1. What is 3-Phase Current?

Definition: This calculator determines the current in a three-phase electrical system based on power, voltage, and power factor.

Purpose: Essential for electrical engineers, technicians, and electricians to properly size wires, circuit breakers, and other electrical components.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( I \) — Current (amperes)
• \( P_{kW} \) — Power (kilowatts)
• \( V \) — Line-to-line voltage (volts)
• \( PF \) — Power factor (unitless, between 0 and 1)

Explanation: The formula converts kW to watts (×1000), then divides by the product of voltage, power factor, and √3 (approximately 1.732) which is the factor for three-phase systems.

3. Importance of 3-Phase Current Calculation

Details: Accurate current calculation ensures proper equipment sizing, prevents overheating, and maintains system efficiency in three-phase power systems.

4. Using the Calculator

Tips: Enter the power in kW, line-to-line voltage (default 480V), and power factor (default 0.8). All values must be > 0, with PF between 0.01 and 1.

5. Frequently Asked Questions (FAQ)

Q1: What is power factor and why does it matter?
A: Power factor represents the ratio of real power to apparent power. Lower PF means more current is needed for the same real power.

Q2: What's a typical voltage for 3-phase systems?
A: Common voltages include 208V, 240V, 480V (North America), and 400V (Europe). Always verify your system voltage.

Q3: When would I use a different power factor?
A: Motors typically have PF of 0.8-0.9, while purely resistive loads have PF=1. Check equipment specifications.

Q4: How does this differ from single-phase current calculation?
A: Single-phase uses \( I = P/(V \times PF) \) without the √3 factor.

Q5: What if I know power in HP instead of kW?
A: First convert HP to kW (1 HP ≈ 0.746 kW) before using this calculator.