Transformer formulas

Buck transformers are used when galvanic isolation from the supplying network (i.e., between the input and output windings) can be omitted. In this case, the input and output windings are electrically connected. There is a distinction between transmission power and rated power, with the rated power always being smaller than the transmission power. The rated power becomes smaller the smaller the difference between the input and output voltages is.

The relevant standard for buck transformers is EN 61558-2-13.

Calculation formula:
Rated Power = Nominal Power * (1 – (Lower Voltage / Higher Voltage))