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# How To Calculate kVA Rating of a Three Phase Transformer?

How do you Calculate Kilovolt Ampere (kVA) Rating of a Three Phase Transformer?

## Find Kilovolt Ampere (kVA) Rating of a Three Phase Transformer

KVA rating measures the apparent power flow through a transformer, without exceeding the temperature rise linking with the rating. Current flowing through the transformer is comprised of two loses, they are copper loss and iron loss. Due to temperature rise, the rating of the transformer is generally measured in kilo-volt-ampere(kVA) instead of Kilowatts(kW). Refer this online tutorial to learn how to calculate kilovolt-ampere(kVA) in a three phase transformer.

Formula Used:
kVA Rating of Three Phase Transformer = (âˆš3 x V x I) /1000
Where,V = Voltage
I = Current.

Let us consider a load voltage of 480 volts and load current of 80 amps, determine the kVA rating of the three phase transformer.
Step 1: Given,
Load Voltage V = 480 volts
Load Current I = 80 amps.

Step 2: Applying the three-phasehe formula,
kVA Rating of Single Phase Transformer= (âˆš3 x V x I) /1000
= (âˆš3 x 480 x 80) /1000
= (1.732 x 480 x 80) /1000
= 66508.8 /1000
= 66.5088