What color will a transformer turn if it becomes too hot?

Transformers can overheat due to various factors, including overloads, inadequate cooling, or electrical faults. When a transformer overheats, the insulation materials inside it can degrade, which often causes a change in color. Typically, the insulation materials can turn yellow or brown as they get hotter and begin to break down. This color change serves as a visual indication of overheating and potential failure.

In addition to indicating overheating, the yellow or brown color reflects the changes in the chemical structure of these materials due to excessive heat. Therefore, this color change acts as a warning sign to maintenance personnel that there may be an issue with the transformer's operation that needs to be addressed to prevent further damage or failure.

The other color options provided do not commonly relate to the specific issue of transformer overheating and its effects on insulation.