How to convert apparent power in kilovolt-amps (kVA) to electric current in amps (A).
You can calculate amps from kilovolt-amps and volts, but you can't convert kilovolt-amps to amps since kilovolt-amps and amps units do not measure the same quantity.
The phase current I in amps is equal to 1000 times the apparent power S in kilovolt-amps, divided by the RMS voltage V in volts:
I(A) = 1000 × S(kVA) / V(V)
So amps are equal to 1000 times kilovolt-amps divided by volts.
amps = 1000 × kVA / volts
or
A = 1000 ⋅ kVA / V
Question: What is the phase current in amps when the apparent power is 3 kVA and the RMS voltage supply is 110 volts?
Solution:
I = 1000 × 3kVA / 110V = 27.27A
The phase current I in amps 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 in volts:
I(A) = 1000 × S(kVA) / (√3 × VL-L(V) )
So amps are equal to 1000 times kilovolt-amps divided by the square root of 3 times volts.
amps = 1000 × kVA / (√3 × volts)
or
A = 1000 ⋅ kVA / (√3 × V)
Question: What is the phase current in amps when the apparent power is 3 kVA and the line to line RMS voltage supply is 190 volts?
Solution:
I = 1000 × 3kVA / (√3 × 190V) = 9.116A
The phase current I in amps is equal to 1000 times the apparent power S in kilovolt-amps, divided by 3 times the line to line RMS voltage V in volts:
I(A) = 1000 × S(kVA) / (3 × VL-N(V) )
So amps are equal to 1000 times kilovolt-amps divided by 3 times volts.
amps = 1000 × kVA / (3 × volts)
or
A = 1000 ⋅ kVA / (3 × V)
Question: What is the phase current in amps when the apparent power is 3 kVA and the line to neutral RMS voltage supply is 120 volts?
Solution:
I = 1000 × 3kVA / (3 × 120V) = 8.333A
