Source: https://guthlabs.ai/docs/instruments/dc-motor-starting-current-back-emf-estimator/implementation/

instrument implementation / implementation-contract

# DC Motor Starting Current & Back-EMF Estimator implementation

A source-bound implementation contract for DC Motor Starting Current & Back-EMF Estimator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t4-102

**Effect**: Computation or source lookup only

## Input and validation requirements

The specification provides no stated validation for Ra=0, which makes Ia undefined. It also leaves the speed and motor-constant units unspecified, allowing materially different back-EMF and current results.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "V_V": 240,
    "Ra_ohm": 1.2,
    "motor_constant_Vs_per_rad": 0.8,
    "speed_rad_per_s": 0
  },
  "expected_outputs": {
    "Eb_V": 0,
    "Ia_A": 200,
    "starting_current_warning": null
  },
  "working": "Eb=K_e·ω=0.8·0=0 V. Ia=(V−Eb)/Ra=(240−0)/1.2=240/1.2=200 A. Speed is zero, so this is the locked-rotor case; the warning result is null because the specification defines no warning policy."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/dc-motor-starting-current-back-emf-estimator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/dc-motor-starting-current-back-emf-estimator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/dc-motor-starting-current-back-emf-estimator/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`