Source: https://guthlabs.ai/docs/instruments/transformer-efficiency-losses-estimator/

instrument / verified-clean

# Transformer Efficiency & Losses Estimator

The current ledger marks this instrument verified clean within the source-bound verification corpus.

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

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/transformer-efficiency-losses-estimator/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/transformer-efficiency-losses-estimator/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/transformer-efficiency-losses-estimator/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/transformer-efficiency-losses-estimator/qualification/>)

## Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

**Area**: Electrical & Electronics Engineering — Circuits, Power Systems, Electronics Lab

**Tranche**: tranche-4

**Evidence ID**: t4-066

**Ledger rows**: 1

No ledger note is attached.

## Review findings

The honest label is appropriate, but the implementation needs an explicit full-load copper-loss reference, decimal-versus-percent load convention, output-power formula, valid input constraints, and a defined efficiency-curve sweep before the specification can pass.

### Formula and scope findings

- η=Pout/(Pout+Pcu+Pfe) is standard when Pout is real output power and Pcu and Pfe are real losses in watts.

- Pcu∝(load%)² is incomplete as an executable formula: it must define a reference copper loss, normally Pcu(load)=Pcu_full_load×load_fraction².

- The specification does not state whether the copper-loss input is the full-load copper loss; this is required to calculate load-dependent copper loss.

- The specification uses load% while the input is called load fraction; the representation must be explicitly defined as either a decimal fraction from 0 to 1 or a percentage from 0 to 100.

- No explicit formula is provided for output power. Under the usual transformer model, Pout=rated_VA×load_fraction×PF.

- An efficiency curve requires a defined load sweep, domain, step size, and treatment of invalid load fractions; these are missing.

### Unit assumptions

- rated_VA is apparent power in VA.

- copper_loss_full_load_W and core_loss_W are real power losses in watts.

- PF is dimensionless and lies from 0 to 1; it is assumed constant over the load curve.

- load_fraction is a decimal fraction from 0 to 1, so 25% is entered as 0.25.

- Pout=rated_VA×load_fraction×PF, producing watts because VA×PF is treated as real watts.

- Core loss Pfe is assumed constant with load and frequency, voltage, and waveform.

## Boundary hardening

**BREAK_CLAIMED** · SELF_FLAGGED

The zero-output, zero-loss combination produces an undefined 0/0 efficiency, and the specification does not define behavior for load fractions above 1.0 or the PF unit convention.

## Errata and corrections

No applied erratum is attached to this unique-name record.

## Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

````
{
  "inputs": {
    "rated_VA": 1000,
    "copper_loss_full_load_W": 40,
    "core_loss_W": 10,
    "PF": 0.8,
    "load_fraction": 0.5
  },
  "expected_outputs": {
    "Pout_W": 400,
    "Pcu_W": 10,
    "Pfe_W": 10,
    "total_loss_W": 20,
    "efficiency": 0.9523809523809523,
    "efficiency_percent": 95.23809523809523
  },
  "working": "Pout=1000×0.5×0.8=400 W. Pcu=40×0.5²=40×0.25=10 W. Pfe=10 W. Total loss=10+10=20 W. η=400/(400+10+10)=400/420=20/21=0.9523809523809523=95.23809523809523%."
}
````

## Related workflows

No source-defined multi-instrument workflow membership is recorded.

## Sources and evidence

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

- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`

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

- `BOUNDARY_HAZARD_CATALOG.json`