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    The KIRR retaining ring inspection can be performed in approximately 2.5 shifts, depending on the size and accessibility of the generator. If required, multiple teams can be sent to reduce inspection time to 24 hours.

  • KIRR measurements

    The KIRR manipulator is equipped with several probes whereby different tests are performed simultaneously:

    • Ultrasonic testing: includes UT-TOFD for the  inner surface and volume of the ring, scanning for both axial and circumferential flaws. UT-PE (Pulse Echo) is applied for high accuracy in shrink fir zones.
    • Eddy current Testing (ET): for the outer surface with high accuracy.

    Dye penetrant on removed rings is discouraged: cracks in the shrink zone may close due to removal.


    What type of generators and machines can be tested?

    The height of the probes is 8 mm which allows for testing of almost all generators. The chain link system to mount the KIRR manipulator is suited for rings of a diameter of > 600 mm. In case of rings with ‘nose area’ (the sloping part of the ring where the outer diameter becomes smaller): this can be tested separately, maximum slope angle is 45°. We have performed retaining ring testing for more than 25 years, in which we have tested over 100 different generator (sub) types, including larger H2-cooled generators that are difficult to access (like THDD-type generators) and (in case of removed rotor) generators with rings with cooling holes, as well as exciter motor rings.

  • Downloads

    [PDF] KIRR Reference List per Jan 2010                                 [PDF] KIRR Leaflet

  • Neem gerust contact op:


Arthur Stam

Business Development Manager