What is the maximum permissible temperature for normal transformer operation?

The maximum permissible temperature for normal transformer operation is typically established to ensure the reliability and longevity of the transformer. In this context, 85°C is within the acceptable range for most transformer designs, particularly for insulation materials and cooling processes commonly used in the industry. Exceeding this temperature can cause insulation breakdown, reduce efficiency, and ultimately lead to failure of the transformer.

Transformers are often rated based on their ability to continue functioning effectively within specific temperature limits. Staying at or below these limits helps maintain operational integrity, ensuring that the insulating materials do not degrade and that the transformer operates efficiently.

Temperatures above this threshold can lead to excessive wear on components, while lower temperatures such as 50°C, 75°C, or even 100°C would not be suitable for continuous, normal operation, making 85°C the most appropriate answer.