Answer / suresh

The power factor of an AC electric power system is defined
as the ratio of the real power flowing to the load to the
apparent power [1] [2], and is a number between 0 and 1
(frequently expressed as a percentage, e.g. 0.5 pf = 50%
pf). Real power is the capacity of the circuit for
performing work in a particular time. Apparent power is the
product of the current and voltage of the circuit. Due to
energy stored in the load and returned to the source, or due
to a non-linear load that distorts the wave shape of the
current drawn from the source, the apparent power can be
greater than the real power.
In an electric power system, a load with low power factor
draws more current than a load with a high power factor, for
the same amount of useful power transferred. The higher
currents increase the energy lost in the distribution
system, and require larger wires and other equipment.
Because of the costs of larger equipment and wasted energy,
electrical utilities will usually charge a higher cost to
industrial or commercial customers where there is a low
power factor.
Linear loads with low power factor (such as induction
motors) can be corrected with a passive network of
capacitors or inductors. Non-linear loads, such as
rectifiers, distort the current drawn from the system. In
such cases, active power factor correction is used to
counteract the distortion and raise power factor. The
devices for correction of power factor may be at a central
substation, or spread out over a distribution system, or
built into power-consuming equipment.

Answer / ayub

By defenition , power factor is the cosine of the phase
angle between voltage and current in any electric circuit

Suppose we have an electric circuit to which an AC supply
is applied . Now the flow of current depends on the circuit
constants like Resistance, inductance ,Capacitance of the
circuit

Now if the circuit is purely resistive in nature, then we
see that the AC current flowing through the circuit has got
the same variation as that of the Voltage at the same time
ie the current reaches the maximum value at the same time
the voltage reaches the maximum value and so on . here we
say that the voltage and current is in phase

Now if the circuit is purely inductive, then the current
reaches the maximum after 1/4 of time of one cycle and so
on . In this case the current is said to be lagging the
voltage . The fundamental reason for this time lag is the
property of the inductor by which it doesnot allow any
sudden change of current through it

Finally, if the circuit is purely capacitive in nature then
in such circuit we will see the voltage lagging the current
(in otherwords current is leading the voltage )by 1/4 th
cycle . The basic reason is that when the capacitor is
getting charged from zero ,the current will be maximum
initially and it reduces to zero when the capacitor is
fully charged .ie the current is maximum when the voltage
across it is zero and so on ( or otherwise capacitor will
not allow any sudden voltage acoss it

The foregoing expalnations are put in mathematical form to
define power factor as described in the first paragraph

Answer / ibrahim

power factor is the cosine angle b/w curent &voltage

Answer / khilendra pant

power factor = cos(phai)
in any electric circuit,power factor is the cosine of the
phase
angle between voltage and current

Answer / shriram.....

This is the angle in between voltage & current.
it generate at inductive & capacitive load.The power factor
we can maintain by capacitors,it should be near 0.95 to 0.99


Shriram.........

Answer / yash

It's the Cosine of the angle between the Voltage and Current.
It primarily depend on the type of circuit,
ie :- whether inductive or capacitive.
It gives a measure of the useful output power

Answer / s

Power factor is the ratio of real power flowing to the load
to apparant power.It is relevant because the power which we
are giving(Apparant power) is not utilized fully because of
the inducatance and capacitance of the system.Apparant
power is expressed in VA because on applying a potentail
difference between two end of a conductor current is
flowing through the circuit. This is the power given. Real
power is the power utilised by the inductive load

Answer / jigar parikh

power factor can be define as the all type of (induction
motor) load as inductive load has lagging power factor and
due laggin power factor will increase the current which
will cause the losses .. so that power factor should be
nearly unity.

Answer / tareq harb

simply power factor is a scale for the useful power (KW) in
the system to the hole power (KVA) in the system.
so in case of 1 power factor the hole power in the system
is useful & thats perfect.

Answer / yogeesh.b

It is aratio of resisyance and impidence

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