Interested to Buy Any Domain ? << Click Here >> for more details...
Answer Posted / raghav
kW is the unit of real power & kVA is the unit of Apparent
power.
Apparent Power= real power + reactive power
Looking at different electrical equipment you will notice
that the power ratings are either expressed in kVA
(kilo Volt Ampres) or sometimes in kW (kilo Watts). The
next question is what’s the difference? Both are
measurements of power however they are truly different.
To understand the differences consider how each are
derived. kW is called actual or real power, or simply
the amount of power that is available to do real work. kVA.
On the other hand kVA is known as “apparent”
power. This is because only a portion of the available kVA
may be available to do real work. The remainder
is simply excess current.
The difference between kVA and kW really depends on the
power factor (PF). When the voltage and
current are in phase with each other in an AC circuit, the
power factor is 1.0 or “unity”. The more the
voltage falls out of phase with the current the lower the
power factor becomes and the less “real power” or
kW the device uses; however it may still be using the same
amount of current as a device with a higher
power factor. Power factor will be "leading" or "lagging"
depending on which way the load shifts the
current’s phase with respect to the voltage’s phase.
Inductive loads cause current to lag behind voltage,
while capacitive loads cause current to lead voltage hence
leading or lagging power factor.
kVA = Volts x A
kW= Volts x Amps x Power Factor or [kVA x Power Factor]
The next question is why express the kVA value of a device
and what use is
kVA if only part of it can do work? The reason kVA is used
as a rating is
because the rating of an electrical device is dependent on
the amount of
current they can sustain. A kW rating does not indicate how
much current
a device can carry (as the power factor may not be known)
where kVA
does indicate the maximum current at a specific voltage
level.
| Is This Answer Correct ? | 136 Yes | 14 No |
Post New Answer View All Answers
How much current will a 5 HP delta connected motor at no load will take?Is tat need a starter
why normally Generator rating are between 11Kv to 22Kv?
We have 110Vac ,10A ac supply which is converted into 110VDC & How much DC current? which factor is reqired for dc current calulation?
in general it is observed in power stations, the tertiary winding is used in higher rating Y-Y auto transformer but not in Y-Y power transformer. is the tertiary winding is compulsory then why it is not using in power transformer
ROC converges if poles and zeros lie inside a. Origion b. Z=1
What should be setting for alarm,tripping and cooling fan on for power transformer's oil temp. and winding temp. indicator?
what is the condition for YnD11
What is tan delta & PPM in transformer? and whats its IS value?
how to carried out DAR test in 11 KV Alternator ?
why the rotor current becomes in steady state during high slip region? please verify with equations.
In a large office how do we calculate required number of light fittings, assuming fittings are 4x18W or 2x36W fluorescent fitting ?
What is minimum permicible value of leackage current for LT Panle when applying voltage up to 3 KV for 5 Minuits?
what is the minimum requirement gigaohms for the insulation test using 5kv in 300mm xlpe cable
what is package substation.how many types they have
what will be the effect if you were using different brands of outlets?
