in case of transformer, when load is connected to the
secondary winding so flow load current. this altenating
current generate an alternating field around conductor
(winding. when this alternating field cut the conductor or
winding, an e.m.f induced in that winding.this is called
back e.m.f and current is called eddy current(Lenz's Law).
this eddy current is a cause of losses in transromer
winding. so the losses in transformer winding due to eddy
current are called stray losses. these losses also called
eddy losses. these losses are dependent on the frequency of
altenating supply because skin effect is involve in this
case. thes losses are directly propotional to the frequency.
during inrush current (harmonics) thes losses increase
because frequency increase.