Moisture Holders

Moisture holders are used to take out the moisture of the air that enters the expansion vessel when the transformer is operating. In this way, it hinders water condensation in the expansion vessel and operation safety of the transformer is increased.

Moisture Holders of Types MH 1.2 to 2.4Kg (DIN42562)

All the flanges are GG-14 casting and coated with a special wet paint having high resistance to corrosion. The upper connection flange (Item-5) and its pipe are made of St 37 material. Container cylinder and oil bowl is made of glass. The oil bowl dome can be Ms 63 brass or aluminum depending on the request. The sieves are made of zinc sheet. The butterfly nuts are forged CrNi material.

Moisture Holders MH 0.15Kg

The top flange is casted aluminum and electrostatic powder painted. Container cylinder and oil bowl is made of polycarbonate.

Operation Principle

When the transformer gets air in, an air flow from and to the oil bowl occurs. The oil layer in the bowl prevents the dryer material from continuous contact with the damp external air and cleans the air flowing in. If the operation temperature of the transformer decreases, the volume of the isolation oil gets smaller. During this lessening, an amount of air equal to the lessening amount is absorbed in to the oil bowl through air holes. This air then transfers to the expansion vessel and contacts with the oil layer. During this transfer, air contacts with the dryer material and leaves its moisture there. With the heating of the oil in the transformer tank, the air inside flows out from the opposite direction of the moisture holder.

In the selection of the size of the moisture holders, various factors such as oil volume in the transformer, required life of the silica gel charge, operating cycle of the transformer, temperature and moisture contents of the ambient air should be taken into consideration by the transformer designer. For average operating conditions, the models and recommended transformer oil capacities are given in the following table.

Construction

Moisture holders of 0,5-1 kg (Form A,B,C) The top and the bottom sections are casted aluminum and electrostatic powder painted. The shafts are made of nickel plated steel and the sieves are made of zinc sheet. Container cylinder is glass or polycarbonate depending on the customers' request. Oil bowl is of polycarbonate and the bowl holder is made of CrNi material.

Catalogue

GANELEC/OUCO Transformer Equipment Accessories Catalogue - pg 32