Copper Loss Calculation Calculator for Single Phase & Three Phase Transformer

Copper loss calculator:

Enter the primary current and resistance, secondary current and resistance. Then press calculates button to get copper loss in watts.

If you need to find single-phase transformer copper loss, then take the first results or if you need three-phase copper loss then consider the second result.

Enter Primary Current: Amps
Enter Primary Resistance Ohms
Enter secondary Current: Amps
Enter secondary Resistance: Ohms
Result – Single Phase Copper Loss: Watts
Result – Three Phase Copper Loss: Watts

Copper loss calculation formula:

Copper loss Pc in Watts is equal to the resistance R(Ω) in ohms times of the square of the current I(A) in Amps.

Copper loss Pc = I2 x R   Watts

But the transformer has two winding such as primary winding and secondary winding. Hence we need to calculate the copper loss for both primary and secondary windings.

Therefore, transformer copper loss Pc in watts is equal to the sum of the primary copper loss and secondary copper loss. The formula can be written as

Pc = Primary copper loss + Secondary Copper loss

Pc = I(P-A)2 x R1(Ω) + I(S-A)2 x R2(Ω)


I(P-A) = Primary Current in Amps.

I(S-A) = Secondary Current in Amps.

R1(Ω) = Primary Resistance in ohms.

R2(Ω) = Secondary resistance in ohms.

Three-phase Transformer copper loss calculation:

Three-phase copper loss Pc in watts is equal to 3 times of the single-phase copper loss. Hence we can write it as,

Pc = 3 * (I(P-A)2 x R1(Ω) + I(S-A)2 x R2(Ω)) Watts


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