The small transformer rated 50 kVA until the little coils are cooled by infiltration of transformer oil to determine the density of current in the coil is in the range of 1.1-2.3 A/mm2.
Transformer smaller capacity than the 50 kVA windings are cooled by the insertion of transformer oil. To determine the density of the current in the coil is in the range 1.1 -2.3 A / mm2.
Small transformers with the coordinates, little until 50 kVA coil is cooled by using infiltration of transformer oil. To set the current density in the coil in the 1.1 - 2.3 A / mm2.