Why are transformer ratings taking in KVA not in KW?

Transformer is a static device, which will be used for only converting voltage or current into higher or lower levels, all that unit of measurement is watts only. the unit of measurement is needed when we need to convert one form into another, but transformer not converters the energy it will manipulates the energy with certain loss, that loss consists of copper and iron losses which will completely depend on current and voltage,so the unit of measurement is VA(volt amperes), where powerfactor is used to indicate type of load.

Thanks for invitation

it is no matter, you can use KW and KVAR

but as we know transformer produce the both like generator so we are using KVA because it is more accurate to disciple the rating

S=3*I*V

you can return to power rectangle where the base is KW and the vertical is KVAR and the between them is KVA

so when KVAR equal to zero, we can say KVA=KW, KVA^2=KW^2+KVAR^2

The rating of transformer is in kVA because transformer has mainly two losses viz IRON LOSSES which depends upon the voltage, frequency and maximum flux density, other COPPER LOSSES which depends on the current. Thats why rating is in kVA not in KW..  if any one is still not an able, then i can clear more if you can?

 

A transformer designer doesn't know what is going to be the the load power factor. That is why transformer capacity is declared in KVA, not in kw. Because KW = KVA * powet factor.

Ok Thanq Sir,but I think  in Transformer2 losses are there one is copper nd another is core or iron losses ,so when copper loss of a transformer  depends on current and core or iron loss on voltage.,hence total transformer loss depends on volt-ampere(VA) and not on phase angle between voltage and current.,,so that is it is indipendent on load power factor..,so I think thats why transformer ratings taking in KVA.....,

Is my answer right or wrong????

Transformers work on mutual induction and can be taken as two inductors kept closely to one another. Whenever, ac power is provided to an inductor or a capacitor it creates reactance i.e a resistive property with respect to the inductance or capacitance value and frequency of ac voltage applied accross it. Due to this property the inductor or capacitor creates real and reactive power. both powers are in total known as apparent power whose unit is VA (volt-ampere) and as transformers usually deal with high powers it  is best denoted by KVA (Kilo (^3) Volt-Ampere).