Every electrical machine and device have its own power rating. Devices and machines at home such as fan, light bulb, television, heater, motor, refrigerator e.t.c. are rated in Wattage(W) or Kilowatts(KW) but transformer is rated in Volt-Ampere(VA), Kilo-Volt-Ampere(KVA) or Mega-Volt-Ampere(MVA).
Why Transformer is Rated in KVA?
A transformer has two types of power losses (copper loss and iron loss). Copper loss depends on the current(I) and the iron(or core) loss depends upon the voltage(V) of the transformer. Thus, the total losses in a transformer depend upon voltage and current only not on the power factor and phase angle between them. That is why the transformer is rated in kVA not in kW.
At the time of manufacture, power factor of transformer cannot be determined therefore, transformer is manufactured without considering the types of the load that is to be connected to it. So any type of Load either resistive (R), inductive (L), capacitive (C) or mixed load can be connected to the transformer without affecting the power rating of the transformer. KVA is the unit of apparent power which is the combination of real power and reactive power and independent upon power factor or phase angle of electric power system. That’s why transformers is Rated in KVA not in KW.
Conclusion
Hope, you must have clearly understand about the reason why Transformer is Rated in KVA, not in KW. Make sure to Leave your opinion and suggestion about this post in the comment section below.