1965
By acquiring a 10-year license from a French company Alsthom Savoisienne, and building new facilities, the company develops the capacity to produce transformers of up to 150 MVA rated power and of 145 kV rated voltage.
1961
Jambor merges with Energoinvest group from Sarajevo. The company trades under the name Energoinvest Sarajevo, Tovarna transformatorjev Ljubljana. Its activity is exclusively dedicated to manufacturing power transformers.
1960
The extent of production, which is growing annually reaches a total of approximately 130 MVA transformers per year.
1954
The first transformer, which is entirely the result of our own knowledge, is developed.
1951
The company changes its name to Jambor.
1949
The plant changes its name to Elektromehanične delavnice Črnuče and becomes an independent company. Its business activities are focused on the maintenance of electro power equipment.
1933
The founding year of ETRA 33, Energetski transformatorji, d.o.o.. Its initial activity includes the servicing of small transformers and manufacturing of components for power distribution.