Transformer Tap Voltage Calculator
Estimate ideal secondary voltage from actual supply voltage, a selected primary nameplate tap, and nominal secondary voltage.
Enter nameplate or test values
Estimated secondary voltage
About this calculator
Estimate ideal secondary voltage from actual supply voltage, a selected primary nameplate tap, and nominal secondary voltage.
This is a no-load ideal-ratio estimate. Use the actual nameplate tap values. It is not an instruction to change taps; follow the manufacturer’s de-energized tap-change procedure.
Method and assumptions
Estimated secondary voltage = nominal secondary voltage × actual primary supply voltage ÷ selected primary tap voltage. The voltage change is compared with the nominal secondary value.
Enter manufacturer nameplate or test data for the exact transformer and operating condition. Default values are examples and should be replaced with project data.
FAQs
Does this provide wiring or switching instructions?
No. It estimates electrical quantities from entered values. Follow manufacturer diagrams, safe work procedures, and qualified design review for any equipment application.
Are these results equipment approval or certification?
No. Confirm ratings, test conditions, load profile, thermal limits, and applicable installation requirements independently.
Sources
Transformer nameplate or test data supplied by the user and the ideal relationships described above.