Why generator rated in KVA not in KW ?

Generator is rated in both KW and KVA. Its KVA rating is used to determine process limit of power factor with respect to KW

Generator can process power factor along with volts and amps, this is why we rate it in KVA. Its a bit different from transformer because transformer does not process power factor. It only alters volts and amps. The other point, reactive power KVAr is only controlled through generator.

KVA is the total of KW and KVAR

KW is the true power we use to run any load

KVAR is an imaginary power wasted as a heat or electromagnetic field within motor winding or capacitor, so it is not useful and we pay for it 

 

KVA is the total and we pay for 

KVA=KW+KVAR

so we must reduce KVAR as much as possible 

Transformers rated in KVA because it delivers the total power consumed in any plant.

VA : (active + reactive)  

W  : active

:)

Cu Losses depend on the rating current of the load so the load type will determine the powerfactor P.F , Thats why therating of Transformer in kVA,Not in kW