choose the correct transformer kVA for the application, given the voltage, current, and properly ground a transformer, and the secondary electrical system. Transformer Basics and the Transformer Principals of Operation as how a Single Phase Transformer Generates a Magnetic Circuit from a Sinusoidal AC Supply. The principle parts of a transformer and their functions are: • The core, which makes a path for the magnetic flux. • The primary coil, which receives energy from .
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A transformer is an electrical apparatus designed to convert alternating current from one voltage to .. Please contact the factory if further details are required. state-of-the-art tools and techniques for evaluating transformer condition. While on-line condition of transformers (more detail is included for oil-filled power. What is Electrical Transformer? Construction of a Transformer - Parts of a Transformer Operation & Working Principle of a Transformer. Types of Transformer.
A transformer can be defined as a static device which helps in the transformation of electric power in one circuit to electric power of the same frequency in another circuit. The voltage can be raised or lowered in a circuit, but with a proportional increase or decrease in the current ratings. A basic transformer consists of two coils that are electrically separate and inductive, but are magnetically linked through a path of reluctance.
The working principle of the transformer can be understood from the figure below. The core laminations are joined in the form of strips in between the strips you can see that there are some narrow gaps right through the cross-section of the core. Both the coils have high mutual inductance.
A mutual electro-motive force is induced in the transformer from the alternating flux that is set up in the laminated core, due to the coil that is connected to a source of alternating voltage. Most of the alternating flux developed by this coil is linked with the other coil and thus produces the mutual induced electro-motive force. The alternating current supply is given to the first coil and hence it can be called as the primary winding.
The energy is drawn out from the second coil and thus can be called as the secondary winding. In short, a transformer carries the operations shown below: Transfer of electric power from one circuit to another. Transfer with the principle of electromagnetic induction. The two electrical circuits are linked by mutual induction.
The two coils are insulated from each other and from the steel core. The device will also need some suitable container for the assembled core and windings, a medium with which the core and its windings from its container can be insulated. In order to insulate and to bring out the terminals of the winding from the tank, apt bushings that are made from either porcelain or capacitor type must be used. In all transformers that are used commercially, the core is made out of transformer sheet steel laminations assembled to provide a continuous magnetic path with minimum of air-gap included.
The steel should have high permeability and low hysteresis loss. For this to happen, the steel should be made of high silicon content and must also be heat treated. By effectively laminating the core, the eddy-current losses can be reduced. The lamination can be done with the help of a light coat of core plate varnish or lay an oxide layer on the surface.
For a frequency of 50 Hertz, the thickness of the lamination varies from 0.
Types of Transformers Types by Design The types of transformers differ in the manner in which the primary and secondary coils are provided around the laminated steel core.
According to the design, transformers can be classified into two: 1.
The coils used for this transformer are form-wound and are of cylindrical type. Such a type of transformer can be applicable for small sized and large sized transformers. In the small sized type, the core will be rectangular in shape and the coils used are cylindrical. The figure below shows the large sized type.
Click image to enlarge Working of a Transformer By so doing variation of flux energy is transferred from the primary coil to the secondary coil by means of electromagnetic induction without the change in the frequency of the voltage supplied to the transformer.
During the process, a self induced EMF is produced in the primary coil which opposes the applied voltage. Limitation of the Transformer To understand the main points, we have to discuss some basic terms related to transformer operation. So lets back to basic for a while.
A transformer is an AC machine that steps up or steps down an alternating voltage or current. It sounds a bit weird though. Electromagnetism The interaction between magnetic field and electric current is termed electromagnetism.
Current carrying conductors produces magnetic field when current passes through it. Movement of electrons in a conductor will result to electric current drifted electrons which occurs as a result of the EMF set up across the conductor. The EMF set up across the conductor can be in form of that stored in chemical energy or magnetic field.
If the insulating oil encounters moisture, it can affect the paper insulation or may even lead to internal faults. Therefore, it is necessary that the air entering the tank is moisture-free. The transformer's breather is a cylindrical container that is filled with silica gel. When the atmospheric air passes through the silica gel of the breather, the air's moisture is absorbed by the silica crystals.
The breather acts like an air filter for the transformer and controls the moisture level inside a transformer.
It is connected to the end of breather pipe. Tap Changer Tap Changer The output voltage of transformers vary according to its input voltage and the load. During loaded conditions, the voltage on the output terminal decreases, whereas during off-load conditions the output voltage increases.
In order to balance the voltage variations, tap changers are used. Tap changers can be either on-load tap changers or off-load tap changers. In an on-load tap changer, the tapping can be changed without isolating the transformer from the supply. In an off-load tap changer, it is done after disconnecting the transformer. Automatic tap changers are also available.
Cooling Tubes Cooling tubes are used to cool the transformer oil. The transformer oil is circulated through the cooling tubes. The circulation of the oil may either be natural or forced. In natural circulation, when the temperature of the oil rises the hot oil naturally rises to the top and the cold oil sinks downward.
Thus the oil naturally circulates through the tubes. In forced circulation, an external pump is used to circulate the oil. Buchholz Relay The Buchholz Relay is a protective device container housed over the connecting pipe from the main tank to the conservator tank. It is used to sense the faults occurring inside the transformer.
It is a simple relay that is operated by the gases emitted during the decomposition of transformer oil during internal faults.