Formula
Single Phase: W = V × A × PF
Three Phase: W = √3 × V × A × PF
√3 = 1.7321
Single phase, 230V, 10A, PF=1.0:
W = 2,300W = 2.3 kW
3-phase 415V 10A: 7,188W
Frequently Asked Questions
At 230V single phase with unity PF, 1 amp = 230 watts. At 120V (US), 1 amp = 120 watts. Formula: W = V × A × PF.
PF is the ratio of real power (W) to apparent power (VA). Motors have PF 0.7–0.9, meaning more current than strictly needed for the power delivered.
W = √3 × V(line) × I(line) × PF. Example: 415V, 20A, PF=0.85: W = 1.732 × 415 × 20 × 0.85 = 12,215W.