Transformer Calculator Toolkit
Transformer Calculator
All-in-One Electrical Engineering Toolkit
kVA to Current Calculator
Calculation Results
Primary Current
--
A
Secondary Current
--
A
Phase Type Used
--
Copper Loss Estimation
Copper Loss Results
Copper Loss (Total)
--
W
Condition
--
Loss at full load condition
Transformer Efficiency
Efficiency Results
Efficiency
--
%
Total Losses
--
W
Performance
--
Percentage Impedance (%Z)
Impedance Results
Transformer Impedance
--
%
Short Circuit Current
--
A (approx.)
Impedance Rating
--
Lower %Z means higher short-circuit current
📐 Formulas Used
Single Phase Current
I = (kVA × 1000) / V
Current equals kVA rating times 1000 divided by voltage
Three Phase Current
I = (kVA × 1000) / (√3 × V)
Includes √3 factor for three-phase systems
Copper Loss
P = I² × R
Power loss proportional to current squared times resistance
Efficiency
η = [Output / (Output + Losses)] × 100
Ratio of output power to total input power
% Impedance
%Z = (Vsc / Vrated) × 100
Percentage of rated voltage for short circuit test
💡 Practical Engineering Notes
Load Variation: Transformer efficiency varies significantly with load. Maximum efficiency typically occurs at 50-75% of full load.
Copper Loss: Depends on current squared (I²R). Even small current increases cause large loss increases.
% Impedance: Affects short-circuit current magnitude. Lower %Z means higher fault currents requiring larger protective devices.
Verification: Always verify calculations with manufacturer test reports and nameplate data for critical applications.
Temperature: Copper loss increases with temperature. Use hot resistance values for accurate calculations.
Standards: Follow IEC 60076 or IEEE C57 standards for transformer testing and calculations.
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