Transformer current and kVA workflow

How to prepare transformer kVA, voltage and phase inputs before using the Australian transformer current calculator.

Transformer-current purpose

Transformer current calculations connect kVA, voltage and phase. They are useful when checking primary current, secondary current or a missing kVA relationship, but they do not decide transformer selection by themselves.

The record should show which side of the transformer is being reviewed.

Workflow

  1. Identify whether the question is primary current, secondary current or kVA.
  2. Record transformer kVA and voltage ratings from the source available.
  3. Keep primary voltage and secondary voltage fields separate.
  4. Use the transformer current and kVA calculator for the relationship value.
  5. Carry the result into load, protection or sizing records with the transformer source attached.

Transformer record

Transformer current worksheet fields
FieldRecordReview concern
Transformer kVANameplate, specification or design assumptionDrives current calculation
Primary voltageEntered voltage for primary sideMust match the reviewed side
Secondary voltageEntered voltage for secondary sideMust match load or switchboard context
PhaseSingle-phase or three-phaseFormula path changes
Current outputPrimary or secondary A valueNot a transformer selection on its own

Boundaries

  • Do not mix primary and secondary voltage bases.
  • Do not use current alone to approve transformer size.
  • Do not ignore impedance, fault level, cooling, duty or utility requirements.
  • Do not copy transformer data between projects without naming the source.