asking about the impedance of transformator

HI

% IMPEDENCE = Vsc/Isc

For all these given rating transformer Kva rating is different but voltage is 220/380v,here you will have to do short circuit test of these tranformer,

short the 220voltage side terminal,Apply the voltage at 380v side xmer terminal start from Zero.Also measure the current at 220Voltage side short circuited terminal

Increase the voltage slowly till full load current flows at 220voltage side.

Measured the Short circuit voltage at that time it is your Vsc & Isc you can take as full load current at 220v side.

Each name plate of xmer can give the details of %z also.

any this is the test from that Manufacturer get %Impedence.

regards

SJ

It depends on the transformer design, some transformers like Drive Isolation transformers are designed with a higher impedance to reduce distortion caused by VFD drives. You will need to check with the manufacture but 3%-4% is a typical value for impediance of a standard transformer.