A transformer is specified as a passive electrical component that transfers electrical energy from one circuit to another via the procedure of electromagnetic induction. It is most frequently used to increase (‘step up’) or decrease (‘step down’) voltage levels between circuits

Most straightforwardly, a transformer can be described as a thing that converts. However, when we research more about it in detail and link it to electrical current, it is specified as a fixed tool that changes the voltage level in between circuits. The transformer is primarily a voltage control tool used extensively in the distribution and transmission of AC (Alternating Current) power.

The concept of a transformer was first reviewed by Michael Faraday in the year 1831 and was carried forward by several other noticeable scientific scholars. However, the general objective of using transformers was to keep an equilibrium in between the electrical power that was created at very high voltages and also consumption which was done at really low voltages

What is a Transformer?

A transformer is an electric device used in the power distribution and transmission of electric energy. The transmission current is Alternating Current (AC). It is frequently made use of to enhance or reduce the supply voltage level without a change in the frequency of Alternating Current in between circuits. The transformer works on basic concepts of electromagnetic induction and also mutual induction.


Transformer Classifications

Transformers are used in different fields like power generation grid, distribution industry, transmission as well as electrical power consumption. There are many types of transformers which are classified based on the list below aspects –

  • Working voltage range.
  • The medium used in the core.
  • Winding arrangement.
  • Installation location

Based on Voltage Levels,

They are categories as:

  • Step-up Transformer: They are used in between the power generator and the power grid. The secondary voltage is greater than the input voltage level.
  • Step down Transformer: These transformers are made use of to convert the high voltage level of the primary supply to the low voltage of the secondary output.

Based on the Medium of Core Used

In a transformer, we will differentiate different kinds of transformer based on cores that are used

  • Air core:  The flux linkage between the main as well as the second winding is with the air. The coil or windings wound on the non-magnetic strip
  • Iron core: Windings are wound on quite a lot of iron plates piled with each other. It gives a perfect linkage path to generate flux.

Based on the Winding Arrangement

Autotransformer: It consists of one winding wound over a core that is laminated. The primary and secondary share the same coil. Auto also means “self” in the Greek language.

Based on Install Location

  • Power Transformer: It is made use of at power generation stations as they are suitable for high voltage application
  • Distribution Transformer: They are widely used at distribution lanes in domestic objectives. They are planned for booming low voltages. It is really simple to mount and identified by low magnetic losses.
  • Measurement Transformers: They are mainly used for the measurement of the current, power voltage.
  • Protection Transformers: They are utilized for component protection purposes. In circuits, some elements have to be secured from voltage fluctuation, etc., defense transformers to make sure the component security.

How Transformers Work

It is essential to remember that transformers do not create electrical power; they transfer electric power from one AC circuit to another using magnetic coupling. The transformer’s core is used to give a regulated path for the magnetic flux change produced in the transformer by the current streaming through the windings, which are likewise called coils. There are 4 primary parts to the standard transformer. The components include the Input Connection, the Output connection Link, the Windings or Coils as well as the Core


  • Input Connections – The input side of a transformer is titled the primary side because the main electrical power to be changed is coupled at this point.
  • Output Connections – The transformer’s output side or secondary side  Reliant to the load condition, the incoming electric energy is either level up or level down.
  • Winding – Transformers have two windings, being the primary winding and the secondary winding. The primary winding is the coil that draws power from the source. The secondary winding is the coil that delivers the energy at the transformed or changed voltage to the load. Usually, these two coils are subdivided into several coils in order to reduce the creation of flux.
  • Core – The transformer core is used to provide a controlled path for the magnetic flux generated in the transformer. The body is generally not a solid steel bar, rather a construction of many thin laminated steel sheets or layers. This construction is used to help eliminate and reduce heating.
    Transformers generally have one of two types of cores: Core Type and Shell Type. These two types are distinguished from each other by how the primary and secondary coils are placed around the steel core.
  • Core type – With this type, the windings surround the laminated core.
  • Shell type – With this type, the windings are surrounded by the laminated core.

When an input voltage is applied to the primary winding, alternating current starts to flow in the primary winding. As the current flows, a changing magnetic field is set up in the transformer core. As this magnetic field cuts across the secondary winding, an alternating voltage is produced in the secondary winding.
The ratio between the number of actual turns of wire in each coil is the key in determining the transformer type and what the output voltage will be. The ratio between the output voltage and input voltage is the same as the ratio of the number of turns between the two windings. A transformer’s output voltage is greater than the input voltage if the secondary winding has more turns of wire than the primary winding. The output voltage is stepped up, and considered to be a “step-up transformer”. If the secondary winding has fewer turns than the primary winding, the output voltage is lower. This is a “step-down transformer”.

Transformer Configurations

There are different configurations for both single-phase and three-phase systems.

  • Single-phase Power

Single-phase transformers are frequently used to supply power for housing lighting, air-conditioning, and heating systems. Single-phase transformers can be made more flexible by having both the primary winding and also second winding made in two equivalent components. Both parts of either winding can then be reconnected in parallel  or series arrangements

  • Three-phase Power

Power may be provided via a three-phase circuit including transformers in which a trine single-phase transformers is used, or on the three-phase transformer is utilized. When a significant quantity of power is associated with the transformation of three-phase power, it is much more economical to utilize a three-phase transformer. The special setup of the windings and also core conserves a great deal of iron

  • Delta and Wye Defined

There are two connection configurations for three-phase power: Delta and Wye. Delta and Wye are Greek letters that represent the way the conductors on the transformers are configured. In a delta connection, the three conductors are connected end to end in a triangle or delta shape. All the conductors radiate from the center for a wye, meaning they are connected at one common point.

  • Three-phase Transformers

Three-phase transformers have six windings; three primaries and three secondaries. The manufacturer connects the six windings as either delta or wye. As previously stated, the primary windings and secondary windings may each be combined in a delta or wye configuration. They do not have to be connected in the same structure in the same transformer. The actual connection configurations used depend upon the application.

Why do we use high voltages?

Do you ever think about our homes as well as workplaces are using copiers, computers, washing machines, and also electric razors power rated at 110–250 volts. Why don’t power stations simply transfer electricity at that voltage? Why do they supply in KVA or higher voltages? To clarify that, we need to know a little about how electricity travels.

high voltage transformers

As electrical energy moves down a metal wire or plate, the electrons that carry its power jiggle with the steel structure, bashing as well as crashing around and usually wasting energy like rowdy schoolchildren running down a hallway. That’s why cords get hot when electricity flows via them (something that’s very helpful in electric toasters and also various other appliances that use burners). It ends up that the greater the voltage power you use, and also the lower the present, the much less power is wasted this way. So, the power that comes from the nuclear power plant is sent out down the cords at exceptionally high voltages to conserve energy

But there’s another motive as well. Industrial plants have higher power-rated machines that are huge and more energy-hungry than anything you have at home. The energy an appliance uses is proportional to the voltage it uses. So, instead of running on 110–250 volts, power-starving machines might use 10,000–30,000 volts. Smaller factories machine may prerequisite supplies of 400 volts or so.

To put it simply, different power customers require various voltages. It makes sense to deliver high-voltage electrical energy from the power plant and after that change it to reduced voltages when it reaches its different destinations. (All the same, centralized power stations are still very inefficient. Regarding two-thirds of the energy that comes to a nuclear power plant, in the form of raw fuel, is wasted in the plant itself and on the journey to your home.)

Uses and Application of Transformer


The most important uses and application of transformer are:

  • It can make up/down the level of Voltage or Current. The power remains the same in an AC Circuit.
  • It can raise or decrease the value of the capacitor, an inductor, or resistance in an AC circuit. It can thus work as an impedance transferring device.
  • It can be used to prevent DC from passing from one circuit to the other.
  • The transformer isolates two circuits electrically.
  • Transformers with multiple secondary’s are used in radio and TV receivers which require several different voltages.
  • Transformers are used as voltage regulators.
  • The transformer used in voltmeter, ammeters, protective relay, etc.
  • The transformer used for step-up low voltage in case of measurement.
  • The transformer used to step down the high voltage for safety.
  • The transformer used in the rectifier.
  • It requires voltage regulators, voltage stabilizers, power supplies, etc.

The transformer is the key purpose to transmit and distribute power in AC form instead of DC because the transformer does not function on DC. There are some problems with transferring power in DC. in the DC Transition and distribution, Buck and Boost Converter are usually used to up-down voltage level, but it is too costly and not suitable economically. The main application of a transformer is to Step up (Increase) or Stepdown (Decrease) the level of voltage. in other words, Increase or decry the current level, while power must be the same.

Other Uses and application of transformer:

It steps up the voltage level at the power generation side before electric power transmission and distribution to the consumers. In the distribution section, for commercial or domestic use of electric power, the transformer step down the voltage level. For instance, it converts 33kV to 220 V single-phase and 440 V three-phase. The Current Transformer and Potential Transformer also require for power systems and in the industry. Also, it is used for impedance matching.  So, these were the simple uses and applications of the transformer.

How do you select transformers?

electric transformer

We should strictly flow some common steps to choose the right transformers –

Step 1 – Determine primary voltage and frequency.

Step 2 – Determine the secondary voltage required.

Step 3 – Determine the capacity required in volt-amperes.

This is performed by multiplying the load current in amperes by the load voltage in volts for a single phase. Always one should select the transformer larger than the actual load. This is complete for safety purposes and allows for expansion in case more load is added at a later date. For 3 phase KVA, multiply rated volts x load amps x 1.73 (square root of 3), then divide by 1000.

Step 4 – Determine whether taps are required. Fixtures are usually specified on larger transformers.  Use the selection charts in the Acme catalog

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