Transformer with Losses but no Magnetic Leakage

How does loss without Magnetic Leakage in a Transformer?

To base our knowledge about the electrical transformer, we assumed an ideal transformer i.e. one in which there were no core losses and copper losses. 

But in practical conditions of a real transformer, it requires that certain modifications be made in the foregoing theory. 

When an actual transformer is put on the load, there is an iron loss in the transformer core and copper loss in the transformer windings both in primary and secondary coils and these losses are not entirely negligible.

Considering an actual transformer, there will be some resistance in both primary & secondary windings due to the presence of copper winding.

Transformer with Losses but no Magnetic Leakage

Let us describe what is the effect in the transformer due to the presence of winding resistance but no magnetic leakage.


Let consider, 

R₁ = Primary winding resistance,
R₂ =Secondary winding resistance,
V₁= Primary applied voltage,
V₂=Secondary terminal voltage,
E₁= Primary induced e.m.f,
E₂= Secondary induced e.m.f,
I₁= Primary current,
I₂= Secondary Current, ( which are shown in fig.)


Due to the presence of secondary winding resistance ( R₂), an amount I₂R₂ voltage drop will occur in the secondary winding.
Hence, the secondary terminal voltage (V₂) is equal to the vector difference of E₂ and resistance voltage drop I₂R₂,

i.e E₂=V₂-I₂R₂

Similarly, Primary induced e.m.f E₁ is equal to the vector difference of V₁ and primary resistance voltage drop I₁R₁,

i.e E₁=V₁ - I₁R₁

We shall consider the following two cases:

1. When a transformer is on no-load;
2. When a transformer is on load.

Transformer on no-load. 

A transformer is said to be on no-load if its secondary side is open and primary is connected to a sinusoidal alternating voltage V₁ The alternating applied voltage will cause flow of alternating current in the primary winding which will create alternating flux.

Transformer on load. 

The transformer is said to be loaded when the secondary circuit of a transformer is completed through an impedance or load. The magnitude and phase of secondary current I₂ with respect to secondary terminal voltage will depend upon the character of the load, i.e. current I₂ will be in phase, lag behind and lead the terminal voltage V₂ respectively when the load is purely resistive, inductive, and capacitive.

You may know the details about the electrical transformer from the following articles:

 

1. Working Principle of Transformer;
2. Transformer Construction;
3. Core-type Transformers;
4. Shell-type Transformers;
5. Elementary Theory of an Ideal Transformer;
6. E.M.F. Equation of Transformer;
7. Voltage Transformation Ratio;
8. Transformer with losses but no Magnetic Leakage;
9. Transformer on No-load;
10. Transformer on Load;
11. Transformer with Winding Resistance but no Magnetic Leakage;
12. Equivalent Resistance;
13. Magnetic Leakage;
14. Transformer with Resistance and Leakage Reactance;
15. Simplified Diagram;
16. Total Approximate Voltage Drop in Transformer;
17. Exact Voltage Drop;
18. Equivalent Circuit Transformer Tests;
19. Open-circuit or No-load Test;
20. Separation of Core Losses;
21. Short-Circuit or Impedance Test;
22. Why Transformer Rating in KVA?;
23. Regulation of a Transformer;
24. Percentage Resistance, Reactance, and Impedance;
25. Kapp Regulation Diagram;
26. Sumpner or Back-to-back-Test;
    
27. The efficiency of a Transformer;
28. Condition for Maximum Efficiency;
29. Variation of Efficiency with Power Factor;
30. All-day Efficiency;
31. Auto-transformer;
32. Conversion of 2-Winding Transformer into Auto-transformer;
33. Parallel Operation of Single-phase Transformers;
34. Questions and Answers on Transformers;
35. Three-phase Transformers;
36. Three-phase Transformer Connections;
37. Star/Star or Y/Y Connection;
38. Delta-Delta or ∆/∆ Connection;
39. Wye/Delta or Y/ Connection;
40. Delta/Wye or ∆/Y Connection;
41. Open-Delta or V-V Connection;
42. Power Supplied by V-V Bank;
43. Scott Connection or T-T Connection;
44. Three-phase to Two-Phase Conversion and vice-versa;
45. Parallel Operation of 3-phase Transformers;
46. Instrument Transformers;
47. Current Transformers;
48. Potential or Voltage Transformers.