Difference between Ideal Transformer and Practical Transformer

In this article, we will discuss all the important differences between ideal transformer and practical transformer. In electrical and electronics engineering, a transformer is a static electrical machine used to increase or decrease the level of voltage and current.

Based on internal characteristics, there are two types of transformers namely, ideal transformer and practical transformer.

The most elementary difference between ideal transformer and practical transformer is that the ideal transformer is a transformer with 100% efficiency and zero losses, whereas, the practical transformer is a transformer having efficiency always less than 100% and a finite amount of losses.

Before studying the comparison of ideal and practical transformer, let us first discus the basic definition of ideal transformer and practical transformer.

Definition of Ideal Transformer

When a transformer has 100% efficiency and zero power loss, it is referred to as an ideal transformer. In real practice, nothing is ideal. Therefore, the ideal transformer is just a theoretical model of a real transformer which is for analysis purposes.

Characteristics of Ideal Transformer:

A transformer is said to be ideal if it possesses the following characteristics:

• It has an efficiency equal to 100%.
• It has zero winding (primary winding and secondary winding) resistance.
• It has no leakage flux. That means, the entire magnetic flux follows the path through the magnetic core.
• All the power losses (constant losses and variable losses) are zero.
• The permeability of the magnetic core material is infinite.

If a transformer has all of these properties mentioned above, then it is called an ideal transformer. However, the ideal transformer does not exist in the real world. Hence, it is a hypothetical model that can never be realized practically.

Definition of Practical Transformer

A transformer which has certain energy losses inside it due to winding resistances and properties of the magnetic core is referred to as a practical transformer. The practical transformer is also known as a real transformer. All transformers that we see around us in practice are real transformers or practical transformers. Since, there is a finite loss of energy inside a practical transformer, hence the efficiency of a practical transformer is always less than 100%.

Therefore, we can express a practical transformer as an ideal transformer having certain energy losses, i.e.

Practical Transformer = Ideal Transformer + Energy Losses

Characteristics of Practical/Real Transformer:

The following are the important characteristics of a practical transformer:

• It has efficiency always less than 100%.
• It has a finite winding (primary winding and secondary winding) resistance.
• It has a certain amount of leakage flux, which means all the flux is not confined to the core.
• It has finite energy losses due to winding resistance, magnetic core (eddy current loss and hysteresis loss), oil dielectric properties, etc.
• It has a magnetic core of finite permeability.

After having sufficient knowledge about the ideal transformer and practical transformer. Let us now discuss the significant differences between them.

Differences between Ideal and Practical Transformer

The important differences between ideal transformer and practical transformer are listed in the following comparison chart-

S. No.	Ideal Transformer	Practical (Real) Transformer
1.	A transformer with no losses is known as an ideal transformer.	A transformer with finite losses is known as a practical transformer.
2.	An ideal transformer has 100% efficiency.	The practical transformer has an efficiency of always less than 100%.
3.	An ideal transformer has no energy losses inside it.	The practical transformer has a certain amount of energy loss inside it.
4.	In an ideal transformer, the primary and secondary windings do not have resistance.	In a practical transformer, there is a finite resistance of the primary and secondary windings.
5.	An ideal transformer has zero core losses (hysteresis loss and eddy current loss).	The practical transformer has finite core losses.
6.	The ideal transformer has no copper loss due to zero winding resistance.	The practical transformer has finite copper loss due to winding resistance.
7.	In an ideal transformer, the primary and secondary windings are purely inductive.	In a practical transformer, the primary and secondary windings have a combination of resistance and inductance.
8.	The ideal transformer has no leakage flux.	The practical transformer has a certain leakage flux.
9.	In an ideal transformer, the permeability of the magnetic core is infinite.	In a practical transformer, the magnetic core has finite permeability.
10.	The ideal transformer does not exist practically.	A practical transformer exists in the real world.
11.	Ideal transformer requires a very small magnetization current to produce the magnetic flux in the core.	A practical transformer requires a large magnetizing current to produce the magnetic flux in the core.
12.	It is impossible to construct an ideal transformer.	All practically constructed transformers are practical transformers.
13.	An ideal transformer is used for the theoretical analysis of transformer circuits.	Practical transformers are widely used in real practice for voltage and current transformation.

Hence, this is all about the major differences between ideal and practical transformers. In conclusion, the ideal transformer is a theoretical model of a transformer having no energy loss and 100% efficiency. On the other hand, a practical or real transformer is one that has a finite energy loss and efficiency of less than 100%.

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