There are two types of induction motors, one with wound type rotor, also called slipring motor and another one with squirrelcage rotor. Slipring or woundrotor induction motors construction of squirrel cage induction motor any induction motor has a stator and a rotor. 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. Construction of squirrel cage induction motor explained. Its torquespeed and currentspeed characteristics are such that, on starting, a torque of typically twice fullload torque is produced but a large current typically, six to eight times fullload current is drawn from the supply. The basic idea of an electric motor is to generate two magnetic fields. A squirrel cage rotor or a wound rotor can be used. Types of single phase induction motors electronics hub. How are squirrel cage induction motors constructed. Squirrel cage induction motor is used in lathes, drilling machine, fan, blower printing machines etc. Squirrel cage wound rotor with slip rings the rotating magnetic field the basic idea of an electric motor is to generate two magnetic fields. Oct 10, 2016 hi friends, i hope you are fine and having fun. But the rotor construction differs with respect to the type of motor. Sep 18, 2018 in the induction motors used in lift and hoists, you will see a type of rotor called a slip ring rotor, whereas in most of the other applications you will see a simpler, squirrel cage type of rotor.
These motors are tested to strict quality control for routine and type tests at every stage of production and are ideally suitable for various. Threephase ac induction motors are widely used in industrial and commercial applications. 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. Pdf principles of electrical machines book by vk mehta and. Introduction to induction motor instrumentation and control. A highspeed squirrel cage induction machine requires totally different design compared to the traditional squirrel cage industrial motor because of mechanical limitations caused by the high speed. Because of the large rotor resistance, this motor has a pullout torque occurring at a high slip, and its starting torque is quite high. As the name suggests, this type of motor has only one stator winding main winding and operates with a singlephase power supply. It is called a squirrel cage motor because the rotor inside of it known as a squirrel cage rotor looks like a squirrel cage. Pdf principles of electrical machines book by vk mehta. Mostafa elshahed objectives learn a brief history of the electrical power systems construction. Kalsi group product categories squirrel cage induction motors. Most of the application of industrial as well as domestic are this type of induction motor.
In operation, the nonrotating stator winding is connected to an alternating current power source. Traditional design of cage rotor induction motors ronald g. The construction of these motors is more or less similar to a threephase squirrelcage induction motor. Pdf squirrel cage rotor design and manufacturing for high. The induction motor was invented by nikola tesla much earlier than this around 1891. Who invented the squirrel cage name for an induction motor. Why are there two different designs of rotor construction for. The majority of commercial and industrial applications usually involve the use of a threephase squirrelcage induction motor. Squirrel cage induction motor an overview sciencedirect. This rotor is a cylinder of steel laminations, with highly.
These motors have the advantage of adopting any number of pole pairs. Pdf squirrel cage rotor design and manufacturing for. This fact causes several studies to improve the existing windmills. Know about the different winding slots, lamination of the stator and its construction. A squirrel cage induction motor therefore draws a very high starting. It consists of a cylinder of steel laminations, with aluminum or copper conductors embedded in its surface. Menzel squirrel cage motors are available in all standard motor cooling and protection types for lowvoltage from 75 kw as. Oct 09, 2016 a 3 phase induction motor has two types based on the rotor construction, named as. An induction motor is an alternatingcurrent motor in which a primary winding on one member usually the stator is connected to the power source and a polyphase secondary winding or a squirrelcage secondary winding on the other member usually the rotor carries induced current. The information contained in this book is intended.
Cheap copare to slipring im maintainance is easy cost is less compare to slipring im can use at explosive area starting torque is low compare to slip ring im application. Reaction of a squirrelcage rotor in a 2pole field in the rotor reference frame. A squirrel cage motor with this type of rotor construction is called nemadesign class d. A squirrelcage rotor is the rotating part of the common squirrelcage induction motor. In my last article, we have discussed squirrel cage induction motor which is a type of 3 phase induction motor. Introduction to induction motor instrumentation and.
Squirrel cage motor low rotor resistance low starting torque centrifugal pumps, wood working tools etc. Current signature analysis for condition monitoring of cage induction motors serves as a reference for professional engineers, head electricians and technicians working with induction motors. November 27, 2019 february 24, 2012 by electrical4u. Former is cheaper and broadly used as it requires less maintenance than later one. The principal advantages of the squirrel cage induction motor are its simplicity of design and robust construction. Nov 27, 2019 the three phase induction motor is the most widely used electrical motor. May 20, 2015 the threephase induction motor the squirrel cage induction motor the woundrotor induction motor 3 4. However, should the motor require service, this manual includes a section that assists the. 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. The squirrel cage induction motor was designed for an extended service life under very demanding. Wound rotor induction motor the engineering projects. Squirrel cage induction motor squirrel cage induction motors are usually used in various industrial applications.
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. This is the simplest form of a cage, where the bars have a circular crosssection. The principal advantages of the squirrelcage induction motor are its. The singlephase ac induction motor best fits this description. Normally, we use the motors in industrial drives because they are rugged, reliable and economical. In wound rotor, windings are also permanently shortcircuited, hence no slip rings are. An induction motor is an alternatingcurrent motor in which a primary winding on one member usually the stator is connected to the power source and a polyphase secondary winding or a squirrel cage secondary winding on the other member usually the rotor carries induced current. Low and high voltage three phase induction motors m line squirrel cage rotor horizontal date. In all singlephase induction motors, the rotor is the squirrel cage type. They are particularly suited for applications where the motor must maintain a constant speed, be selfstarting, or there is a desire for low maintenance. 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. An induction motors rotor can be either wound type or squirrelcage. Slip ring induction motor is made up from wound rotor and squirrel cage induction motor is made up from the squirrel cage rotor.
The stator is a stationary part and it has laminated construction, which is made up of stampings. The rotor will constantly be turning to align its magnetic field with that of the stator field. The 3phase set of currents, each of equal magnitude and with a phase. The theoretical speed of the rotor in an induction motor depends on.
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. Squirrel cage induction motor and wound rotor induction motor. Text book pdf principles of electrical machines book by vk mehta and rohit mehta pdf download. When a 3 phase supply is given to the stator winding it sets up a rotating magnetic field in space. Difference between synchronous motor and induction motor. In this thesis, the design of a threephase squirrel cage induction motor have been done according to nema and iec standards with using ansys maxwell 16. Search wegthreephaseinductionmotorstlinesquirrelcage. Three phase squirrel cage induction motor with inverter section model 0100hz. Principleofthreephase induction motor perphase equivalent circuit motor slip r 1. These are of two types, squirrel cage and slip ring motors. Induction motor basics, single phase and three phase. Tesla polyphase induction motors ac motors electronics. 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.
Harley and yao duan georgia institute of technology november, 2009. Modeling and control of squirrel cage induction generator. Squirrel cage motor high rotor resistance high starting torque compressors, crushers, reciprocating pumps etc. This motor is very much like a woundrotor induction motor with extra resistance inserted into the rotor. In synchronous ac motors, the rotor turns at exactly the same speed as the rotating magnetic field. Cheap copare to slipring im maintainance is easy cost is less compare to slipring im can use at explosive area starting torque is low compare to slip. Introduction this manual provides information on how to safely install, couple to the driven equipment, and maintain the toshiba squirrel cage mediumvoltage induction motor. 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. Stator winding is similar to that of a synchronous motor. These motors have the advantage of adapting any number of pole pairs. The principal advantages of the squirrelcage induction motor are its simplicity of design and robust construction. Threephase currents flowing within the stator create a rotating magnetic field which induces a current and consequent magnetic field in the rotor.
Squirrel cage motor higher rotor resistance higher starting torque. List and describe the more commonly used equipment in. Oct 19, 20 three phase squirrel cage induction motor with inverter section model 0100hz. The name squirrel cage, thus, stems from the shape of the conducting bars. 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. Ac induction motors how ac motors work explain that stuff. Working principle of 3 phase squirrel cage induction motor. The singlephase induction motor is not selfstarting. Almost 90% of induction motors have squirrel cage rotors. The threephase induction motor the squirrelcage induction motor the woundrotor induction motor 3 4. The rotor consists of a cylindrical laminated core with axially. By far the most commonly used ac motor is the induction motor.
The construction of stator of the induction motor is almost the same as other motors. Today, i am going to tell you about a wound rotor induction motor, which is also a type of 3 phase induction motor. A 3 phase induction motor has two types based on the rotor construction, named as. Control of motorcharacteristics by squirrelcage rotordesign the reactance x2 in an induction motor equivalent circuit represents the referred form of the rotors leakage reactance. Know about the most popular and almost unbreakable construction of squirrel cage induction motor. An induction motor s rotor can be either wound type or squirrel cage type. In simple words, the type of 3 phase induction motor which uses a squirrel cage rotor is called squirrel cage induction motor. Almost 80% of the mechanical power used by industries is provided by three phase induction motors because of its simple and rugged construction, low cost, good operating characteristics, the absence of commutator and good speed regulation. Firstly, i am going to tell you about the structure of squirrel cage induction motor. A highspeed squirrelcage induction machine requires totally different design compared to the traditional squirrel cage industrial motor because of mechanical limitations caused by.
The squirrelcage induction motor linkedin slideshare. Single phase induction motors consist of two main parts. Squirrel cage induction motors menzel elektromotoren. These motors are selfstarting and use no capacitor, start winding, centrifugal switch or other starting device. Researchers were not able to successfully breed and domesticate hamsters until 1939. These stampings consists of slots on its periphery to carry the. Although single phase induction motor is more simple in construction and is cheaper than a 3phase induction motor of the same frame size, it is less efficient and it operates at.
Control of motorcharacteristics by squirrelcage rotordesign. Current signature analysis for condition monitoring of. Electrical interview questions which motor is best. Designing of three phase squirrel cage induction motor for.
Also appreciate the rugged construction of squirrel cage rotor and know the spectacular reasons for the skewed arrangements of the rotor conductors. A 3 phase ac induction motor photoed by hordu motor. These motors are tested to strict quality control for routine and type tests at every stage of production and are ideally suitable for various industrial applications. Induction motor damage curves motor thermal limit curve ieee 620, ieee guide for the presentation of thermal limit curves for squirrel cage induction machines rotor temperature limits during starting stator temperature limits during running. The book principles of electrical machines book by vk mehta and rohit mehta is an ideal text for students who look to gain a current and clear understanding of the subject as all theories and concepts are explained with lucidity and clarity. Menzel squirrel cage induction motors are manufactured for various industries and industrial applications of all kinds. Advantages of three phase squirrel cage induction motor. I g crow beng, phd, ceng, fimeche, fimare, memasme, r robinson bsc, ceng, fiee, in plant engineers reference book second edition, 2002. Products 14618 downloads 49649 pages 1 news 492 you searched for.
Construction of three phase induction motor electrical4u. Recall that leakage reactance is the reactance due to the rotor flux lines that do not also couple with the stator windings. List and describe the more commonly used equipment in an electric substation. Figure 2 cage structure of squirrel cage induction motor. A 1phase induction motor is similar to a 3phase squirrel cage induction motor in. Menzel squirrel cage motors are available in all standard motor cooling and protection types for lowvoltage from 75 kw as well as medium and high voltage up to 25000 kw 25 mw.
In squirrel cage rotor, the rotor bars are permanently shortcircuited with end rings. Horizontal squirrel cage mediumvoltage induction motor. The construction of stator for any induction motor is almost the same. Rating considerations dimensions of a machine depend on torque at a specific speed. The rotor is constructed using a number of single bars shortcircuited by end rings and arranged in a hamsterwheel or squirrelcage configuration. The below diagram shows squirrel cage induction rotor having aluminum bars short circuit by aluminum end rings. Basically, it is the construction of rotor which makes squirrel cage induction motor different from wound type induction motor. Threephase squirrel cage induction motors are widely used as industrial drives because they are selfstarting, reliable and economical.
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. Starting of squirrel cage induction motors485 an induction motor can be regarded as a transformer with a small air gap in the magnetic circuit. This final thesis will mostly be dedicated to induction motors but also to synchronous permanent magnet and reluctance motors. Rg,rset advantages simple and robust construction disadvantages low starting torque squirrel cage rotor s. As there are no brushes and slip ring, these motors requires less maintenance. The squirrel cage induction motor was designed for an extended service life under very demanding conditions. Lecture 6 three phase induction motors cairo university. This is because the squirrel cage rotor has a simple and rugged construction. Mainly we discuss a threephase squirrel cage induction motor. Squirrel cage construction, the rotor winding consists of a number of rotor bars, shortcut by rings from both side, see figure below. An induction motor can therefore be made without electrical connections to the rotor. Jul 27, 2019 hamsters arent indigenous to the america. In this work a conventional three phase squirrel cage 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. The absence of slip ring and brushes make the construction of squirrel cage threephase induction motor very simple and robust and hence widely used three phase induction motor.