Calculate Total Current in 3 Phase

3-Phase Current Formula:

\[ I = \frac{P_{kW} \times 1000}{V \times PF \times \sqrt{3}} \]

Current (I): amps

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1. What is 3-Phase Current Calculator?

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

Purpose: It helps electricians, engineers, and technicians properly size conductors, circuit breakers, and other electrical components.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ I = \frac{P_{kW} \times 1000}{V \times PF \times \sqrt{3}} \]

Where:

\( I \) — Line current (amps)
\( P_{kW} \) — Power (kilowatts)
\( V \) — Line-to-line voltage (volts)
\( PF \) — Power factor (unitless, 0-1)

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

3. Importance of 3-Phase Current Calculation

Details: Accurate current calculation ensures safe and efficient electrical system design, preventing overheating and voltage drops.

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's the difference between line and phase current?
A: In star (wye) systems, line current equals phase current. In delta systems, line current is √3 times phase current.

Q2: What's a typical power factor value?
A: Motors typically have 0.8-0.9 PF, while resistive loads have 1.0. Always check equipment specifications.

Q3: Why √3 in the formula?
A: √3 accounts for the 120° phase difference between voltages in three-phase systems.

Q4: Can I use this for single-phase systems?
A: No, use I = P×1000/(V×PF) for single-phase. Remove the √3 factor.

Q5: How do I measure actual current?
A: Use a clamp meter on one conductor while the system is under normal load.