Tyler borysiak, myles moore, alex sklar, joshua lamb, stephen. Synchronous machines notes part1 electric equipment. Induction experiments faraday henry if the magnetic flux through a circuit changes, an emf and a current are induced. Sep 01, 2017 working and construction of ac generator buy this books for exam preparation vk mehta. Ac synchronous generator alternator construction and. The stator in figure 36 consists of two singlephase. But there is one important difference between the two. Lecture notes on electrical machines ii for students btech 4th semester. The output of an alternator is direct current, however ac voltage is actually created and then converted to dc as voltage leaves the alternator on its way to the battery and the electrical loads.
Lecture notes institute of aeronautical engineering. Since the zener voltage is constant, the increase in v o causes v be to decrease. An unloaded diesel engine will fly to pieces unless it. Alternators are also referred as synchronous generators. Bee1101 1 st and 2 nd semester syallabus modulei 10 hours dc networks. The decrease in v be reduces conduction through the pass transistor. There are also links to powerpoint slideshows that show the animations seen in the presentations. The output of the alternator section supplies alternating voltage to the load. The electromagnetism lecture notes is a book to provide an introduction to electromagnetism for electrical and electronics engineers.
A threephase stator winding is connected to the threephase rectifier bridge with power rectifier or zener diodes. N is known as synchronous speed, because it is the speed at which an alternator must run, in order to generate an e. This video gives an elaborated explanation on working of alternators ac generators with help of animation. This document does not claim any originality and cannot be used as a substitute for prescribed textbooks. An unloaded diesel engine will fly to pieces unless it is under governor control.
Alternators are aircooled synchronous threephase generators with claw poles and a builtin semiconductor rectifier. Clicking on the following links will allow you to down load adobe acrobat files of the class lecture notes. The battery provides the power to crank the starter. Department of electrical engineering, veer surendra sai university of technology, orissa, burla, india. Notes for electrical machine 2 em2 by deepak kumar sahoo lecture notes, notes, pdf free download, engineering notes, university notes, best pdf notes, semester, sem, year, for all, study material. Pdf electromagnetism lecture notes university of cambridge. The operation of connecting an alternator in parallel with another alternator or with common busbars is known as synchronizing. Lecture alternator relay bearing mechanical scribd. These are compiled by david tong, department of applied mathematics and theoretical physics, university of cambridge. Other members of the family are the directcurrent dc motor or generator, the induction motor or generator, and a number of derivatives of all these three. The behavior of ir tand can also be represented with a phasor diagram, as shown in figure 12.
During the ex ecution of a single action, a process pi checks that its priority is not less than the priority of e very neighbor. They supply the electric power used by all sectors of modern society. Feb 28, 2014 this video gives an elaborated explanation on working of alternators ac generators with help of animation. Transients in rl, rc and rlc circuits with dc excitation. Explain the constructional details of alternator in detail with neat sketches. Synchronous generators usually operate in parallel forming a large power system. Synchronous machines notes introduction synchronous machines are principally used as alternating current generators. The synchronous electrical generator also called alternator belongs to the. Construction of ac alternator synchronous generator. Ig is the ignition input that turns on the alternatorregulator assembly. The alternator is a threephase, 12pole synchronous selfexcited generator with builtin rectifier and regulator and cooled by an external fan. Electrical machines ii unit i alternator basic principle a.
Synchronous generators usually operate in parallel forming a large power system supplying electrical power to consumers or loads. Basic electrical and electronics engineering lecture notes aee018 prepared by. An alternator has 3,phase winding on the stator and a d. Alwash lecture notes university of babylon electrical machines mechanical department d. The pole pieces are shaped and positioned as shown to concentrate the magnetic field as close as possible to the wire loop. Cylindrical rotor alternators are usually long, and the problem of air flow requires. Syllabus of bachelor of technology in electrical engineering, 2010. A typical alternator is shown in figure 33, view a. Tyler borysiak, myles moore, alex sklar, joshua lamb. A synchronous generator is a machine for converting mechanical power from a prime mover to a. The amplitude of the voltage output from the ac generator is a function of the current supplied to the. Mar 28, 2015 synchronous machines notes introduction synchronous machines are principally used as alternating current generators. For producing a frequency of 50hz, the alternator will have to run at the following speeds.
Stator it is the stationary part of the machine and is built up of. The only purpose for the dc exciter generator is to supply the direct current required to maintain the alternator field. Synchronous machine is an important electromechanical energy converter. This alternator is uniquely engineered to provide the finest performance and durability for your vessel. P517617 lec5, p1 diodes and transistors diodes what do we use diodes for. Alternators basic principle stationary armature rotor armature windings wye and delta connections distribution or breadth factor or winding factor or spread factor equation of induced e. Lecture notes on electrical machinesii of alternator will produce an appreciable error. Factors affecting alternator size alternator on load synchronous reactance vector diagrams of loaded alternator. A phasor is a rotating vector having the following properties. The equivalent circuit of a synchronous generator the voltage ea is the internal generated voltage produced in one phase of a synchronous generator. They supply the electric power used by all sectors of modern societies. Note for electrical machines 2 em2 by bulbul sharma lecturenotes. Note for electrical machines 2 em2 by deepak kumar sahoo.
The working principle of an alternator or ac generator is similar to the basic working principle of a dc generator. N shiva prasad, assistant professor, eee department of mechanical engineering institute of aeronautical engineering dundigal 500043, hyderabad. They also consist of an armature winding and a magnetic field. The synchronous electrical generator also called alternator belongs to the family of electric rotating machines. Electrical machinesii 310 4th semester subject code. Perreault vahe caliskan massachusetts institute of technology abstract this paper introduces a new design for alternator systems that provides dramatic increases in peak and average power output from a conventional lundell alternator, along with substantial improvements in efficiency. A timevarying magnetic field can act as source of electric field. When a prime mover drives an alternator supplying electrical power at a given frequency, a governor must be used to hold the prime mover at a speed that will yield this frequency. Power and torque in synchronous generators the real output power of the synchronous generator is p v i v i out t l a 3 cos 3 cos the reactive output power of the synchronous generator is q vi viout t l a 3 sin 3 sin recall that the power factor angle is the angle between v and i a and not the angle between e a and i a. The alternator generates a stronger voltage that builds up after buildup the field is supplied by rectified voltage from stator with brushes direct connected dc generator smaller generator to excite the field coils brushes to excite the rotor variation. Various design solutions are available depending upon the application. The effects of armature reaction in a salientpole synchronous generator. Lesson 20 alternator operation of synchronous machines. As it will be shown latter, in synchronous machines the term power angle.
Class notes chapter 9 synchronous machine and winding models. Alternator if there are n ph turns per phase, then synchronous generator e ph 4. Lecture alternator free download as powerpoint presentation. If the machine is not connected to a load no armature current flowing, the terminal voltage will be equivalent. An alternator is an electrical machine which converts mechanical energy into alternating electric energy. Explain the infinite bus concept and compute power. Stator it is the stationary part of the machine and is built up of silicon steel laminations having slots on its inner periphery. The pole pieces marked n and s provide the magnetic field.
Kondragunta jagadish babu,assistant professor chadalawada ramanamma engineering college autonomous chadalawada nagar, renigunta road, tirupati 517 506 department of electrical and electronics engineering. Understanding the alternator four wires connect the alternator to the rest of the charging system. Courses at engineering lecture notes, previous year questions and solutions pdf free download electrical engineering ee, engineering class handwritten notes, exam notes, previous year questions, pdf free download. Power and torque in synchronous generators the real output power of the synchronous generator is p v i v i out t l a 3 cos 3 cos the reactive output power of the synchronous generator is q vi viout t l a 3 sin 3 sin recall that the power factor angle is the angle between v and. If you need a powerpoint viewer follow this link to the microsoft download site.
K devender reddy,assistant professor department of electrical and electronics engineering institute of aeronautical engineering autonomous dundigal, hyderabad 500 043. Notes for electrical machine 2 em2 by deepak kumar sahoo lecture notes, notes, pdf free download, engineering notes, university notes, best pdf. This alternator works together with the battery to supply power when the vehicle is running. A typical 7800 series voltage regulator is used for positive voltages. The slow speed salient pole alternators are ventilated by the fan action of the salient poles which provide circulating air. The rotor magnetic field induces a voltage in the stator which becomes maximum in the conductors directly under the pole faces fig. Lecture notes threephase synchronous machines saad m. The information presented here is merely a collection by the committee members for their respective teaching assignments. The rotor is then turned by external means producing a. Generation of harmonic emf s in a three phase alternator.
B is the alternator output wire that supplies current to the battery. Then the total number of turns in any given phase of a single. Kirchhoffs laws, node and mesh analysis, deltastar and stardelta transformations. If load resistance increases, load voltage also increases. Pdf electromagnetism lecture notes university of cambridge categories books, basic electrical, electrical machines the electromagnetism lecture notes is a book to provide an introduction to electromagnetism for electrical and electronics engineers. Chapter 4 synchronous generators or alternators notes. Lecture notes on electrical machines ii for students btech 4th. The water turbine and the alternator are coupled together and mounted vertically. Working and construction of ac generator buy this books for exam preparation vk mehta. The rotor consists of a smooth solid forged steel cylinder, having a number of slots milled out at intervals along the outer periphery and parallel to the shaft for accommodating field. Interpret alternator phasor diagrams under different load conditions. This alternator works the same as the others we have discussed. Explain the constructional details of alternator in detail. S is used by the regulator to monitor charging voltage at the battery.
In fact, a given synchronous machine may be used, at least theoretically, as an alternator, when driven mechanically or as a motor, when driven electrically, just as in the case of d. In a synchronous generator, a dc current is applied to the rotor winding producing a rotor magnetic field. Eeeb344 electromechanical devices chapter 5 chapter 5. These voltage regulators when used with heatsinks can safely produce current values of 1a and greater. An alternator drives the electrical devices and stores energy in the battery. Transistor series regulator since q 1 is an npn transistor, v o is found as. Note that in large, modern generators, the rotor will always contain the field. Ee301 ac generators part i 5 112016 the slip rings allow dc current to flow to the field windings on the rotor to produce the magnetic field.