The beginnings of the Kolektor-Era date back to 1933 when a small transformer repair shop was founded. In the 1960s, by the license contract with the French factory Alstom Savoisienne, the company specialized in the production of transformers up to 150 mega volts ampere and 145 kilovolts of nominal voltage. After 1990, the transformer company now named: ETRA 33 positioned itself as a competent partner adapted to the needs of its customers. In 2010, ETRA 33 became part of the Kolektor Technology Group under the name Kolektor ETRA.
With its own development and innovative approaches, Kolektor-Etra is now one of the largest suppliers of high-tech transformers in Europe.
Our research and development department is proud of experienced professionals, reinforced by a team of young engineers who works in concert with academic specialists, the whole that guarantees technological progress.
By using grain-oriented electrical transformer steel, including technologically advanced manufacturing and the "Step Lap" stacking system, we are able to get base-core losses from the magnetic core and reduced noise level of our finished products.
The elastic attachment of the active part with specialized knowledge of resonant frequencies and zones ensures that the vibrations are managed efficiently. This allows us to further reduce noise levels and extend the life of our transformers. The windings of the high power transformers are optimized for voltage, current and their dynamic and thermal properties. Since the windings have been finished, the thermal stabilization of the insulation is carried out, enabling us to obtain the prescribed geometry of the windings.
In order to extract moisture from the insulation of the transformers, the most advanced, computer-controlled drying process is used in the vacuum chamber using kerosene vapors. This process is known as drying of kerosene vapors.

The whole process of assembling the transformer is done in rooms that are physically and optically clean after the final assembly of the 400 kilovolt transformers. We guarantee moisture levels of less than 15% in these parts, sealing them according to EN 13829 and using powerful air conditioning and drying devices, which guarantees the longer life of the transformer.
The best modern laboratory is the prerequisite for the technological progress of the company, providing accurate measurements and highly reliable results. It is equipped with measuring devices prescribed by International Standard as well as equipment based on the company's innovative approach.
The company's business processes are carried out in accordance with ISO 9001 ISO 14001 and OHSAS 18001. We improve them by our technical competence and by treating our customers as partners. We believe that partnership and mutual trust between the customer and the producer are the basis for long-term cooperation.
Our business excellence is enhanced by the after-sales service of transformers from various manufacturers, either on site or in our workshop.
In addition to power transformers, Kolektor-Etra also manufactures furnace, injection and rectifier transformers.
We market our products in more than 40 countries, on 5 continents, in the tropical jungles and in the deserts, in the glacial north and on the coast, on the marine platforms in the engine rooms of hydroelectric and thermal power stations although in the hostile environment of industrial facilities.