Complete Guide to Phase Conversion: Single vs Three Phase Systems
The Phase Conversion Calculator converts power, voltage, current between single-phase and three-phase. Essential for motor sizing, transformer selection.
Single vs Three Phase
Single Phase: 1 hot + neutral. Residential.
Three Phase: 3 hots (Δ or Y). Industrial, balanced.
Power Formulas
Single: P = V × I × PF
Three: P = √3 × V_L × I_L × PF
Conversion Rules
- Power: Same total power
- Current: 3-phase carries more per conductor
- Voltage: V_phase = V_line / √3 (Y)
Why Convert?
- Run 3-phase motor on single: Phase converter
- Size conductors: Different currents
- Transformer banks: Open delta
Use with 3-Phase Load and Motor Load.
Formulas Summary
| Type | Formula |
|---|---|
| Single → 3-Phase Power | Same kW |
| 3-Phase → Single Power | Same kW |
| Line → Phase Voltage | V_p = V_l / √3 |
| Phase → Line Voltage | V_l = V_p × √3 |
| Current (3-phase) | I_l = P / (√3 × V_l × PF) |
Voltage Relationships
| System | Line Voltage | Phase Voltage |
|---|---|---|
| 120/208Y | 208 V | 120 V |
| 277/480Y | 480 V | 277 V |
| 240 Δ | 240 V | 240 V |
Calculation Steps
- Identify system: Δ or Y
- Apply √3 factor
- Include PF
- Verify units
Example: 10 kW Single Phase
- 240 V, PF=0.9 → I = 10,000 / (240 × 0.9) ≈ 46.3 A
- Same 10 kW on 480 V 3-phase → I = 10,000 / (√3 × 480 × 0.9) ≈ 13.3 A
Phase Converters
- Rotary: Motor-generator
- Static: Capacitor start
- VFD: Electronic
Common Mistakes
- Forgetting √3: Voltage/current error
- Using kVA vs kW: Include PF
- Delta vs Wye: Different voltages
Applications
- Farms: 3-phase pumps on single
- Shops: CNC on single phase
- HVAC: 3-phase chillers
Advanced Topics
- Open Delta: 2 transformers → 86.6% capacity
- Scott-T: 3-phase to 2-phase
- Harmonics: 3rd in neutral
FAQs
Can I run 3-phase on single? Yes — with converter.
Why 1.732? √3 ≈ 1.732
Is power the same? Yes — total energy.
Conclusion
Phase conversion ensures proper sizing and operation. Our Phase Conversion Calculator simplifies design. Optimize with 3-Phase Load, Motor Load, and Construction tools. Power smart with 1000 Calculators.