1. What is 3-Phase Power Calculation?

The 3-phase power calculation determines the real power consumed by an electric motor or generator in kilowatts (kW). It accounts for voltage, current, power factor, and the √3 constant for three-phase systems.

2. How Does the Calculator Work?

The calculator uses the 3-phase power formula:

Where:

• \( P \) — Power in kilowatts (kW)
• \( V \) — Line voltage (volts)
• \( I \) — Current (amps)
• \( PF \) — Power factor (0-1)
• \( \sqrt{3} \) — Constant for 3-phase systems (≈1.732)

Explanation: The formula calculates real power by accounting for the phase difference between voltage and current in AC systems.

3. Importance of Power Factor

Details: Power factor (PF) represents the ratio of real power to apparent power. A higher PF (closer to 1) indicates more efficient power usage, while lower PF means more reactive power is being wasted.

4. Using the Calculator

Tips: Enter line-to-line voltage in volts, current in amps, and power factor (typically 0.8-0.95 for motors). All values must be positive numbers (voltage > 0, current > 0, 0 < PF ≤ 1).

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between real and apparent power?
A: Real power (kW) does actual work, while apparent power (kVA) is the product of voltage and current. The ratio is the power factor.

Q2: Why divide by 1000 in the formula?
A: This converts the result from watts to kilowatts (1 kW = 1000 W) for more practical units.

Q3: What's a typical power factor for motors?
A: Induction motors typically have PF of 0.85-0.9 at full load, dropping to 0.2-0.3 at no load.

Q4: Can this be used for single-phase systems?
A: No, single-phase uses P = V × I × PF / 1000 (without the √3 factor).

Q5: How does this help with generator sizing?
A: The calculated kW helps determine the minimum generator capacity needed, though startup currents may require larger capacity.