Transformer Calculator

Blog post description.

Wiratama

11/15/20251 min read

Transformer – Definition

A transformer is an electrical device that transfers energy between two circuits through electromagnetic induction. It changes voltage levels—either stepping voltage up or stepping it down—while maintaining the same frequency. Transformers are essential in power distribution, industrial equipment, and electronic systems.

Background Theory

The fundamental transformer relationship is based on Faraday’s law of electromagnetic induction. The voltage ratio between primary and secondary windings is proportional to the turns ratio:

Where:

  • Vp = primary voltage

  • Vs = secondary voltage

  • Np/Ns = turns ratio

Transformer power is rated in kVA, not kW, because it must supply both real and reactive power.

These equations allow analysis of power flow, current distribution, and voltage transformation.

How This Calculator Works

This calculator determines transformer performance parameters by:

  1. Letting you choose single-phase or three-phase mode

  2. Accepting primary voltage, secondary voltage, and load current

  3. Calculating:

    • kVA rating

    • Primary current

    • Secondary current

    • Turns ratio (Np/Ns)

  4. Displaying all results instantly in a clean, readable format

This provides a quick and reliable method for sizing transformers in power distribution, industrial machinery, and electrical engineering design.