Basic function of Transformer | practical need of Transformer

Q: What is the basic function of transformer ? Why do we need transformer in practice ?

Introduction Of Transformer

Electrical energy is generated at generating stations and it is transmitted over transmission lines to distant places here it is utilized to industries, house hold purpose. agriculture purpose, industrial purpose etc. Normally power generation is at a voltage level, in the order of 6.6 KV, 11 KV; it is uneconomical to transmit large amounts of power over long distances, at this voltage level due to large voltage drops and excessive power losses. because of the flow of very high currents. By increasing transmission voltage level, we can reduce voltage drops and power losses in the transmission line. The AC transmission voltages used in India are usually 132 KV, 220 KV and 400 KV. However, the voltage required for domestic, commercial and industrial purposes is 230,415 V. Thus, at generating stations, voltage has to be stepped up to transmission level and it is to be stepped down to consumer end.

A transformer is a static device, comprising coils, coupled through a magnetic medium. It allow: electrical energy transfer via magnetic field from one coil to the other. It can be used to step up or step down voltage levels. Thus a transformer is an important and essential component of an electric energy system, as it makes possible to generate electrical energy at the most economic voltage level, transmit electric energy at the most economic transmission level and distribute electric energy at the voltage suitable at the consumer end.

A transformer is the most widely used device in both low and high circuits. In a transformer, the electrical energy transfers from one circuit to another circuit takes place without the use of moving parts, It has, therefore, the highest possible efficiency out of all electrical machines and requires almost negligible amount of maintenance and supervision.

Q: what is single phase transformer ?

Principle Of Transformer

A transformer is a static device by which electric power in one circuit is transformed into electric power of the same frequency in another circuit. It can raise or lower the voltage in a circuit but with corresponding decrease or increase in current.

fig: transformer : single phase transformer diagram

Transformer Construction

single phase transformer construction and working principle ?

Transformers consist of primary winding, secondary winding, core and tank with cooling arrangement.

There are two separate windings made up of number of turns. Both the coils are not electrically but they are placed on same core. The coils are also insulated from core.

The core is made up of laminated strips of transformer steel in order to minimise eddy current loss. Each strip is insulated from each other. High silicon content steel with low hysterisis loop is used in order to minimise hysterisis losses.

The complete assembly is then placed in steel tank. The tank is filled with special insulating oil to cool the transformer. Radiators arc provided on the tank to have effective cooling, The transformer coil should be free from moisture. Cooling system may be improved for higher capacity transformer.

Transformer Working

Single phase transformer working ?

The basis or a transformer is mutual induction between two circuits linked by a common magnetic flux. It consists two coils with high mutual inductance. one coil is connected to a source of alternating voltage, an alternating flux is set up in the laminated core, most of which is linked with the other coil in Which it produces mutually induced c.m.f. If the second coil circuit is closed, a current flows in it and so electric energy is transferred from the first coil to the second coil. The first coil, in which electric is fed from a.c. supply mains called ‘primary winding’ and the other from which energy is drawn out, is called ‘secondary winding’.

Practical Need Of Transformer

Need of 1 phase transformer ?

Need of Transformer : We used A.C. system for generation transmission and utilisation of electric voltage. Transmission voltage is very high to losses, also utilisation is as per need of users. So that level of voltage system has to be changed. And this is achieved by transformer. It also provides electrical isolation between two circuits.

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