Public evidence

electrical.apparent_power

Machine-checked verification for calculation version 1.4.3 · tier engine_tested

Open calculator API Capability Download JSON CVP Manifest MCP Review policy

CVP: CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance· PF optional for derived real power only — not applied to S · Protocol · Schema · Production report

Declared partition coverage: PASS · 5/5 declared partitions (amps-va-1phi, amps-va-3phi, va-amps, amps-kva, invalid-domain)
Versions: Calculation 1.4.3 · CVP protocol 1.0.0-proposed · Evidence 2026-09-10.cvp-bootstrap
Verification revision: 2026-09-10.cvp-bootstrap · 14/14 property · digest c57787417bc3

Verification

Legacy regression suite: 36/36 calculation tests · Production surface contract 4/4

Three distinct suites: educational examples on the calculator page, this legacy regression count (36/36 golden + boundary), and the CVP verification suite below. They are not the same number. Property, metamorphic, round-trip, O3, and interface statuses/checks are recorded in the CVP Manifest . SKIP (0/0) means that suite has no published vectors.

This calculator CURRENT · Public schema 1.4.3 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓

CVP verification suite

Protocol checks from the Evidence Manifest. Distinct from the legacy regression suite above. Verification revision 2026-09-10.cvp-bootstrap. Calculation version 1.4.3. CVP 1.0.0-proposed. 4/4 golden · 12/12 CVP boundary · 10/10 invalid · 14/14 property · 1/1 cross-interface · 1/1 CVP contract. digest c57787417bc3.

Golden (oracle-backed) 4 / 4
CVP boundary 12 / 12
Invalid input 10 / 10
Property 14 / 14
Cross-interface 1 / 1
CVP contract 1 / 1
Interfaces PASS · UI (SSR) / REST / MCP
Interface claim ui-ssr is query-result HTML, not a live browser session.
Assurance Engineering

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

Fingerprint sha256:8f1fe71ef5ac163067373cca83fd06606a09cf26222e4f7549938786262e71d7

Input schema sha256:5bf23cb0b374dc943d075d420a742cbbfabfe8dd5b7f4a26a608ec186c0b9835 · Output schema sha256:550be97c601f18e5c860c9a6aaf3d5f117474eda14f4121568ae369861f1b19c · 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: amps-to-va
Engine: amps-va
Engine build: 2026-09-10
Evidence core: 2026-09-10T22:48:17.762Z
Rendered: 2026-09-16T22:03:43.697Z
Last reviewed: —

Assumptions

AC steady-state with RMS voltage and current magnitudes.
Three-phase mode is balanced sinusoidal AC using line-to-line RMS voltage, where V_LL = √3 V_LN and line currents are equal. IEEE 1459 covers a wider set of conditions; this calculator does not.
Total power factor λ is not applied to VA/kVA results.

Limitations

Not for DC systems
Not for unbalanced or nonsinusoidal three-phase; √3 formula assumes balanced sinusoidal V_LL = √3 V_LN and equal line currents
Not for line-to-neutral three-phase mode
Not for equipment protection or conductor sizing
When power_factor is supplied, REST/MCP include derived.estimated_real_power; omitted when λ is absent

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: S = U × I definition of apparent power; unit volt-ampere (VA)
IEC 60050 — International Electrotechnical Vocabulary — Power factor (IEV 131-11-46)
Supports: λ = |P| / S, so λ = 0 when P = 0 and S > 0; optional page/API estimate P_est = S × λ_entered uses this definition
IEEE Std 1459-2025 — Definitions for electric power measurement under sinusoidal, nonsinusoidal, balanced, or unbalanced conditions · 2025-05-16 · errata checked
Supports: IEEE 1459 covers sinusoidal, nonsinusoidal, balanced, and unbalanced conditions. This calculator implements only the balanced sinusoidal three-phase model S = √3 × V_L-L × I_L (V_LL = √3 V_LN, equal line currents).
BIPM SI Brochure (9th edition, version 4.01) — SI base and derived units for ampere, volt, and power · 2026-06 · DOI
Supports: V, A, W, and VA unit relationships

Legacy published checks

Golden and boundary cases from the legacy Evidence JSON. CVP property, metamorphic, round-trip, O3, and interface statuses/checks are recorded in the Manifest — including SKIP when a suite has no vectors.

ID	Kind	Status	Detail
`1phi-20A-120V`	golden	pass	Expected 2400 · Actual 2400
`1phi-12A-230V`	golden	pass	Expected 2760 · Actual 2760
`3phi-10A-400V`	golden	pass	Expected 6928.203 · Actual 6928.203230275509
`3phi-60A-480V`	golden	pass	Expected 49883.06 · Actual 49883.06325798366
`va-to-amps-2760`	golden	pass	Expected 12 · Actual 12
`boundary-volts-zero`	boundary	pass	Expected VOLTAGE_MUST_BE_POSITIVE · Actual VOLTAGE_MUST_BE_POSITIVE
`boundary-volts-negative`	boundary	pass	Expected VOLTAGE_MUST_BE_POSITIVE · Actual VOLTAGE_MUST_BE_POSITIVE
`boundary-primary-negative`	boundary	pass	Expected VALUE_MUST_BE_NON_NEGATIVE · Actual VALUE_MUST_BE_NON_NEGATIVE
`boundary-pf-80`	boundary	pass	Expected POWER_FACTOR_OUT_OF_RANGE · Actual POWER_FACTOR_OUT_OF_RANGE
`boundary-pf-zero`	boundary	pass	Expected 1200 · Actual 1200
`boundary-pf-one-ok`	boundary	pass	Expected 1200 · Actual 1200
`boundary-unknown-mode`	boundary	pass	Expected INVALID_MODE · Actual INVALID_MODE
`boundary-unknown-phase`	boundary	pass	Expected INVALID_PHASE · Actual INVALID_PHASE
`boundary-tiny-positive-volts`	boundary	pass	Expected 0.000001 · Actual 0.000001
`boundary-missing-volts`	boundary	pass	Expected MISSING_REQUIRED_INPUT · Actual MISSING_REQUIRED_INPUT
`boundary-missing-primary`	boundary	pass	Expected MISSING_REQUIRED_INPUT · Actual MISSING_REQUIRED_INPUT
`boundary-overflow-va`	boundary	pass	Expected NON_FINITE_RESULT · Actual NON_FINITE_RESULT
`boundary-infinity-volts`	boundary	pass	Expected INVALID_NUMBER · Actual INVALID_NUMBER
`golden-zero-current`	golden	pass	Expected 0 · Actual 0
`3phi-va-to-amps-400V`	golden	pass	Expected 10 · Actual 10
`3phi-amps-kva-10A-400V`	golden	pass	Expected 6.928203230275509 · Actual 6.928203230275509
`property-double-current`	property	pass	Expected 5520 · Actual 5520
`property-double-voltage`	property	pass	Expected 5520 · Actual 5520
`property-roundtrip-va-amps`	property	pass	Expected 60 · Actual 59.9999960812547
`amps-kva-12A-230V`	golden	pass	Expected 2.76 · Actual 2.76
`property-linearity-current`	property	pass	S(2I,V)=2S(I,V)
`property-linearity-voltage`	property	pass	S(I,2V)=2S(I,V)
`property-roundtrip-va-amps-va`	property	pass	VA→A recovers I
`property-three-phase-sqrt3`	property	pass	S3φ=√3·V·I
`property-pf-omitted-equals-pf-one`	property	pass	S(λ omitted)=S(λ=1)
`property-pf-zero-equals-omitted`	property	pass	S(λ=0)=S(λ omitted)
`property-roundtrip-grid`	property	pass	VA↔A round-trip over 64 pairs
`property-derived-pf-08`	property	pass	12 A × 230 V × λ0.8 → S=2760 VA, P_est=2208 W
`property-derived-pf-zero`	property	pass	10 A × 120 V × λ0 → S=1200 VA, P_est=0 W
`property-derived-pf-omitted`	property	pass	power_factor absent → derived omitted
`property-derived-zero-s`	property	pass	S=0 with λ supplied → P_est=0 W and note