Tesla, as a difference from his contemporaries, was the first to prove experimentally that induction motors with high degree of efficiency can be made. An induction motors rotor can be either wound type or squirrelcage type. Polyphase induction motor definition of polyphase induction. Starting methods for polyphase induction machine electrical4u.
There are two general types of polyphase induction motors. The torquespeed characteristic is required in order to predict behavior of induction machines in electrical motor drives 1. A 3phase induction motor runs at almost 1200 r min at no load and 1140 rmin at full load when supplied with power from a. That phase difference, p, is simply one full cycle expressed as an angle, 360 degrees or radians, divided by the number of phases. On the other hand, the polyphase induction motor shown in cutaway in fig. An induction motor can therefore be made without electrical connections to the rotor. Construction of three phase induction motor electrical4u. Electrical machines 2 pdf notes em 2 pdf notes smartzworld.
Instructions for conducting and reporting the more generally applicable and acceptable tests of polyphase induction motors and generators are covered. Free online polyphase induction motors electrical engineering quiz questions test. Electrical machines questions and answers induction machines. This article will focus on what needs to be specified for. Pdf version the following animation shows how the rotating magnetic field of a threephase ac induction motor is produced by the interaction of three stator winding sets energized with different phases a, b, and c of a threephase ac power source. An induction motor is composed of a rotor, known as an armature, and a stator containing windings connected to a polyphase energy source as shown in the figure below. The three phase induction motor is the most widely used electrical motor. Polyphase induction motors free online test for all. What is a squirrel cage motor and how does it work. We design our ac polyphase induction motors and motor parts for variable speed applications in conjunction with many scr drives on the market today. Ieee standard test procedure for polyphase induction motors and generators 3 park avenue, new york, ny 100165997, usa ieee power engineering society sponsored by the electric machinery committee 4 november 2004 print. We classify starting methods for squirrel cage induction motor into two types on the basis of voltage. Record all nameplate information for the induction motor.
Test procedure for polyphase induction motors and generators name of standards organization. Squirrelcage induction motor the operation of the squirrelcage motor is simple. Therefore, motor troubleshooting involves the entire system, not just the. The squirrelcage motor is the simplest to manufacture and the easiest to maintain. The most common type of motor in this group is the squirrelcage polyphase induction motor so. Many of the tests described may be applied to both motors and generators, as needed, and no attempt is made to partition the test procedure into clauses and subclauses that. It is advisable to avoid linestarting of induction motor and use starter because a motor takes five to seven times its full load current b it will pickup very high speed and may go out of step. Polyphase induction motor chapter 5 polyphase induction. It is a motor, that works only with 3 phases or harmonics of 3, where application of voltage induces a rotating magnetic field or rather, the varying values of voltage values make it seem like the field is rotating, which causes a shorted roto.
The rotor will constantly be turning to align its magnetic field with that of the stator field. Determination of the torquespeed characteristic of. Polyphase induction motors for power generating stations part i. Practicing all polyphase induction motors electrical engineering questions and answers in online helps you to improve your ability to attend the real time gate, ies and bsnl jto exams. Polyphase induction motors objective type questions and answers pdf 61. The motor is mounted in a test rig that allows one to control the torque applied to the motor shaft and to measure both rpm and torque. Polyphase induction motors objective type questions and. Rotating magnetic fields in threephase ac induction motors. Many of the tests described may be applied to both motors and generators, as needed, and no attempt is made to partition the test procedure into clauses and subclauses that separately apply to motors or to generators. Polyphase induction motors mcqs answers pdf electrical. Pdf drfoc of polyphase induction motor based on fuzzy logic. A threephase ac induction motor is the only type where the rotating magnetic field is created naturally in the stator because of the nature of the supply.
Polyphase induction motors mcq question is the important chapter for a electrical engineering and gate students. Selfstarting polyphase induction motors produce torque even at standstill. In a threephase induction motor a iron losses in stator will be negligible as compared to that in rotor. Stator frame it is the outer most part of the three phase induction motor. Teslas polyphase system and induction motor petar miljanic1 1 introduction while new scientific knowledge is acquired by learning, observation, experiments and thinking, the inventions are mostly the fruit of the intuition of individuals and of their creative impulses. A polyphase induction machine operated by an inverter drive system. To learn more, feel free to visit our article on the types of ac motors. Polyphase ac motors polyphase motors make up the largest single type in use today and usually are the first to be considered for the average industrial application. Applications of polyphase induction motors instrumentation.
List and describe the more commonly used equipment in an electric substation. The 3phase set of currents, each of equal magnitude and with a phase. You should also make a dc measurement of stator winding linetoline resistance using a dmm. Problems and premature failures often indicate input power system troubles, poor or deteriorating mechanical installations, or malfunctions in the driven machinery. This dissertation is brought to you for free and open access by the student. The machine is constructed with concentrated full span windings. The simple 2phase induction motor below is similar to the 12 horsepower motor which nikola tesla introduced in 1888. Singlephase induction motor threephase induction motor singlephase induction motor there are probably more singlephase ac induction motors in use today than the total of all the other types put together. An induction motor or asynchronous motor is an ac electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding. Polyphase induction motors for power generating stations. This standard covers instructions for conducting and reporting the more generally applicable and acceptable tests of polyphase induction motors and generators. In a polyphase motorgenerator the sinusoidal waveforms found in each phase have a fixed angular relationship, determined by the number of phases. Starting methods for polyphase induction machine february 17, 2019 february 24, 2012 by electrical4u in this article we are going to discuss various methods of starting a 3 phase induction motor.
In three phase induction motor, the power is transferred from stator to. Ieee standard test procedure for polyphase induction. Plus, the direction of shaft rotation for polyphase motors is very easily reversed. Ieee standard test procedure for polyphase induction motors. Tesla polyphase induction motors ac motors electronics. It is simple and relatively inexpensive, and the absence of sliding contacts in the squirrelcage machine reduces maintenance to a minimum.
Principle of operation of single phase induction motor. Polyphase induction motor definition is an alternatingcurrent motor having polyphase as 3phase windings. Us6054837a polyphase induction electrical rotating machine. Enter your email below to receive free informative articles on electrical. Starting of 3 phase induction motors, high starting torque motors, speed control, rheostatic method, pole changing method, cascade control of speed, double cage induction motor, cogging an d crawling of induction motor, induction generator. Ieee std 1122004, ieee standard test procedure for. Three phase induction machine philadelphia university. It has been shown in chapter 1 that the polyphase induction motor can be considered as a polyphase transformer with variable frequency in the shortcircuited. Perhaps the most important benefit of polyphase ac power over singlephase is the design and operation of ac motors. The good power factor of an induction motor can be achieved if the average flux density in the air gap is a absent b small c large d infinity ans. Direct rotor field oriented control of polyphase induction machine based on fuzzy logic controller april 2017 revue roumaine des sciences techniques serie electrotechnique et energetique 621. In this study an equivalent circuit is proposed that permits the analysis of, or even the calculation for, singlephase, twophase and threephase induction motors. Our polyphase motors vary in size from 120 to 50 horsepower, 690, 850, 1150, 1750, 3500 rpm.
Objective polyphase induction motors questions and answers pdf. Read about tesla polyphase induction motors ac motors in our free electronics textbook. Polyphase induction motor mcq set 03 objectivebooks. Realtime polyphase induction motors multiple choice questions. In fact, an induction motor can be treated as a rotating transformer i. The polyphase squirrel cage induction motor can handle heavyduty requirements. Direct rotor field oriented control of polyphase induction. Twelve or more phases are used to sufficiently cover the airgap region, in contrast to the conventional three phases using distributed and chorded windings. Analysis and design of ac induction motors with squirrel cage rotors. Our article all about induction motors explains the specifications for all types of induction motors and is a good place to see all the different induction motor characteristics. Nov 27, 2019 the three phase induction motor is the most widely used electrical motor.
All of the ac motors, the polyphase induction motor is the one which is extensively used for various kinds of industrial drives. Home mcq polyphase ind motors polyphase induction motor mcq set 03 polyphase induction motor mcq set 03. Tesla polyphase induction motors ac motors electronics textbook. The stator of three phase induction motor is made up of numbers of slots to. Request pdf equivalent circuit for a polyphase induction motor in this study an equivalent circuit is proposed that permits the analysis of, or even the calculation for, singlephase, two. Equivalent circuit for a polyphase induction motor request pdf.
Polyphase induction motors objective type questions and answers pdf. A simple explanation of how a 3 phase induction motor works. Ac induction and synchronous motors work by having a rotating magnet follow the alternating magnetic fields produced by stationary wire windings. Polyphase power is particularly useful in ac motors, such as the induction motor, where it generates a rotating magnetic field. Ieee std 1122004, ieee standard test procedure for polyphase. Its main function is to support the stator core and the field winding. Pdf this paper presents a new control system of the sevenphase induction machine based on direct rotor field oriented control. Various methods of speed control 3phase induction motor.
In this video, ankit goyal cofounder at kreatryx and air 1 in gate 2014 describes star delta starter method of starting induction motor. The electrical machines 2 notes pdf em 2 notes pdf book starts with the topics covering single phase transformers, performance equivalent circuit, testing of single phase transformer and auto transformer, polyphase transformers, polyphase induction motors, rotor power input, circle diagramno load and blocked rotor testspredetermination of. An887, ac induction motor fundamentals microchip technology. Available squirrel cage induction motor starting methods include directonline starting, reducedvoltage reactor or autotransformer starting, stardelta starting or, increasingly, new solidstate soft assemblies and, of course, variable frequency drives vfds. As its name indicates stator is a stationary part of induction motor. The polyphase current produces a rotating magnetic. By order of the executive director office of the federal register washington, d. Polyphase motor design polyphase ac circuits electronics.
The basic idea of an electric motor is to generate two magnetic fields. Objective polyphase induction motors questions and answers pdf 71. Polyphase induction motors, electrical engineering multiple choice questions objective type questions, mcqs, with question and answers, download free pdf, electrical engineering, multiple choice questions, objective type questions, electrical engineering short notes, rapid fire notes, best theory. Institute of electrical and electronics engineers legally binding document. Mostafa elshahed objectives learn a brief history of the electrical power systems construction. It has been shown in chapter 1 that the polyphase induction motor can be considered as a polyphase transformer with variable frequency in the shortcircuited secondary winding and an equivalent circuit can be derived per phase of the motor in the same general way as that of a transformer. A 4pole 60h z induction motor is driving a load at 1740 rmin. As we studied in the first chapter of this book, some types of ac motors are virtually identical in construction to their alternator generator counterparts, consisting of stationary wire windings and a rotating magnet assembly.
Overview this user manual applies to nord motor products and it provides general information for motor operation, installation, maintenance, inspection, repair, and trouble shooting, which is relevant to most of the motor products shipped by nord. Almost 80% of the mechanical power used by industries is provided by three phase induction motors because of its simple and rugged construction, low cost, good operating characteristics, the absence of commutator and good speed regulation. Lecture 6 three phase induction motors cairo university. Motor wg112 motor sc test procedure for polyphase induction. Spacephasor appro polyphase induction machine model 10 one equivalent stator and one rotor winding.
Differentiate between the various types of generating electric power stations. Pdf noise of polyphase electric motors joseph lai and. Polyphase definition of polyphase by the free dictionary. The comparison of starting torque with star and delta. That is why such motors are known as induction motors. The starting torque of the motor is slightly larger than its fullload torque, so this motor will start carrying any load that it can supply at full power 4. Polyphase induction motors, analysis by paul cochran. It is logical that the least expensive, lowest maintenance type motor. Drfoc of polyphase induction motor based on fuzzy logic controller speed. The polyphase induction motor the polyphase induction motor is the most commonly used industrial motor, finding application in many situations where speed regulation is not essential.
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