Answer / prashant

As the losses of Transfomefer depend on VA characteristic
(copper loss on current & iron loss on current).So the
total loss depend on VA characteristic & power factor doses
not play any role.so rating are given in KVA not in KW.

Answer / raja

kVA is the unit for apparent power. Apparent power consists
of active and reactive power. Active power is the share of
the apparent power which transmits energy from the source
(generator) to the user. Reactive power is the share of the
apparent power which represents a useless oscillation of
energy from the source to the user and back again.

It occurs when on account of some inertia in the system
there is a phase shift between voltage and current. This
means that the current does not change polarity synchronous
with the voltage. But the heat generated in a winding as
well as the eddy current losses generated in a transformer
core depend on the current only regardless of whether it
aligns with the voltage or not.

Therefore the heat is always proportional to the square of
the current amplitude irrespective of the phase angle (the
shift between voltage and current). So a transformer has to
be rated (and selected) by apparent power.

Answer / bhavana

the losses of transformers are
1.iron loss
2.copper loss
the iron loss depends on the supply voltage & copper loss
depends on the current. but these two losses does not depend
on the phase angle between the voltage and current. hence
the ratings of transformer is expressed in terms of product
of voltage and current i.e VA rating. it is not expressed in
watts or KW. it is mostly expressed KVA.

Answer / ashok mishra

transformers are rated in kva not kv
ur question is wrong

Answer / sethu

Transformer is give to primary voltage then output take to secondary supply, so transformer mension to kva.

Motor only take the power supply, so motor mension the kw

Answer / bijendra chhetri

because transformer is not rated in kv is smalest and kw is
bigers ones.

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