Electrical monitoring of damper bar condition in salient-pole synchronous motors without motor disassembly

Jose Antonino-Daviu, Vicente Fuster-Roig, Sanguk Park, Yonghyun Park, Hanchun Choi, Jongsan Park, Sang Bin Lee

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


The damper (or amortisseur) winding of synchronous motors (SMs) is a critical component required for starting the motor. Several cases of the forced outage of industrial processes due to the starting failure of salient-pole SMs caused by damper bar failure have recently been reported. The detection of broken damper bars is difficult since they are active only during rotor acceleration, and offline visual inspection is the only means of testing available in the field. It was recently shown that the broken damper bars can be detected from the airgap flux, but this requires the installation of airgap flux sensors inside the motor. In this article, a method based on the analysis of the stator starting current is proposed for detecting broken damper bars. In addition, an electrical detection method based on signal injection from the motor terminals is proposed. The new methods have been devised to provide remote testing from the motor control center without motor disassembly required in existing tests. Finite-element analysis (1 MW) and experimental testing (30 kW) performed on salient-pole SMs with emulated broken damper bars show that the proposed methods can provide the sensitive and reliable detection of damper bar failures.

Original languageEnglish
Article number8957277
Pages (from-to)1423-1431
Number of pages9
JournalIEEE Transactions on Industry Applications
Issue number2
Publication statusPublished - 2020 Mar 1


  • Condition monitoring
  • fault diagnostics
  • motor testing
  • salient-pole synchronous motor (SM)
  • spectral analysis

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering


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