All slides will preserve the formatting and layout. Furthermore, the online pdf converter offers many more features. Transformers designed with a square bh loop will result in better line regulation. Worlds best powerpoint templates crystalgraphics offers more powerpoint templates than anyone else in the world, with over 4 million to choose from. Because the iron or steel core is an electrical conductor as well as a magnetic circuit, the changing current in the primary will tend to set. Instrument transformer in power system, the currents and voltages are very large therefore, their direct measurements are not possible.
Transformers transformers in the home there are huge transformers in towns and cities where the highvoltage electricity from incoming power lines is converted into lowervoltages. A basic transformer consists of two coils that are electrically separate and inductive, but are magnetically linked through a path of reluctance. The two windings of the transformer are called high voltage winding and low voltage winding. Motor start theory auto transformers thermal overload 3 phase auto transformer b start contactor a start contactor run contactor 3 m the auto transformer starter employs an auto transformer to reduce the voltage during the start period. Basic substation configurations and the components. Ironcore transformers are usually used when the source frequency is low below 20 khz. A transformer is a device used to change the voltage levels of electricity to facilitate the. Basic electrical theory overview of ac motors, transformers and measuring instruments instructor. Potential transformer pt definition the potential transformer may be defined as an instrument transformer used for the transformation of voltage from a higher value to the lower value. These devices use standard transformer theory with 23 windings one primary with one or two secondary windings with a magnetic connection via an iron core.
Oct 08, 2016 in principle, the only difference between a current transformer and a voltage transformer normal type is that the former is fed with a constant currentwhile the latter is fed with a constant voltage, where constant has the strict circuit theory meaning. The output powerpoint presentation will retain its original formatting, for you to revise and edit. Use our online converter to quickly transform your powerpoint presentations into pdf documents for easy sharing. An autotransformer is a kind of transformer with only one winding, but one or more taps. Its electrical purpose is to transfer power from the primary winding to the other windings with no energy storage or loss.
Instrument transformer theory and testing steve hudson, pe engineering manager 10737 lexington drive knoxville, tn 37932 phone. The teaching of basic science often involves what are known as lies to children, and. The core, which makes a path for the magnetic flux. A transformer whose core is constructed of laminated sheets of. An electrical power transformer is a static device, which transforms electrical energy from one circuit to another without any direct electrical connection. The magnetic material used to design transformer, tl, has an impact on line regulation. The transformer the principle parts of a transformer and their functions are. For example, the potential transformer mentioned above having a rating of 480. Pdf file contains bookmarks, thumbnails, and hyperlinks to help you navigate through the document. The terminal of the transformer should be designed so that the variation of the voltage ratio with load is minimum and the phase shift between the input and output voltage is also minimum.
A transformer in which the secondary voltage is greater than the primary voltage is called a stepup transformer the ratio of secondary voltage v sec to primary voltage v pri is equal to the ratio of the number of turns in the secondary winding n sec to the number of turns in the primary winding n pri vsec v pri n sec n pri. Module transformers this module introduces transformer theory and includes the types of transformers, voltagecurrent relationships, and application. A transformer operates on the principals of electromagnetic induction, in the form of mutual induction. Figure 3 the circuit from figure 2, after replacing the transformer and the 9 w resistor with an equivalent resistor the equivalent resistance is given by 2 2 94 eq 3 r. Capability for handling a short circuit is an inherent feature of a constantvoltage transformer.
The regulation of a constantvoltage transformer can be designed to be better than a few percent. Transformer type k single phase shell type single phase core type three phase shell type three phase core type, distrbiuton i transformer three phase core type, power transformer 1 0 to 1 2 0. To understand how voltage droop and pulse distortion continue reading pulse transformer. Theory of operation of singlephase transformers custom. The transformer consists of two separate windings placed over the. This current creates a magnetizing force that produces the magnetic flux in the transformer core. Basics, maintenance, and diagnostics vii contents continued page 4. If your pdf is in a presentation format, the conversion should be no problem. The transformer does this by linking together two or more electrical circuits using a common oscillating magnetic circuit which is produced by the transformer itself. If it increase the input voltage, it is called step up transformer and if it decreases the input voltage, it is called step down transformer. Pulse transformer operating principles butler winding. The potential transformer is made with highquality core operating at low flux density so that the magnetising current is small. Ppt transformer powerpoint presentation free to download.
When ac theory is introduced, and especially when there is a bias towards radio frequencies, the very first new idea required by many people at least is a correct understanding of the word electricity. This module introduces transformer theory and includes the types of transformers, voltagecurrent relationships, and application. The secondaries for balanced supply system have equal number of turns. The transformer has a range of output voltage taps that can be used to set the start voltage.
In this way, transformer losses are reduced and the system becomes more efficient and economical. Typically current transformers consist of a silicon steel ring core wound with many. A transformer is a static apparatus, with no moving parts, which transforms electrical power from one circuit to another with changes in voltage and current and no change in frequency. Scribd is the worlds largest social reading and publishing site. You can easily convert your pdf files to ppt with this online tool. It also performs this with the help of mutual induction between two windings. Transformer operates when both circuits take effect of mutual induction.
Sistece 2 coil 1 i1t i2t coil 2 m e1t e2t s1 s2 i1t i2t the transformer primary has n1 turns secondary has n2 turns v2 3. Buckboost transformers are an economical way to correct this potentially very serious problem. Assuming the desired voltage is the same on the two and three phase sides, the scottt transformer connection consists of a centertapped 1. The centertapped side of t1 is connected between two of the phases on the threephase side. Content what is transformer structure and working principle construction of transformer losses in transformer ideal vs practical transformer uses and application of transformer 3. The basic principle of operation of a transformer is explained in chap. While operating principles of transformers remain the same, the challenges of. Transformer a has an impedance of 4%, transformer b which is to be parallel to a must have an impedance between the limits of 3. Pulse transformer designers usually seek to minimize voltage droop, rise time, and pulse distortion.
An autotransformer is generally used either for providing a second leg in a single phase system giving you 120240 vac from a single 120 vac line or to provide a 120 vac tap from a 240 vac. A transformer bank composed of three singlephase units may be replaced by one 3phase transformer the magnetic core has three fluxcarrying legs two yokes, bottom and top, couple the flux of the three legs the sum of the three fluxes equals zero each leg contains the primary and secondary windings of one of the phases. Working principle of a transformer the basic principle on which the transformer works is faradays law of electromagnetic induction or mutual induction between the two coils. A transformer is an electrical device for converting an alternating current at low voltage into that at high voltage or vice versa. Module 14 test instruments and measuring devices this module describes electrical measuring and test equipment and includes the. Transformer oil breakdown voltage tester for health check of transformers in order to buy the best quality transformer oil breakdown voltage tester or any kind of other testing kit for health check and performance of transformer, what all you have to do is simply search for the right manufacturer or reach the right supplier. There are three basic styles used to transformer system voltages to control voltages. The singlephase distribution transformer consists of a primary winding and a secondary winding wound on a laminated steel core. Some of the slides include animations, which can be seen by viewing the powerpoint file as a slide show. This is the same problem caused by the series capacitors used in distribution systems 70 years ago. Note the fused cutout and lighting arrestor combination external to the transformer.
Droop is the decline of the output pulse voltage over the duration of one pulse. Potential transformers pts or voltage transformers vts pts or vts are the most common device used. Sep 16, 2017 a transformer is a static apparatus, with no moving parts, which transforms electrical power from one circuit to another with changes in voltage and current and no change in frequency. Anytime a line voltage change in the 520% range is required, a buckboost transformer should be considered as your first line of defense. The current it is the current in the series resistors and vst is the voltage across the series resistors. The ironcore transformer provides better power transfer than does the aircore transformer. Most state electrical exams include questions on general electrical theory and you need a solid foundation to pass your exam. Transformer banks 3phase transformer banks can be analyzed using simplifying assumptions excitation currents are negligible winding impedances are negligible total apparent input power equals the total apparent output power singlephase transformers connected into a 3phase bank retain all basic singlephase properties. If the constant voltage transformer is subjected to a line voltage frequency change the output voltage will vary, as shown in figure 115.
Autotransformer theory in an auto transformer, one single winding is used as primary winding as well as secondary winding. Electrostatics gausss law and boundary conditions ppt 3. The word transformer comes form the word transform. Transformer cant stepup or stepdown the level of dc voltage or dc current. An autotransformer is a kind of electrical transformer where primary and secondary shares same common single winding. The transformer is a electrostatic device which is used to transfer electrical energy voltage or current from one circuit to another by mutual induction of two electric circuits without change in frequency, which is working under the principle of electromagnetic induction. Download as ppt, pdf, txt or read online from scribd. Unit 14 transformers objectives after studying this unit, the student will be able to state the purpose of a transformer. Basic transformer operation can be described by two formulae relating the transformation ratio to the turns ratio of the transformer windings. A schematic drawing of a singlephase distribution transformer appears in fig. Find materials for this course in the pages linked along the left. Winner of the standing ovation award for best powerpoint templates from presentations magazine.
It is cause by the magnetizing current increasing during the time duration of the pulse. The basic transformer source voltage is applied to the primary winding the load is connected to the secondary winding the core provides a physical structure for placement of windings and a magnetic path so that. Module 14 test instruments and measuring devices this module describes electrical measuring and test equipment and includes the parameters measured and the principles of operation of common instruments. A transformer is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction. When the constant voltage transformer is operating as a line regulator, the output voltage will vary as a function of the input voltage, as shown in figure 1. Transformers have been used at powerplants since the inception of alternatingcurrent generation, a century ago. This example is an actual laboratory measurement of a small 1. This section contains lecture notes in both pdf and powerpoint formats.
Transformer basics two or more wire windings placed around a common magnetic core is the physical structure of a transformer. In addition, impedance values of each transformer must be within 7. The primary coil, which receives energy from the ac source. Transformer only stepup or stepdown the level of ac voltage or ac current. The ratio of an instrument transformer is the relationship of its primary rating to its secondary rating. Use our online service to convert pdf to ppt in a heartbeat. Unit 2 electrical circuits unit 3 understanding alternating current unit 4 motors and transformers note. There are two types of transformers classified by their function. It might appear that the extension of range could be conveniently done by the use of shunts for currents and multiplier for voltage measurement, as in dc. When paralleling three phase transformers the same precautions must be. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Transformer book is still in demand is a tribute to the publishers and to the authors who have carried the torch to light our way for 75 years.
An alternating voltage v p applied to the primary creates an alternating current i p through. Theyll give your presentations a professional, memorable appearance the kind of sophisticated look that todays audiences expect. Electric appliances such as washing machines and dishwashers use voltages of 110240 volts, but electronic devices laptop. Single wire skin effect and multiwire proximity effects alter both primary and secondary rwire coil via effective a cu wire changes 3. Transformer basic objective introduce basic transformer theory as it relates to diagnostics provide a better understanding of the diagnostic test environment identify important information that should be collected in the diagnostic test process. Pdf power transformers principles and applications. Transformer is not an energy conversion device, but it is device that changes ac electrical power at one voltage level into ac electrical power at another voltage level through the action of magnetic field but with a. Geometry of cu wire windings and core wire winding window 2. In core type transformer the ratio of depth to width of core varies between 1. When the primary of a transformer is energized with the secondary unloaded, a small current flows in the primary. Figure 1 represents the essential elements for a transformer a magnetic core, with a primary and secondary coil wound on the limbs of the magnetic core. Depending upon the load, transformers can be switched on off.
If the power demand increases with time then extra spare transformer can be taken into service to meet the power demand. A softironcore transformer is useful when the transformer must be physically small, yet efficient. Morgan lacey in 1925, based on a series of pamphlets entitled transformer abstracts that were. To keep for free in the future, please deactivate your adblocker or support this project by sending a small donation. Conversion from pdf to ppt works on all computers the operating system you use doesnt matter. This article covers a wide range of transformer theory and voltechs testing capability. The main principle of operation of a transformer is mutual inductance between two circuits which is linked by a common magnetic flux. In figure 3, the 8 w is connected in series with the equivalent resistor, req. Ideal transformer transformer applications summary e1. Instrument transformer basic technical information and. This transformer step down the voltage to a safe limit value which can be easily measured by the ordinary low voltage instrument like a voltmeter, wattmeter and watthour meters, etc. This module introduces transformer theory and includes the types of transformers, voltagecurrent relationships, and.
In shell type transformer width of central limb is 2 to 3 times the depth of core. Transformer construction a transformer consists of two windings coupled through a magnetic medium. Mutual induction is the process by which a coil of wire magnetically. The secondary coil, which receives energy from the primary winding and delivers it to the load.
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