Enter your system's Power (kW), Line Voltage (V), Power Factor, and Connection Type into the Three-Phase Current Calculator, and it'll work out your Line Current alongside Phase Current, Apparent Power, and Reactive Power — whether you're wiring a star or delta setup.
Line Current
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Phase Current
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Apparent Power
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Reactive Power
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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.
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.
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.
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)).
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.
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.
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.