Excessive Winding Tension Can Consume Transformer Insulation Margin

What the evidence preview establishes

The strongest correlation with suspect transformers was conductor spacing below the expected two-insulation-thickness margin. Excessive winding tension likely compressed or strained the insulation, with reflow thermal expansion adding stress; variable tape and winding counts documented broader process inconsistency.

Why this case matters

Nominal insulation thickness does not guarantee electrical spacing after winding. Minimum local gap, winding tension, impregnation, turn count, tape construction, and reflow strain should be controlled as a system.