What is defined as the temperature rise in a transformer?

The temperature rise in a transformer is defined as the difference between the winding temperature and the ambient temperature. This parameter is crucial for understanding how well the transformer operates under various conditions. When the transformer is energized and operating, its windings heat up due to electrical losses, primarily from resistance in the conductors. This increase in temperature above the surrounding ambient temperature is critical for assessing the performance and longevity of the transformer. If the temperature rise exceeds the design limits, it can lead to insulation failure and reduced efficiency. Understanding this concept helps ensure that transformers are adequately rated and managed for their operational environment, promoting safety and reliability in electrical systems.