Why transformer ratings are in kva

But in Transformer that is not the reason for calculating losses. Save my name, email, and website in this browser for the next time I comment. Why transformer rating in KVA: Actually, every one says it is due to core losses and copper loss of the transformer, but actually, that is not the correct answer.

Remember that a transformer, as the name suggests, is only a transformation device or a pass through device and not a power producing device like a generator or an UPS, where their capacity to produce real power kW is an independent limit from the thermal kVA limit.

To take it a step further, if you have an ability to cool the transformer further, you can augment the kVA or MVA rating of a transformer. If you think of it, this is not different from a cable or a conductor's capacity expression. Except that a transformer can have more than one voltage levels and different ampacities on primary and secondary, but the kVA rating remains the same on either side. So that makes kVA a more convenient way to express its thermal capacity vs. How is Vector Control improving motor output torque capability?

Transformers are an energy transfer device that transfers power from the primary side to the secondary side without altering the energy level considering zero power loss. Iron loss and copper loss occurring in the transformer are also independent of the power factor. Moreover, the output power factor of the transformer purely depends on the connected load.

The transformer does not alter the power factor of its output power. Transformers are rated in kVA because the losses occurring in the transformers are independent of power factor. KVA is the unit of apparent power. It is a combination of real power and reactive power. Transformers are manufactured without considering the load being connected.

So any kind of electrical load can be connected to it either resistive, capacitive, inductive or combination loads. If the transformer is rated in KW, there may be confusions regarding the type of load being connected. So as the transformer does not consume power it can only transfer power with increasing and decreasing voltage and current that is why the Transformer always rated in KVA.

And the power factor depends upon the load. If an Inductive Load is connected then the current will be lag which flows through the secondary winding of the transformer as well as the primary winding of the transformer. You May Also Like:. When Capacitor store more Energy Series or Parallel connection?