Three Phase Air Cooled Power Transformer

Three-phase transformers are passive machines that pass electrical energy between circuits. In the secondary circuit, a magnetic flux induces an electromotive force (emf), thus stepping up (increase) or stepping down (decrease) voltages without altering the frequency.The primary winding of the three phase transformer is energized from a three phase supply. Then, the flux is produced in the core by the primary currents in the three windings. The core has three limbs, where any two limbs act as return path for the flux in the third limb.A three-phase transformer is made of three sets of primary and secondary windings, each set wound around one leg of an iron core assembly. Essentially it looks like three single-phase transformers sharing a joined core as in Figure below. Three phase transformer core has three sets of windings.