Power Factor

.. because the COS ϕ gives you the real power, the Watt, the sin ϕ gives you the reactive power , the VAR.

Do a bit of study of basic circuit theory, refer to the phasor diagram of voltage and current, you will understand.

Here is one good explanation. Check the red options on the left for more info.

http://www.the-power-factor-site.com/

WHAT IS POWER FACTOR (PF)?

PF by definition is the ratio of real to apparent power:

PF=W / VA.

If you know trigonometry u can get the answer.
Else, study it to know the meaning of cosine of angle.

why we put the real power in X - axis :

what will happen if i put real power in Y - axis:

please tell me....

Good idea

Too bad it doesn't work.

To add to my awesome post, here is another famous explanation of PF.

The 'SIN' is above and the 'CAUSE' is below.

Quite true. But if engineering standards had chosen to define the power factor angle by the complimentary angle of this right triangle θ instead of φ on this diagram where θ+φ=π/2 then we would be using sinθ to calculate the real power.

A cos by any other name.....

V = Phasor (or some sort of a vector if you want it that way)

I - ditto

P = Scaler

P = V.I (dot product)

and as one knows from the vector dot products it is the cos components that multiply.

The component of one vector into the direction of of the other is the cosine multiplier where as the sine part is at the 90^o from it (and that infact if you look is the imaginary power)

The basic definition of power factor is Cos of angle between Applied voltage to a load and current through it.