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Suppose we have a 2200/220 V non-ideal transformer.

Based on the image below of a non-ideal transformer, would 2200V be the primary terminal voltage (V1) or the primary induced voltage (E1)?

Similarly, is 220V the secondary induced voltage (E2) or the secondary terminal voltage (V2).

If neither, could someone explain what this rating is about?

I came across this explanation in my search, that this means that if 2200V is applied to the primary winding, then 220V is induced in the secondary. Now, my understanding of "applied to the primary winding" refers to the primary terminal voltage (V1) rather than the primary induced voltage.

I am really confused about this voltage rating for the transformers and any information is welcome.

enter image description here

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A '2200/220 V' transformer rating is ambiguous. It might mean that is the transformation ratio at zero load current. It might mean that's the transformation ratio at the rated load current.

The difference between those two ratings is the voltage dropped at load current across the series R and X components, or the difference between En and Vn. In an ideal transformer of course they are the same.

A transformer is usually rated at the full load current, and the voltages specified are the terminal voltages.

Generally we don't get too hung-up about these loss terms, but roll them all up into a 'regulation' figure. If a transformer has 5% regulation, that means that at rated current, the output voltage drops to 95% of its no load value.

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  • \$\begingroup\$ A transformer is usually rated at the full load current, and the voltages specified are the terminal voltages. - Based on this statement, 2200V would be V1 and 220V would be V2 at full load? However my understanding is that full load current is the current it is delivering when it is supplied with rated voltage and rated frequency. This would then imply the terminal voltages i.e. 2200/220V is the rated voltage. If not, what is the rated voltage voltage then? \$\endgroup\$ Mar 1 at 17:37
  • \$\begingroup\$ I should indicate I am asking this question to further understand what is being thought at my University and answer the questions in my exam. For example, in this link: allaboutcircuits.com/textbook/alternating-current/chpt-9/… , the max primary and secondary current is determined by using kVA rating/rated voltage. So I am really trying to figure out if this rated voltage is the given values in the question and wrt the equivalent circuit, which variable does it correspond to? \$\endgroup\$ Mar 1 at 17:52
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Given that what you have drawn is the equivalent circuit of a power transformer, the only nodes a user has access to physically are shown with the red dots below: -

enter image description here

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  • \$\begingroup\$ OK but I dont follow how this is related to the rated voltage. \$\endgroup\$ Mar 1 at 19:10
  • \$\begingroup\$ @EdmundBlackadder you can only apply the rated voltage to the primary red dots so, that should be clearer now. \$\endgroup\$
    – Andy aka
    Mar 1 at 19:42

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