What commonly destroys transformers in an overload situation?

In an overload situation, the primary factor that commonly destroys transformers is heat. When a transformer is subjected to loads that exceed its designed capacity, it generates excess heat due to increased electrical resistance. This heat can elevate the temperature of various components within the transformer, such as insulation materials and windings.

As the temperature rises, the insulation can degrade, leading to potential short circuits, failure of the windings, and ultimately catastrophic damage to the transformer. Over time, if the transformer consistently operates in an overload condition, the cumulative heat damage can significantly shorten its lifespan and reliability. This heat management is crucial in transformer design; engineers must ensure that transformers have sufficient cooling mechanisms to dissipate heat generated under normal operating conditions to prevent destructive thermal overload.

Moisture, voltage surges, and physical damage can also contribute to transformer failures but are not the primary concern during an overload situation. Moisture can lead to insulation breakdown, voltage surges can cause insulation failure, and physical damage can result from external impacts, but heat remains the dominant factor because of its direct relationship with overload conditions.