types of transformer

There are various types of transformer, each with its own applicable usage. In this blog we will give you an overview of Transformer, their Working Principle, types of Transformer with Equations, Advantages and Limitations. We have published this topic in detail on our Website, we recommend you to read it on AllumiaX blog Types of Transformer.


An electrical device that can be used to transfer the power from one circuit to another by using the principles of electromagnetic induction.

Working Principle of Transformer

The transformer working depends upon Faraday’s law of electromagnetic induction. According to Faraday’s laws,

“The Rate of change of flux linkage with respect to time is directly proportional to the EMF induced in a conductor or coil”.

Faraday’s Law

Types of Transformer

Transformer can be categorized on the basis of voltage level, medium, uses, configuration and place of usage. Now we will an overview on these types.

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1. Based on Voltage Level

On the basis of voltage level, transformer types are listed below.

  • Step-Up Transformer
  • Step-Down Transformer
  • Isolation Transformer

Step-Up Transformer

A transformer that increases the voltage from primary to secondary.

Vp/Vs = Ns/Np

The three advantages of Step-Up Transformer are:

  • Transmit electricity over long distances at low cost.
  • Helps in reducing the resistance on the line.
  • Ability to work continuously.


One of the limitation is that applications are limited to AC operations only.

Step-Down Transformer

A transformer in which the output voltage is greater than its input voltage.

Vp/Vs = Ns/Np

The three advantages of Step-Down Transformer are:

  • Easy power transmission at low cost.
  • Highly reliable and efficient.
  • Provides varied voltage requirements.


One of the limitation is requirement of a lot of maintenance, which can damage the transformer.

Isolation Transformer

A transformer used to transfer electrical power from a source of alternating current (AC) power to some equipment or device while isolating the powered device from the power source.

Vs/Vp = Ns/Np Where Ns=Np

The three advantages of Isolation Transformer are:

  • Provide safety to electronic components and the persons against electrical shock.
  • Suppress the electrical noise.
  • Avoids ground loops.

One of the limitation is to produce distortion at secondary side when operates as pulse transformer.

2. Based on the Core Medium

On the basis of core medium, transformer types are listed below.

  • Air-Core Transformer
  • Iron Core Transformer
  • Ferrite Core Transformer

Air-Core Transformer

A Transformer designed to transfer radio-frequency currents.


The three advantages of Air Core Transformer are:

  • Zero distortion.
  • Zero dissipation of signal quality.
  • Noise-free operation.

One of the limitation it’s low degree of coupling.

Iron Core Transformer

A transformer in which lamination of iron or other magnetic material make up part or all of the path for magnetic lines of force that link the transformer winding.

Ferrite Core Transformer

A transformer whose magnetic core is made up of ferrite.


The three advantages of Air Core Transformer are:

  • Low reluctance magnetic path.
  • High current resistivity.
  • Provides low eddy current losses over many frequencies.

One of the limitations is it’s Easily saturated.

3. Based on Usage

On the basis of usage, transformer types are listed below.

  • Power Transformers
  • Distribution Transformers

Power Transformers

A transformer is an electrical apparatus designed to convert alternating current from one voltage to another.

The three advantages of Air Core Transformer are:

  • Suitable for high voltage applications (greater than 33KV).
  • High insulation level.
  • Minimize the power loss.

One of the limitation is it’s big in size.

Distribution Transformers

a transformer that provides the final voltage transformation in the electric power distribution system.

4. Based on Electrical Supply

On the basis of configuration, transformer types are listed below.

  • Single-phase transformer
  • Three-phase transformer

Single Phase Transformer

A type of power transformer that utilizes single-phase alternating current, meaning the transformer relies on a voltage cycle that operates in a unified time phase.

The three advantages of Air Core Transformer are:

  • Simple network.
  • Cost effective.
  • Most efficient AC power supply for up to 1000 watts.

One of the limitation is it’s Supply is only 1-ph load.

Three Phase Transformer

A three-phase transformer is made of three sets of primary and secondary winding, each set wound around one leg of an iron core assembly. Three phase transformer core has three sets of winding.

The three advantages of Three Phase Transformer are:

  • Large motors or heavy loads materials.
  • Transmission of power to long distance through magnetic field.
  • Maximum power transfer capability.

One of the limitation is requirement of many cooling systems depending on the transformer rated power.

5. Based on Place of Usage

On the basis of place of usage, transformer types are listed below.

  • Indoor Transformers
  • Outdoor Transformers

Indoor Transformers

Indoor transformers are usually a Dry type transformer. These transformers use air as cooling medium and usually their primary and secondary side connections are isolated.

The two advantages of Indoor Transformer are:

  • Low maintenance cost.
  • Safer option as compare to oil-filled transformer.

One of the limitation is it’s higher operating loss.

Outdoor Transformers

Outdoor transformers are usually an Oil filled transformers. These transformers use oil as cooling medium and are designed to be utilized in outdoor environments due to the chance of oil leakage and spills that create a fireplace risk, and must be protected against environmental conditions.

The two advantages of Outdoor Transformer are:

  • Smaller and more efficient.
  • Lower operational costs.

One of the limitation is it’s high Maintenance cost.

we have given you an overview of Types of Transformer and we hope that after reading this you would gain some valuable insights and ideas out of this blog but if you are curious to know more and want to unlock all five advantages of each type with their complete limitations (free of cost/no signup required) then we think you should consider visiting Types of Transformer to get a detailed description with valuable content and information.

We are covering all topics about Transformer one by one with best of our knowledge of our “AllumiaX engineering staff” with collaboration of “General Pac engineering staff”. Till yet we have also covered Open Phase Condition in Transformers, Introduction to Current Transformers, Introduction to the Delta Wye Transformer, Fault Analysis In Power Systems and much more. Our many topics related to transformer are also almost complete and will be published soon. Stay tuned with us to learn more at Allumiax and our co-operate sponsor GeneralPac.

Let us know if you have any queries regarding this topic and do provide us with your feedback in the comments.

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