1. What is the 3-Phase Power Formula?

The 3-phase power formula calculates current (amperes) from power (watts), voltage (volts), and power factor. It's essential for electrical system design, load calculations, and equipment sizing in three-phase power systems.

2. How Does the Calculator Work?

The calculator uses the 3-phase power formula:

Where:

• \( I \) — Current in amperes (A)
• \( P \) — Power in watts (W)
• \( V \) — Line-to-line voltage in volts (V)
• \( PF \) — Power factor (unitless, 0 to 1)
• \( \sqrt{3} \) — Approximately 1.732 (constant for 3-phase systems)

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

3. Importance of Power Factor

Details: Power factor is crucial in AC circuits as it indicates how effectively electrical power is being converted into useful work. A lower power factor means higher current is required for the same real power.

4. Using the Calculator

Tips: Enter power in watts, line-to-line voltage in volts, and power factor (typically 0.8-0.95 for industrial loads). All values must be positive (power > 0, voltage > 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. This calculator uses line-to-line voltage.

Q2: What is a typical power factor value?
A: For motors, 0.8-0.9 is common. Resistive loads have PF=1. Always check equipment specifications for exact values.

Q3: Why is √3 used in the formula?
A: It accounts for the 120° phase difference between the three phases in a balanced system.

Q4: Can I use this for single-phase calculations?
A: No, for single-phase use I = P/(V×PF) without the √3 factor.

Q5: How does power factor affect current?
A: Lower power factor means higher current for the same real power, which increases conductor sizing requirements.