Experimental evaluation of using the surge PD test as a predictive maintenance tool for monitoring turn insulation quality in random wound AC motor stator windings

Jinkyu Yang, Tae June Kang, Byunghwan Kim, Sang Bin Lee, Young Woo Yoon, Dongsik Kang, Jintae Cho, Heedong Kim

Research output: Contribution to journalArticle

21 Citations (Scopus)


Turn insulation degradation is one of the major root causes of stator insulation failure leading to motor breakdown. The surge test is the only test available for testing the integrity of turn insulation; however, it is a high voltage pass/fail test that provides an indication only if an arc is instigated between the turns of weakened turn insulation, and therefore does not provide information regarding remaining lifetime. The surge PD test measures the partial discharge (PD) activity under surge excitation, and is used to date for assuring that voltage source PWM inverter-fed motors (IEC 60034-18-41 type I) are PDfree. In this paper, the potential of using the surge PD test as a predictive maintenance tool for turn insulation quality assessment is evaluated. Under the expectation that increasing PD activity in the voids formed by insulation degradation may be detectable before turn insulation failure, the test is performed periodically under accelerated thermal degradation on 6 windings. It is shown that change in the PD inception voltage under the surge PD test can be clearly observed before any other insulation test indicator. The results suggest that the surge PD test can be used for monitoring the condition of turn insulation for providing an early indication of stator insulation problems without the risk of puncturing turn insulation.

Original languageEnglish
Article number6148502
Pages (from-to)53-60
Number of pages8
JournalIEEE Transactions on Dielectrics and Electrical Insulation
Issue number1
Publication statusPublished - 2012 Feb 1



  • AC machines
  • Impulse testing
  • Monitoring
  • Partial discharges (PD)
  • Rotating machine insulation test
  • Surges

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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