The Dry type H transformers, Open Winding are manufactured in two classes:

• The so-called LOW-LOW, powers from 15 kVA to 500 kVA three-phase and between 10 kVA and 100 kVA single-phase in voltages less than 600 V (three-phase and single-phase with taps up to 45 kVA and 50 kVA, respectively).

They are commonly used for the conversion of low voltages such as 440V / 220V or 220V / 440V, in commercial or industrial premises that have equipment at different voltage levels.

They usually do not carry voltage derivations and are confined in tanks that protect them from atmospheric agents, with IP grade enclosures requested by clients.

• The so-called HIGH-LOW transformers, in powers from 15 kVA to 1250 kVA, 15 kV class, according to the NTC standard are commonly used in shopping centers, buildings and industries where fire risks have to be minimized.

They are constructed with windings of circular section and stacked cores of stepped section. All its insulation scheme is designed with 180 ° C class material, to support heating and overload conditions established by the standard.

They do not have a tank, because they are designed to be included in the cabinets of high voltage substations.