Full Content is available to subscribers

Subscribe/Learn More  >

Generator Retaining Rings: In Situ Inspection and Life Assessment

[+] Author Affiliations
Jan Willem Noteboom

KEMA, Arnhem, The Netherlands

Paper No. POWER2009-81072, pp. 315-324; 10 pages
  • ASME 2009 Power Conference
  • ASME 2009 Power Conference
  • Albuquerque, New Mexico, USA, July 21–23, 2009
  • Conference Sponsors: Power Division
  • ISBN: 978-0-7918-4350-5 | eISBN: 978-0-7918-3853-6
  • Copyright © 2009 by ASME


Stress corrosion cracking (SCC) in retaining rings of generators has been a major issue since large generator manufactures started to advise generator owners to replace and inspect retaining rings made from certain materials in the mid 1990’s. KEMA has been inspecting generator retaining rings with automated systems from the seventies on. Since 1995 new developments led to the possibility of also testing rings in situ, eliminating the need of removing the rotor from the stator and thus saving considerable down-time. Over the years, step by step improvements to the system and its application to generator retaining ring inspections have been implemented, one of which is the use of smaller probes and manipulators. Another improvement is the implementation of eddy current testing (ECT) to increase the detection capability for cracking at the outside surface in parallel to the automated ultrasonic testing (AUT). Experience obtained with this method contradicts some of the common ideas about reliability of other Non-destructive testing (NDT) methods, in particular the application of Dye Penetrant inspection (DPI) which appears to be less reliable. By performing fracture mechanics calculations to evaluate detected and sized flaw indications, predictions of remaining life of the rings can be made (Fitness-for-Purpose analysis). This paper presents results of applying the in situ retaining ring inspection system in the last 14 years and gives an overview of cases — some of those from recent inspections — where defect indications were detected, sized and evaluated. In some cases this resulted in recommendations to replace the retaining rings.

Copyright © 2009 by ASME



Interactive Graphics


Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In