1. What is 3-Phase Current?

Three-phase current is the electric current flowing in a three-phase electrical power system. It's commonly used in industrial and commercial applications due to its efficiency in power transmission and ability to power large motors.

2. How Does the Calculator Work?

The calculator uses the 3-phase current formula:

Where:

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

Explanation: The formula converts kW to watts (×1000), accounts for 3-phase power (√3), and divides by voltage and power factor to get current.

3. Importance of Current Calculation

Details: Accurate current calculation is essential for sizing wires, circuit breakers, and other electrical components to ensure safe and efficient operation of electrical systems.

4. Using the Calculator

Tips: Enter power in kW, line-to-line voltage in volts, and power factor (typically 0.8-1.0 for most systems). All values must be positive (power > 0, voltage > 0, 0 < PF ≤ 1).

5. Frequently Asked Questions (FAQ)

Q1: What is power factor?
A: Power factor is the ratio of real power (kW) to apparent power (kVA). It represents how effectively current is being converted into useful work.

Q2: Why use line-to-line voltage?
A: In 3-phase systems, line-to-line voltage is the standard measurement between any two phases, and most equipment ratings are based on this value.

Q3: What's typical power factor for motors?
A: Induction motors typically have a power factor of 0.85-0.90 at full load, lower at partial loads. Power factor correction may be needed.

Q4: How does this differ from single-phase current calculation?
A: Single-phase uses I = P/V without the √3 factor. Three-phase is more efficient for the same power transfer.

Q5: What safety margin should I add?
A: For practical applications, add 10-20% margin to the calculated current for safety and future expansion.