25 - 5000 kVA power range, up to 36 kV high voltage level, three or single phase, oily, natural cooling (ONAN), with idle tap changer or automatic tap changer under load, can be used both externally and internally. Hermetic oil type distribution transformers are manufactured with the principles of balancing the oil pressure and atmospheric pressure at the desired temperature by filling oil under vacuum and preventing the cooling oil from contacting the atmosphere.
In hermetic oil type distribution transformers, internal heat as a result of changing oil pressure due to thermal changes is controlled by natural expansion and contraction of the boiler wave walls. They are mechanically designed and manufactured to withstand these effects.
Hermetic oil type distribution transformers have lower height compared to transformers with expansion tank. Therefore, they can be used in smaller areas.
Since the oil does not come into contact with the atmosphere in hermetic transformers, oil change is not required in certain periods as in transformers with expansion tank.
