How to use this calculator
Choose wye or delta, enter the line voltage and either the impedance per phase or the total power and power factor. Add a target power factor to size the correction capacitors.
Formulas
WyeVL = √3 Vφ, IL = Iφ
DeltaVL = Vφ, IL = √3 Iφ
PowerP = √3 VLIL cos θ, Q = √3 VLIL sin θ
Worked example
480 V line voltage, wye load of 8 + j6 Ω per phase (the default)
- Vφ = 480/√3 = 277.1 V and |Z| = 10 Ω, so IL = 27.7 A.
- P = 3 × 27.7² × 8 = 18.4 kW, Q = 13.8 kVAR, S = 23.0 kVA.
- pf = 0.8 lagging.
Frequently asked questions
Why correct the power factor?
Reactive current loads the lines and transformers without doing work. Capacitors supply it locally, lowering the line current and losses.