Answer / venkatesh a

Because of the inductive property of load connected in
source lagging power factor is created. When voltage is
applied across the load current starts following through
the load. Due to the induction effect current is stored as
magnetic field around the coil (0 to 90 degree). After the
90' voltage instantanous value reduces and the energy
stored in load is starts discharging (90 to 180').
Like this in all part cycle some time difference is
happens. Power= Voltage x current

If we multipling these values with respect to the time we
can understand that.

In Leading power factor voltage is stored in load. When
load is capacitance property. Here all so same charging and
discharging happens in load. And net power across the load
is getting reduced due the time difference.

BUT IN RESISTIVE LOAD, NO CAPACITANCE OR INDUCTIVE
PROPERTY. SO NO CHARGING AND DISCHARGING IN LOAD. SO NO
POWER LOSS. SO VOLTAGE AND CURRENT ALWAYS IN SAME DEGREE
VALUE. SO NO ANGLE DIFFERENCE BETWEEN THE VOLTAGE AND
CURRENT. POWER FACTOR= COS()

()= DIFFERENCE BETWEEN VOLTAGE AND CURRENT

If this angle is 0 means,
Power factor= cos 0'

cos 0'= 1

That means maximum power utilisation.

Answer / sudhir s rao

the power factor occurs only in inductive loads because, in inductive loads, the current lags the voltage.
where as in resistive load, the current is in phase with the voltage.

Answer / sudhir s rao

ramya mam..
firstly i am sorry if i am wrong, i am a diploma (electrical and electronics) student, so i may be wrong!!

the meaning of current in phase with voltage is that :
in a "PURE RESISTIVE LOAD", the cosine angle between current and voltage is 0 (ZERO).
Hence the power factor is minimun is "PURE RESISTIVE LOADS"

Answer / a. venkatesh

Venkatesh.amaran@gmail.com.

This is y Email Id. If any body having doubt and interested to learn can mail this Id.
I am a Erection and commissioning engineer in a MNC company.

Answer / ramya

Mr.sudhir what is meaning for current is in phase with voltage ?

Answer / &

Mr sudhir.. i appreciate your answer.. u being a student u gave the best answer

Answer / aloke

HI MR. Sudhir & Ramya ...actually the ans is..."power factor
occur means" ,The current and voltage applied to the load
already has a phase difference (difference between the
approximate sinosoidal voltage and current wave). The load
which is now connected can makes a change or not in the
phase which already they have. In the case of pure resistive
load the phase will not be changed and in the case of
inductive load the current will more lags of the voltage
wave. thanku

Answer / gobi

basically there is no phase difference in resistive load. so the power factor is nearly unity. but the inductor and capacitor will introduce phase shift between voltage and current which will affect the power factor........

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