# Basic Electrical Engineering (3110005)

BE | Semester-1   Winter-2019 | 11-01-2020

## Q4) (a)

#### Explain working principle of single-phase Transformer.

A transformer is defined as a static device converts the electric power from one electrical circuit to another electrical circuit without change of frequency. It can also up and down the voltage level.

#### Working Principle of Transformer

• The main principle of operation of a transformer is mutual inductance between two circuits which is linked by a common magnetic flux.
• A basic transformer consists of two coils that are electrically separate and inductive, but are magnetically linked through a path of reluctance.
• The transformer has two windings, (1) Primary and (2) Secondary winding. Primary winding is connected with input supply side and the secondary winding is connected with output load side.
• The core laminations are joined in the form of strips in between the strips you can see that there are some narrow gaps right through the cross-section of the core. These joints are said to be ‘laminated’.
• Both the coils have high mutual inductance. A mutual electro-motive force is induced in the transformer from the alternating flux that is set up in the laminated core, due to the coil that is connected to a source of alternating voltage.
• Most of the alternating flux developed by this coil is linked with the other coil and thus produces the mutual induced electro-motive force. So the produced electro-motive force can be explained with the help of Faraday’s laws of Electromagnetic Induction as,
• If the secondary coil circuit is closed, a current flow in it and thus electrical energy is transferred magnetically from the first to the second coil. In short, the transformer carries the operations as shown below:
1. Transfer of electric power from one circuit to another.
2. Transfer of electric power without any change in frequency.
3. Transfer with the principle of electromagnetic induction.
4. The two electrical circuits are linked by mutual induction.