PRELIMINARY ENGINEERING TOOL
Transformer full-load current calculator
Calculate primary and secondary current from transformer kVA and nominal voltages.
Inputs
Calculation steps
I₁ = 100000 / (√3 × 11000)
I₂ = 100000 / (√3 × 415)
Formula ID: TRANSFORMER_3PH_FULL_LOAD_V1
Assumptions and references
Nameplate apparent power is treated as available on both sides. This does not model losses, regulation, impedance, tap position or inrush.
UNDERSTAND THE TOOL
What this calculator does
Convert nameplate kVA into full-load current, or switch to operating loading mode to compare measured apparent power with the nameplate. Neither mode establishes thermal capacity.
How to use it
- Choose the transformer phase arrangement.
- Enter the nameplate kVA rating.
- Enter primary and secondary nominal voltages.
- Review both current results and the excluded design checks.
Fields and meanings
- Rating
- Transformer apparent-power rating in kVA.
- Primary voltage
- Nominal supply-side voltage.
- Secondary voltage
- Nominal load-side voltage.
- Phase
- Select single phase or balanced three phase.
- Operating loading mode
- Enter nameplate kVA, operating voltage and current from the same transformer side to estimate loading percentage, not safe capacity.
Review required. Inrush, impedance, regulation, losses, protection and fault levels require separate assessment.
Read the full explanation →