A Guide to Calculating Transformer Power for Various Configurations

The power of a transformer can be calculated by multiplying the output voltage by the output current. For single-phase transformers, the calculation is adjusted by multiplying the total power consumption by 120%, considering an 80% efficiency. In three-phase systems, using an example with a phase voltage of 220V and line voltage of 380V, the rated power is calculated as 1.732 × rated current × rated line voltage. For an unequal power distribution across phases, such as 9KW for phase A, 10KW for phase B, and 11KW for phase C, the total power would be 33KW. With a standard power factor of 0.8, the final transformer power calculation would be 41.25kW.