why transformer ratings in kva?
Answers were Sorted based on User's Feedback
Answer / rohan
copper losses of a transformer depends on CURRENT and irons
of a transformer depends on VOLTAGE not an phase angle
between voltage and current. that is why transformer rating
in KVA not an KW.Thus power depends on product of current
and voltage only and not on product of current voltage and
phase angle.
Is This Answer Correct ? | 0 Yes | 1 No |
Answer / john mohd
Transformers are rated in kva's because at the time of manufacture the power factor (cos phi)of the machine is not known I.e at the time of desighning you do not know which type of load is placed on that I.e the power factor is unknown
Is This Answer Correct ? | 0 Yes | 1 No |
Answer / ankaraju.k
The losses in trasformer only depends on voltage under no
load condition and curret under load condition,so it is
independent on power factor on which it is operating load
Is This Answer Correct ? | 41 Yes | 43 No |
Answer / vimal raj
transormer is mainly depend on the current an voltage .were
the core an copper losses are due to voltage an current an
this is independent to power factor so power factor is not
alter due this losses for this reason transformer rated in
kva..........
Is This Answer Correct ? | 0 Yes | 2 No |
Answer / fred gleicher
KW, or kilowatt, assumes both current and voltage are in
phase. In a transformer, it is possible for current and
voltage to be out of phase ( since a transformer is
inherently normally an inductive device ). Therefore, the
rating is given in VA or volt amps, instead of watts,
showing that current and voltage may be out of phase. The K
comes from the MKS system and is an abbreviation for
thousand. It just makes it easier to write the power rating
of the device, most transformers ordinary folks see are
rated in the VA range, but electrical linemen see devices
rated in the KVA range every day.
Is This Answer Correct ? | 0 Yes | 2 No |
Answer / vicky
voltage unit is volts and current unit is amps then high
voltage for transformer that called kva
Is This Answer Correct ? | 0 Yes | 2 No |
Answer / prasad
In all A.C. machines (which includes motors whose rating
are in KW )iron losses are proportional to voltage & copper
losses are proportional to current.
The machine rating is given in terms of its output. The
transformer output is electrical energy & thus its rating
is same as energy i.e. KVA.
Same is the case with generator
Is This Answer Correct ? | 15 Yes | 18 No |
Answer / tarun
Because Transformer does not depend on PF it depends on
the max. current. but motor depends upon the PF and work
acc. to their PF. thats why it denoted in KW while
Generator denoted in KVAQ.
Is This Answer Correct ? | 11 Yes | 19 No |
Answer / bhavesh
adding to above answer Transformer is not a load and having
no effect on P.F and it only transfer the constant power
from one voltage level to another voltrage level without
changing frequency thats why transformer are rated in KVA
or MVA
Is This Answer Correct ? | 117 Yes | 152 No |
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