Answer / manish kumar meena

in transformer cu loss depends on current and iron loss on
voltage.Hence total loss depends on volt-ampere(VA) and not
on phase angle between voltage and current.Thats is why
rating of transformer is in KVA.

Answer / annakka

the power factor of the loads connected in transformer are
not same.

Answer / sanket patil

THE POWER FACTOR OF A TRANSFORMER FEEDING THE LOAD
DEPENDS ON THE NATURE OF THE LOAD; HENCE THE ACTIVE(P) AND
REACTIVE(Q) POWERS SUPPLIED BY THE TRANSFORMER MAY CHANGE
FOR A FIXED APPEARENT POWER(S).
HENCE THE TRANSFORMER RATING IS ALWAYS SPECIFIED IN KVA
AND NOT IN KW OR KVAR AS THEY CHANGE AS PER THE LOAD
CONNECTED TO THE TRANSFORMER.

Answer / mukund

The KW rating is assigned for equipments that consumes power with certain leading/lagging between Voltage and Current depending on the nature of the load (A resistive load is more towards V&I in sync whereas an inductive load has V&I lagging and A capacitive load featuring V&I leading). A transformer is supposed to only transfer the power, although there are inherent losses while doing the same, however for practical purposes, eliminating transformer's own consumption, a transformer is rated on its original purpose with the simple V&I relationship disregarding the Cos-phi factor (the lead/lag of V&I). Hope I am making some sense

Answer / mahantesh

IN TRANSFORMER THERE ARE MANY LOSSES AS CORE LOSS ,OHMIC
LOSS WINDAGE N FRICTIONAL LOSS ETC.....THE CORE LOSSES ARE
PROPORTIONAL TO VOLTAGE AND OHMIC LOSSES ARE PROPORTIONAL TO
CURRENT THAT'S THE MAIN REASON WHY TRANSFORMER ATING IS IN KVA.

Answer / robert harper (ee tech)

KW=work
VA=ability to do work, no power factor considered.

Answer / chandrashekhar sahu

The rating of any machine depends on the factor that always
remain same at any condition. In case of a transformer the
multiplication of voltage and current for primary and
secondary side remain the same at all load conditions. so
the transformer rating denoted as VA.

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