Working principle of an induction motor the motor which works on the principle of electromagnetic induction is known as the induction motor. Apr 09, 2014 a three phase ac induction motor can be controlled by varying its input according to a mathematical model of the rotor flux field in a complex vector space vector control. The basic idea of an electric motor is to generate two magnetic fields. The capacitorrun motor will have the best torque performance over the operating speed range. Induction motor is an ac electric motor, having a stator and a rotor. Basic induction motor concepts the development of induced torque in an induction motor. An electrical motor is an electromechanical device which converts electrical energy into mechanical energy. Watch this video to understand the working principals of the three phase induction motors. Construction of induction motor the three phase induction motor is a preferable type of motor. An984, an introduction to ac induction motor control using. The threephase ac induction motor is a rotating electric machine that is designed to operate on a threephase supply. Induction motor driving a centrifugal compressor advantages.
This 3 phase motor is also called as an asynchronous motor. In the case of three phase ac alternating current operation, the most widely used motor is a 3 phase induction motor, as this type of motor does not require an additional starting device. The modeling of induction motor as the example of impact loads in equipment power system is presented. Induction motor testing and evaluation summary as energy costs rise, more emphasis is being placed on determining the health of large inductive motors. The induction motor is made up of the stator, or stationary windings, and the rotor. Concept of vector control of induction motor page 2 concept of vector control of induction motor nawaraj kumar mahato department of electrical and electronics engineering school of engineering and technology sharda university, gr. The use of induction motors has increased because of the improvements in microprocessorcontrolled inverter circuits. Advantages of 3 phase induction motor generally easy to build and cheaper than corresponding dc or synchronous motors induction motor is robust. An induction motor also known as an asynchronous motor is a commonly used ac electric motor.
For example, in an induction motor, it may be as high as 3050 % of rated current whereas it is only 15% of rated current in a transformer. Induction motor definition of induction motor by merriam. Other motors that are included are 1phase induction motors, permanent synchronous motors and synchronous reluctance motors. The major difference between them is that transformer is static in nature i.
When describing a three phase induction motor by a system of non linear equations, following assumptions are made. The threephase induction motor is the extensively used for various kinds of industrial drives. The speed of an ac motor depends on the frequency of the input power and the number of poles for which the motor is wound. Pdf transfer of the induction motor to the ups system after. Dynamic model in space vector form mathematical description of induction motor is based on space vector notation. Rating considerations dimensions of a machine depend on torque at a specific speed how intensively the magnetic circuit is. The singlephase induction motor is not selfstarting. This paper explores the construction process of a linear induction motor lim, the basic concepts behind key aspects of linear induction machines construction and. In a dc motor, supply is needed to be given for the stator winding as well as the rotor winding. Electromagnetical model of an induction motor in comsol. The stator or the stationary part consists of three phase winding held in place in the slots of a laminated steel core which is enclosed and supported by a. The induction motor also called asynchronous motor works on the principle of inducing an electric current in the rotor by the alternating current in the stator. Harley and yao duan georgia institute of technology november, 2009. But producing goods and services is strongly related to the use of energy in an intelligent way.
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. The stator current and electromagnetic torque transients of induction motor have been investigated in this paper, when the motor is transferred to uninterruptible power supply ups. These are also called as asynchronous motors, because an induction motor always runs at a speed lower than synchronous speed. Induction motor totallyenclosed fancooled nema standard epact three phase induction motors sdesign versatility teco totally enclosed fan cooled squirrelcage induction motors are designed, manufactured and tested to meet or exceed the latest nema, ieee, csa and. These types of motors are known as selfstarting induction motors. The rotor of an induction motor can be a squirrel cage rotor or wound. No, a synchronous motor cannot become an induction motor without modifications in rotor circuit. List and describe the more commonly used equipment in. There are two major components of an ac induction motor.
There are two basic reasons for the use of singlephase motors rather than 3phase motors. Single phase induction motor 1introduction the singlephase induction machine is the most frequently used motor for refrigerators, washing machines, clocks, drills, compressors, pumps, and so forth. Fall 2005 ee595s electric drive systems 3 voltsperhertz control history. This motor housing is made of cast aluminum or cast iron.
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. This paper presents the main concept of vector control of induction motor and also study weather this control provides efficient and smooth control of motors speed and. Three phase induction motors mcqs with explanatory answers. Induction motors the motor housing consists of three parts. The induction motor stator resembles the stator of a revolving field, three phase alternator. It is also called asynchronous motor because it does not run at a synchronous speed. 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. The ac induction motor is the most used electrical motor in industrial applications worldwide. Working principle of an induction motor circuit globe. The torque of a rotor in an induction motor under running condition is maximum. Among 3 phase induction motors and synchronous motors are more widely used. Induction motors the singlephase induction motor is the most frequently used motor in the world most appliances, such as washing machines and refrigerators, use a singlephase induction machine highly reliable and economical figure 1 singlephase induction motor. When selecting a 3phase induction motor for an application several motor types can fill the need manufactures often specify the motor class best suited to drive the load 3phase induction motors under 500 hp are standardized the frames have standard dimensions a 25 hp, 1725 rpm, 60 hz motor from one manufacture can be. The theory used in the work was collected by studying literature on how electrical motors work, and by simplifying the.
There are two types of induction motors, one is named as single phase induction motor, while the second one is named as 3 phase induction motor. Induction motors horizontal and vertical weg electric machinery, wem, induction motors have been specifically designed and manufactured for the most severe industrial applications, such as heavy duty fans, pumps, refiners, compressors, crushers and grinding mill drives. The electromagnetic induction is the phenomenon in which the electromotive force induces across the electrical conductor when it is placed in a rotating magnetic field. The alternating current ac induction motor is one of the most rugged and most widely used machines in industry. Sep 27, 2016 induction motor is an ac electric motor, having a stator and a rotor just like other motors, but the working principle is a little different which would be discussed further. Record all nameplate information for the induction motor.
The motor which works on the principle of electromagnetic induction is known as the induction motor. The construction of stator of the induction motor is almost the same as other motors. Induction motor theory jerry bednarczyk, pe course content introduction the ac induction motor is well suited to applications requiring constant speed operation. Let a be an integer, and let pn be a statement or proposition about n for each integer n.
The induction motor, which is the most widely used motor type in the industry, has been favored because of its good selfstarting capability, simple and rugged structure, low cost and reliability, etc. When the motor is connected to a singlephase power supply, the main winding carries an. The principle of operation of this motor is based on. Synchronous speed means the speed of the rotating magnetic field in the stator. The legs at the middle section permit the attachment of. May 31, 2019 a linear induction motor or lim is a special type of induction motor used to achieve rectilinear motion rather than rotational motion as in the case of conventional motors. Induction motors are the most commonly used motors in many applications.
Working principal of three phase induction motor electrical. Introduction to induction motor the engineering projects. Induction motors p3 typical torquespeed and powerspeed curves for a 4pole induction motor torque power p these curves are greatly affected by the rotor resistance r2 in our model. This book details the operation and control of induction motors in both steadystate and transient conditions. Nov 03, 2019 an induction motor also known as an asynchronous motor is a commonly used ac electric motor. Nov 09, 2016 no, a synchronous motor cannot become an induction motor without modifications in rotor circuit. As the torque at zero rotor speed is nonzero, the induction motor is selfstarting. This book is appropriate for power or electrical engineers studying and working with induction motors. Differentiate between the various types of generating electric power stations. The field orientation principle in control of induction motors.
But the rotor construction differs with respect to the type of motor. The cylindrical middle piece that holds the stator iron core, the two bellshaped end covers holding the ball bearings. Chapter 3 induction motor and different speed control methods page no 3. The electromagnetic induction is the phenomenon in which. Slip ring induction motor is made up from wound rotor and squirrel cage induction motor is made up from the squirrel cage rotor. Induction motor definition is an alternatingcurrent motor in which torque is produced by the reaction between a varying magnetic field generated in the stator and the current induced in the coils of the rotor. When a 3 phase electric conductors are placed in a certain geometrical positions.
The performance over a wide range of applications makes threephase induction motors accountable for 85 percent of the installed capacity of the industrial driving systems. Current is induced in these bars because the rotor normally turns at speed which is slower than the synchronous speed. Let us discuss on basic information about this motor and its special controlling technique of svpwm. Pdf construction of three phase linear induction motor. The rotor will constantly be turning to align its magnetic field with that of the stator field. Motion and temperature heat control are paramount in energy. Induction motors ppt transformer electrical engineering. Motor current monitoring and analysis mcsa is a straight forward tool to diagnosing problems with large inductive motors. An electromagnetical model of an induction motor is. The 3phase set of currents, each of equal magnitude and with a phase.
Introduction types of electrical machines types of 3ph induction motor basic principle working principle compnents of induction motor application comparision between 1ph i. Along with variable frequency ac inverters, induction motors are used in many adjustable speed applications which do not. In traditional designs of 60 hz linefed induction machines, skin effect is represented by correction coefficients k r and k x for bar resistance and slot leakage inductance. Electric energy and induction motors the level of prosperity of a community is related to its capability to produce goods and services. In the squirrelcage induction motor the rotor slots are usually given slight skew a to reduce the magnetic hum and locking tendency of the rotor b to increase the tensile strength of the rotor bars c to ensure easy fabrication d none of the above ans. Ac induction motors are also the most common motors used in main powered home appliances.
Asplitphase induction motor the stator of a splitphase induction motor is provided with an auxiliary or starting winding s in addition to the main or running winding m. In general, the induction motor is cheaper and easier to maintain compared to other alternatives. To get a good understanding of the working principle of a three phase. An electrical motor is a device that has brought about one of the biggest advancements in the fields of engineering and technology ever since the invention. Three phase induction motors mcqs with explanatory answers 1. Of all the different types of single phase acims, a capacitorrun motor makes the best choice for variable speed control. Induction motor general principle free download as powerpoint presentation. Fall 2005 ee595s electric drive systems 2 overview of strategies voltsperhertz control constant slip control fieldoriented control.
Today, i am going to give you an introduction to induction motors, the term which is very common and familiar but still many of us do not know its working and difference from other motors. It has been more than a century since the principle of the operation of induction motors was discovered. If the frequency of 3phase supply to the stator of 3phase induction motor is increased, then. The principle of induction is a way of proving that pn is true for all integers n. The rotor winding of induction motor is short circuited by end rings in case of a squirrel cage rotor or connected to variable external resistance in. For reason of economy, most houses, offices and also rural areas are supplied with single phase a. Pdf transfer of the induction motor to the ups system. Linear induction motors are quite an engineering marvel, to convert a general motor for a special purpose with more or less similar working principle, thus enhancing its. The stator is composed of laminations of highgrade sheet steel. You should also make a dc measurement of stator winding linetoline resistance using a dmm. Woundrotor induction motor the magnetizing branch can not be neglected i0 may be 40% of ip due to the air gap for motors greater than 2 hp, the magnetization branch can be shifted to the input terminals for a motor running at a slip s, the rotor speed is ns1s this will modify the values of e1, i1, e2 and i2. Induction motor general principle electromagnetism.
It is logical that the least expensive, lowest maintenance type motor should be used most often. There basically 2 types of induction motor depending upon the type. The starting winding is located 90 electrical from the main winding see fig. Fall 2005 ee595s electric drive systems 2 overview of strategies voltsperhertz control.
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