POWER FACTOR

hello friends.

can u help me with this confusion.

Given

if power factor is given as lagging for example pf .8 lagging

so angle would be = + ( positive) ( inductive)

and if power factor is given as leading for example Pf 08 leading

so angle would be = - (negative) (capacitive)

FIND I ( current) = S / 1.732 * V ( line) angle for lagging will be -ve or positve for leading ? ( other will be vice verse)

in some book its opposite. very confused.

i got the concept of power factor lagging and leading , just numerically confused

thank you

i am confused because some book are taking a leading angle as positive and lagging as negative !

S=VI*

The sign of the angle for power will be the opposite of the angle for the current.

ops i forgot .

but even before this step .......... if pf lagging, the angle will always be +ve

and in case of leading angle is always - ve

thank you

And beware the differences between P and S.

S should be a vector, P is a scalar.

I always do these as vectors. Some books get confusing to me when with the trig formulas.

Because power factor is cos phi, it will yield a positive number whether current I is lagging voltage V (phi negative) or whether current I is leading voltage V (phi positive). Hence it has to be clarified in the form "power factor = 0.8 (leading) or 0.8 (lagging). Just remember that inductance is representative of INERTIA in the system, so if the circuit is net inductive, current will LAG voltage, while if the circuit is net capacitive, current will LEAD voltage.

As far as the sign of the angle, use the source (VOLTAGE) as the reference. So, if current lags voltage, phi is negative and if current leads voltage, phi is positive