Leakage Reactance of transformer

As long as study that flux induced in primary winding in linked with secondary of the transformer without any losses. But in practical scenario it is not correct. There are few amount of flux definitely leaks while linking with secondary winding. If transformer is air core, flux transfer via air medium. On other hand iron core transformer flux transfer through iron core medium. This article will show about what is leakage reactance in transformer

In similar way, when external load current flows through secondary winding , there also flux induced in it. This flux gets linked with primary winding. Few amount of secondary flux also leaks between winding.

These flux are called leakage flux

Let the flux generated by both winding may be denoted as Φ₁ and Φ₂

Further,

leakage flux produced by primary winding = Φ_L1

Leakage flux produced by secondary winding = Φ_L2

Both Leakage flux Φ_L1 and Φ_L2 are in phase with primary current I₁ and secondary current I₂

It is very important to note that leakage fluxes are not lost in air or core. These flux are definitely gets linked with primary and secondary windings

Hence there are self induced emf is available in both winding of the transformer.

e_L1 in self induced emf in primary winding due to leakage flux Φ_L1

and e_L2 in self induced emf in primary winding due to leakage flux Φ_L2

To deliver desired amount of , primary voltage must over come to e_L1 , on other hand secondary output voltage must be induced more to over come e_L2

So transformer can supply its designed output voltage V₂

In conclusion self induced emf e_L1 , e_L2 are considered as voltage drop inside the transformer

In other words , it assumed that imaginary reactance are connected in series with primary wind secondary windings. These reactance are called as leakage reactance of transformer