Power Factor

You are at least correct about cos φ, inductive lagging, and capacitive leading. Your reasoning sounds correct also, but I haven't seen it expressed that way before, so I'm not totally sure.

While your assessment "P.F= COSine of angle between V & I" is precisely correct further assessment falls short of expectations; Do take into account of the time i.e. Time Constant.

In an inductive circuit the inductance causes delay for the current in reaching its final value and in a capacitive circuit the voltage is time delayed in reaching its final value.

How and why these time delays happen has nothing to do with P.F.

Ok.. I agree.. But please explain How Inductance causes lagging power factor..?

I agreed with you .

Now ,I am trying to make you understand........why lagging is happening .........

The lag is the amount of settling time required for all the field effects to be overcome.

The shape of a coil (inductor) with current through it creates a magnetic field (ex: electromagnet). A magnetic field changing near such a coil induces current in the coil. (ex: generator)

When current is increased the magnetic field is increased.
When the magnetic field increases it induces current in the coil in the opposite direction.
When current is decreased the magnetic field decreases.
When the magnetic field decreases, it induces current in the coil in the opposite direction.

Two oppositely charge plates (a capacitor) creates an electric field between them.

When voltage is increased the electric field is increased.
When the electric field is increases, it induces voltage between the plates in the opposite direction.
When voltage is decreased the electric field decreases.
When the electric field decreases, it induces voltage between the plates in the opposite direction.

That is what happens, thus the "lag". The lag is the amount of settling time required for all the field effects to be overcome.

Anyone have any other explanation?

http://en.wikipedia.org/wiki/Power_factor

Hi Good day to all CR4 members..

Will someone elobarate on --> When the magnetic field decreases, it induces current in the coil in the opposite direction...

it explained by Manvendra.....

I am explaining my concept why capacitor have leading current and inductor having lagging current,

Cosider the initial condition of capacitor is fully discharged.

When we are applying a voltage across capacitor initially capacitor will act as a short circuit (Because it is empty and charge will rush into the capacitor) so volage will be zero. When charge accumalation in the capacitor increases current flow decreases and voltage getting higher. Finally capacitor getting full of charge and current flow decreases and volage (Vmax) will be formed between two plates.

Vice versa in case of discharging. When we are plotting this voltage and current against time we can see 90 degree leading of current.

In case of inductor because of inductance voltage is forming first then current flow starts slowly increases and getting full of charged as magnetic field. At that moment no factor for inductor to oppose (Since there is no rate of change in current flow) as a result voltage will be zero.

When we plotting this waves we can observe that current is lagging 90 degree

does the above explaination given by justinanto1987 is true in the case of charged capacitors and Inductor..???

It is already explained

''Vice versa in case of discharging''

i thought this was a forum for engineers............??????

Hi SAK why you are thinking like this..?