Three-Phase Power - Equations
Calculate three-phase power parameters including real power, apparent power, and brake horsepower using line-to-line or line-to-neutral voltages.
Three-Phase Power Calculator
This calculator computes real power, apparent power, and brake horsepower for three-phase AC systems. Three sinusoidal voltages are generated out of phase with each other.
Power Types:
- Real Power (W): Actual power consumed by resistive loads
- Apparent Power (VA): Total power in the circuit
- Brake Horsepower (hp): Actual power delivered to/by a shaft
Equations
Real Power (Line to Line):
- W = √3 × Ull × I × PF
Real Power (Line to Neutral):
- W = 3 × Uln × I × PF
Apparent Power:
- W = √3 × U × I (line to line)
- W = 3 × U × I (line to neutral)
Brake Horsepower:
- BHP = (√3 × U × I × PF × μ) / 746
where:
- U = Voltage (V)
- I = Current (A)
- PF = Power Factor (0.7 - 0.95)
- μ = Device Efficiency
- √3 ≈ 1.732
Typical Power Factors
| Device | Power Factor |
|---|---|
| Lamp, fluorescent uncompensated | 0.5 |
| Lamp, fluorescent compensated | 0.93 |
| Lamp, incandescent | 1.0 |
| Motor, induction 100% load | 0.85 |
| Motor, induction 50% load | 0.73 |
| Motor, induction 0% load | 0.17 |
| Motor, synchronous | 0.9 |
| Oven, resistive heating element | 1.0 |
| Oven, induction compensated | 0.85 |
| Pure resistive load | 1.0 |