Answer / sanjay dalvi

power factor of DC system is allways 1,why??
in DC POWER SUPPLY a power supply is constant in nature,
p=v*i angle between voltage & current is zero that is
current is in phase with voltage, cos$=0
for dc supply $ =0
& we know that cos 0 =1
so we can proove that cos $ =1 hence
p= V I COS$
P= V I KW

Answer / k.prakashchandra

unity

Answer / kesavan.03

Power Factor is nothingbut the phase angle between Voltage
& Current. In AC System power factor will be lag & lead
system due to its nature of wave form & phase angle
difference.

As in the case of DC System there is no power factor term
is used because DC System has constant voltage & Current..
So phase difference is zero.

Power = V x I x cosØ

for DC System cosØ = 1 ( Ø = 0 degree)

Since cos 0 = 1

Answer / eng.ahmad

the power factoe is 1 in dc system if tehere is no ripple.
for example if you test the pf of battery charger you will
find it less than 1 because of the ripple, and you can
solve this problem by using coil (chock).

eng.ahmad from iraq

Answer / t swetha

powerfactor of dc supply is 1 why because there is no phase
difference between the voltage and current

Answer / fazul

In a.c system current and voltage are lag or lead according
to the inductance or capacitance.
but in d.c system current and voltages are inphase with each
other.so phase angle between current and voltage is zero.
we know p.f=cosO
p.f=1

Answer / aye thwin

1) Assuming DC supply is pure DC or constant, if load current is pure dc current, it is power factor=1, if not pf <1.
2) For DC system, should not use cos value which is related to ac system.
3) Power factor is not only relative to reactive power , but also need to consider the distortion power which is related to harmonic.

Answer / sakthivel

in dc system voltage and current are in phase so here no
power factor

Answer / naagaraju badara

In dc capacitor acts as o.c and inductor as s.c and in pure resistor angle b/w v&i is zero hence it will be unity always

in ring main system we use the isolater b/w transfer bus and main bus if we r not use isolatar than wat will be the effect in our sys.

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