What does a transformer do?

A power transformer is a static electrical device that is used to change a certain value of AC voltage (current) into another or several voltages (current) of the same frequency with different values. When the primary winding is energized with alternating current, alternating magnetic flux is produced. The alternating magnetic flux passes through the iron core to induce an alternating electromotive force in the secondary winding. The level of the secondary induced electromotive force is related to the number of turns of the primary and secondary windings, that is, the voltage is proportional to the number of turns. The main function is to transmit electric energy, so the rated capacity is its main parameter. Rated capacity is a customary value for power. It is a representation of the size of the transmitted electrical energy, expressed in kVA or MVA. When a rated voltage is applied to the transformer, it is used to determine the rated current that does not exceed the temperature rise limit under specified conditions