What is Transformer? | Working principle, Energy losses, Diagram, Types, How does work |

What is Transformer?

What is transformer? - A transformer is a device that can convert alternating current of low voltage to alternating current of high voltage.  

And can convert alternating current of high voltage to alternating current of low voltage. The stabilizer that is installed in our houses also has a transformer, The mobile charger we use also has a transformer, etc.

The transformer works on the basic principles of electromagnetic induction and mutual induction.

The transformer which can change the alternating current voltage can cause the voltage to low from high. And the voltage can be high as low, which transformer transforms the flame voltage to high voltage, it is called stepup transformer (voltage is larger). 

And the transformer which converts the alternating current of high voltage into alternating current of low voltage is called step down transformer (that is reducing voltage).  

Keep in mind that the main mechanism of the transformer works only on alternating current and does not work in direct current.

Step-up transformer

Reversing the situation, we can make a step-up transformer that increases the low voltage to high.  This time, we have more terns on the secondary coil than on the primary one.  

In a step-up transformer, we use more turn in the secondary than in the primary to obtain a larger secondary voltage and a smaller secondary current.

Step-down transformer

If the first coil has more turns than the second coil, the secondary voltage is smaller than the primary voltage.  This is called a step-down transformer.  

In a step-down transformer, the current is changed in the opposite way - increasing in size.

Working principle of transformer

Working principle of transformer - It works on the principle of mutual induction of two coils or Faraday's Law of Electromagnetic Induction.  

When the current in the primary coil is changed, the flux associated with the secondary coil also changes.  

Therefore an EMF is induced in the secondary coil due to the electromagnetic induction of Faraday's Law.

The transformer is based on two principles: first, that an electric current can generate a magnetic field (electromagnetism), and second that a changing magnetic field within a coil of wire produces a voltage at the ends of the coil. 

Changing the current in the primary coil changes the magnetic flux that develops. The changing magnetic flux induces a voltage in the secondary coil.

How the transformer works?

A transformer is based on a very simple fact about electricity: electromagnetic induction.

How When an electric current flows through a wire, it produces a magnetic field or magnetic current around it.  

A magnetic field can be considered the means by which forces are transmitted between magnetic materials. 

In everyday life, the magnetic field is often encountered as an invisible force created by permanent magnets that pull ferromagnetic materials such as iron, cobalt, or nickel and attract or repel other magnets.  

The strength of this field is directly proportional to the value of the current.  Thus a magnetic field generated in this way can be turned on and off, reversed, and very easily varied in power. 

Magnetic fields can be seen as lines of magnetic flux that form closed paths. The figure above  represents the magnetic field (flux line) created around a wire that carries current.

Now another interesting fact about electricity. When a magnetic field fluctuates around a piece of wire, it generates an electric current in the wire. We can produce a fluctuating magnetic field by allowing current in a wire which is also fluctuating.

Next we try to reconcile the above two phenomena.  So if we place the second wire of the wire next to the first wire, and send a fluctuating electric current to the first wire, we will create an electric current in the second wire.  This is called electromagnetic induction because alternating current in the first coil produces current in the second coil.  

All transformers work according to this principle.  If the first wire has a sine-wave AC of a certain frequency, then the current induced in the second wire will be the sine-wave AC of the same frequency.

The closer the two wires are to each other, the greater the induced current for the current given in the first wire.

If the wires are bent into the coil and placed along a common axis, the induced current will be greater if the wires are straight and parallel.

The first coil, which takes electrical power from the source, is called primary winding, and the second coil, which gives the desired output voltage, is known as secondary winding.

We can more efficiently pass electrical energy from one coil to another by wrapping it around a soft iron core.

If the second coil has the same number of turns as the first, then the current in the second coil will be exactly the same as the size of the first one.  

But if we have more or less turns in the second coil, we can make the secondary current and voltage larger or smaller than the primary current and voltage.

An important thing to note is that this trick works only when the electric current is fluctuating in some way.  In other words, you have to use a type of continuously reversing power with a transformer called alternating current (AC).  Transformers do not work with direct current (DC), where a steady current continuously flows in one direction.

In general:

Secondary voltage ÷ Primary voltage = number of turns in secondary Number of turns in primary

Secondary current Primary stream = Number of turns in primary Number of turns in secondary

The power in an electric current is equal to the current-time voltage (watt = volts x amps is one way to remember this), so you can see that the power in the secondary coil is theoretically the same as the power in the primary coil.  

(In fact, there is some loss of power between the primary and secondary as some "magnetic flux" exits the core, some energy is lost as the core heats up, and so on).

Energy losses in a transformer 

Even though transformers are very efficient machines, they cause less energy loss for four main reasons:

• Resistance to winding - The low resistance copper cable used for winding remains resistant and thus causes heat loss.  

• Flux Leakage - If the core design is not good then the flux produced by the primary coil cannot all be connected to the secondary coil.  This can be reduced by considering the shell type core.  

• Loss of eddy currents - Different magnetic fields induce not only secondary coil currents but also iron core currents.  In the iron core, these currents flow in small circles and are called eddy currents.  

• Hysteresis - This is caused by repeated magnetization of the iron core and demagnetization induced by alternating input current.  This can be reduced by using alloys such as mumetal or silicon steel.

Method of reducing energy loss in transformer

To reduce winding resistance, thicker wires with significantly lower resistance are used.  The use of a shell style core will reduce flux loss.  In addition, sound is emitted as a result of the vibration of the core, resulting in loss of energy.  The heel current loss can be reduced by considering laminated cores.  By using alloys such as mumetal or silicon steel, hysteresis losses can be reduced.

(What is Transformer? Working principle, Energy losses, Diagram, Types, How does work )

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