Transformer

Introduction
      
       A transformer is a static electrical machine which transfers AC electrical power from one circuit to the other circuit at the constant frequency, but the voltage level can be altered that means voltage can be increased or decreased according to the requirement.
Working Principle

       The working principle of transformer is very simple, Mutual inductions between two or more windings is responsible for transformation action in an electrical transformer. 
                      Basic Theory of Transformer

       Say you have one winding which is supplied by an alternating electrical source. The alternating current through the winding produces a continually changing flux or alternating flux that surrounds the winding. If any other winding is brought nearer to the previous one, obviously some portion of this flux will link with the second. As this flux is continually changing in its amplitude and direction, there must be a change in flux linkage in the second winding or coil. According to Faraday's law of electromagnetic induction, there must be an EMF induced in the second. If the circuit of the later winding is closed, there must be a current flowing through it. This is the simplest form of an electrical power transformer, and this is the most basic of working principle of transformer.
Construction of a Transformer


        It mainly consists of.
  1. Magnetic circuit (consisting of core,limbs,yoke and damping structure).
  2. Electrical circuit (consisting of primary and secondary windings).
  3. Dielectric circuit (consist of insulations ).
  4. Tanks accessories (conservator, breathe, bushings, cooling tubes etc.).

Types of Transformer

       Based on voltage level

       These are the most commonly used transformer types foe all the applications.depends upon the voltage ratios of primary to secondary windings. 
  • Step - up Transformer. 
                                                      The secondary voltage is stepped up with a ratio compared to primary voltage.In power plant,this transformer is used as connecting transformer of the generator to grid.
  • Step - Down Transformer.
                                                         It used to step down the voltage level from lower to higher level at secondary side.In distribution networks the step-down transformer is commonly used to convert the high grid voltage to low voltage that can be used for home appliances.
Based on core medium used
  • Air Core Transformer.
  • Iron Core Transformer.
Based on winding arrangement  
  • Auto Transformer.
Based on Usage
  • Power Transformer.
  • Distribution Transformer.

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