Three Phase Power Calculator
Calculation Results
What Is Three-Phase Power?
Three-phase power is an electrical system that uses three alternating voltages, each separated by 120 electrical degrees. Instead of one fluctuating power source, three-phase systems provide continuous and balanced power.
Why Three-Phase Power Is Used
Three-phase power is preferred because it:
- Delivers more power using less conductor material
- Runs motors more smoothly with less vibration
- Improves efficiency in industrial equipment
- Reduces power losses over long distances
This is why most motors, pumps, compressors, and large machines operate on three-phase electricity.
Purpose of a Three Phase Power Calculator
A Three Phase Power Calculator helps you quickly determine:
- Apparent power (kVA)
- Real or active power (kW)
- Reactive power (kVAR)
- Motor shaft power (kW and HP)
Instead of doing complex calculations by hand, the calculator produces accurate results instantly based on standard electrical formulas.
Inputs Used in the Three Phase Power Calculator
Understanding the inputs ensures accurate results and better system design.
Line Voltage (VL-L)
Line voltage is the voltage measured between any two phases.
Example values:
- 415 V (common in many countries)
- 480 V (industrial systems)
Higher voltage allows more power transfer with lower current.
Line Current (I)
Line current is the current flowing through each phase conductor.
Measured in: Amperes (A)
Higher current usually means higher power demand, but it also increases heat and losses.
Power Factor (PF)
Power factor represents how effectively electrical power is converted into useful work.
- Range: 0 to 1
- Typical industrial value: 0.8 to 0.9
A low power factor means more wasted energy and higher electricity costs.
Motor Efficiency (η)
Efficiency shows how much electrical input power becomes mechanical output power.
Example efficiencies:
- 95% – Premium efficiency motors
- 90% – High efficiency motors
- 80–85% – Standard motors
Higher efficiency means less energy loss and lower operating cost.
System Configuration
The calculator supports multiple system types:
- 3-Phase Wye or Delta (Standard)
- 3-Phase Open Delta
- 2-Phase Scott-T System
Each system uses a different constant in the power formula to reflect real-world electrical behavior.
Power Calculations Explained in Simple Terms
The calculator performs several important calculations behind the scenes.
Apparent Power (kVA)
Apparent power is the total power supplied to the system.
It depends only on voltage, current, and system configuration.
Why it matters:
It determines transformer size, generator capacity, and cable ratings.
Real Power (kW)
Real power is the usable power that actually performs work.
It accounts for power factor, which reflects losses due to inductive loads like motors.
Why it matters:
Utilities bill customers based on real power consumption.
Reactive Power (kVAR)
Reactive power supports the magnetic fields required by motors and transformers.
It does not perform useful work but is necessary for system operation.
Why it matters:
High reactive power increases current and reduces system efficiency.
Motor Shaft Power (kW and HP)
Shaft power represents the mechanical output of the motor after efficiency losses.
The calculator also converts this value into horsepower (HP), which is commonly used for motor sizing.
1 HP ≈ 746 watts
Formula Used in the Calculator
For a standard three-phase system, the calculator uses:
P = √3 × V × I × PF × η
This formula follows industry practice and aligns with IEEE Standard 112, making it suitable for industrial analysis.
The calculator automatically adjusts the constant depending on the selected system type.
How to Use the Three Phase Power Calculator
- Enter the line voltage
- Enter the line current
- Set the power factor
- Choose the motor efficiency
- Select the system configuration
- Click Calculate Power
Results appear instantly, showing kVA, kW, kVAR, and shaft power.
Practical Applications of the Calculator
This calculator is useful in many real-world scenarios, including:
- Motor sizing and selection
- Electrical load estimation
- Energy efficiency analysis
- Power factor correction planning
- Industrial equipment design
- Educational and training purposes
It helps engineers make informed decisions before installing or upgrading electrical systems.
Common Mistakes to Avoid
- Entering phase voltage instead of line voltage
- Using unrealistic power factor values
- Ignoring motor efficiency
- Assuming all three-phase systems behave the same
Accurate inputs lead to reliable results.
