Transformer Manufacturing Process - Tank Fabrication & Insulation

Tank integrity is essential for reliability and long transformer life. To ensure a perfect fit to the application, Prolec GE Waukesha designs all transformer tanks to high internal standards and customer specifications.

Transformer Tank Fabrication Welding
Transformer Tank Manufacturing Process
Welding for Transformer Tank Fabrication
Transformer Tank Fabrication


  • Constructed from hot-rolled, low carbon steel plates plasma cut to critical tolerances then joined via submerged arc welding to ensure against cracked seams and irregularities
  • Built with tank wall stiffeners so walls are braced to withstand full vacuum and pressures 25% greater than achieved during normal operation
  • Manufactured with bent corners (no corner welds)
  • Designed with jack pads and lifting hooks for lifting, jacking or pulling
  • Engineered with guides used to solidly “fit” and brace the completed core and coil assembly inside the tank to prevent shifting during shipment
  • Produced with slightly domed covers to help prevent water accumulation
  • Constructed with raised flanges and machined gasket grooves in cover openings
  • Fabricated with conveniently located hand holes and/or manholes for easy access to the lower end of bushings, terminal boards and the upper portion of core and coil assembly

Additionally, Prolec GE Waukesha’s standard coating system exceeds the requirements of ANSI C57.12.28, the specification for pad-mounted equipment:

Substrate: Hot-rolled, low carbon, A36 & A50 plate steel.
Surface Preparation: Interior surfaces of the tank and cover are thoroughly cleaned and prepared prior to application of the white, two-part, oil-resistant epoxy enamel.
Coating Procedure: Interior surfaces of the tank and tank cover are coated with white, two-part, oil-resistant epoxy enamel.

Exterior surfaces are primed with a two-part epoxy primer and top-coated using two-part urethane high gloss finish coat.

All coating materials are applied with air-assisted spray guns, with the paint delivered to the guns using plural component equipment that automatically measures and mixes the paint systems to eliminate operator error.

Coatings then “sit” to produce a uniform cured coating.

Coating Result: Interior coating compatible with transformer oil per ASTM 3455 and a 3 mil exterior coating capable of meeting ANSI C57.12.28.