# Types of transformer

## Types of Transformer

Classification of transformer on different base

### A. According to construction

#### 1. Core type transformer

In the core type transformer the coil used are form-wound and are of cylindrical type .These coils general form may be circular or oval or rectangular. A simple rectangular core is used in small size core type transformer. Which are being circular or rectangular in form. But round or circular cylindrical type coil are used in large size core type transformer.

#### 2. Shell type transformer

In shell type transformer also the coil are form-wound .but there are multi -layer discs type usually wound in the form of pancakes. In this type transformer multi-layer discs are insulated each other by paper.

### B. According to output voltage

According to output voltage there are classified in two types

#### 1. Step-up transformer

The transformer is called step-up transformer which Secondary winding turn is greater than primary winding turn which means the transformer which output voltage is greater than input voltage is called step-up transformer .In this type transformer secondary voltage or output voltage is more as compare to primary voltage or input voltage. it is depend only on number of  turns in primary winding and secondary winding  .logically  these relation shown in below.
But primary current is greater than secondary winding current because power become same in both circuit. When transformer work.

P=V*I

Secondary Winding Voltage > Primary Winding Voltage

Or
Output Voltage > Input Voltage

Secondary Winding Turns > Primary Winding turns

Primary Winding current > Secondary Winding current

#### 2. Step-Down transformer

The transformer is called step-down transformer which primary winding turns is greater than secondary winding turns  we are called step-down transformer  which primary winding  number of turns is greater than secondary winding  number of turns bit primary winding current is less than secondary winding current is greater than primary winding current  because in both circuit power are being same ,P=V*I
Which means when voltage will increase then current will decrease.
Primary Winding Voltage > Secondary Winding Voltage
OR
Input voltage > Output Voltage
Output current > Input Current
Secondary Winding Current > Primary Winding current.

### C. According To Phase

According to phase transformer divide in two parts

#### 1. Single phase transformer

Single phase transformer has single phase winding in primary and secondary it is work on single phase it has one phase and one neutral. It has two single phase winding primary and secondary winding. Its input and output supply is being single phase .

#### 2. Three phase transformer

Three phase transformer has three phase winding in primary and secondary it works on three phase it has three separate winding consequently R,Y ,B.
Its input and output supply is being three phase.
In this type of transformer connected in two type of connection
Star connection ( In which produced neutral )
Delta connection
Transformers output depend In these both connection

### D.According to service

According to service transformer also classified in two parts

#### 1. Power Transformer

The transformer having rating above 200 kv and are used in generating station and substation for stepping up voltage is known as power transformer.

#### 2. Distribution Transformer

The Transformer up to the power rating  about 200KVA used to step down the distribution voltage stranded services voltage are known as distribution transformer.