Three-Phase Power Calculator
Three-phase power systems are the backbone of industrial and commercial electrical distribution. This calculator computes apparent power (kVA), real power (kW), and reactive power (kVAR) using the formula P = sqrt(3) x V x I x pf, along with line and phase current relationships for star and delta configurations.
Three-phase power uses three alternating currents 120° apart, providing constant power delivery and more efficient use of conductors than single-phase. The total power is P = √3 × Vline × Iline × cos(φ), where cos(φ) is the power factor.
In a star (Y) configuration, each winding connects between a line and the neutral point. The phase voltage is Vline/√3, and the line current equals the phase current. In a delta (Δ) configuration, each winding connects between two lines. The phase voltage equals the line voltage, but the line current is √3 times the phase current.
The power factor represents the ratio of real power to apparent power. Inductive loads (motors, transformers) cause the current to lag the voltage, reducing the power factor below 1. Low power factor means more current is needed to deliver the same real power, increasing losses and requiring larger conductors. Power factor correction capacitors are commonly installed to improve the power factor toward unity.