This document discusses the equivalent circuit model of transformers. It explains that an equivalent circuit is needed to analyze a transformer's performance under different loading conditions like regulation and efficiency. The equivalent circuit models the transformer's windings using resistors and inductors obtained from open and short circuit tests. This allows analyzing the transformer using circuit analysis to find values like no-load and full-load voltages, losses, and regulation percentage under different load conditions like lagging, leading, or unity power factor. The key point is that the equivalent circuit is required to evaluate a real transformer's performance for various load scenarios.

1. TRANSFORMERS
EQUIVALENT CIRCUIT OF
TRANSFORMERS

2. OBJECTIVE
 Why to find equivalent circuit of transformer.
 How to find equivalent circuit of transformer.

3. Why to find equivalent circuit of transformer
• By seeing this picture on can say this is
transformer but without knowing its actual
electrical parameters, on one can say about its
performance on different loading.

4.  What is meant by performance of transformer?
There must be no voltage drop in the transformer winding during
no load and full load. No power loss should occur in transformer. Based
on these two condition we can decide the performance of transformer.
By knowing Regulation and Efficiency of transformer we can
know the performance of transformer.
 How can we say transformer has better regulation?
If no load voltage of secondary terminal and full load voltage of
secondary terminal are same then we can say our transformer have
good regulation.(0 percentage) {condition 1}
 How can we say transformer has better efficiency?
If input and output of the transformer are equal then we can say
our transformer have good efficiency. { condition 2}

5.  If we have only practical transformer, then we need to apply different load
on transformer to find regulation and efficiency.
 If we are in position to model a practical transformer into a electrical circuit
using resistor and inductor, then we can easily apply mesh and nodal
analysis to find no load and full load secondary terminal voltage and losses
for different loading.
But above two condition will not be possible for
practical transformer.
Then how to know what is the value of regulation and
efficiency of the transformer

6. Above circuit is the equivalent circuit of transformer.
If E2 and V2 are same during full load, then we can say its regulation is good.
But in the above circuit its clearly mention there is two parameter R2 and X2 between E2
and V2 so we can definitely say that E2 and V2 are not same.
V1 I1 input power and V2 I2 output power are not same, since there are resistor R1 and R2
Which produce heat energy. So definitely we can say input power and output power are
not same.

7. KEY POINT:
 To analysis the performance of transformer for
different type of loading (lagging, leading, unity
powerfactor)
 To get efficiency of different loading
 To get regulation percentage for different loading

8. How to find R0, X0, R1,X1, R2 &X2 ……???
 This is why we are doing open circuit test and short
circuit test in machine
 By doing open circuit test we can calculate R0 and X0.
 By doing Short circuit test we can calculate equivalent
circuit of Resistance and Inductance of winding (R01 &
X01 ) or (R02 & X02 )

9. THANK YOU
MADHAN N