Engine and documentation history
Changelog
Every engine change and every correction is recorded here. When a result was wrong, it is listed, not quietly fixed.
Engine 0.6.1 2026-09-28
Correction- Ground rod: mutual resistance between rods now uses the logarithmic rod-to-rod expression instead of the hemisphere approximation, which overstated it at close spacing. Combined resistances for closely spaced rods are slightly lower than before.
- Cable check (Workbench): feeders serving only single-phase loads now use the single-phase current formula.
- Printable screening report from the Workbench; Korean interface option; quick add of loads from a pasted list; security headers and rate limiting.
Update 2026-09-28
Phase 5- Three more data center templates: distributed redundant UPS, block redundant (catcher) UPS, paralleled generators.
- Report a problem from any result; the message includes the page and engine version, never your inputs.
Web update 2026-09-28
Phase 4- Compare two model files: differences by node and connection, and both models recalculated side by side.
- Reference: NEMA vs IP enclosures, ANSI device numbers, standard ratings.
Engine 0.6.0 · Schema 1.1 2026-09-28
Phase 3- Workbench: Loading & Headroom and batch Cable Check with an editable condition preset; overloaded elements and failing cables are marked on the canvas.
- Maintenance Checklist for six equipment types, printable, with instrument classes and document pointers and no pass/fail values.
- Correction: resilience survival ratios now count only upstream elements. Previously, adding unrelated branches could raise the score of a load. Scores for radial arrangements are lower than before.
- Schema 1.1 adds project settings; files saved with 1.0 are migrated on import.
Engine 0.5.0 2026-09-28
Phase 2- Workbench: Topology Editor with 13 generic templates, outage mode with automatic transfers, auto layout.
- Resilience Score (relative index, not an availability figure), SPOF Finder, scenario table and explain sentences.
- Methods: Resilience Score and Single Point of Failure.
Engine 0.4.0 2026-09-28
Phase 1- Tools: Power Factor Correction, kVA Triangle, Conduit Fill, Tray Fill, Ground Rod Resistance, IR Temperature Correction.
- Methods pages for each new tool.
- kVA Triangle, Tray Fill and IR Correction calculate in your browser; they use public formulas only.
Engine 0.3.0 2026-09-28
Phase 1- Tools: Full-Load Current, Transformer Secondary Short-Circuit, Unit Converter.
- Methods: Full-Load Current and Transformer Short-Circuit.
- Reference: Conductor Resistance, Full-Load Current tables, Unit Conversions, IR Temperature Correction, Voltage Systems, Wire Colors, EN–KR Glossary.
Engine 0.2.0 2026-09-28
Phase 1- Reference: AWG / kcmil to mm², generated from the AWG geometric definition, with CSV download.
- Tool: Cable Check — load current, ampacity per set, running and motor-starting voltage drop, with explained warnings.
- Methods: how Cable Check works, including what it does not check.
- Cable data comes from a library built from manufacturer data sheets; the source is cited with each result.
Engine 0.1.0 · Schema 1.0 2026-09-27
Foundation- Electrical Data Model v1 (JSON Schema) with migration framework.
- Workbench: empty model, JSON import / export, draft recovery in this browser.
- Compute API skeleton: health check, origin allow-list, per-IP rate limit, 2 MB request limit. Request bodies are not stored.
- Legal pages, About, and the screening banner on every page.