Generator Power Output

How to use this calculator

Apparent power is S = V·I (single-phase) or S = √3·V·I (three-phase, line-to-line voltage and line current). Real power is Pout = S·PF. The mechanical input power is Pin = Pout / η, and the difference is the generator's losses. Choose the phase, enter the voltage, current, power factor and efficiency, and all values update live.

What it means in a real circuit

For a 3-phase, 400 V, 100 A generator at PF 0.8 and 90% efficiency: S = √3×400×100 ≈ 69.3 kVA, Pout ≈ 55.4 kW, and Pin ≈ 61.6 kW (about 6.2 kW lost as heat). The power factor tells you how much of the apparent power is actually doing work — an inductive load (PF < 1) wastes capacity. Use this to size a generator for a given load, to check that it's not overloaded, and to estimate the fuel/energy it must consume.