kVA to amps calculator

The kVA to amps formula

For a three phase system, I = S ÷ (√3 × V), with S the apparent power in volt amperes and V the line voltage. For a single phase system the √3 drops out, and I = S ÷ V.

Real power in kilowatts and apparent power in kilovolt amperes differ by the power factor. A transformer is rated for apparent power, so divide a load given in kilowatts by its power factor before comparing it with a rating.

Standard ratings and rated current

Rated current at 400 V and 433 V, three phase. Each linked rating also gives its currents at other voltages.

Which voltage to calculate at

The answer depends on the voltage you enter, so use the one your network states. In Great Britain the ESQCR declare low voltage supply as 230 V between phase and neutral, with a variation of 10 % above or 6 % below. UK transformer specifications can ask for 433 V at no load to help provide it, and one distribution network operator lists its ratio as 11000/433-250 V. Kahramaa's low voltage network in Qatar runs at 240/415 V within 6 %, and DEWA in Dubai keeps low voltage variation within 6 % as well.