Why transformer ratings in KVA not in KW?
Answers were Sorted based on User's Feedback
Answer / maranatha
in t/f core and cu losses are occur these losses are
depending on voltage and current and it is independent of
power factor so t/f rating kva
Is This Answer Correct ? | 15 Yes | 4 No |
IN ANY MACHINE THE RATING DEPEND UPON HEAT,HEAT LOSS DEPEND
ON HOW MUCH OF POWER LOSS IN THE MACHINE,IN THE TRANSFORMER
THE CORE LOSS DEPENDS ON VOLTAGE AND COPPER LOSS DEPENDS ON
LOAD CURRNT,i.e NO LOSSES DEPEND UPON POWER FACTOR THAT IS
THE TRANSFORMERS ARE RATED IN KVA INSTEAD OF KW.(reffer in
p.s bimbra text book electrical machines)
(OR OTHER WORDS)
KW RATTING IS DEPENDS ON POWER FACTOR ,THAT IS KW VARIES
WITH LOAD POWER FACTORS ,IF TRANSFORMERS RATED KW THE
RATING CHANGE WITH LOAD TO LOAD ,THAT IS THE TRANSFORMERS
ARE RATED IN KVA INSTEAD OF KW.(GENERAL ANSWER
rajeee43@gmail.com)
Is This Answer Correct ? | 5 Yes | 1 No |
Answer / kotaprolu.raneela
fffffff
in transformer we only bother with voltage rating and
losses.the 3 phase power is given by [sqrroot3* vi cos
(fi)].the power factor cos(fi) depends on the load we
connect.we dont know the type of load.so the rating of
transformer is in kva but not in kw...
Is This Answer Correct ? | 4 Yes | 2 No |
As we know,capacity of conductor carrying conductor is
fixed in a perticular atmospheric conditions.Current in
transformer or DG set or alternators depends on load power
factor, current drawn by a perticular KW machine is more if
power factor is low whereas same KW rating machine wil draw
less current if it has high power factor.Hence
Transformer/DG/Alternator can not be designed for KW but
for KVA rating.It will feed high KW with high power factor
and low KW with low power factor without damaging winding
conductor/insulatin.
Is This Answer Correct ? | 2 Yes | 0 No |
Answer / deepankar
In fact,
generally there is no
neutral or return
conductor on the
primary side of
transformer and hence
all reactive power
demanded by load is
fed by transformer
itself. In this sense
transformer power is
independent from
powerfactor. That is
why transformer rating
is in kva.
Is This Answer Correct ? | 2 Yes | 0 No |
Answer / sakthivel
if any electrical apparatus rating are depend on power
factor, transformer rating (are permanent load we not fixed
or base load are we not fixed so we noted the rating of
transformer rating )is KVA vanthni@yahoo.com
Is This Answer Correct ? | 2 Yes | 2 No |
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