How to Calculate Three Phase
What is Three Phase?
Analyzes three-phase AC power systems used in industrial applications. Calculates power, current, and relationships between phases.
Formula
Line voltage = phase voltage × √3
Step-by-Step Guide
- 1Three sinusoidal voltages 120° apart
- 2Line voltage = phase voltage × √3
- 3Line current = phase current (Y-connection) or √3 × phase current (delta)
- 4Power = √3 × V × I × PF
Worked Examples
Input
Line voltage 480V
Result
Phase 277V
Common Mistakes to Avoid
- ✕Confusing line voltage with phase voltage
- ✕Applying single-phase formulas to three-phase
Frequently Asked Questions
Why is three-phase used in industry?
More efficient power distribution, smaller cables, smoother motors, better line utilization.
What's Y vs. delta connection?
Y (star): common on supply side, neutral available; delta: high voltage, no neutral.
Ready to calculate? Try the free Three Phase Calculator
Try it yourself →