Answer / siva

since the losses in the transformer is iron and copper loss
which depend upon the voltage and current but not on the
angle between them

Answer / veerendra

the transfor rating is in kva because as the iron losse &
copper losses in transformer depend on the volage & current
so depending on the losses the heat geeration occurs & hence
the rating is explained in KVA to give a detail how much
amount of power it can transfer without getting damaged.

Answer / sangayya s k

the transfor rating is in kva because as the iron losse &
copper losses in transformer depend on the volage & current
so depending on the losses the heat geeration occurs & hence
the rating is explained in KVA to give a detail how much
amount of power it can transfer without getting damaged.

Answer / okereke okorie daniel

Transformer is rated in kva because the efficiency of a
transformer depends on the copper losses annd the iron
losses which are voltage and current respectively, hence
the rating in kva.

Answer / padmaja

The x'mer rating is in kva because as the iron losses in
x'mer is depends on voltage i.e. as per o.c. test carried
out on x'mer & copper losses is depends on current i.e. as
per s.c. test carried out on transformer.
so depending on the losses reflects voltage & current unit.
hence the rating is explained in KVA to give a detail how
much amount of power it can transfer.

Answer / sangayya sk

the transformer dus not concider power factor because trans
former's r rating in Kva P= v*i

Answer / rsundareee

The transfor rating is in kva because as the iron losse
depending on the voltage and copper loss depending on the
current,so total loss depending on the voltage and current
so it,s called kva.

Answer / m.gopinath

All ac machines rating is mentioned in kva on name plates
where as dc machines rating is mentioned in kw. In the case
of dc, there is no question of pf as the loads for dc are
always resistive in nature and the pf is always unity. But
in the load can be resistive, inductive or capacitive in
nature in case of ac machines.

Let us calculate current for different loads (ie for
different pfs) in case of ac machines if their rating is
mentioned in kw:

16 MW (not in MVA as in normal case), 132/33 KV T/F

Case 1: For resistive load

HV Current = 16000/(1.732*132*1)= 70 A (approx.)

Case 2 : For inducive/capacitive load at 0.8 pf

HV Current = 16000/(1.732*132*0.8)= 87.5 A (approx.)

observe the above two cases, for a given rating in MW(16 MW)
the current is quiet different and it will depend on the
nature of the load on T/F. This is not in the case of DC as
the nature of load is always resistive.

Answer / uddin

the transformer dus not concider power factor because trans
former's r rating in Kva P= v*i

Answer / varun

i m not sure but i thik due to p.f. beacause p.f different
at all time.

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