How are squirrel cage induction motors constructed. Thats why its called squirrel cage induction motor. The construction of stator for any induction motor is almost the same. Wound rotor induction motors ac motors electronics. Kanpur, india design of a three phase squirrel cage induction motor for electric propulsion system ravi prakash,mohammad junaidakhtar, r. The rotor of shaded pole induction motors is the squirrel cage type rotor.
Some of the advantages, disadvantages and applications of squirrel cage induction motor compared with slipring induction motor are discussed below. Design, construction, and manufacture of squirrel cage rotors. Difference between synchronous motor and induction motor. The generator is coupled to the wind turbine rotor via a gearbox as shown in figure 5. Oct 27, 2007 on the morning of 25th october 2007, i had an electrical applications class and i had to explain the principle of operation of 3phase squirrel cage motor. A wound rotor induction motor has a stator like a squirrel cage induction motor, but a rotor with insulated windings brought out via slip rings and brushes. Oct 10, 2016 hi friends, i hope you are fine and having fun. Three phase squire cage induction motor, fully enclosed. Therefore, the rotor can be additionally equipped with a highly conductive nonmagnetic metal squirrel cage or only end rings to minimize the end effect to increase the torqueproducing. Also a provision can be made in the switching device to avoid the condition of an open transient during the changeover from y to d as discussed in section 4. A squirrel cage rotor consists of a laminated cylindrical core having semiclosed circular slots at the. Third international conference on advances in control and optimization of dynamical systems march 15, 2014. This is to obtain an optimum starting torque and for limiting the torque dip during the runup. In squirrel cage rotor, the rotor bars are permanently shortcircuited with end rings.
These bars are shorted at each end with shorting rings. Their sole purpose is to allow resistance to be placed in series with the rotor windings while. The rotor terminals are connected to three slip rings which turn with the. Know about the most popular and almost unbreakable construction of squirrel cage induction motor.
In slip ring induction motors the rotor is wound type. Squirrel cage induction motor and wound rotor induction motor. Know about the different winding slots, lamination of the. These drawbacks are removed by a double squirrel cage motor, which has high starting torque without sacrificing efficiency. The stator of slip ring induction motor is very much the same as that of the squirrel cage induction motor, but the construction of its rotor is very much different. A squirrelcage rotor is the rotating part of the common squirrel cage induction motor. One can not even add external resistance for starting of purposes, as the rotor bars are permanently short circuited construction of a squirrel cage rotor is here. When a 3 phase supply is given to the stator winding it sets up a rotating magnetic field in space. Explain starting methods of 3 phase induction motor. Main machine parameters are given in table i and the rotor model is depicted by fig. These motors can operate at any working conditions.
Mostafa elshahed objectives learn a brief history of the electrical power systems construction. Pdf improving squirrel cage induction motor efficiency. Squirrel cage induction motor is used in lathes, drilling machine, fan, blower printing machines etc. Depending upon the type of rotor construction used the three phase induction motor are classified as squirrel cage 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. What is the difference between a squirrel cage motor and a. However, it suffers from the disadvantage of a low starting torque. Know about the different winding slots, lamination of the stator and its construction. 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. A rotor also composed of punched laminations, with rotor slots for the rotor winding. Stator fundamental field induces rotor cage loops with rotor frequency. However, should the motor require service, this manual includes a section that assists the.
Novel method of improving squirrel cage induction motor. Design, construction, and manufacture of squirrel cage. Stator winding is similar to that of a synchronous motor. Slip ring rotor or wound rotor or phase wound rotor. In a squirrel cage induction motor, the rotor has conductive bars embedded in slots in the laminations, running the length of the rotor. The rotor is not power supplied externally and the currents that flow through it are induced. Double squirrel cage motor we have already discussed that the rotor which is of squirrel cage type has two end rings, which are permanently shorted with the rotor conductors. Torquespeed characteristics of three phase squirrel cage induction motor aim. It consists of a cylinder of steel laminations, with aluminum or copper conductors embedded in its surface. Double cage rotor of an induction motor a double cage induction motor is that type of motor in which a double cage or two rotor windings or cages are used. A squirrel cage motor with this type of rotor construction is called nemadesign class d. Induction motors, squirrel cage rotors, application engineering. Squirrel cage induction motor an overview sciencedirect. Oct 09, 2016 a 3 phase induction motor has two types based on the rotor construction, named as.
Former is cheaper and broadly used as it requires less maintenance than later one. Torquespeed characteristics of three phase squirrel cage. Pdf squirrel cage rotor design and manufacturing for. Introduction this manual provides information on how to safely install, couple to the driven equipment, and maintain the toshiba squirrel cage mediumvoltage induction motor. The rotor of the three phase induction motor are further classified as. Stator winding can be either star or delta connected depending upon the design.
A synchronous motor may have a squirrel cage winding embedded in its rotor, used to increase the motor starting torque and so decrease the time to accelerate to synchronous speed. Pdf design and analysis of squirrel cage induction motor in short. Those induction motors which employ squirrel cage rotor are called squirrel cage induction motors. When the 3 phase supply is provided to the stator, a magnetic field is produced which rotates the rotor and motor starts. In my last article, we have discussed squirrel cage induction motor which is a type of 3 phase induction motor today, i am going to tell you about a wound rotor induction motor, which is also a type of 3 phase induction motor. Squirrel cage induction motor the engineering projects. Its torquespeed characteristic is also shown in figure 726. Induction motor construction squirrel cage rotor youtube. The rotor is separated from the stator by a small airgap which ranges from 0. Squirrel cage rotor construction can be stated as follows lamination or motor core material are stacked in cylindrical shape, metal bars are placed in to this lamination slots perpendicularly.
Three phase induction motor construction your electrical guide. The bars are permanently shorted at both the ends with the help of conducting rings called end rings. Starting performance improvement of linestart permanent. Horizontal squirrel cage mediumvoltage induction motor. It is usually designed for fixedspeed operation, larger ratings having such features as deep rotor bars to limit direct on line dol starting currents. This arrangement is used for obtaining high starting torque at a low value of starting current. The squirrel cage induction motor was designed for an extended service life under very demanding conditions. It is usually designed for fixedspeed operation, larger ratings having such features as deep rotor bars to limit direct on line dol. This simplest form of ac induction motor or asynchronous motor is the basic, universal workhorse of industry.
A 3 phase induction motor has two types based on the rotor construction, named as. We saw the construction of the squirrel cage induction motor. This results in a more complicated rotor construction, expensive. Recall that leakage reactance is the reactance due to the rotor flux lines that do not also couple with the stator windings. The construction of the rotor is rugged and simple. Pdf a highspeed squirrelcage induction machine requires totally different. Wound rotor induction motor the engineering projects. Fundamental wave model of lineoperated induction machine. This project is thought for to get a dynamic simulation model which allow us to study if a squirrel cage induction generator with a full power converter connected to its stator side.
The design and construction of the stator and rotor of an induction generator are similar to that of a large induction motor having a squirrel cage rotor. This rotor consists of uninsulated copper or aluminium bars, placed in the slots. Because of the large rotor resistance, this motor has a pullout torque occurring at a high slip, and its starting torque is quite high. Please have a look at the below figures of squirrel cage induction and wound rotor slip ring induction motor.
Control of motorcharacteristics by squirrelcage rotordesign the reactance x2 in an induction motor equivalent circuit represents the referred form of the rotors leakage reactance. A squirrel cage rotor or a wound rotor can be used. Most of three phase induction motor use squirrel cage rotor as it has a remarkably simple and robust construction enabling it to operate in the most adverse circumstances. But the rotor construction differs with respect to the type which is specified above. The rotor of the motor consists the cylindrical laminated core having semiclosed circular slots and short circuit at each end by copper or aluminium ring, called short circuiting ring. Differentiate between the various types of generating electric power stations. Construction of ac cage and wound rotor motors blogger. Squirrelcage rotor almost 90 per cent of induction motors are squirrelcage type, because this type of rotor has the simplest and most rugged construction imaginable and is almost indestructible. Cylindrical laminated core rotor is wound like winding on the stator. The rotating magnetizing field represented by the space vector b m or, equivalently by the magnetizing current i m moves at the synchronous speed. There is no electrical connection between these bars. It is called a squirrel cage motor because the rotor inside of it known as a squirrel cage rotor looks like a squirrel cage. Construction of three phase induction motor electrical4u. They are constructed in two parts, a fixed outer portion, called the stator and an inner portion which rotates inside the stator, this is called the rotor.
Control of motor characteristics by squirrelcage rotor design. Parida department of electrical engineering national institute of technology, silchar,assam, india email. Squirrel cage rotor and slip ring rotor squirrel cage vs wound rotor. It provides knowledge for industrial engineers, who use motor current signature analysis mcsa to determine if there are any cage winding breaks in their squirrel cage induction motors scims. A wound rotor, has a 3phase winding similar to the stator winding. Also appreciate the rugged construction of squirrel cage rotor and know the spectacular reasons for the skewed arrangements of the rotor conductors. Pdf squirrel cage rotor design and manufacturing for high.
There is no slipin a synchronous motor, that is, the rotor always moves at exactly the same speed as the. The induction motor is started by itself that we know. Squirrel cage rotor almost 90 per cent of induction motors are squirrel cage type, because this type of rotor has the simplest and most rugged construction imaginable and is almost indestructible. In operation, the nonrotating stator winding is connected to an alternating current power source. Abstract this chapter presents the essential features of the design, construction, and manufacture of squirrel cage induction rotors. Designing of three phase squirrel cage induction motor for. Squirrel cage induction motors are cheaper in cost compared to slip ring induction motors. The main difference between slip ring and squirrel cage induction motor is the rotor construction. The slip ring induction motor could be used for industrial wires where variable speed and high starting torque are prime requirements.
The squirrel cage rotor consists of laminated steel in the core with evenly spaced bars of copper or aluminum placed axially around the periphery, permanently shorted at the ends by the end rings. The figure itself depicts many difference between the two types of motors. A squirrelcage motor with this type of rotor construction is called. Wound rotor induction motors chapter ac motors pdf version. Difference between squirrel cage and slip ring induction. Basically the design of electric motor involves the study of the voltages designing of three phase squirrel cage induction motor for good efficiency 1jagdish singh, 2khushdeep singh, 3harleen kaur.
Their sole purpose is to allow resistance to be placed in series with the. This chapter presents the essential features of the design, construction, and manufacture of squirrel cage induction rotors. Advantages and disadvantages of squirrel cage induction motor. Control of motorcharacteristics by squirrelcage rotordesign. The squirrelcage rotor consists of laminated steel in the core with evenly spaced bars of copper or aluminum placed axially around the periphery, permanently shorted at the ends by the end rings.
The entire structure looks like cage hence it is called a squirrel cage rotor. Advantages and disadvantages of squirrel cage induction motor x transformer tap changing working principle electrical machines tap changing in transformers it is a normal fact that increase in load lead to decrease in the supply voltage. Most of the induction motors are of this type because of simple and rugged construction of rotor. The design and construction of the stator and rotor of an induction generator are similar to that of a large induction motor having a squirrelcage rotor. Jul 23, 2016 please have a look at the below figures of squirrel cage induction and wound rotor slip ring induction motor. Squirrel cage motors the majoritory of 3phase ac induction motors are of the squirrel cage construction.
What characterizes an induction motor is the fact that only the stator is connected to the power supply. Design of a three phase squirrel cage induction motor for. Closedform analysis of squirrelcage induction motors with. Studying and improving of squirrel cage induction motor scim efficiency is a continuous area of interest not only among the researchers but also the industry, manufacturer and government. This simple and rugged construction makes it the favorite for most applications. Watch video if you want to learn about induction motor construction squirrel cage rotor, you wil get basic knowledge about basic parts of induction motor fan, rotor. Parida department of electrical engineering national institute of technology, silchar. Construction of squirrel cage induction motor any induction motor has a stator and a rotor.
Wound rotor induction motors ac motors electronics textbook. Normally, we use the motors in industrial drives because they are rugged, reliable and economical. Three phase induction motor construction your electrical. The rotor consists of a cylindrical lamina ted core with parallel slots for carrying the rotor conductors which, it should be. The stator of a double cage rotor of an induction motor is same as that of a normal induction motor.
Three phase slip ring induction motor my tech info. Building a large post frame garage full timelapse construction. As there are no brushes and slip ring, these motors requires less maintenance. Depending upon the type of rotor construction used the three phase induction motor are classified as squirrel cage. In wound rotor, windings are also permanently shortcircuited, hence no slip rings are. Cage induction machines institut fur elektrische energiewandlung. Shaded pole induction motors working and construction. Construction of squirrel cage induction motor explained. Considering merits by adding axial slots and squirrel cage, a 6pole, 50hz, 10kv, 355kw, threephase lspmsm with a new composite solid rotor is designed. Know about the construction of double squirrel cage motor with a graphical comparison with single cage. Firstly, i am going to tell you about the structure of squirrel cage induction motor. Working principle of 3 phase squirrel cage induction motor.
A squirrelcage rotor is the rotating part of the common squirrelcage induction motor. A squirrel cage induction motor consists of the following parts. Reaction of a squirrel cage rotor in a 2pole field in the rotor reference frame. The sinusoidally distributed flux density wave is moving at slip speed inducing in the rotor cage voltages of magnitude indicated by the blue vertical lines. Jul 25, 2019 what is squirrel cage induction motor. The motor which employing squirrel cage type rotor is known as the squirrel cage motor. Nov 27, 2019 the rotor of the three phase induction motor are further classified as. This rotor is made up from parallel aluminum or copper bars. Modeling and control of squirrel cage induction generator. A 3 phase squirrel cage induction motor is a type of three phase induction motor which functions based on the principle of electromagnetism. The squirrel cage winding of a synchronous machine will generally be smaller than for an induction machine of similar rating. The squirrel cage induction motor was designed for an extended service life under very demanding. Compared to squirrel cage rotor the rotor construction is not simple. This fact causes several studies to improve the existing windmills.
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