1. What is the 3-Phase Power Formula?

The 3-phase power formula calculates current (amperes) from power (watts) in a balanced three-phase electrical system. It accounts for the phase relationship between voltage and current through the power factor.

2. How Does the Calculator Work?

The calculator uses the 3-phase power formula:

Where:

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

Explanation: The formula converts real power to current in a 3-phase system, accounting for the phase difference between voltage and current through the power factor.

3. Importance of Power Factor

Details: Power factor represents the ratio of real power to apparent power. A lower power factor means more current is required to deliver the same amount of real power, increasing system losses.

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 (e.g., 400V line-to-line = 230V line-to-neutral).

Q2: Why is power factor important?
A: Low power factor increases current for the same real power, causing higher energy losses and requiring larger conductors.

Q3: What's a typical power factor value?
A: Induction motors: 0.85-0.9 at full load, fluorescent lights: 0.5-0.9, resistive loads: 1.0.

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

Q5: How does voltage affect the calculation?
A: Higher voltage requires less current for the same power, which is why transmission lines use high voltages.