What is Transformer? Different Types of Transformer

What is Transformer

Principle- 

A transformer works on the electromagnetic induction law or mutual induction law.The primary or secondary coils are coupled with magnetic field.

Construction of transformer-

The transformer is a static device which can be transfer power one palace to another palace (one circuit to another circuit) it means the current and voltage  through by medium of magnetic field without changing frequency. The main supply connected to input terminal that called a primary winding and output terminal connected to a load that called a secondary winding.the transformer is an electromagnetic energy conversion device. The primary winding and secondary winding are not connected electrically But they are coupled by magnetic field. The magnetic field transfer the high voltage to low voltage and low to high voltages as per direction same voltage from primary to secondary winding.The transformer magnetic core is made of cold rolled grain oriented sheet steel layers.This layers are laminated thin silicon-steel. The layers wound by copper winding that winding are called a primary and secondary Winding.
Working- Transformer core is working on magnetic flux.In a diagram shown the primary or secondary winding have a Np or Ns turns in transformer.Coil are connected with magnetic field.Primary current or voltage are supply terminals of transformer.Secondary current or voltage are load side of terminal.In core magnetic flux will be produce same current or voltage secondary winding respect with primary winding.but such case like step up or step down transformer both side current or voltage is depended on theirs turns. 

Types of Transformer: 

1.Step up transformer

2.Step down transformer

According to Construction of transformer

3. Core type

4. Shell type

Step up transformer-

If the secondary winding turns has more than the primary winding.The secondary voltage more than the primary voltage So the input voltage is lower than the output voltage is called a step up transformer. In a step up transformer winding increase in secondary winding the output voltage is more than input voltage.

Step down transformer-

If the secondary winding turns has less than the primary winding.The secondary voltage less than the primary voltage So the input voltage is higher than the output voltage is called a step down transformer. In a step up transformer winding decrease in secondary winding the output voltage is less than input voltage.

According to Construction of transformer

The transformer works on the principle of electromagnetic induction between two coils.Transformer is generally construct two type
1. Core type

2. Shell type

                 The transformer is very simple in construction and consists of magnetic circuit linking with two winding primary and secondary winding. Transformer assembled core and winding. The magnetic core is a stack of thin silicon steel lamination about 0.35 mm to 0.5 mm for a 50 Hz transformer.In order  to reduce the eddy current  losses , these lamination are insulated from by thin layer of varnish. The magnetic core made from cold rolled gain oriented sheet steel material is magnetized in the rolling direction has low core loss and high permeability.

Core type-

Core type has two legged core. In core type transformer the flux has a single path around the leg or yokes , the flux in the central limb divides equally and returns through the outer two legs.This type of transformer is used high voltage and high power level. The concentric coils are used in transformer.

Shell type-

Shell type has three legged core. In winding are wound over the central limb and are interleaved or sandwich. This type of transformer is used low voltage and low power level. Interleaved or sandwich coils are used in transformer.

                                       

During the transformer construction, first the primary and secondary wound a winding and lamination the open coils.The lamination are tightened by clamps and bolts.Low power transformer are air cooled  based and high power transformer are oil cooled (coolant). For power frequency range 25 to 400 Hz and radio frequency range 20 to 20000 Hz. The core is made of powdered ferromagnetic alloy.The various assumption are as follows.

1. Negligible resistance of winding.

2. The hysteresis and eddy current losses are negligible.

3. Permeability of core is a constant.