Explain the construction and working of an electric motor. The two motors are mechanically coupled together to drive a common load. Various induction motor speed control methods advantages. Induction motors, with emphasis on the the exact analysis of rotor rotation. If you happen to have a string of blinking christmas lights to use as a prop in illustrating a rotating magnetic field, this would be a good thing to show your students. We need to give double excitation to make a dc motor to rotate. In normal conditions, the slip ring motor functions like a squirrel cage motor. Chapter2 principle operationapplications of different stepper motors and significance of permanent magnet hybrid stepper motor 2. The rotational speed of the rotating magnetic field is called as synchronous speed. Advantages of 3 phase induction motor generally easy to build and cheaper than corresponding dc or synchronous motors induction motor is robust.
Working principle of 3phase induction motor eduction motor works on the principle of electromagnetic induction. Induction motors ppt transformer electrical engineering. Dec 22, 2015 the current flows through the rotor due to principle of induction. Any mechanical load applied to the motor shaft will introduce a torque on the motor shaft. A motor is a device which converts electrical energy into mechanical energy. 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. Induction motor theory jerry bednarczyk, pe course content introduction the ac induction motor is well suited to applications requiring constant speed operation. If the copper ring is moved away from the end of the permanent magnet, the direction of force will reverse and become attractive rather than repulsive followup question. A linear induction motor lim is an alternating current ac, asynchronous linear motor that works by the same general principles as other induction motors but is typically designed to directly produce motion in a straight line.
For this motors, we require three phase power supply, whereas thus. Pdf calculation of induction motor starting parameters. Pdf construction of three phase linear induction motor. Induction motor testing and evaluation summary as energy costs rise, more emphasis is being placed on determining the health of large inductive motors. Plugging phenomena, which are very important for any induction motor. 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. Hi friends, in this article, i am going to discuss about induction motor working principle and hoping you will like my effort. An induction motor also known as an asynchronous motor is a commonly used ac electric motor. Thus the rotor rotates in the same direction as that of stator flux to minimize the relative velocity. This method needs two motor, one of them is wound motor.
Performance analysis of the linear induction motor for the. Target motor theory 4 3phase ac induction motor vector control motorola 3. Jul 26, 2017 it can be of two types, single phase induction motor or three phase induction motor. This is the basic working principle of induction motor of either type, single phase of 3 phase. The operating principle of a 3 phase induction motor is based on the production of a rotating magnetic field r. The frame also contains the stator winding of induction motor. It looks at how a centrifugal load and its associated speed vs. 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. Generally, induction motors are categorized based on the number of stator windings. 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.
For variable speed drives, the source is normally an inverter that uses power. An induction motor can be used as induction generator, or it can be unrolled to form the linear induction motor which can directly generate linear motion. Induction motor working principle when a threephase stator winding of an induction motor is connected to the ac supply, current starts flowing in the stator conductors. A pulsating magnetic field is produced, when the stator winding of the singlephase induction motor shown below is energised by a single phase supply. The electric motor operation is based on the following points. In motors, the first magnet is the stator, the second is the rotor. Multi phase induction motors types, their working and. Motor current monitoring and analysis mcsa is a straight forward tool to diagnosing problems with large inductive motors. Our 60 minute guide to motor maintenance is designed to give you, the engineer, all the information you need in industrial electric motor maintenance in a format that is concise, easy to understand and is a point of reference. The necessary of variable speed drives in dynamic states for reducing electrical losses by help of power converters is presented. Induction motor working principle your electrical guide. 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 ns. Induction motor, as the most used in industry, has been treated.
Working principle of an induction motor circuit globe. The starting winding is located 90 electrical from the main winding see fig. But the three phase motor has a wider use in industries and homes. An electrical motor is an electromechanical device which converts electrical energy into mechanical energy. Construction and working of induction motor electrical. Its value is at least twice the fullload value when the motor is operated at rated voltage and frequency. Dec 23, 2016 working principle of three phase induction motor induction motor how does an induction motor workan electrical motor is such an electromagnetically device which converts electrical energy into a. 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. The rotor will constantly be turning to align its magnetic field with that of the stator field. The threephase induction motor is the extensively used for various kinds of industrial drives. An induction motor can therefore be made without electrical connections to the rotor. The concept of the rotating magnetic field is central to ac motor theory, so it is imperative that students grasp this concept before moving on to more advanced concepts. This tutorial will introduce the user to the fundamental electrical and mechanical principles of ac electric induction motor design and application. 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.
Ac induction motors are also the most common motors used in main powered home appliances. Know about the various losses and comparison of induction motor with a mechanical friction clutch for understanding slip. 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. Speed control of single phase induction motor using triac.
This torque is related to the motor output power and the rotor speed and out. Electric motor principle, working, diagram explained step by step. Working principle of 3phase induction motor electrical. The speed at which the rotating magnetic field revolves is called the synchronous speed ns. 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. Chapter2 principleoperationapplications of different. 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. Consider the working of a motor for a better understanding of these indicators.
There basically 2 types of induction motor depending upon the type. Electric motor class 10, magnetic effects of electric current. The stator winding is connected to the three phase supply terminals. To understand its working principle, lets take a look at its structural parts. Its function is to provide mechanical support to the entire construction.
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. The working of the threephase induction motor is based on the principle of electromagnetic induction. Synchronous speed means the speed of the rotating magnetic field in the stator. The induction motor consists of two major parts stator and rotor. This paper explores the construction process of a linear induction motor lim, the basic concepts behind key aspects of linear induction machines construction and the testing process of a working. Introduction to induction motor the engineering projects. In this work a conventional three phase squirrelcage type induction motor with specifications 10 hp, 415v, stardelta connected and 4 poles is chosen for comparison with our motor, which is designed for good efficiency. 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. Characteristically, linear induction motors have a finite primary or secondary length, which generates endeffects, whereas a conventional induction motor is arranged. Designing of three phase squirrel cage induction motor for. The induction motor is made up of the stator, or stationary windings, and the rotor. We saw the working principle of squirrel cage induction motor which is the same in all induction motor. In general, the induction motor is cheaper and easier to maintain compared to other alternatives. In the dc motor, we give one supply to the stator and another to the rotor through brush arrangement.
Specifically, the squirrel cage design is the most extensively used electric motor in industrial applications. A pulsating magnetic field is produced, when the stator winding of the singlephase induction motor shown below is energised by a single phase. These types of motors are known as selfstarting induction motors. 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. Working principle of a single phase induction motor. Introduction types of electrical machines types of 3ph induction motor basic principle working principle compnents of induction motor application comparision between 1ph i. The rpm sensor operates on a hall effect principle and consists of a disk bearing on its periphery two magnetic polepairs and a detector that pulses once each time a polepair is rotated past it. The working principle of dc motor, is based on the principle that in a magnetic field, when a current carrying conductor is placed, a mechanical force is. The threephase induction motor is also called an asynchronous motor and it is the most commonly used type of motor in industrial applications. The rotor winding terminals are permanently connected to the slip. For this motors, we require three phase power supply, whereas thus three phase power must be supplied in a sequence. 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.
Air gap provides the space for the rotating magnetic field between the stator and rotor. Due to this current, a rotating magnetic field of constant amplitude and a constant speed is set up in the air gap between stator and rotor. The following diagram shows categorization of motors by their operation principles and structures. 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. This motor handbook was created by infineon technologies ag together with.
Chapter2 principleoperationapplications of different stepper motors and significance of permanent magnet hybrid stepper motor 2. Threephase induction motors are run at a constant speed from noload to fullload. Induction motor design and operating principles bright. However, the rotor never succeeds in catching up the synchronous speed. Performance analysis of the linear induction motor for the deepunderground highspeed gtx 202 maximum speed should be around 34. The principle of rotating type phase sequence indicator is like that phase motor.
A simple circuit diagram of the squirrel cage induction motor is shown in the figure. Working principle of a single phase induction motor circuit. Single phase induction motors arenot a selfstarting motor, and three phase induction motor are a selfstarting motor. A portion of rotating magnetic field in a threephase. This is because does not require any starting device i. The operation principles and characteristics of the different types of electric. The rpm sensor operates on a hall effect principle and consists of a disk bearing on its periphery two magnetic polepairs and a detector that pulses once each time a. Induction motors are the most commonly used motors in many applications. General principle conversion of electrical power into mechanical power takes place in the rotating part of an electric motor i.
A number of methods for estimating acceleration time are discussed along with the concept of moment of inertia and wk2wr2. The 3phase set of currents, each of equal magnitude and with a phase. Aug 31, 2017 how motors work for beginners episode 3. This maximum torque in an induction motor is called pullout torque or breakdown torque. 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. Nov 03, 2019 single phase induction motors arenot a selfstarting motor, and three phase induction motor are a selfstarting motor. 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. The major difference between them is that transformer is static in nature i. What is the operating principle of a 3 phase induction motor. An induction motors rotor can be either wound type or squirrelcage type.
When a three phase supply is given to the three phase stator winding, a rotating magnetic field of constant magnitude is produced as discussed earlier. Due to this flux rotor current induced and rotor flux also generated. The rotor of an induction motor can be a squirrel cage rotor or wound type rotor. The basic idea of an electric motor is to generate two magnetic fields. The stator winding can be either deltaconnected or starconnected. The starter of slip ring induction motor is connected to threephase supply and its rotor is connected to stator of the other machine. C supply to stator winding flux generated in the stator winding. These are also called as asynchronous motors, because an induction motor always runs at a speed lower than synchronous speed. Working principle of a single phase induction motor a single phase induction motor consists of a single phase winding which is mounted on the stator of the motor and a cage winding placed on the rotor. The electromagnetic induction is the phenomenon in which the electromotive force induces across the electrical conductor when it is placed in a. At least one of the two magnetic field is generated by a solenoid. To get a good understanding of the working principle of a three phase. Question 2 on what principle does electric motor works.
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