A Delta/Delta connected transformer is connected to V/V connected transformer.

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Question: A Δ/Δ connected transformer is connected to V/V connected transformer. Find the ratio of the VA rating of the V/V connected transformer and Δ/Δ connected transformer.

Solution: For a Δ/Δ connected transformer, the line voltage is the same as the phase voltage.

Let the line voltage be VL.

For a V/V connected transformer, the line voltage is √3 times the phase voltage.

Let the line voltage be √3VL.

The product of voltage and current gives the power rating of a transformer. Since the current in a transformer's primary and secondary windings is the same, the VA rating is proportional to the voltage rating. Thus, power formula in physics can be written as: \(P = V\times I \)

Therefore, the ratio of the VA rating of the V/V connected transformer to the Δ/Δ connected transformer is: (√3VL / VL) = √3

Hence, the VA rating of the V/V connected transformer is √3 times the VA rating of the Δ/Δ connected transformer.


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