Moisture Holders for transformers

For Oil Transformers ; Moisture Holders 

Moisture Holders are used to remove moisture from the air entering the tank of transformers with oil-cooled expansion tanks. In this way, it prevents water condensation in the expansion tank and increases the operating safety of the transformer.

Structure of Moisture Holders
Moisture Holders type L Form E (DIN 42562 / EN 50216-5)
Moisture Holders type Form A / B / C (DIN 42567 / EN 50216-5)
Our moisture holders for Transformers with Oil Type Expansion Tanks are produced in accordance with the standards of Din 42562, Din 42567, EN 50216-5. Our metal parts in our products are produced using aluminum injection process. Our air dryers are painted with corrosion and UV resistant electrostatic powder paint.
Working Principle
Moisture holders are installed in the expansion tanks of oil-type transformers and keep the humidity of the air entering the transformer while the transformer is operating. When the transformer starts to breathe and start to breathe in, air flows from the environment towards the oil container. The oil layer in the oil container prevents the drying material from constantly contacting the outside environment and cleans the incoming air. If the operating temperature of the transformer decreases, the volume of the insulating oil decreases. During this shrinking, air as much as the shrinkage amount is supplied from the air holes in the oil container. This air is then transferred to the expansion tank and comes into contact with the oil film. During this transfer, the air comes into contact with the desiccant material (silicagel) and leaves its moisture. With the heating of the transformer oil, the air inside is discharged from the moisture holder from the inside to the outside with a reverse flow. Moisture holders are protected against corrosion. During the operation and breathing of the transformer (air inlet and outlet), bubbles may appear inside the oil container. The maximum diameter of the dehumidifying material (Silicagel) to be placed in the Moisture holder should be around 3 mm.
Capacity
Factors such as oil volume in the transformer, silica gel change time, operating period of the transformer, ambient temperature and humidity should be considered by the designer of the transformer while choosing the size of the moisture holder. In average operating conditions, you can find the model and recommended oil capacity in the table.