Transformer Transportation Damage, A Case Presentation of a Low ...

Examples of Coil Blocks (Between Coils and Top Clamping
Ring) Displaced from their Radial Spacer Column
Figure 4
Wraps were used on the outside of the windings. On one winding a segment of the wrap had slipped down over the
blocks and was resting on the bottom clamping ring, blocking oil flow to about 1/3 of the bottom ducts, see Figure 5.
This was possible since the wrap was made of more than one piece of pressboard, one segment of the wrap had
shifted down.
Shifted
Wrap
Outside Winding Wrap Segment that Shifted Down, Blocking Bottom Oil Flow Ducts
Figure 5
The main blocking located between the core clamping frames and the clamping rings showed shifting and
displacement, see Figures 6 and 7. Figure 6 shows blocks at the clamping frame end; the two blocks labeled “A”
and “B” should be parallel. Block “A” is oriented correctly but block “B” had pivoted about 45 to the right as
shown. The block on the far right has sections that have also shifted. In Figure 7 it can be seen that glued layers of
the blocking separated, which allowed sections of the block to shift significantly. About 50% of the bearing surface
of this large block was left in contact.
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