Dry-type Transformer Temperature Cannot Exceed How Many Degrees
04-08 2025 | By:
The temperature of a dry-type transformer cannot exceed the maximum temperature allowed by its insulation material, which is usually 155℃ (F-class insulation) or 180℃ (H-class insulation)
The maximum allowable temperature of a dry-type transformer mainly depends on the heat resistance grade of its insulation material. The following is a detailed analysis:
Insulation material and temperature limit
F-class insulation: The maximum allowable temperature is 155℃, and the temperature rise does not exceed 100K.
H-class insulation: The maximum allowable temperature is 180℃, and the temperature rise does not exceed 125K.
Other insulation classes (such as class A, class E, and class B) have lower temperature limits, but modern dry-type transformers mostly use class F or class H insulation.
The impact of excessive temperature
If the temperature of a dry-type transformer exceeds the maximum allowable temperature of its insulation material, it will accelerate insulation aging, shorten the life of the equipment, and may even cause faults such as short circuits or fires.
Therefore, the operating temperature should be kept as low as possible, especially in high temperature environments.
The relationship between temperature rise and ambient temperature
The temperature rise of a dry-type transformer refers to the difference between the temperature of a certain component and the temperature of the external cooling medium. For example, under rated load, if the ambient temperature is 40℃, the maximum temperature of the F-class insulation transformer should not exceed 140℃ (40℃ + 100K).
In winter, the maximum temperature will be reduced accordingly.
Precautions in actual operation
Perform regular inspections and monitor the temperature of the transformer to ensure that it operates within the allowable range.
Avoid overload operation to reduce the risk of temperature abnormalities.
In summary, the temperature of a dry-type transformer cannot exceed the maximum temperature allowed by its insulation material, which is usually 155℃ (F-class insulation) or 180℃ (H-class insulation). In actual operation, the temperature should be strictly controlled to ensure safe and stable operation of the equipment.
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