Transformers are devices which is used to supply electricity everywhere. They are the medium through which is used for generating electricity and also is a stationary device used for transferring energy all over the world. Our power systems simply won’t be running in the absence of these electric marvels. Today, in this article we will be discussing about the working and construction of transformers.
This motionless machine will help to supply electric power from one circuit to another without the change in the system’s frequency. Transformers also work in two main modes. They are step up and step down transformers. Generally, distribution transformers that are used in our homes are of the type step down. Similarly, the transformers that are being used in the electric plants are step up transformers.
Depending on the manner in which it is connected to the circuits, the same transformer can be used both as a step up and step down transformer. In step-up devices, low voltage winding is primary and high voltage winding is primary in step down type transformers. We have written this article with an intention to let the readers know about the various aspects of transformers. From the construction of transformers to its working and types, we have got you all covered in this fascinating read.
Working of Transformers
The basic principle behind the working of transformer is simply the phenomenon of mutual induction that occurs among the windings that are linked by the common magnetic flux. In general, a transformer consists of two separate inductive coils. They are known as primary and secondary windings. These coils are separated electrically but are magnetically connected and linked to one another. While construction of transformers, its working principles should also be considered.
When transformers run, its primary winding is joined to an alternating voltage source. This in turn helps in achieving an alternating magnetic flux and is generated around the winding. Similarly, the role of a core of a transformer is to provide the magnetic way for the flux. The flux generated will then link up with the secondary windings. Most flux will be connected to the secondary windings and is known as useful or main flux. Similarly, the flux that isn’t connected is called leakage flux.
The flux that is produced is of alternating type. Which means its direction is ever changing. Due to this, EMF also gets induced in the secondary windings. This EMF is called as mutually induced EMF and its frequency is also same as that of the supplied EMF. When the secondary winding is converted into a closed circuit, the mutually induced current flows through it.
Therefore, the electrical energy also gets transferred from one circuit to the other in such instance. This is how transformers work. During the construction of transformers, these things should also be taken in to consideration. A transformer that is produced will only work efficiently is all its working principles and conditions are met during the construction of transformer.
General Construction of Transformers
We have already discussed on how important windings are to a working of a transformer. Therefore, the part where the focus is given during its making is also in its windings and core. Generally, a transformer has two separate inductive type windings and also a laminated steel core. The coils are insulated from one another and are along with being insulated with the steel core. Transformers are also built with a tank. This container is used for winding and core assembly purposes. In addition, these tanks are also used for many purposes including suitable bushings in order to take to the terminals, provide oil for cooling purposes, etc.
However, the core of the transformer is always made by assembling and stacking sheets of laminated steel. While assembling, it is made sure that there is minimal air-gap in between them. This is done to achieve the continuous magnetic path in the transformer system. In addition, the sheets that are used in stacking also have a very high silicon content. By doing so, the sheets will have a high permeability value and also a low hysteresis loss.
These sheets are used to helps to reduce the eddy current loss and are usually cut in the shape of E, I and L. In order to avoid the high reluctance in the joints, the laminations are also assembled in an alternative manner by the side of the joints. In case the joints of the first sheet assembly is in the front face, the joints of the following assemble is kept facing the back. In this manner, construction of transformers is done in a way which will need a lot of precision to make sure that these devices work to their optimum.
Types of transformers based on the construction
On the basis of construction of transformers, they can be divided into two types. They are core type transformer and shell type transformer.
Core Type Transformer
In this type of device, the windings are of cylindrical former wound, and is mounted to the core limbs of the windings. Cylindrical coils that are used have different layers. Each of them layers is insulated from each other. For the insulation, substances like paper, mica, and cloth is even used in core type transformers. Also, the low voltage windings are kept near the core as it’s easy to insulate.
Shell Type Transformer
In transformers that are shell type, coils are mounted and former wound on the layers that is stacked with insulation between them. This type of transformer may simply have a rectangular for or it might even be created in a distributed manner.
Now that we have learned about the working, types and construction of transformers, we have a proper idea about these fantastic electrical equipment. In addition, we will even have a proper knowledge about how to best use them to get the most out of them.
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