Basics of Electrical Transformer Theory And Its Operation

Electrical Transformer TheoryThe main purpose of electrical transformer theory is convert one voltage level into another voltage level. By this method electricity can transfer for longer distances with good effciency.Today we are plan to discuss about the three-phase transformer and its working principal of it.

Basic Electrical Transformer Theory

Electromagnetic induction is the basic theory behind the electrical transformer. A varying magnetic flux which associate with the loop will induce electromotive force across it. Those kind of changing magnetic field can produce by using a coil.

The fluctuation behaviour of AC current the magnetic field connected with the coil can also fluctuate .This magnetic flux can be effectively link to secondary winding of the transformer with the help of the core of the transformer.

The magnetic field of the transform create electro magnetic force in the secondary side of the transformer from electromagnetic induction.The operation of the electrical transfomer is more similar to the operation of induction motor

Equations of Electrical Transformer

Normally winding arrangement of the transformer connect in series . The emf induce in the winding will be the sum of the each emf induce in each turns of the winding.

Es =QsxNs


The same magnetic flux is passing form the primary and secondary of the transformer.  So the per turn emf of primary and secondary are the same.

Qs= Qp

The EMF per turn on primary is also proportional to the applied voltage to the transformer.


Es= Ep/NpXNs

The meaning of this equation is If you reduce number of turns in secondary you can increase  You can reduce the voltage level of primary side of the transformer. This can also apply as reverse too.

Primary and secondary current equation according the power theory


Basic Configuration of Electrical Transformer

Three phase transformer is equal to three single phase transformer. But the configuration of the coil is slightly differnce.In this type of three-phase transformers the primary and secondary coils sit concentrically. Three windings are employed in three-phase transformer.

There are two type of configuration on three-phase transformers which popularly known as Star configuration and Delta configuration.

In transformer high voltage electrical bushes are required to bring out the electrical energy. In three-phase transformers the low voltage windings are slit near the core of the transformer.

Transformer Losses

When in transformer power transfer from primary to secondary coil , various energy losses can happen such as eddy current losses, hysteresis loss and iron losses. Most of the mention energy losses are dissipate as heat. Due to this reason transformer coil is immersed into cooling oil. There are several cooling methods are use to get cool and to reduce the heat dissipations of the transformer.

Normally the when oil of the transformer tank absorb the heal , it will expand. So to maintain the required oil level additional conservation tank install into the transformer. We are also discuss several articles regarding the Electrical Transformer Theory and operation before and plan to discuss more on future. 

One thought on “Basics of Electrical Transformer Theory And Its Operation

  • August 31, 2017 at 1:25 am

    I like how you explained that power can be lost between transferring from one coil to the next. It’s interesting that there are also different coolants used for the coils. I didn’t even know there was a thing called cooling oil.


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