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Transformer generally rated in KVA

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Answer :

Copper losses ( I²R)depends on Current which passing through transformer winding while Iron Losses or Core Losses or Insulation Losses depends on Voltage. That's why the Transformer Rating may be expressed in kVA,Not in kW.
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Answer :

The power of transformer is apparent power because it has no power factor and it is the product of voltage and current.
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