TRANSFORMER

 Electromagnetic induction is used to transmit electricity from the primary winding to the secondary winding (EMI). At the very same frequency as the supply voltage, the flux within the core alternates.

What is a transformer?

A transformer is an electrical device that uses mutual inductance to transmit electrical energy from one circuit to another by EMI. The transformer operates on the mutual inductance concept and runs at about the same frequency. The transformer contains two windings: primary and secondary, both of which are isolated from one another. These windings are made up of a magnetic material and are coiled on common material. Primary windings are those that are linked to alternating voltage, whereas secondary windings are those that are not. Electromagnetic induction is used to produce electromotive force in both windings.

Working :

An exciting current runs through primary windings when they are coupled to an AC source. The core creates alternating flux because the current is alternating. The applied voltage will be opposed by the induced emf inside the primary, which is nearly equivalent to the applied voltage. Any load placed all over the secondary windings receives power from the electromotive force created in the secondary windings. Electromagnetic induction is used to transmit electricity from the primary winding to the secondary winding (EMI). At the very same frequency as the supply voltage, the flux within the core alternates. The amplitude of induced emf inside the secondary winding is generally equivalent to the number of revolutions in secondary windings, and the frequency for induced emf within secondary winding is like the supply voltage. The transformer is termed a step-down transformer if a primary winding no. of turns is greater in respect to the secondary windings no. of turns, and a step-up transformer if the secondary winding number of turns is greater than the main winding number of coils.

Construction :

The construction of a transformer is as basic as it gets because there are no moving parts. Components of a transformer are:

1. Magnetic core: 

• The magnetic core is usually laminated and constructed of excellent magnetic material such as silicon steel.
• Thickness ranges from 0.35mm to 0.5mm.
• By applying a thin layer of varnish on each lamination, it is isolated from one another.
• To avoid the creation of eddy currents, the joints are staggered.
• It will give less mechanical strength if it is not staggered, and a buzzing noise will be heard during operation.
• After that, it was bolted together.
• There are two types of transformers based on the core.

a) Transformer with a core:

• It encircles a narrow route.
• It only has a single magnetic route.
• It makes use of wounded coils that are cylindrical in shape.
• Windings are separated from the core to each other by insulating cylinders.

b) A shell transformer:

• It is one that has a large amount of space around it.
• Stamped with the letters E and I.
• It features two magnetic flux lines that run parallel to each other.
• These are disc-type coils with many layers.

2. Windings :

• There are two types of windings: main and secondary.
• Copper is used to make the windings.
• Primary windings are those that are linked to alternating voltage, whereas secondary windings are those that are not.
• Both are apart from one another.

3. Insulation of windings:

• In basic conductor insulation, paper is utilised as insulation.
• In such a low voltage transformer, an enamel solution is utilised as insulation.
• In power transformers, an enamel copper coil can be utilised as insulation.
• Insulating oil protects the paper against dirt and moisture while also removing heat generated therein core and coils. It also functions as an insulator.

4. Expansion tank or conservator:

• A small supplemental oil tank can be installed well above the transformer and piped into the main tank.
• Its purpose is to maintain the tank filled owing to the squeezing of the coil inside the tank when the temperature changes.
• The gas just above the oil inside the transformer can enter the expansion tank through a tiny pipe connection in between the gas space inside the expansion tank as well as the cap of the transformer tank. In order for the transformer tank to be entirely filled.

5. Temperature gauge:

• A temperature gauge is used by the transformer to display hot oil or the temperature of the hottest region.
• A bourdon metre and thermometer bulb are used to power it.
• An oil gauge is used by transformers to show the level of oil inside the tank.
• Due to its own oil tank, it is equipped with an alert contact that sounds whenever the oil level drops below the allowable height.

6. Buchholz relay:

The appearance of bubbles inside the oil may be the first indication that a defect exists. The gas bubbles will ascend up the pipe connecting the conservator to that same tank if the transformer has filled with only a conservator and there are no spaces in which gas can accumulate. In this pipe, a gas-operated relay can be installed to sound an alert in the event of a small failure and disconnect this same transformer from supply mains in the event of a major problem.

7. Breather:

• The most basic method for preventing moisture from entering the transformed container is to add breathing chambers.
• It contains a drying agent such as silica gel.
• Allows dry air to enter the transformer tank by absorbing moisture.
• The drying agent should be replenished on a regular basis.
• Through the breath, a little surface area with transformer oil is exposed to the environment.

8. Bushings:

• Bushings are used to bring connections out from transformer windings out.
• Capacitor and coil-filled bushings are employed above 33kv.

Conclusion:

Hence transformers are generally used to transfer electricity from one circuit to another by means of EMI and this can be done in two types that means by using step-up transformer and a stepdown transformer. A transformer’s construction and parts are explained in the article.