Ratio of Transformer,Ideal Transformer and Uses of Transformer.

As-Salaam-Alaikum, Welcome to my blogger "World of Knowledge".Here we discuss some important topics of a Transformer.

Points to be discuss in this Article are given below :

• Ratio of a Transformer
• Ideal Transformer
• Uses of a Transformer

Ratio of a Transformer:

• Voltage Ratio
• Current Ratio

Voltage Ratio:

E.M.F equation of a Transformer,

                                                      E1 = 4.44 f ϕ_{m N1 volts}   

                                                 E2 = 4.44 f ϕ_{m N2 volts}   

Taking ratio of equation we get,

                                                           
                                                            _{E2 / E1 = N2 / N1 = K}


This ratio of secondary induced e.m.f to primary induced e.m.f is known as voltage transformation ratio denoted as K.

     Thus,

                                                 E2 = K E1                      Where K = N2 / N1

•     If N2 > N1 i.e K > 1,we get E2 > E1 then the transformer is  called step up transformer.
•     If N2 < N1 i.e K < 1,we get E2 < E1 then the transformer is  called step down transformer.
•     If N2 = N1 i.e K = 1,we get E2 = E1 then the transformer is  called isolation transformer or 1:1 transformer.          

Ideal Transformer:

A transformer is said to be an ideal transformer,if it satisfied following properties :

• It has no losses.
• Its winding have zero resistance.
• Leakage flux is zero i.e. 100 % flux produced by primary links with secondary.
• Permeability of core is so high that negligible current is required to establish the flux in it.

NOTE: For an ideal transformer, the primary applied voltage V1  is same as the primary induced e.m.f E1 as there are no voltage drops.

Similarly,

The secondary induced e.m.f E2 is also same as the terminal voltage V2 across the load. Hence for an ideal transformer.

We can write,

                                                     E2 / E1 = V2 / V1 = K

NOTE: No transformer is ideal in practical but the value of E1 is almost equal to V1 for properly designed transformer.

Current Ratio:

For an ideal transformer there are no losses.Hence the product of primary voltage V1 and primary current I1 is same as the product of secondary voltage V2 and the current I2.

So,

                                                    

                                  V1 I1 = input VA           AND           V2 I2 = output VA 

For an ideal transformer,

                                                          V1 I1 = V2 I2 

                                                                 

                                                          V2 / V1 = I1 / I2 = K

Hence the current are in the inverse ratio of the voltage transformation ratio.

Uses of Transformer:

There are many uses of transformer in our daily life some uses ares,

• The transformer used for isolate two circuits electrically.
• The transformer used in voltmeter, ammeters, protective relay etc.
• The transformer used for step up low voltage in case of measurement.
• It is used in voltage regulators, voltage stabilizers, power supplies etc
• The transformer used for impedance matching.
• It is used to increase or decrease the alternating voltages in electric power applications.
• The transformer used in rectifier.
• The transformer used for step down high voltage for safety.

     

t