Manufacturing of transformers core

Transformer Vapor Phase Drying (VPD)

Leybold robust vacuum pumps for efficient production of power transformers

Production of Power transformers with Vapor Phase Drying (VPD)

Power transformers contain big amounts of non-metallic components as e.g., insulation paper, wood, oil or resin which can absorb moisture. To avoid electrical short-cuts during the operation of the transformer, vacuum pumps and systems are used to remove the trapped humidity.

There are three typical drying processes during power-transformer production:

  • Pre-drying / sizing of transformer coils (mostly done in humid countries only)
  • VPD (vapor phase drying) of transformer core
  • Final drying of the assembled transformer (often operated with mobile vacuum systems). 

What we recommend

Oil-sealed rotary-vane pumps were typically used for all drying steps of transformer production. They are cost-effective but will require a certain amount of maintenance as the applications are demanding.

As the vacuum pumps are challenged by considerable water vapor outgassing during pre-drying and final drying as well as organic solvent vapor and acids during the vapor phase drying, we propose using dry compressing, screw-type vacuum pumps of our DRYVAC or SCREWLINE families as these can handle such challenges without extra maintenance needs and will optimize your cost of ownership.

Explore ATEX-certified solutions

During the vapor phase drying hydrocarbon solvents are used, which could build-up potentially flammable gas-mixtures with air leakage. There are various safety strategies to avoid this. In case that the user decides to use ATEX-certified products, Leybold also provides a line of products with a suitable ATEX certification.

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