Ideal transformer
characteristics
(1)
Windings have zero resistance. It means there is no ohmic power loss and no
resistive voltage drop.
(2)
The core loss (hysteresis as well as eddy-current loss) is zero.
(3)
There is no leakage flux. i.e all the flux is confined to the core and links
both the windings.
(4)
The core has infinite permeability i.e No magnetizing current is needed to
estaiblish the required amount of flux.
Ideal
transformer equivalent circuit
Below
shown is the equivalent circuit of a practical transformer.
Lets apply ideal transformer characteristics into this
circuit to get equivalent circuit for ideal transformer.
(1) Windings have zero resistance i.e R1=R2=0
(2)
Core loss is zero i.e Core loss component of current is zero or RC
is infinite.
(3)
There is no leakage flux i.e X1=X2=0
(4)
Core has infinite permeability i.e magnetizing component of current is zero or
Xm=0.
We get the equivalent circuit of ideal transformer as
shown below.
From above circuit, we can write equations of ideal transformer as
Ideal
transformer on no load
Above diagram shows ideal transformer with secondary open and
its phasor diagram.
Ideal
transformer on load
Let a lagging power factor load ( let impedance angle be Ï´2 ) be connected to ideal
transformer shown below. Corresponding phasor diagram is also shown.
It is clear from phasor diagram that the source power factor
angle Ï´1 is decided by the load power factor angle Ï´2 and is always equal to it.
Related concepts :-
Related concepts :-
