Source: https://guthlabs.ai/docs/instruments/transformer-turns-ratio-sizing-calculator/mechanism/

instrument mechanism / verified-clean

# Transformer Turns Ratio & Sizing Calculator mechanism

The inspectable method record for Transformer Turns Ratio & Sizing Calculator, kept separate from implementation and qualification.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Model scope

The core ideal-transformer relationships are standard, but the instrument fails its stated feature set because % regulation has no defined formula and required VA sizing is conflated with load apparent power. The honest-label text appropriately discloses ignored losses, but the UI must explicitly identify all results as ideal-model values and must not imply a certified or thermally sufficient transformer rating.

- The turns-ratio identity a=N1/N2=V1/V2=I2/I1 is correct only for an ideal transformer with RMS AC quantities, negligible losses, and consistent primary/secondary labeling.

- No formula is provided for the claimed % regulation estimate. In the stated ideal model, regulation would conventionally be 0%, but that assumption and the regulation definition are not specified; a real-transformer regulation estimate requires additional parameters.

- VA=V·I correctly computes apparent power, but it does not by itself determine a required transformer VA rating. A sizing rating normally requires a design margin, duty cycle, temperature/thermal constraints, and possibly inrush considerations.

- The input alternatives are underspecified: the spec does not state how to derive missing V2 from N1,N2 and V1, or missing current from a supplied VA, nor how conflicting simultaneous inputs are handled.

## Units and conventions

- V1 and V2 are RMS AC voltages in volts, measured on consistently labeled primary and secondary windings.

- I1 and I2 are RMS currents in amperes; N1 and N2 are winding turns and therefore dimensionless counts.

- The transformer operates at the same frequency on both windings and is modeled as ideal, so V1/V2=N1/N2 and I2/I1=N1/N2.

- VA is apparent power in volt-amperes, calculated using RMS voltage multiplied by RMS current, with power factor excluded.

- A supplied load current is treated as secondary load current I2; a supplied VA value is treated as secondary apparent load power unless explicitly stated otherwise.

- A current ratio or voltage ratio must not use a zero denominator, and all voltage, current, and turns inputs must be positive for normal transformer operation.

## Inspectable vector

One of 4 source-bound review vectors:

````
{
  "inputs": {
    "V1_V": 120,
    "V2_V": 12,
    "load_current_A": 5
  },
  "expected_outputs": {
    "ratio_a": 10,
    "secondary_voltage_V": 12,
    "secondary_current_A": 5,
    "primary_current_A": 0.5,
    "required_VA": 60
  },
  "working": "a=V1/V2=120/12=10. I1=I2/a=5/10=0.5 A. VA=V2·I2=12·5=60 VA."
}
````

## Failure boundary

**BREAK_CLAIMED** · SELF_FLAGGED

The zero-turn secondary input produces an undefined ratio and must be rejected. Signed-voltage inputs also expose an unresolved polarity/sign convention: signed and magnitude interpretations produce different ratio and current signs.

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/transformer-turns-ratio-sizing-calculator/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/transformer-turns-ratio-sizing-calculator/implementation/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/transformer-turns-ratio-sizing-calculator/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche4/tranche4-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`