3-Phase Power Calculator
Calculate Real, Apparent, and Reactive Power
Calculation Results:
Real Power (kW):
0.00
Apparent Power (kVA):
0.00
Reactive Power (kVAR):
0.00
Total Phase Amps:
0.00
Understanding 3-Phase Power Calculations
Three-phase electrical systems are the standard for industrial and commercial power distribution worldwide. Calculating the power consumption or output of these systems requires an understanding of voltage, current, and the "power factor."
The 3-Phase Power Formula
The primary formula used to calculate Real Power (P) in a balanced three-phase system is:
P (Watts) = V × I × √3 × PF
- V (Voltage): The line-to-line voltage (not line-to-neutral).
- I (Current): The current in one of the phases (assuming a balanced load).
- √3 (Square Root of 3): A constant (approximately 1.732) that accounts for the phase displacement between the three legs.
- PF (Power Factor): The ratio of real power to apparent power, ranging from 0 to 1.
Real vs. Apparent vs. Reactive Power
In AC circuits, power is categorized into three types, often represented by the "Power Triangle":
- Real Power (kW): The actual work being done (e.g., turning a motor or heating an element).
- Apparent Power (kVA): The total power delivered to the system. It is the product of voltage and current multiplied by √3.
- Reactive Power (kVAR): Power that circulates between the source and the load, usually caused by inductive loads like motors and transformers. It does no useful work but takes up capacity in the wires.
Example Calculation
Suppose you have a 3-phase motor running at 480 Volts with a measured current of 50 Amps and a power factor of 0.85.
- Apparent Power (kVA): (480 × 50 × 1.732) / 1000 = 41.57 kVA
- Real Power (kW): 41.57 × 0.85 = 35.33 kW
- Reactive Power (kVAR): √(kVA² – kW²) = 21.90 kVAR