Public evidence

electrical.watts_to_kva

Machine-checked verification for calculation version 1.3.1 · tier engine_tested

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Verification

11/11 calculation tests · Production surface contract 4/4

Golden tests 11 / 11
Boundary tests 0 / 0
Property tests 0 / 0
Production surface contract 4 / 4
Engine tested Yes
Source checked Yes
Artifact integrity PASS
Production attestation Embedded snapshot: STALE · Last attested schema matched 1.3.1 snapshot / local build · Semantic contract ✓ · Last attestation PASS · current evidence changed · re-attestation required · Public/cache ✓ · Origin ✓ · Live production status PASS (0 stale; 164 CURRENT) @ 2026-09-16T06:44:24.909Z
Semantic contract PASS
Evidence attested at 2026-09-16T06:44:24.203Z
Last production check 2026-09-16T06:44:24.203Z
Public / cache PASS
Origin PASS
Supplemental domain review Not performed
Named expert review Not performed

release artifacts aligned PASS
schema valid input executes PASS
engine success output validates schema PASS
schema rejects incomplete input PASS

Fingerprint sha256:38f332eb2dd6c8c1aa80f1b0ee0278953a64a6994fb9eb887474b66a49e145a5

Input schema sha256:c5c4cd498c7801cf23ae00b091e1c7b0d4621f02d00abb306e08d8cdd287e39a · Output schema sha256:3e4e1d7c02b0977888f8662c53faec045f16f67ddf9d0c50840942af558a9e26 · Build-time SHA-256 digests prove published artifacts agree with each other (release_integrity.scope=workspace). Production attestation GETs canonical URLs twice (public/cached view and origin), including Capability HTML, via npm run attest:production --write (published at /.well-known/calculatorx-production-attestation.json) and fails if the public Capability page advertises a different calculation_version. This is artifact consistency, not an independent immutable release log.

Build & scope

Engine identity and declared limitations.

Tool: watts-to-kva
Engine: scale-quotient
Engine build: 2026-09-15
Evidence core: 2026-09-15T06:31:46.555Z
Rendered: 2026-09-16T22:03:43.707Z
Last reviewed: —

Assumptions

PF between 0 and 1 (runtime treats missing/zero PF carefully on quotient)
No voltage/phase required

Limitations

PF ∈ (0,1] hard
No voltage/phase required
Shares the scale-quotient helper with kWh→W; contracts are distinct (PF vs time)

Sources

Standards and references supporting this tool specification. Methods are listed separately — they are algorithms, not bibliographic sources.

IEC 60050 — International Electrotechnical Vocabulary — Apparent power (IEV 131-11-41)
Supports: kVA is apparent power S; distinct from active power P (W); unit volt-ampere (VA) at 10³ scale
IEC 60050 — International Electrotechnical Vocabulary — Power factor (IEV 131-11-46)
Supports: λ = |P| / S; S(kVA) = P(W) / (1000 × λ) and P = S × 1000 × λ
IEEE Std 1459-2025 — Apparent power from real power and power factor · 2025-05-16 · errata checked
Supports: S(kVA) = P(W) / (1000 × PF); P = S × 1000 × PF
BIPM SI Brochure (9th edition, version 4.01) — SI units for watt and volt-ampere · 2026-06 · DOI
Supports: 1 kVA = 1000 VA scaling in W↔kVA conversion
NIST Guide to the SI (SP 811) — Watt and related power units
Supports: 1 kVA = 1000 VA scaling in W↔kVA conversion

Published checks

Golden, boundary, and property cases included in this evidence build.

ID	Kind	Status	Detail
`2000W-0.8`	golden	pass	Expected 2.5 · Actual 2.5
`1000W-1`	golden	pass	Expected 1 · Actual 1
`5000W-0.9`	golden	pass	Expected 5.5556 · Actual 5.555555555555555
`kva-to-w`	golden	pass	Expected 2000 · Actual 2000
`linear-2x-w`	golden	pass	Expected 5 · Actual 5
`inverse-half-pf`	golden	pass	Expected 5 · Actual 5
`soft-zero-pf`	golden	pass	Expected 0 · Actual 0
`soft-zero-w`	golden	pass	Expected 0 · Actual 0
`800W-0.8`	golden	pass	Expected 1 · Actual 1
`soft-zero-kva-reverse`	golden	pass	Expected 0 · Actual 0
`1kVA-unity-to-w`	golden	pass	Expected 1000 · Actual 1000