kVA to Amps Calculation Formulas

Single Phase Calculation

The current I in amps is equal to 1000 times the apparent power S in kilovolt-amps, divided by the voltage V in volts:

I(A) = 1000 × S(kVA) / V(V)

Where:

• I(A): Current in Amperes (A)
• S(kVA): Apparent power in kilovolt-amps (kVA)
• V(V): Voltage in Volts (V)

This formula is commonly used in electrical engineering to determine the current flowing through a circuit when the apparent power and voltage are known.

Three Phase Calculation

Calculation with Line to Line Voltage

The phase current I in amps (with balanced loads) is equal to 1000 times the apparent power S in kilovolt-amps, divided by the square root of 3 times the line to line RMS voltage V_L-L in volts:

I(A) = 1000 × S(kVA) / (√3 × V_L-L(V))

Where:

• I(A): Current in Amperes (A)
• S(kVA): Apparent power in kilovolt-amps (kVA)
• V_L-L(V): Line to line voltage in Volts (V)

This formula is used for three-phase systems where the voltage is measured between two phases. It is essential for calculating the current in industrial applications where three-phase power is common.

Calculation with Line to Neutral Voltage

The phase current I in amps (with balanced loads) is equal to 1000 times the apparent power S in kilovolt-amps, divided by 3 times the line to neutral RMS voltage V_L-N in volts:

I(A) = 1000 × S(kVA) / (3 × V_L-N(V))

Where:

• I(A): Current in Amperes (A)
• S(kVA): Apparent power in kilovolt-amps (kVA)
• V_L-N(V): Line to neutral voltage in Volts (V)

This formula is particularly useful in systems where the voltage is measured from a phase to the neutral point, such as in residential electrical systems.

Practical Example

For instance, if you have a single-phase system with an apparent power of 5 kVA and a voltage of 230 V, the current can be calculated as follows:

I(A) = 1000 × 5 kVA / 230 V = 21.74 A

This means that the current flowing through the circuit is approximately 21.74 Amps.