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Transformer Ratio Calculator

Calculate winding turns and voltage ratios with explicit phase-voltage and line-voltage definitions.

#56 / #57 · CANDIDATE WORKFLOW

Transformer ratio calculator

System

02 / Results

Enter values and calculate.

Method and boundaries

Under the ideal induction model, N₁/N₂ = Vφ₁/Vφ₂. Wye line voltage converts with Vφ = VLL/√3; delta winding voltage equals VLL.

For example, with 400 primary turns and 100 secondary turns, the turns ratio is 4. If both windings are wye, 400 V line-to-line primary corresponds to 100 V line-to-line secondary. Cross-connected line-voltage ratios differ by √3.

This calculator reports magnitudes only. It excludes impedance drop, regulation, tap changes, autotransformers, unbalanced loads, open-delta and non-sinusoidal operation. Source: SRC-058.

FAQ

Is voltage ratio always equal to turns ratio?

Winding phase-voltage ratio equals turns ratio under the ideal model. Three-phase line-voltage ratio also depends on each side’s wye or delta connection.

Does this calculate phase shift?

No. Vector-group phase displacement and polarity are not modeled.

Can I use this for a loaded transformer?

It is an ideal magnitude calculation and does not include winding impedance or load-dependent voltage drop.

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