isbn
urn-nbn

Altmetric score

doi
isbn
urn-nbn
Total: 66 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf