TRANSFORMERS

A transformer is a static electric device which transfers electrical energy from one circuit to another without change in frequency under the principle of Faraday's law of electromagnetic induction.

FARADAY'S LAW OF ELECTROMAGNETIC INDUCTION:

Faraday's law of electromagnetic induction states that

"When a current carrying conductor is placed in varying or static magnetic field, it induces an emf statically or dynamically as it experiences a force and induced emf is directly proportional to the rate of change flux linkages of the conductor in the magnetic field".

PARTS OF A TRANSFORMER:

The parts associated with a transformer are 

1. Transformer core
2. Copper winding
3. Bushings
4. Transformer oil
5. Conservator
6. Radiator
7. Breather
8. Tank

1. TRANSFORMER CORE:

A transformer core is made up of steel which acts a medium for the flux passages between the winding's present on either side of the core.
The construction of the transformer core depends upon the rating and utility of the transformer and these transformer types are classified as

1. Core type
2. Shell type 

Depending on these types, the transformer core construction differs.

To ensure maximum flux density through core, it is necessary to laminate the core and these laminations are to be insulated in order to reduce eddy current losses which occurs due to the usage of core.

The insulation between each steel lamination is given by thin coating of varnish or by using thick paper between them.

Considering the weak properties of paper insulation like less heat-resisting, heat conducting and mechanical strength, varnishing is highly preferred in high capacity transformers. 

In core type transformers, the steel core laminations are in the shape of 'L' , and these laminations are placed one above the other alternatively.

   

In shell type transformers, the steel core laminations are in the shape of 'E and I' and placed similar to that of core type.

The laminations are placed in the similar manner as shown below:

 2.   COPPER WINDING:

Transformer windings are made of solid copper or aluminium strip conductors.

For carrying large amount of current conductors of large cross-section are required.