Transformers

 INTRODUCTION 

A transformer transfer wlectrical energy from one circuit to another through intuitively coupled conductors. It is widely used to change the voltage and currents can either be increase or decrease as per required. A transformer has no moving parts.

WORKING PRINCIPLE OF TRANSFORMER
A transformer is a static device wich means of wich electric power in one circuit in transformed to another circuit without a change in frequency.

CONSTRUCTION OF TRANSFORMER
The transformer is very simple and durable in construction and consists of magnetic circuit linking with two winding known as primary and secondary winding. The following are the main components of the transformer as shown in figure.
 

Core
Transformer core is constructed from thin sheet of high grade Silicon with 4% of silicon. The sheets are laminated and they are coated with an oxide layer to reduce the iron losses. The purpose of the core is provide a magnetic path of low reluctance between the two windings.

Winding
A transformer has two winding. The winding which receive the electrical energy is called the primary winding and the winding which delivers the electrical energy is known as a secondary winding. Windings are generally made of high grade copper. Pressed board or paper insulation is also sometime used for supporting the winding.

Conservator
Oil immersed transformers are normally equipped with conservative. It consists of an airtight cylindrical metal drum supported horizontally on the Transformer lid. It should be provided with a detachable bottom or an acess hole so that the conservator can be painted from inside and cleaned from oil sludge.

Breather  
The shape of breather is like a box. When the temperature changes the oil expands for contacts and there is a displacement of air. Displacement of air due to the changes of oil volume takes place through the breather, which extracts the moisture from the air. The breather consists of a small vessel which contains a drying agent like slice gel crystal impregnated with Cobalt crystal.

Bushing
The Terminal connections of the windings are taken to the insulator bushings mounted on the Transformer tank top. The bushing consists of a current carrying part in the form of the conduction rod and a porcelain cylinder installed in the whole of the cover and used to isolate the current carrying part. Ordinary fosolin isolators can be used up to a voltage rating of 33 kilo volt condenser bushing for oil field terminal bushings are generally used. For certain cases a combination of the two typeof bushing is also used.