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

Example of Buckled Core Lamination
Figure 11
It appeared that the top yoke laminations shifted toward the end where the derailment impact occurred. When the
laminations were removed from the top core yoke, some displayed deformation along the miter cut edge at one end,
see Figure 12. The deformation consisted of groups of parallel ridges that appeared to be due to compression of the
yoke steel at the miter joint during the derailment event. It appeared that the ridges were created by the offset edges
of the step lapped joint. The insulation was breaking away from the core steel at some of the deformed ridges.
Examples of Core Steel Deformation near the Miter Cut Edges
Figure 12
When the core yoke was removed additional damage to the core steel was revealed. In one location a core block
came loose causing damage to the core steel on the edges, see Figure 13. The insulation had delaminated from the
steel due to the mechanical deformation and the steel was cracked in some locations, as indicated in the right frame
of Figure 13 with a red arrow. This damage was localized to the area shown in the figure.
Top Core Yoke Steel Damage due to a Loose Block
Figure 13
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