Name Plate Rating – The voltage ratio is specified as V1 (rated)/ V2 (rated). It means that when voltage V1 (rated) is applied to the primary, the secondary voltage on fifflload at specified pf is V2 (rated). The ratio V1 (rated)/ V2 (rated) is not exactly equal to NI/N2, because of voltage drops in the primary and secondary. These drops being small are neglected and it is assumed that for all practical purposes
The rating of the transformer is specified in units of VA/kVA/MVA depending upon its size.
where V and I are referred to one particular side. The effect of the excitation current
is of course ignored.
The transformer name plate also specifies the equivalent impedance, but not in
actual ohm. It is expressed as the percentage voltage drop (see Sec. 3.8) expressed as
where all quantities must be referred to any one side.