Power Calculation Formula for 3 Phase Cable

3-Phase Power Formula:

\[ P = \sqrt{3} \times V \times I \times PF \]

Voltage (V):

volts (V, line-to-line)

Current (I):

amperes (A)

Power Factor (PF):

(unitless, 0 to 1)

Power (P):

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1. What is 3-Phase Power Calculation?

The 3-phase power calculation formula determines the real power in a balanced three-phase electrical system. It's essential for sizing cables, circuit breakers, and electrical equipment in industrial and commercial applications.

2. How Does the Calculator Work?

The calculator uses the 3-phase power formula:

\[ P = \sqrt{3} \times V \times I \times PF \]

Where:

\( P \) — Real power in watts (W)
\( V \) — Line-to-line voltage in volts (V)
\( I \) — Current in amperes (A)
\( PF \) — Power factor (unitless, between 0 and 1)
\( \sqrt{3} \) — Constant for 3-phase systems (≈1.732)

Explanation: The formula accounts for the phase difference in three-phase systems and the power factor which represents the ratio of real power to apparent power.

3. Importance of Power Calculation

Details: Accurate power calculation is crucial for electrical system design, ensuring proper cable sizing, overload protection, and energy efficiency in three-phase installations.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between line-to-line and line-to-neutral voltage?
A: In 3-phase systems, line-to-line voltage is √3 times the line-to-neutral voltage (e.g., 400V line-to-line = 230V line-to-neutral).

Q2: Why is power factor important?
A: Lower power factor means more current is required for the same real power, increasing losses and requiring larger conductors.

Q3: What's typical power factor for different loads?
A: Motors: 0.8-0.9, Incandescent lights: 1.0, Fluorescent lights: 0.5-0.9, Induction furnaces: 0.7-0.85.

Q4: How does this differ from single-phase power calculation?
A: Single-phase uses P = V × I × PF without the √3 factor, as there's no phase difference to account for.

Q5: What about unbalanced three-phase systems?
A: This calculator assumes balanced load. For unbalanced systems, calculate each phase separately and sum the powers.