Three-Phase Current Calculator

Three-phase electrical systems power most industrial equipment, and knowing the current drawn is critical for safe wiring, breaker sizing, and motor selection. Enter your Power (kW), Line Voltage (V), and Power Factor into the Three-Phase Current Calculator, then select your Connection Type (Star or Delta) to get the Line Current in amps. Secondary outputs include Phase Current, Apparent Power (kVA), and Reactive Power (kVAR).

kW

Enter the three-phase power in kilowatts

V

Enter the line-to-line voltage in volts

Enter power factor between 0.1 and 1.0

Results

Line Current

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Phase Current

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Apparent Power

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Reactive Power

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Frequently Asked Questions

How do I calculate three-phase current?

Three-phase current is calculated using the formula: I = P / (√3 × V × PF), where I is current in amperes, P is power in watts, V is line voltage, and PF is power factor. For star connections, line current equals phase current, while for delta connections, line current is √3 times phase current.

What is the difference between line current and phase current?

In a star (Y) connection, line current equals phase current. In a delta (Δ) connection, line current is √3 (1.732) times larger than phase current. This difference is due to how the currents combine at the junction points in each configuration.

What is apparent power in a three-phase circuit?

Apparent power is the total power in a three-phase circuit, measured in kVA (kilovolt-amperes). It represents the combination of active power (real power that does work) and reactive power (power that oscillates between source and load). Apparent power = √3 × V × I.

What is reactive power and why does it occur?

Reactive power is the power that oscillates between the source and load due to inductive or capacitive elements in the circuit. It doesn't perform useful work but is necessary for creating magnetic fields in motors and transformers. It's measured in kVAR and calculated as: Q = P × tan(arccos(PF)).

What are typical power factor values for different devices?

Typical power factors vary by device: resistive heaters (1.0), incandescent lamps (1.0), fluorescent lamps (0.5-0.95), electric motors (0.8-0.9), and welding equipment (0.7-0.9). Higher power factors indicate more efficient power usage.

What is the difference between star and delta connections?

In star (Y) connections, one end of each phase winding connects to a common neutral point, while the other ends connect to supply lines. In delta (Δ) connections, windings form a closed loop. Star connections provide a neutral point and lower phase voltage, while delta connections provide higher power capacity.

How do I calculate apparent power using line voltage and current?

Apparent power in a three-phase system is calculated as: S = √3 × VL × IL, where S is apparent power in VA, VL is line voltage, and IL is line current. The √3 factor (1.732) accounts for the phase relationship in three-phase systems.