Formula to Calculate Amps from kVA [kVA to Ampere]

Electrical transformers and heavy machines are often rated in kVA (kilovolt-ampere). Today you'll learn the formula to calculate amps from kVA.

Learn top 100 Basic Electrical Engineering formulas

Single Phase Circuits

Single phase amps are defined as multiple of 1000 times kVA divided by voltage.

Mathematically

Amps (1 φ) = [kVA * 1000] / E

Example: Find the current drawn by a single phase 5 kVA circuit at a rated voltage of 400 volts.

Solution: I = [5 * 1000] / 400 = 12.5 A

Two Phase Circuits

Three phase amps are defined as 1000 times kVA divided by 2 times system voltage.

Mathematically

Amps (2 φ) = [kVA * 1000] / [E * 2]

Example: Find the current drawn by a two-phase 3 kVA circuit at a rated voltage of 230 V.

Solution: I = [3 * 1000] / [230 * 2] = 6.52 A

Three Phase Circuits

Three phase amps are defined as 1000 times kVA divided by 1.73 times system voltage.

Mathematically

Amps (3 φ) = [kVA * 1000] / [E * 1.73]

Example: Find the current drawn by a three phase 8 kVA circuit at a rated voltage of 480 volts.

Solution: I = [8 * 1000] / [480 * 1.73] = 9.63 A