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Management policy


          The factory was established on March 28th 1968 in Kyustendil as a subsidiary of the existing Power Transformer Factory in Sofia. In the beginning of 1970 “Elprom Trafo CH” laid the foundation of mass production of its first type power oil immersed transformer TM 100 kVA. In a short period of time the factory introduced the manufacture of several power ratings such as 160 and 250 kVA. During the next decade the factory develops with rapid rates, new machines are being bought, new technologies being adopted. By the end of the same decade commenced the production of oil immersed transformers with power rating up to 1600 kVA and by the end of the 90’s “Elprom Trafo CH” already produces the full range of middle voltage transformers – up to 2500 kVA. Thus before the end of the century the factory reaches maximum production capacity of 10 000 units per year.
          For the years to follow “Elprom Trafo CH” manages to introduce new laboratories for the incoming quality control of materials and a testing laboratory to perform routine tests on the ready-made transformers. In parallel, into the company’s structure are being formed two new departments – for design and technology, in such way closing the entire process of production.


          “Elprom Trafo CH” is manufacturer with own proven “know-how” of its own and more than decades of presents on the home and the international trade markets. For over 10 years the factory holds license on ISO 9001, which allows development in rapid terms and meet the increasing customer requirements. In 2010 we were certificated by ISO 14001:2004 and BS OHSAS 18001:2007.
          The team of young, high qualify specialists of “Elprom Trafo CH” is responsible for the existing fully automated system of commercial orders, technical documentation and resource management. Thus domestic communication is ensured between the separate departments and production process is accelerated. Another one of our advantages is the developed genuine software for the optimal design of transformers along with 3D CAD-CAM software with an option for automatic creating of technical data sheets. This way the time from receiving the customer’s order to manufacturing the product is being vastly reduced.
          Accept the full range of three-phases oil-filled distribution transformers with rated power from 25kVA up to 2500kVA “Elprom Trafo CH” manufactures special types of transformers, such as: earthing transformer, transformer for wind turbines, with on load tap-changers and single phase transformers. Different series are offered for each power, depending on no-load losses and load losses. Each transformer is manufactured in accordance with the international standard series of oil-filled transformers operate at frequency of 50Hz (60Hz), ambient temperature up to 50˚C and altitude up to 1000m. Special modifications according to work conditions, number of phases, vector-croup symbol as well as single phase transformers can be made upon customer request. The manufacturing process is automated to the highest degree and divided in two workshops at a total area of 25 000m2. The production itself is divided on three stages:
          I ‘Tank production’ – tank bottom, corrugated walls, tank cover, conservator, hooks;
          II ‘Active part (core and coil assembly)’ – coils, core cut out and assembling, active part assembling, transformer assembling;
          Production line for longitudinal cut out and of transformer steel, machine for production of foil windings, machines for production of “block-coils” and machines for manufacturing of LV and HV windings are used for active part manufacturing.
          III “transformer assembling”- mounting of active part and tank, closing, final product;
          IV ‘Routine tests of ready-made transformer’ – vector group, transformation ratio, coil resistance, applied voltage, induced voltage, no load losses, load losses and load voltage.
          For every manufactured transformer “Elprom Trafo CH” offers guarantee period and after guarantee period servicing and maintenance. As manufacturer the factory is ensuring the high quality repairing of transformers by qualified specialists. Laboratory tested materials with proven origin are used. Upon request repairing and maintenance of transformers from other products may be performed.
          The plant holds possession of a unique, for the territory of Bulgaria, laboratory complex, equipped with one of a kind installations and qualified specialists. In its facilities incoming, routine and outgoing control of materials and ready-made production is being done. Materials in use are being physically, mechanically and chemically tested before production starts. Their dimensions and width are being compared to the accompanying quality certificates. The Тδ, viscosity, breakdown voltage and the flush point of the transformer oil as well as many others are also tested. Current tests are performed during manufacturing including control measurements of transformer elements, assembling and suitability control. A number of electrical measurements, such as – insulation impedance, condition of electrical connections and others are done as well. After assembling each transformer is subjected to a number of routine tests before being ready for shipment.
          Today “Elprom Trafo CH” is synonym for quality, expedition and correctness not only on the Bulgarian trade market, but abroad as well. The consolidated long term position of the factory on the international market is easing the cooperation with new and newer partners. In the last years the products of “Elprom Trafo CH” is more on demand on the European market which is a reserved territory of the big producers in the transformer branch. The successful work of our specialists on power effective transformers, short terms of production and relatively low prices make us desirable business partner. At the moment 70% of the total production of “Elprom Trafo CH” is shipped abroad and 30% goes to the home market. Our long term business partners are countries from North Africa, Asia, South America, Balkan region and Near East.


          The future of “Elprom Trafo CH” lies in improving the material base and adopting of even newer technologies. We are already working on adopting new ecological technologies in the manufacturing process. The team of young designers continues to find new ways to optimize the production cycle. Increasing of production range is being developed, as well as manufacturing of transformers from the next power class. The work on the project for manufacturing of transformers with fire resistance equal to the one of dry transformers also continues.
          The main goal of the factory is to increase the level of automation production, to hire more young and qualified specialists. The updating of the existing computer network in order to fully synchronize it with the production cycle is also continues. We are planning to increase existing car fleet, to buy trucks with even bigger loading capability, in order to facilitate deliveries, as well as transportation of transformers for and after repairs.
          The team of “Elprom Trafo CH” continues its hard work on introducing the newest international standards and technologies in manufacturing to the customers. Our specialists will continue to work for you and to save your time and money.