For Large Power Transformers, Self Oil Cooled Type or Air

Multiple Choice

For large power transformers, self oil cooled type or air blast type which of the following values of current density may be used ?

A) 1.0 to 1.2 A/mm²
B) 1.5 to 2.0 A/mm²
C) 2.2 to 3.2 A/mm²
D) 3.2 to 4.2 A/mm²