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What is a Transformer?
An electric transformer is a device used in electrical power systems to transfer electrical energy between two or more circuits through electromagnetic induction. Its primary function is to change the voltage level of alternating current (AC) electrical energy while keeping the frequency the same.
The basic structure of an electric transformer consists of two or more coils of wire, known as windings, which are usually wound around a laminated iron core. The winding connected to the power source is called the primary winding, while the winding connected to the load is called the secondary winding. The transformer operates on the principle of Faraday's law of electromagnetic induction.
When an AC voltage is applied to the primary winding, it produces a time-varying magnetic field in the core. This changing magnetic field induces an electromotive force (EMF) in the secondary winding according to Faraday's law. The ratio of the number of turns in the primary winding to the number of turns in the secondary winding determines the voltage transformation ratio of the transformer.
Electric transformers are widely used in power transmission and distribution systems. They serve several important purposes:
Voltage Transformation: Transformers are used to step up or step down the voltage levels of electrical energy to match the requirements of different parts of the power system. High-voltage transmission lines use step-up transformers to increase the voltage for efficient long-distance power transmission, while step-down transformers reduce the voltage for distribution to households and businesses.
Power Distribution: Transformers are used to distribute electrical power to various locations. They are often employed in substations to step down the high voltage received from the transmission lines to lower voltages suitable for local distribution.
Isolation: Transformers provide electrical isolation between the primary and secondary circuits. This isolation ensures safety, protects equipment from voltage surges, and prevents the flow of current between different circuits.
Impedance Matching: Transformers can be used to match the impedance between different parts of a power system, ensuring efficient power transfer and reducing losses.
Transformers come in various sizes and configurations, ranging from small ones used in electronic devices to large units employed in power grids. They are essential components in the generation, transmission, and distribution of electrical power, playing a crucial role in the functioning of modern electrical systems.
Hope you have seen Transformer, sometimes it could be a small or big size. A Transformer is a passive electrical device which shifts electrical voltage levels from one circuit to another through the process of electromagnetic induction. It is mostly used to increase the voltage levels between circuits which are called Step Up or decrease the voltage which is called Step Down Transformer.
Today in this blog i am going to explain the working function of the Transformer. Let's start with the main parts of the Transformer.
The Core
The core is the main part and it is called the heart of the Transformer. The core is made up of iron or silicon steel or ferromagnetic materials. It is thin metal strips and lamination insulated by a coat of varnishes or papers. The core of the three-phase Transformer consists of three limbs in the same plane and each limb carries both low voltage LV winding and high voltage HV winding. The chorus provides a magnetic path flux around the core.
The Windings
The first winding is commonly known as a coil, When it is provided by an alternating electrical source, the alternating current through the winding produces a periodically changing and alternating flux surrounding it. If one more winding is driven near to the first winding some part of this alternating flux will automatically link with the second winding. As this linked flux is periodically varying the amplitude and Direction, there should be a changing flux linkage in the secondary winding or coil according to Faraday's law of electromagnetic induction. As a result there will be an EMF induced in the second winding. If the circuit of this secondary winding is closed completely then a current will flow in it. This is the fundamental working principle of any of the transformer. The winding that gets electrical power from the electrical source is called as the primary winding. The winding that supplies the required output voltage due to Mutual induction is commonly known as the secondary winding.
Here if the number of secondary coil turns is greater than the number of turns in primary coils N1 then it is called a Step up Transformer that means increasing voltage between the primary to secondary windings. Conversely a Transformer that decreases voltage between the primary to secondary windings is known as a step-down Transformer. The alternating current through the primary winding of each phase produces a continually changing magnetic field that surrounds the winding of the secondary coil. This magnetic field is linked with the secondary winding by magnetic flux which flows through the Transformer core. EMF will be induced at the secondary winding based on Faraday's law and this induced EMF is described as mutually developed EMF. Insulation is needed between the primary and secondary winding to prevent short circuits.
Insulated Bushings
Finally to receive electric energy from the Transformer insulated bushings are needed. From bushing there come out terminals on which outgoing wires or cables are connected using specialized cable or wire lugs.
Transformer Oil
During its working or transferring the power from the primary to the secondary winding, different energy losses occur like Eddie's current losses, hysteresis losses and copper losses. All these losses will generate heat. To prevent heat Transformer oil is used inside the tank. The main role of Transformer oil is to work as a coolant and to insulate. Transformer oil is an extra ordinary heat conductor which can successfully minimize the copper coil's temperature securing the winding from burning.
Radiator
Not only transformer, externally cooling tubes or radiators are also there for the purpose. The radiator of the Transformer expedite the cooling rate. Thus it plays a key role to increase the loading capacity of an electrical Transformer.
Buchholz Relay
A buchholz relay is used to disengage any fault inside the Transformer.
You might like to watch a small substation installed in a children hospital. link is below.
