25 – 2500 kVA in power interval, hight voltaj level up to 36 kV, single or three-phase, oil immersed, naturel cooling (ONAN), no-load tap changer or with load automatic tap changer, both outdoor and indoor, are designed at form.

Hermetically sealed transformers being closed to atmosphere and pressure of hermetically sealed transformers are manufactured at figüre adjusted in factory.

Oil pressure of hermetically sealed transformers changes because of thermic effect and corrugated wall of tank is holded with expansion-contraction and versus this effects is designed at figüre will withstand.

There is not the conservator tank on hermetically sealed transformers. The oil is filled into tank after air of the oil is got inside of special vacuumrooms. Since the humidity consequently is not existed inside of tank, born of from oxidation deterioration of the oil is
reduced to zero.

Since there is not the conservator tank on hermetically sealed transformers, their heights are smaller than tranformers with oil conservator tank and thereof they are used smaller in fields.

The oil of hermetically sealed transformers is no necessary to changing in specific periods since the oil doesn’t contact with atmosphere.