For duty cycles other than s1 please refer to teco. Stator winding is similar to that of a synchronous motor. However, should the motor require service, this manual includes a section that assists the. In squirrel cage rotor, the rotor bars are permanently shortcircuited with end rings.
Some of the most common types of squirrel cage motor use three phases, meaning the input current is three identical ac frequencies, split by 120 degrees of phase. Rarely 5% 10% slip ring motors are used in industries because it has several disadvantages like it required. The stator of a double cage rotor of an induction motor is same as that of a normal induction motor. What are the advantages of a squirrelcage induction motor. It is called a squirrel cage motor because the rotor inside of it known as a squirrel cage rotor looks like a squirrel cage. 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. Search wegthreephaseinductionmotorstlinesquirrelcage. Construction of squirrel cage induction motor explained. A squirrelcage rotor is the rotating part of the common squirrel cage induction motor. The main purpose of the information that will be presented here is to describe many of the available tests that can be utilized under these different circumstances. It is low cost and requires low maintenance in comparison with other motor types. Former is cheaper and broadly used as it requires less maintenance than later one. Working principle of 3 phase squirrel cage induction motor.
Squirrelcage induction motors are simpler in structure than dc motors and are most commonly used in the vsd industry. Slip ring induction motor is made up from wound rotor and squirrel cage induction motor is made up from the squirrel cage rotor. Difference between synchronous motor and induction motor. Kanpur, india design of a three phase squirrel cage induction motor for electric propulsion system ravi prakash,mohammad junaidakhtar, r. 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. In wound rotor, windings are also permanently shortcircuited, hence no slip rings are.
High speed im with appropriate squirrel cage can reach circumferential speed up to 200 ms, see in 2. Energy efficient induction motors internet archive. Wound rotor induction motors ac motors electronics. Due to high input frequency from laboratory supply, the analysis of power loss made by hysteresis and eddy current become very important. Pdf improving squirrel cage induction motor efficiency. Nov 27, 2019 an electrical motor is an electromechanical device which converts electrical energy into mechanical energy. Pdf three phase squirrel cage induction motor, conctruction.
Know about the most popular and almost unbreakable construction of squirrel cage induction motor. 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. Improving squirrel cage induction motor efficiency. The conversion process is electromagnetic induction. These motors are having the difference in rotor construction. There is no electrical connection between these bars. Normally, we use the motors in industrial drives because they are rugged, reliable and economical. The analysis of 3phase squirrelcage induction motors. The reactance x2 in an induction motor equivalent circuit represents the referred form of the rotors leakage reactance. Speed control of three phase squirrel cage induction motor using vf method is implemented.
Pdf squirrel cage rotor design and manufacturing for high. Basically, it is the construction of rotor which makes squirrel cage induction motor different from wound type induction motor. In simple words, the type of 3 phase induction motor which uses a squirrel cage rotor is called squirrel cage induction motor. At least one end ring is provided with at least two insulating gaps to divide that end ring into at least two separate portions.
Information guide for general purpose industrial ac small and. This rotor is a cylinder of steel laminations, with highly. But increasing the rotor resistance for improving starting torque is not advisory as it will reduce the efficiency of the motor due to more copper loss. Squirrel cage induction motors are suitable for applications where the drive requires constant speed, low starting torque and no. The reason for the name squirrel cage is because of the type of rotor used in these motors. Its synchronous speed with a 50 hz supply is therefore 60 fp, or 1500 rpm. Pdf squirrel cage induction motor design and the effect of. Figure a shows the speedtorque curves of a squirrelcage induction motor and a blower which it drives. That is why such motors are known as induction motors. The theory of three phase induction squirrel cage motors.
An anisotropic homogeneous representation for both squirrelcage rotor and stator windings is used. What is a squirrel cage motor and how does it work. Squirrel cage induction motor an overview sciencedirect. All other regions in the motor are considered nonconducting.
An electrical motor is an electromechanical device which converts electrical energy into mechanical energy. The squirrel cage induction motors are 90% used in various industrial, domestic and commercial applications. A motor rating of 10 horse power, 415 volts with 1440 rpm and 4pole is selected for design problem and an equivalent circuit model is developed to find out the various performance parameters like efficiency, starting torque, torque. The motor which employing squirrel cage type rotor is known as the squirrel cage motor.
This arrangement is used for obtaining high starting torque at a low value of starting current. Yahya shakweh, in power electronics handbook fourth edition, 2018. 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. Squirrel cage induction motors menzel squirrel cage induction motors are manufactured for various industries and industrial applications of all kinds 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. Higher maintenance of brushes and slip rings compared to squirrel cage motor. The two cages being connected in parallel, the combined resistance is lower.
The rotating magnetizing field represented by the space vector b m or, equivalently by the magnetizing current i m moves at the synchronous speed. Know about the different winding slots, lamination of the stator and its construction. A typical 3phase squirrel cage motor has six connection leads in the electrical connection box for the three coils. A squirrel cage induction motor therefore draws a very high starting. 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. The construction of stator of the induction motor is almost the same as other motors. Squirrel cage induction motors from 380 v to,800 v. Almost 95% of the induction motors used is of squirrel cage type. Firstly, i am going to tell you about the structure of squirrel cage induction motor.
Closedform analysis of squirrelcage induction motors with. If someone works with ac 3phase motors, then it is important to know how to connect these motors in star and delta connection, and how to detect an electrical problem. Horizontal squirrel cage mediumvoltage induction motor. Third international conference on advances in control and optimization of dynamical systems march 15, 2014. Pdf studying and improving of squirrel cage induction motor scim efficiency is a continuous area of interest not only among the researchers but also. Pdf squirrel cage rotor design and manufacturing for. Our test motor with squirrel cage has a circumferential speed of 40 ms. It consists of a cylinder of steel laminations, with aluminum or copper conductors embedded in its surface. The slip ring motor has very little application in industries. For a fullload operating slip of 3 per cent, the speed will then be 1 s60 fp, or 1455 rpm. The singlephase induction motor is not selfstarting.
The squirrel cage induction motor is the most commonly used motor in industry. Starting torque is directly proportional to the rotor resistance. It converts electrical energy into mechanical energy and it is used to provide motion. In this article, we will learn about squirrel cage and slip ring induction motors. In a squirrel cage induction motor, the rotor has conductive bars embedded in slots in the laminations, running the length of the rotor. A typical 3phase squirrelcage motor has six connection leads in the electrical connection box for the three coils. Low and high voltage three phase induction motors m line squirrel cage rotor horizontal date. Information guide for general purpose industrial ac small.
Squirrel cage induction motors are widely used in industrial applications than slip ring induction motors due to cheaper in cost, rugged in construction, low maintenance. Wound rotor induction motors ac motors electronics textbook. In addition to conventional squirrel cage rotor testing methods such as the growler test, also covered will be. The torque speed characteristics of double squirrel cage motor for both the cages are shown in the figure below. 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. How are squirrel cage induction motors constructed. The squirrel cage induction motor was designed for an extended service life under very demanding conditions. The most popular squirrel cage induction motor is of a 4pole design. Low starting current compared to squirrel cage induction motor. Their sole purpose is to allow resistance to be placed in series with the. Designing of three phase squirrel cage induction motor for. The construction of the rotor is rugged and simple. This can be done by simply adjusting the shape of the bars in the rotor.
The rotor of the motor can be braked to stop at a predetermined. And in the previous article on types of electrical motors, we have classified induction motors based on the type of rotor used. Squirrel cage induction motor and wound rotor induction motor. For a squirrelcage motor, the rotor as represented in figure 2 is constituted by a system of bars in copper or aluminum, which are coaxial to the rotation axis and directly diecast in the slots made along the external periphery of the ferromagnetic. When the double cage motor is running at normal speed, frequency of the rotor emf is so low that the reactance of both cages is negligible. Squirrel cage ac induction motor opened to show the stator and rotor construction, the shaft with bearings, and the cooling fan.
Torquespeed characteristics of three phase squirrel cage. A squirrel cage motor comprises a stator and a rotor, the latter having a pair of end rings and conductor bars interconnecting the end rings, the bars and rings being supported on the rotor core. Oct 09, 2016 a 3 phase induction motor has two types based on the rotor construction, named as. A 3 phase induction motor has two types based on the rotor construction, named as. At any speed of the blower, the difference between the torque which the motor can deliver at its shaft and the torque required by the blower is the torque available for acceleration. Advantages and disadvantages of squirrel cage induction motor. Supply voltage stock motors are designed for operation as below. Variable voltage variable frequency vf control theory an induction motor compared to a dc motor has some major advantages such as absence of brushes, commutator segments, rugged construction, being cheap, lesser maintenance requirements and smaller.
Speed is the resistance variable over 50% to 100% full speed. When a 3 phase supply is given to the stator winding it sets up a rotating magnetic field in space. Pdf a highspeed squirrelcage induction machine requires totally different design compared to the traditional squirrel cage industrial motor. The squirrel cage induction motor is the most popular type of ac motor. These types of motors are known as selfstarting induction motors. The targeted turbocirculator requires a motor with an output power of 6 kw at 120 000 rpm 37. Squirrel cage induction motors are used a lot in industry as they are.
Threephase motors are selfstarting, meaning the only necessary input is a starting voltage, and makes these motors essentially plugandplay. Motor formulas and calculations, index of helpful tools. In this chapter, we shall focus our attention on the construction, working and. A squirrel cage rotor or a wound rotor can be used. Now let us discuss in detail, the most common form of induction motor, the squirrel cage induction motor. In operation, the nonrotating stator winding is connected to an alternating current power source. According to the labelled notation a represents stator b rotor c bearing shields d fan e venti. 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 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. Squirrel cage induction motor the engineering projects.
Particularly, the squirrel cage type is simplicity, robustness and low cost, which has always made. Parida department of electrical engineering national institute of technology, silchar,assam, india email. Energy efficient induction motors three phase squirrel cage. Abstract from general equations which describe the transient electromechanical behavior of the asynchronous squirrelcage motor, and which include the. In all induction machine design textbooks, notably in 1,21, but also in many other ones, the evaluation of the equivalent circuit series reactances of squirrel cage.
Iec squirrelcage motors type series 1le, 1pc, 1la, 1lg, 1ll, 1lp, 1ma, 1mj, 1pp, 1pq frame sizes 63 to 450 power range 0. These bars are shorted at each end with shorting rings. It is very commonly used in industries because it is very cheap, robust, efficient, and reliable. A squirrel cage rotor is the rotating part of the common squirrel cage induction motor. Wound rotor induction motors chapter ac motors pdf version. Also appreciate the rugged construction of squirrel cage rotor and know the spectacular reasons for the skewed arrangements of the rotor conductors.
The implementation is done using a rectifier and an inverter, where the pwm triggering pulses were generated by using pic micro controller for switching the igbts of the inverter. Control of motor characteristics by squirrelcage rotor design. The principal advantages of the squirrel cage induction motor are its simplicity of design and robust construction. Design of a three phase squirrel cage induction motor for. But the rotor construction differs with respect to the type of motor. What is the difference between a squirrel cage motor and a. 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. It is logical that the least expensive, lowest maintenance type motor should be used most often. Speed control of three phase squirrel cage induction motor.
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