Apparent Power is the product of the rms voltage times rms current
Apparent Power = E-rms x I-rms <—- also called (VA)
The single phase (θ) power factor of a load is a ratio of real or true power (EI cos θ) to the apparent power (EI or volt-amperes). In sinusoidal applications, power factor is related to the phase angle between voltage and current as:
You may also examine the vector relationship Power Factor has with harmonics in the Advanced Power measurement topics chapter of this handbook. Valhalla’s 2110 Power Factor Wattmeter series directly provides the operator with a display of power factor from zero to unity with 0.001 resolution.
In addition, all Valhalla Digital Wattmeters provide a true watt (EI cos θ) direct measurement and simultaneously display selectable volt-ampere parameters to allow the calculation of power factor. Power factor can range in value from 1 to zero depending upon load circuitry being resistive, inductive or capacitive.
In non-sinusoidal volt-ampere waveform applications, power factor values provide more insight into the nature of the load circuit than does phase angle (since phase angle primarily describes sinewave relationships of the same frequency).