Answer / panda n.n

Transformer has two type of loss.1-Iron Loss ,2-Copper Loss.
Iron loss depend upon Voltage where as copper loss depend
upon Current. ther is no significant role of power factor
on these losses.So transformer are rated on KVA or MVA.

Answer / pankaj

TRANSFORMER LOSSESS ARE INDEPANDANT OF POWER FACTOR BECAUSE
COPPER LOSSES DEPENDS ON CURRENT AND IRON LOSSESS DEPENDS
ON VOLATGE. HENCE, RATED IN KVA

Answer / srinu

in tf core lossdepends on voltage rating and cu loss
depepends on current ,as the rating of any machine depends
on it's heating that is losses. so in tf heating is
proportional to product of v and i.so tf rating is in terms
of kva rather than kw.
and one more reason is as the load on tf is not constant,we
dont know the exact power factor value.that is also one of
the reason to express tf rating in kva.

Answer / pritesh

simple, the load which is joint with the transformer is not
known so that we dont know the actual power factor because
of reasion the rating of the transformer is in the kva not
in kw.

Answer / rcv

It is because of load power factor,Transformer is always
designed on unity power factor. It has only 2 type of
losses Iron loss due to voltage, I2R loss and Stray loss
due to load and there is no involment of powerfactor. Thats
why transformer is rating in KVA.

Answer / aditya shirbavikar

The power factor of transformer is unknown and is derived according to the load connected. Therefore the rating of transformer is in KVA

Answer / syed vikhar ahmad

power factor is not constant it varies in different load
thats why manufaturer can not keep the rating in kw.suppose
the transformer rating is 500 kva we can put 500 kw load at
unity power factor but at .8 power factor we can put only
400 kw load as per formula kw= kva* pf

Answer / saida shaik

KVA is the unit for apparent power
Apparent power consists of Active and Reactive power. Active power is transmits energy from the source to the user. Reactive power is represents a usless oscillation of energy from the source to the user and back again. Reactive power occurs when on account of some inertia in the system there is a phase shift between voltage and current. This means that the current dose not change polarity synchronous with the volage but the heat generated in a winding as well as the eddy current losses generated in a t/f core depend on the current only ,regardless of whether it aligns with the voltage or not. Therefore the heat is always propotional to the square of the current amplitude irrespective ofphase angle so a t/f has to be rated by apparent power.(it means KVA instead of KW)

Answer / a.alexander

do n't know the connecting load .for inductive load ,
capacitive load and Reactive load. transformer is copper
loss dependable for I and core loss dependable for v .told
Kva.

Answer / joseph

since it has no load losses, transformer rating in KVa

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