Frequently asked questions

FA101600

27 September 2022

 Issue:
Mathematical tools for Transformer calculations

Product Line:
LV Transformers

Environment:
Applies to Low and Medium Voltage Transformers by SquareD/Schneider Electric

Cause:
Mathematical means are often employed to calculate Transformer characteristics


Resolution:
For a three phase Transformer, multiply the load line-to-line voltage by the load current, then by 1.732 (the square root of 3,) and then divide that by 1000. For a single phase Transformer, multiply the load line-to-line voltage by the load current, then divide by 1000.

If the load is provided to you in kW (kilowatts) or watts, you must also have the power factor (pf) of the load. Simply take the watts (converted to kW by dividing by 1000) or kW and divide by the pf. The load power factor is always less than 1.0, and thus if you were to neglect it, you could undersize your Transformer selection.