Lecture 6 three phase induction motors cairo university. Learn for free, pay a small fee for exam and get a certificate. Motor analysis block diagram induction motor starting can be analyzed using electrical, mechanical, and thermal models which interact as diagrammed in figure 1. 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. Ac induction motor fundamentals by rakesh parekh, microchip technology inc 9 induction motor protection and starting by viv cohen circuit breaker industries, p. Selection of slip frequency control for maximum torque per amp. Introduction to induction motor instrumentation and. Shown below are some of the points you should know when sizing a motor. For instance, a 100 horsepower, threephase motor operating with voltages of 598, 575 and 552 applied at the motor terminals is running with a 4% voltage unbalance 100 x 23575. It is available from fractional horsepower ratings to megawatt levels.
Matlab simulation of induction motor drive using vf control. 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. You should also make a dc measurement of stator winding linetoline resistance using a dmm. Find the percentage slip and number of poles of the induction motor.
The basic idea of an electric motor is to generate two magnetic fields. When the mechanical load is applied to induction motor which requires speed. Factors affecting selection of drives, speedtorque characteristics of motors and loads, condition of steadystate stability. It supplies an induction motor ich has a full load speed of 144wh 0 rpm. In an induction motor, the electric current in the rotor needed to produce torque is obtained via electromagnetic induction from the rotating magnetic field of the stator winding. Hi all, let us begin the course on induction motors, in this video, we will have an introduction and basic construction concepts. Induction motor starting methods bright hub engineering. Induction generators are also called as asynchronous generators. Pdf speed control of induction motor using pi and vf. Single phase induction motor, theory of operation double revolving. Lecture 30 speed control of induction motor part 1 by nptelhrd 15,609 views 54.
Massachusetts institute of technology 1 introduction this is a concept paper in response to the foa entitled rare earth alternatives in critical technologies for energy react. There are two basic reasons for the use of singlephase motors rather than 3phase motors. Basic construction and operating principle like most motors, an ac induction motor has a fixed outer portion, called the stator and a rotor that spins inside with a carefully engineered air gap between. Single phase induction motors have very high starting torque b. Nptel provides elearning through online web and video courses various streams. This book details the operation and control of induction motors in both steadystate and transient conditions. The summation of all torques acting on the motor shaft comprises the mechanical model. An induction motor is the most modest electrical machine from constructional point of view, in the majority of the cases. Selection criteria for induction motors for vfd applications.
Starters used in lager industries, it is larger in size and expensive. 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. What is common to all the members of this family is that the basic physical process involved in their operation is the conversion of electromagnetic energy. Induction motor theory jerry bednarczyk, pe course content introduction the ac induction motor is well suited to applications requiring constant speed operation. In the electrical model, the voltage, v, and the slip, s, determine the rotor current. Consequently, the rated output of 100 horsepower should be derated to approximately 82 hp to reduce the possibility of damage to the motor. The rotor of an induction motor can be a squirrel cage rotor or wound type rotor. The stator of an induction motor consists of 3phase windings, which when connected to a 3phase supply creates a rotating magnetic field. Nptel syllabus advanced electric drives video course course outline. Selection of induction motors for industrial applications part 1 photo credit. The induction motor stator resembles the stator of a revolving field, three phase alternator. 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.
Record all nameplate information for the induction motor. A motor with only armortisseur windings is called an induction motor. Squirrel cage wound rotor with slip rings the rotating magnetic field the basic idea of an electric motor is to generate two magnetic fields. Mostafa elshahed objectives learn a brief history of the electrical power systems construction. A three phase, 12 pole, salient pole alternator is coupled to a diesel engine running at 500 rpm. In general, the induction motor is cheaper and easier to maintain compared to other alternatives. The rotor will constantly be turning to align its magnetic field with that of the stator field. Mutilevel converterfed induction motor drive utility friendly induction motor drive 02 03 03 02 01 01 4 control of synchronous motor self controlled synchronous motor vector control of synchronous motor 02 02 nptel. Induction machines 1 introduction the induction machine was invented by nikola tesla in 1888. Nptel, online courses and certification, learn for free. The supply is connected to the stator and the rotor received power by induction caused by the stator rotating flux, hence the motor obtains its name induction motor. The singlephase motor stator has a laminated iron core with two windings arranged perpendicularly. Single phase induction motor the singlephase induction machine is the most frequently used motor for refrigerators, washing machines, clocks, drills, compressors, pumps, and so forth. An induction motor also known as an asynchronous motor is a commonly used ac electric motor.
Induction motor works on the principle of induction where electromagnetic field is induced into the rotor when rotating magnetic field of stator cuts the. Understand the principle and the nature of single phase and 3 phase induction machines. The 3phase set of currents, each of equal magnitude and with a phase. Squirrel cage rotor wound type rotor or slip ring type rotor squirrel cage rotor in this type rotor as the name suggests it is a rotating part of an electrical machine, in which current is induced by transformer action from rotating magnetic field. The singlephase motor stator has a laminated iron core with. For an induction motor, torque t is developed by v2, thus on 50% tapping, torque at starting is only 0. The induction motor essentially consists of two parts. Nptel provides elearning through online web and video courses various. Just like a dc machine, a same induction machine can be used as an induction motor as well as an induction generator, without any internal modifications. Standard ac motors the speed of induction motors and reversible motors vary with the size of the load torque. An induction motor is practically a constant speed motor, that means, for the entire loading range, change in speed of the motor is quite small. List and describe the more commonly used equipment in an electric substation. Selection considerations there are differences in characteristics between standard ac motors and stepping motors.
This video lecture, part of the series basic electrical technology by prof. The control principles of various dc and ac motors using solid state converters are discussed. Right from its inception its ease of manufacture and its robustness have made it a very strong candidate for electromechanical energy conversion. Differentiate between the various types of generating electric power stations. Induction motor 1 chapter 3 induction motor bee23 electrical machine power system 2 learning outcomes. Lecture series on industrial automation and control by prof.
At the end of the lecture, student should be able to. Introduction types of electrical machines types of 3ph induction motor basic principle working principle compnents of induction motor application comparision between 1ph i. 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 cast iron or a steel frame as shown in fig. Induction machines guru nanak dev engineering college. An induction motor always operates at a speed lower than the synchronous speed because the rotating magnetic field that occurs in the stator will generate flux in the rotor that will cause the rotor to rotate, but due to the delay of the flow current in the rotor with current flow in the stator, the rotor will never reach its rotating magnetic field speed, that is, the synchronous speed. For reason of economy, most houses, offices and also rural areas are supplied with single phase a. Tech in electrical engineering iase deemed university. Starting method for induction motors a 3phase induction motor is theoretically self starting. Nptel syllabus electrical machines i video course course outline synchronous machines. 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. Induction motor basics, single phase and three phase. If you have watched this lecture and know what it is about, particularly what electrical engineering topics are discussed, please help us by commenting on this video with your suggested description and title. Introduction to induction motor instrumentation and control.
Matlab simulation of induction motor drive using vf control method mitul vekaria1 darshan thakar2 hitesh prajapati3 1,2,3assistant professor 1,2,3department of computer engineering 1,2,3silver oak college of engineering and technology, ahmedabad abstractthere are several types of method available to control induction motor in industries. The stator is composed of laminations of highgrade sheet steel. Create, select, and apply appropriate techniques, resources, and modern engineering. Hence, an utmost care should be exercised in selection of most appropriate type of motor considering number of technical factors for each application, so that the motor would provide desired and. The induction motor plays very important role in industrial sectors, primarily due to its robustness and low cost. The alternating current ac induction motor is one of the most rugged and most widely used machines in industry. Starting of 3 phase induction motors, high starting torque motors. Motor sizing calculations this section describes certain items that must be calculated to find the optimum motor for a particular application. Hence, an utmost care should be exercised in selection of most appropriate type of motor considering number of technical factors for each application, so that the motor would provide desired and optimum performance. The rotor of an induction motor can be a squirrel cage rotor or wound. Selection of induction motors for industrial applications. Motor current monitoring and analysis mcsa is a straight forward tool to diagnosing problems with large inductive motors. Perform an analysis on induction machines which is the most rugged and the most.
Induction motor testing and evaluation summary as energy costs rise, more emphasis is being placed on determining the health of large inductive motors. In this case, an induction motor is described in terms of the euler. Matlab simulation of induction motor drive using vf. The use of induction motors has increased because of the improvements in microprocessorcontrolled inverter circuits. Before starting to explain how an induction asynchronous generator works, i assume that you know the working principle of an induction motor.
Frequency control of induction motor fed from vsi and csi. Umanand, principal research scientist, power electronics group, cedt, iisc bangalore for more details on nptel visit. Speed of a dc shunt motor can be varied very easily with good efficiency, but in case of induction motors, speed reduction is accompanied by a corresponding loss of efficiency and poor power factor. The magnetization current im flowing in the motors equivalent circuit fig. There are two major components of an ac induction motor. Voltage source inverter fed induction motor drives, current source. 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. 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. Nov 03, 2019 an induction motor also known as an asynchronous motor is a commonly used ac electric motor. Some of the technical discussion is based on work that has been reported in a conference publication1.
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