What aspect of a transformer is directly related to its design temperature?

The current-carrying capacity of a transformer is directly related to its design temperature because it determines how much electrical current can safely flow through the transformer's windings without overheating. Every transformer is designed with specific insulation materials, which have a maximum temperature rating. If the operating temperature exceeds this rating, the insulation can degrade, leading to reduced reliability and potential failure.

When the load on a transformer increases, so does the current flowing through it, which generates heat due to the resistance in the wire. Therefore, as the design temperature rises, the allowable current-carrying capacity can also increase, as long as the insulation can handle the elevated temperatures without compromising its integrity. Understanding this relationship helps ensure that transformers operate safely and efficiently within their rated limits, minimizing the risk of overheating and damage.