Stefek Zaba wrote:

[...] though (and 99.999% of the losses are inductive, too ;-)

A nonsensical statement, Sir. 100% of losses are resistive :-). Pure
inductance, whether of the self or the mutual flavour, can only store
(and retrieve) energy. If losses you want, resistance you need.

Losses in transformers come in three sorts, (i) I^2 * R loss in the
windings (cooper loss), (ii) eddy current loss in the core - which is
just another sort of I^2 * R loss, and (iii) hysteresis loss in the
core, proportional to the area of the B-H loop being traversed and the
frequency, and representable by an equivalent shunt resistance.

Imperfect magnetic coupling between the windings will cause an
additional voltage drop, compared with ideal 100% coupling, but this is
not a dissipative loss. In equivalent circuit terms it appears as the
voltage drop across an inductance - the leakage inductance.

In small transformers of the type likely to be found in domestic
equipment the impedance of the transformer is dominated by the winding
resistances; leakage reactance is negligible. Most of the loss is
copper loss (except off-load).

--
Andy