Thermal instability analysis of a synchronous generator rotor using direct mapping

A. Narain Singh, W. Doorsamy, W. A. Cronje

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


This paper presents a direct and practical method for mapping the thermal behaviour of a synchronous generator. Since temperature variations can lead to rotor thermal instability which adversely affects the operation of the generating unit, a better understanding of this phenomenon is required. The two main methods of performing thermal instability testing - direct current injection and friction/windage - are found to be practiced internationally without preference. Infrared thermography is used here as a means of determining the thermal performance of the rotor under different testing scenarios. The experimental testing is conducted using a scaled setup of a balancing facility and a 600 MW generator rotor. The results obtained are presented in the form of surface temperature maps. The thermal distribution of the two different methods were found to differ substantially with the friction method exhibiting a uniform surface distribution while the current method exhibited areas of higher temperature concentration around the rotor pole faces.

Original languageEnglish
Pages (from-to)4-14
Number of pages11
JournalTransactions of the South African Institute of Electrical Engineers
Issue number1
Publication statusPublished - Mar 2018


  • Infrared thermography
  • Synchronous generator
  • Thermal instability testing

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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