Simplified Diagram of Transformer

Transformer Simplified Diagram

To get an understanding of the simplified diagram of a transformer, you have to study the vector diagram of the transformer. The combined vector diagrams are shown herewith the figure VD-A, VD-B and VD-C.

The vector diagram of Fig. VD-A may be considerably simplified if the no-load current I₀ is neglected. Since I₀ is 1 to 3 per cent of full-load primary current I₁, it may be neglected without serious error. Fig. VD-B shows the diagram of Fig. VD-A with I₀ omitted altogether.

In Fig. VD-B, V₂, V₁, φ₂ are known, hence, E₂ can be found by adding vectorially I₂R₂ and  I₂X₂ to V₂. 

Similarly, V₁ is given by the vector addition of I₁R₁ and  I₁X₁  to E₁. 

All the voltages on the primary side can be transferred to the secondary side as shown in the figure, where the upper part of the diagram has been rotated through 180°. However, it should be noted that each voltage or voltage drop should be multiplied by the transformation ratio K.

The lower side of the diagram has been shown separately in Fig. VD-C laid horizontally where the vector for V₂ has been taken along the X-axis.

It is a simple matter to find transformer regulation as shown in Fig. VD-C left or Fig. VD-C right.

It may be noted that V₂= KV₁ − I₂ (R₀₂ + jX₀₂) 

= KV₁ − I₂Z₀₂.

Also, V₁ = (V₂ + I₂ Z₀₂) #3/K

Hope the simplified diagram of a transformer is explained simply, for more details you may read the transformer related to our other article.

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.