Produced within a power range between 10 – 3.150 kVA, up to 36 kV high voltage level, three phase or single phase, oil immersed, ONAN and/or ONAF, with Off-Load or On-Load Tap Changer, used both external and internal.
Being closed to atmosphere, there is no oxygen in Hermetically Sealed Transformers. Thus, aging due to oxidation does not occur and transformer oil will not gather moisture. For this reason, Hermetically Sealed Transformer are more longlasting compared to Conservator Type Transformers.
Height of Hermetically Sealed Transformer is lower than Conservator Type Transformer due to lack of conservator. It can be installed in small areas and has advantage of being used in compact transformer centers.