Donaldson R F Power Factor Calculator
Find power factor, apparent power (kVA) and reactive power (kVAR) for an AC electrical load.
The power triangle
Real power (kW) does useful work. Reactive power (kVAR) is drawn by motors, transformers and other inductive loads but does no useful work. Apparent power (kVA) is what the supply actually has to deliver, and is the hypotenuse of a right triangle with kW and kVAR as the other two sides: kVA² = kW² + kVAR². Power factor is the ratio kW ÷ kVA — a power factor of 1 means all the apparent power is doing useful work; a low power factor means a supply is working harder (and a bigger cable/transformer is needed) for the same useful output.
Source: standard AC power-triangle identities, e.g. Engineering ToolBox: Power Factor.
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