Formula for 3 Phase Power

3-Phase Power Formula:

\[ P_{kW} = \frac{V \times I \times PF \times \sqrt{3}}{1000} \]

Power (P_kW): kW

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1. What is 3-Phase Power Calculation?

Definition: This calculator computes the real power in kilowatts (kW) for a three-phase electrical system.

Purpose: It helps electricians, engineers, and technicians determine the actual power consumption in three-phase circuits.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ P_{kW} = \frac{V \times I \times PF \times \sqrt{3}}{1000} \]

Where:

\( P_{kW} \) — Real power (kilowatts)
\( V \) — Line-to-line voltage (volts)
\( I \) — Current (amperes)
\( PF \) — Power factor (unitless, between 0 and 1)
\( \sqrt{3} \) — Constant for three-phase systems (≈1.732)

Explanation: The formula accounts for all three phases and the phase difference between voltage and current.

3. Importance of 3-Phase Power Calculation

Details: Accurate power calculation ensures proper equipment sizing, energy efficiency, and electrical system safety.

4. Using the Calculator

Tips: Enter the line-to-line voltage in volts, current in amps, and power factor (default 0.8). All values must be > 0, with PF ≤ 1.

5. Frequently Asked Questions (FAQ)

Q1: What is power factor?
A: Power factor is the ratio of real power to apparent power, representing how effectively current is being converted into useful work.

Q2: Typical power factor values?
A: Motors: 0.8-0.9, Resistive loads: 1.0, Fluorescent lights: 0.7-0.9.

Q3: Line-to-line vs line-to-neutral voltage?
A: This calculator uses line-to-line (phase-to-phase) voltage, which is √3 times higher than line-to-neutral.

Q4: Why √3 in the formula?
A: The √3 accounts for the 120° phase shift between the three phases in a balanced system.

Q5: How to measure current?
A: Use a clamp meter on one phase conductor (the current should be balanced in all three phases).