The three sides
The power triangle is a right triangle where kW is the horizontal side, kVAR is the vertical side, and kVA is the hypotenuse.
This shape mirrors the relationship between real power, reactive power, and apparent power in AC circuits.
Useful formulas
The power triangle gives several practical formulas. Power factor equals kW divided by kVA. Reactive power can be found from the difference between apparent power squared and real power squared.
These relationships are especially useful when sizing capacitor banks or checking whether a transformer has enough remaining capacity.
- Power factor = kW / kVA
- kW = kVA x power factor
- kVAR = square root of (kVA squared - kW squared)
Reading the angle
The angle between kW and kVA is the power factor angle. A smaller angle indicates a higher power factor and less reactive component.
As reactive power increases, the triangle becomes taller and apparent power rises even if useful kW stays the same.