Belt & Pulley Speed/Length Calculator implementation

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

t4-282

Effect

Computation or source lookup only

Input and validation requirements

The calculator can encounter an undefined belt-length expression when C=0, can return a plausible but physically invalid length when C is below the open-belt geometric limit unless that limit is explicitly checked, and can disagree on the sign of N2 because the speed-direction convention is unspecified.

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": {
    "D1": 100,
    "D2": 200,
    "C": 1000,
    "N1": 1200,
    "length_unit": "mm",
    "speed_unit": "rpm"
  },
  "expected_outputs": {
    "N2": 600,
    "belt_length_L": 2473.738898,
    "speed_ratio": 2
  },
  "working": "N2 = N1D1/D2 = 1200 × 100 / 200 = 600 rpm. Speed ratio = N1/N2 = 1200/600 = 2. Belt length L = 2C + π(D1+D2)/2 + (D2−D1)²/(4C) = 2×1000 + π(100+200)/2 + (200−100)²/(4×1000) = 2000 + 150π + 10000/4000 = 2000 + 471.238898 + 2.5 = 2473.738898 mm."
}

Other records

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