Answer / pradeepan

The capacity of the transformer is in KVA because it depends
the load which is connecting to the transformer.
EXAMPLE:
Power = voltage x current x power factor
If we are connecting an equipment with power factor 1 we
will get full power(kw), suppose it is 10W
And if we are connecting the equipment with power factor
0.7, the power out put will be 7W.
So depending upon the load which we are connecting to
transformer its KW varies, so we cannot rate the transformer
in KW.

Answer / shubham

When the transformer is
designed it is not known
what type of load will be
connected to it whether
capacitive,inductive, resistive.
So its rating is only in terms of
V and I and excluding the
power factor. Hence kva or
mva.

Answer / er.kulwinder singh

the iron losses of the transforfomer are occuring even at no
load which depends upon tje operating voltage.Cu losses
comes into play when transfomer is loaded(even though at no
load these also occur but are negligible as compared to iron
losses),Cu losses depends upon load current.As power factor
of the load is not included,that's why this is rated in kva
not in kw

Answer / amit pattnaik

the cu loss of a transformer depends upon the current &
iron loss of a transformer depends upon the voltage. Hence
the total loss depends upon the voltage & current, not the
phase angle batween he voltage and current ,that is
independent of load p
ower factor.That is why rating in kva

Answer / pravin sathalpara

in transformer case current is passing the equipment taht
time current is very lagging so power factor is not unity.

so power factor is include in measurment.when equipment
take less current that time power factor is unity.

Answer / atik pathan

Transformer is a static device which dose not contain any
rotating part.it only transfer the energy from one ckt to
another ckt without change in frequency. it only step up or
down the voltage & current rating as per requirement.during
transmission the energy two types of losses take place
i.e IRON & COPPER, THE iron losses depend on voltage and
copper losses depend on current.and there is no concren on
power factor as its unit in(KW). thats y Xmer is rated in
Kva

Answer / k.boopathi

There are 2 losses in transformer. One is copper loss which depends on current and the other is iron loss which depends on voltage. These two factors are not affected by the power factor. This is why transformers are rated in KVA and not KW. Single phase KVA = Amps x Volts/1000. Single phase KW = Amps x Volts x pf/1000. 3 phase KVA = Amps x Volts x 1.73/1000. 3 phase KW = Amps x Volts x 1.73 x pf/1000

Answer / muzahir hussain

KVA is the unit of apparent power. Apparent power consists of active and reactive power.Active power is the share of the apparent power which transmit energy from source(generator) to user. Reactive is the share of the apparent power which represent a useless oscillation of energy from the source to the user and back again or it used to transfer the power inside the core. So we have to calculate both active and reactive power. therefore we calculate apparent power and the unit of apparent power is KVA.
In shortly we can say that the losses of transformer depends on voltage and current i.e cu loss depends on current(amp) and the iron loss depends on voltage(volts)and k is capacity. So rated in KVA not in KW because it does not depends on power factor.I hope that it is correct up to my knowledge only.

Answer / minakshi

the losses in the transformer are depend on the magnitude of voltage and current.they does depend on the angle of b/w them.... so transformer rating in the kva not in kw

Answer / pravin shilvant

transformer is kva factar is depend on iron loss as well as
cu loss . losses are derant type eddy curent loss and
hesterises los

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