What is Leakage Flux?

A flux which is not accociated with the secondary side of the transformer.Normally we apply the voltage on the primary side of the X'mer and by means of mutual inductance it transfered to the secondary side.Emf is induced in the secondary coil if flux linkage on the secondary side,but leakage flux doesn't produce any emf.

Leakage flux in transformers with magnetic material cores, is all magnetic flux which passes outside the magnetic material circuit - Into the air, insulating oil etc.

The leakage flux is thus wasted energy, and transformer designers try and minimise it, by careful design.

In radio frequency situations (Transmitters/receivers/TV etc, at frequencies above 30 Megahertz (MHz) air-cored transformers are often used.

The leakage flux proportion then is generally greater, than for an iron-cored power transformer, but one again, careful design can minimise the losses.....