Semi-analytical method for predicting shaft voltage in field-excited synchronous generators

Wesley Doorsamy, Willem A. Cronje

Research output: Contribution to journalArticlepeer-review


This study presents an electromagnetic model for predicting shaft voltages in a 2-pole field-excited synchronous generator. After the first observations on shaft voltages were made more than a century ago, extensive work has been conducted on eliminating, mitigating, and integrating the aforementioned phenomena. Given that emphasis has been placed on modeling shaft- and bearing-induced voltages in AC motors driven by variable frequency drives, similar efforts toward a model that is dedicated to generators are insubstantial. This work endeavors to improve current physical interpretation and prediction methods for shaft-induced voltages in generators through semi-analytical derivation. Aside from the experimental validation of the model, investigations regarding the behavior of shaft voltages under varying machine complexities and operating conditions clarify previous uncertainties regarding these phenomena. The performance of the numerical method is also assessed for application in eccentricity fault diagnosis.

Original languageEnglish
Article numberJPE 14-5-6
Pages (from-to)859-865
Number of pages7
JournalJournal of Power Electronics
Issue number5
Publication statusPublished - 2014
Externally publishedYes


  • 2-pole synchronous generator
  • Fault diagnosis
  • Shaft voltage model

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Electrical and Electronic Engineering


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