Harmonic distortion indicators - Power factor: Difference between revisions
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== Definition == | |||
The power factor PF is the ratio between the active power P and the apparent power S. | The power factor PF is the ratio between the active power P and the apparent power S. | ||
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<math>\cos \phi=\frac{P1}{S1}</math><br>Where<br>P1 = active power of the fundamental<br>S1 = apparent power of the fundamental<br>The cos<span class="texhtml">φ</span> concerns exclusively the fundamental frequency and therefore differs from the power factor PF when there are harmonics in the installation. | <math>\cos \phi=\frac{P1}{S1}</math><br>Where<br>P1 = active power of the fundamental<br>S1 = apparent power of the fundamental<br>The cos<span class="texhtml">φ</span> concerns exclusively the fundamental frequency and therefore differs from the power factor PF when there are harmonics in the installation. | ||
== Interpreting the power factor == | |||
An initial indication that there are significant amounts of harmonics is a measured power factor PF that is different (lower) than the measured cos ϕ. | An initial indication that there are significant amounts of harmonics is a measured power factor PF that is different (lower) than the measured cos ϕ. | ||
Revision as of 08:57, 16 June 2011
Definition
The power factor PF is the ratio between the active power P and the apparent power S.
[math]\displaystyle{ PF=\frac{P}{S} }[/math]
Among electricians, there is often confusion with:
[math]\displaystyle{ \cos \phi=\frac{P1}{S1} }[/math]
Where
P1 = active power of the fundamental
S1 = apparent power of the fundamental
The cosφ concerns exclusively the fundamental frequency and therefore differs from the power factor PF when there are harmonics in the installation.
Interpreting the power factor
An initial indication that there are significant amounts of harmonics is a measured power factor PF that is different (lower) than the measured cos ϕ.
