Like any electric motor, a 3phase induction motor has a stator and a rotor. Approximately 6570% of electric energy is consumed by electric motors and over 90% of them are induction motors. Pdf one of the factors that cause the failure of induction motors which are used intensively in industry is the unbalanced loading of the motor. Atul killedar3 1phd scholar, electrical and electronics engg. Designing of three phase squirrel cage induction motor for. This rotating magnetic field has a speed which is known as the synchronous speed this rotating magnetic field induces the voltage in rotor bars and hence shortcircuit currents start flowing in the rotor bars. The stator is supplied by a balanced 3phase ac power source. Induction motor theory jerry bednarczyk, pe course content introduction the ac induction motor is well suited to applications requiring constant speed operation. The singlephase induction motor is much the same in construction as the threephase motor. The develop ment of highfrequency induction power supplies provided a means of using induction heating. Differentiate between the various types of generating electric power stations. Motor speed relationship the synchronous speed of an ac motor is the speed of the rotating magnetic field set up by the stator winding synchronous speed rpm 120 x frequency divided by the number of poles.
The upshot here is that load modeling is our first motivation for being. The singlephase ac induction motor best fits this description. Three phase induction motor using written pole technology, main winding, exciter winding, control circuit for optimum utilization. In general, the induction motor is cheaper and easier to maintain compared to other alternatives. And an electromechanical model of induction motors needs reference frame theory, because induction motors, although similar to synchronous machines, are different from synchronous machines. 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. To capture induction motor load dynamics, we need an electromechanical model.
The performance of the single phase induction motor is analysed by the two theories. Single phase induction motor double revolving field theory the threephase induction motor starting torque inversely depends on the slip this implies that a small positive slip 0. Construction of squirrel cage induction motor explained. The induction motor is made up of the stator, or stationary windings, and the rotor. 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. Some singlephase induction motors are also called squirrel cage motors because of the rotors similarity to a circular animal exercise wheel.
Record all nameplate information for the induction motor. Five induction motors each supplying 60 kw at a power factor of 0,8 and an efficiency of 93%. An induction motor can therefore be made without electrical connections to the rotor. Because the motor load factor is an average of motor load during a period. The working of the threephase induction motor is based on the principle of electromagnetic induction. By far the most commonly used ac motor is the induction motor. Single phase induction motor, theory of operation double revolving field theory, equivalent circuit, determination of parameters methods of starting, split phase starting, repulsion starting, shaded pole starting, performance characteristics. The operating principle of the induction motor can be briefly explained as, when balanced three. Such an induction motor with integrated brake is shown on figure 1. Individual motors in those ranges have even lower load factors.
Accordingly, the theory of induction heating was studied so that motors and transformers could be built for maximum efficiency by minimizing heating losses. The threephase induction motor is the extensively used for various kinds of industrial drives. The premise for motor operation is that if you can create a rotating magnetic field in the stator of the motor, it. One singlephase wattmeter plus miscellaneous apparatus as needed. The theory used in the work was collected by studying literature on how. When the rotor is at a stand still 0 rpm the rotating magnetic field of the stator cuts the conductors of the rotor at a. The synchronous electrical generator also called alternator belongs to the family of electric rotating machines. Introduction to induction motor the engineering projects. The stator is the outer most component in the motor which can be seen. Basic principle of operation of threephase induction machine.
The rotor of an induction motor can be a squirrel cage rotor or wound. It is called a squirrel cage motor because the rotor inside of it known as a squirrel cage rotor looks like a squirrel cage. Three phase ac motor theory motors have been described as a transformer with a rotating secondary. Explain how this motor can be operated as either a synchronous motor or a plain induction motor. Induction motor theory quiz electrician practice tests. 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 to mechanical energy, and vice versa. Theory of heating by induction 7 tromagnetic, or flux around it. A stator winding is placed in the stator of induction motor and the three phase supply is given to it. Nov 03, 2019 an induction motor also known as an asynchronous motor is a commonly used ac electric motor. Rating considerations dimensions of a machine depend on torque at a specific speed how intensively the magnetic circuit is.
Describe how a squirrel cage motor is built, and classify it as either an induction motor or a synchronous motor. One is known as the double revolving field theory, and the other is cross field theory. Introduction induction motors are employed in textile mills, agriculture and almost all the manufacturing industries to drive the loads because of its rugged construction and ease operation. It is logical that the least expensive, lowest maintenance type motor should be used most often. But the rotor construction differs with respect to the type which is specified above. This rotor is a cylinder of steel laminations, with highly. A simple explanation of how a 3 phase induction motor works. Working principle of 3 phase induction motor, three phase induction motor working operation theory, types of induction motor induction motor working principle pdf. For your splitphase motor lab, you may assume the free running current and power represent the zeroslip. One synchronous motor of one mw operating at full load with an efficiency of 92 %.
How an induction motor works by equations and physics. Overall view and cross section of an asynchronous motor. Ac induction motors are also the most common motors used in main powered home appliances. A 3 phase induction motor can be used for different applications with various speed and load requirements. Formats and editions of theory and design of small. There are two major components of an ac induction motor.
When threephase stator winding of an induction motor is energized from a 3 phase supply, a rotating magnetic field is set up which rotates around the stator at synchronous speed n s. Principle of operation of single phase induction motor. The three phase induction motors are simple in construction. The induction coil actually functions as a transformer primary, with the workpiece to be heated becoming the transformer secondary. Free online electrician practice test questions on induction motor theory quiz leave a reply cancel reply. 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. The motor then produces a constant torque and not a pulsating torque as in other singlephase motors. In normal operation, the stator is excited by alternating voltage. When a voltage is applied to the stator of an induction motor, a magnetic field begins to rotate in the stator. The singlephase induction motor is the most frequently used motor for refrigerators, washing machines, clocks, drills, compressors, pumps, and so forth. As its name indicates stator is a stationary part of induction motor. 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. It is a maintenance free, less noisy and efficient motor. As a result of its extensive use in the industry, induction motors consumes considerable amount of electrical energy 15.
Pdf sd control of induction motor by using intelligence. An induction motor im is a type of asynchronous ac motor where power is supplied to. Advantages of 3 phase induction motor generally easy to build and cheaper than corresponding dc or synchronous motors induction motor is robust. Read online now motor rewinding procedure ebook pdf at our library. The stator carries a 3phase winding called stator winding while the rotor carries a shortcircuited winding called rotor winding. Motors, generators, and transformers are similar in that their basic principle of operation involves induction. The construction of stator for any induction motor is almost the same. 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. 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. List and describe the more commonly used equipment in. The most popular type is the 3phase, squirrelcage ac induction motor. Four induction motors each supplying 120 kw at a power factor of 0,75 and an efficiency of 91 %. There are two types of induction motors, one with wound type rotor, also called slipring motor and another one with squirrelcage rotor.
An induction motors rotor can be either wound type or squirrelcage. The basic idea of an electric motor is to generate two magnetic fields. For example, this rotating magnetic field may be 1800 rpm. Harley and yao duan georgia institute of technology november, 2009.
Single phase induction motor working in hindi youtube. The motor then runs as a singlephase induction motor. Only the stator winding is fed from the 3phase supply. The rotor will constantly be turning to align its magnetic field with that of the stator field. Jul 25, 2019 a 3 phase squirrel cage induction motor is a type of three phase induction motor which functions based on the principle of electromagnetism. 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. An induction motor also known as an asynchronous motor is a commonly used ac electric motor. Ppt induction motor powerpoint presentation free to. You should also make a dc measurement of stator winding linetoline resistance using a dmm. A 480v, 60 hz, 6pole, threephase, deltaconnected induction motor has the following parameters. The ac induction motor is the most used electrical motor in industrial applications worldwide. Enter your email below to receive free informative articles on electrical. As discussed in chapter 16, the squirrel cage comprises the bars and. When the induction coil is placed next to or around a workpiece, the lines of force concentrate in the air gap between the coil and the workpiece.
Single phase series motor, theory of operation performance and application, shcrage motor. Four induction motors each supplying 120 kw at a power. Threephase induction motors are the most common and frequently. Theory and analysis of three phase induction motor using written pole technology kishor s.
Mostafa elshahed objectives learn a brief history of the electrical power systems construction. This final thesis will mostly be dedicated to induction motors but also to synchronous permanent magnet and reluctance motors. The 3phase set of currents, each of equal magnitude and with a phase. 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.