top of page


ATEF produces oil immersed Power transformers with a voltage class of up to 525 kV and 800 MVA.

Our company use own design and construction concept which allows us to speed up the design process with a short production time.

ATEF transformers are tested and certified by KEMA and CESI laboratories.

Range of power transformers includes:

  •  Step down / Station Transformers

  •  Step-up / Generator transformers

  •  Phase shift transformers

  •  Rectifier transformers

  •  Electric Arc furnace transformers

  •  Shunt reactors

  •  Traction transformers

  •  Autotransformers

Manufacturing of magnetic cores

At the plant of Large Transformers special attention is paid to the technology of manufacturing magnetic circuits. Furthermore, there is are automatic lines for longitudinal and transverse cutting of electrical steel with a thickness of 0.18mm, incl. at an oblique angle on the assembly technology "Step-Lap", the company SAGMA, GEORG.

Assembly tables with hydraulic adjustment, as well as special bandage machines ensure the manufacture of magnetic cores with minimal electrical losses and reduced noise.

The main factors taken into account in the production of magnetic cores at the plant are:

  •  High reliability

  •  Reduced material and labor costs

  •  Reduction of losses in the magnetic core

  •  Reduction of magnetizing current

  •  Low noise

Quality control is required at every stage of production to ensure quality and reliability of details. The dimensions of chopped electrical steel sheets, as well as the presence of edge burrs in electrical steel are strictly controlled and tested to ensure the calculated values of losses in the magnetic circuit.

Assembling the active part and drying

After completing the assembly of the windings and the core, the active parts are transferred to the vacuum chamber for the maximum productivity of the drying.

For maximum removal of moisture from the active parts of the drying, the process occurs in vapors of the solvent. This technology allows to achieve maximum reliability of transformers produced by ATEF.

Coil manufacturing

The vertical and horizontal winding machines in the winding shop allows to manufacture any type of winding up to 30 tons in a short time.  The vertical winding device allows operators to smooth and easy control in the production of large windings.  In the manufacture of power transformer coils, we use high-quality winding wires, including continuously transposed cables (CTC) and insulation materials (cylinders, rails, gaskets, cones, etc.) to obtain the best possible insulation for the entire service life of transformers.

The factory has well-equipped drying ovens with the simultaneous pressing to extract moisture from insulation materials.  After finishing the winding, each coil undergoes a vacuum drying process. The drying process is fully automated and monitored for maximum drying performance.  During the drying process, the height of the windings is pressed and adjusted automatically in accordance with the design data.

Testing Center

ATEF Group Testing Center that has the equipment of the German company HIGH VOLT and OMICRON is able to perform all types of electrical tests on power transformers and meets the requirements of IEC, ANSI, GOST and other international standards.

The test laboratory room is completely shielded by a Faraday cage for performing susceptibility tests, such as high-voltage noise interference, partial discharges, and noise tests.

 The testing center also includes a laboratory for chemical and physical analysis of the used materials, such as chemical and physical analyzes of the transformer oil and materials.

Our laboratories are equipped with high-tech test equipment with automatic control which allows us to obtain the most accurate test results.

All test results of the protocols are documented according to ISO requirements and can be presented to the customer.