Electrical • Distribution Microsoft Excel (.xlsx)
Transformer Sizing
Transformer rating from diversified load with margin.
Download Excel Workbook (.xlsx)
Version 0.1
What this workbook is
A real, downloadable Microsoft Excel workbook — not a rendered demo. Every sheet is built around a single engineering method: inputs in one place, calculated results and a PASS / WARN / FAIL check sheet, with the method, sources and assumptions recorded next to the numbers. Open it in Excel, Sheets or LibreOffice, change the inputs, and the workbook recalculates.
- Light cells are user-entered inputs on the Inputs sheet.
- Dark cells are calculated automatically and are not editable.
- The method and sources for every calculation are listed below and inside the workbook.
What you enter
- ✓Diversified load kVA
- ✓Power factor
- ✓Margin %
- ✓Ambient derate (user)
What it calculates
- ✓Required kVA
- ✓Selected rating
- ✓Load % at rating
Method
Rating = load / (√3·V·pf) × (1+margin) × derate
Sources
- [1] IEEE C57 (rating practice; method-level)
Inside the workbook
CoverTitle, scope and revision block
SummaryCore inputs and headline results
InputsYour project values (light cells)
CalculationsStep-by-step working sheet (dark cells)
OutputsReadback of results for reporting
ChecksPASS / WARN / FAIL against stated limits
ReferenceSources for each calculation
Notes & AssumptionsScope, exclusions and stated limits