This article presents an understanding of what squirrel cage induction motors. A motor rating of 10 horse power, 415 volts with 1440 rpm and 4pole is selected for design problem and an. Torquespeed characteristics of three phase squirrel cage. Third international conference on advances in control and optimization of dynamical systems march 15, 2014. How are high starting torques obtained in a squirrel cage. The threephase induction motor the squirrelcage induction motor the woundrotor induction motor 3 4. Know about the most popular and almost unbreakable construction of squirrel cage induction motor. The squirrel cage induction motor was designed for an extended service life under very demanding conditions. What is a squirrel cage motor and how does it work. Although the emphasis in this work has been placed on the threephase induction motor with a squirrel cage rotor, the same modelling approaches hold for the. The use of the double squirrel cage arrangement has resulted in the improvement of the startup coefficients for induction motors. The rotor windings in the squirrelcage rotor are shortcircuited at both.
Squirrel cage motors ac squirrel cage motors manufacturers. The singlecage model does not represent the squirrelcage induction motors well, and therefore the doublecage model must be used. The squirrelcage induction motor linkedin slideshare. Totally enclosed squirrel cage three phase motors with cast. Squirrel cage induction motors from 380 v to,800 v. The slip ring motor has very little application in industries. The upper slot conductors from the outer cage and the lower slot conductors form the inner cage. These bars are shorted at each end with shorting rings. Construction of squirrel cage induction motor explained. Squirrelcage motor definition of squirrelcage motor by. What is the difference between a squirrel cage motor and a. A synchronous motor may have a squirrelcage winding embedded in its rotor, used to increase the motor starting torque and so decrease the time to accelerate to synchronous speed.
Starting, switching off during running ac4 squirrelcage induction motors. Squirrel cage motors are the most commonly used induction motors, but the main drawback in them is their poor starting torque due to low rotor resistance. Keeping the vf ratio constant, when frequency is reduced then that results in constant slipfrequency at running. Three starting methods for squirrel cage motors the three most common starting methods for squirrel cage motors are pws part winding start, wds wyedelta start, and electronic softstart. Control of motor characteristics by squirrelcage rotor design. Parameters description table of three phase squirrel cage induction motor i l amp. Construction of double squirrel cage induction motor a double squirrel cage induction motor consists of a rotor which has two independent cages one above the other in the same slot. However, should the motor require service, this manual includes a section that assists the. Double squirrel cage induction motor your electrical guide. Design of a three phase squirrel cage induction motor for. Iec squirrelcage motors type series 1le, 1pc, 1la, 1lg, 1ll, 1lp, 1ma, 1mj, 1pp, 1pq frame sizes 63 to 450 power range 0.
There is no electrical connection between these bars. Starting, switching off during running ac4 squirrel cage induction motors. 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. For the caged rotor of the induction motor, the doublecage model is better than the singlecage model. When a 3 phase supply is given to the stator winding it sets up a rotating magnetic field in space. The reactance x2 in an induction motor equivalent circuit represents the referred form of the rotors leakage reactance. Three most common starting methods for squirrel cage motors. Squirrel cage definition and meaning collins english dictionary. Using variable voltage variable frequency vvvf drive. However, the cage is still subject to nonuniform thermal loads. Pdf improving squirrel cage induction motor efficiency. This is suitable for smooth constant loads, these squirrel cage motors are designed with the qualitytested components and leading technology under the direction of skilled technocrats in accordance with the quality standards. The stator of a double cage rotor of an induction motor is same as that of a normal induction motor.
The starting torque can be improved by increasing the rotor resistance but in case of squirrel cage induction motor external resistance cant be added in the rotor circuit during starting since its rotor. Kalsi group product categories squirrel cage induction motors. Control of motor characteristics by squirrelcage rotor design the reactance x2 in the equivalent circuit of an induction motor represents the rotors leakage reactance. An anisotropic homogeneous representation for both squirrelcage rotor and stator windings is used. Due to high input frequency from laboratory supply, the analysis of power loss made by hysteresis and eddy current become very important. Control of motorcharacteristics by squirrelcage rotordesign. This rotor is a cylinder of steel laminations, with highly. 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. A 3 phase squirrel cage induction motor is a type of three phase induction motor which functions based on the principle of electromagnetism.
But the rotor construction differs with respect to the type of motor. And in the previous article on types of electrical motors, we have classified induction motors based on the type of rotor used. Know about the different winding slots, lamination of the stator and its construction. A 55 kw motorgenerator set of squirrel cage induction machines with a wind emulator to control the torque is used as model for the wind farm. A 3 phase induction motor has two types based on the rotor construction, named as. In general, the farther away a rotor bar is from the stator, the. Pdf the model of doublecage induction motor for the.
The field windings in the stator of an induction motor set up a rotating magnetic field through the 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. Slip ring motor conversion to vsd driven standard squirrel. The reason for the name squirrel cage is because of the type of rotor used in these motors.
The interaction of the magnetic fields produced by the stator and rotor windings produces a torque on the squirrel cage rotor. Search wegthreephaseinductionmotorstlinesquirrelcage. High speed im with appropriate squirrel cage can reach circumferential speed up to 200 ms, see in 2. Cross section of a squirrel cage rotor with drop shaped bars 4. When voltage is applied to the stator winding, a rotating magnetic field is established.
A double squirrel cage rotor is shown in the figure. Section 3 discusses with various methods used for constructing the rotor of a squirrel cage induction motor. Firstly, i am going to tell you about the structure of squirrel cage induction motor. Turning now to the motor a squirrel cage motor may be regarded simplistically as a stator winding through which ac flows thus causing an emf to rotate at synchronous speed,n s given by n s 2. Improving squirrel cage induction motor efficiency. Specific features of the operations of an induction motor. Squirrel cage induction motor the engineering projects. In a squirrel cage induction motor, the rotor has conductive bars embedded in slots in the laminations, running the length of the rotor.
Former is cheaper and broadly used as it requires less maintenance than later one. The basic idea of an electric motor is to generate two magnetic fields. In addition to saving electric energy in some cases up to 70% operational parameters of equipment accuracy, power efficiency, etc. Analysis and design of ac induction motors with squirrel cage rotors. This setup is connected to the grid through back to back converters, as schematically shown in fig. The rotor will constantly be turning to align its magnetic field with that of the stator field. The main disadvantage of a squirrel cage motor is its poor starting torque, because of its low rotor resistance. 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. The squirrel cage winding of a synchronous machine will generally be smaller than for an induction machine of similar rating. Recall that leakage reactance is the reactance due to the rotor flux lines that do not also couple with the stator windings.
Also appreciate the rugged construction of squirrel cage rotor and know the spectacular reasons for the skewed arrangements of the rotor conductors. It consists of a cylinder of steel laminations, with aluminum or copper. Motors terminal box size on top right side left side 71 normal 802 normal on request on request 160400 normal on request on request terminal box the terminal box of motor sizes 71 to 250 can be turned 4x90 as option in sizes 280 to 400 and in. Starting, plugging, inching for ac3 operation, allowance must always be made in practice for sporadic inching operations, for example during commissioning, in case of faults or in service work. Squirrel cage induction motor and wound rotor induction motor. Slip ring motors can have many different ratings depending on the duty cycle for which they are specified. 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. This is the reactance due to the rotor flux lines that do not couple with the stator windings. Section 4 investigates problems involved in dcr technology and their solutions to overcome. All other regions in the motor are considered nonconducting. Designing of three phase squirrel cage induction motor for.
Parameters estimation of squirrelcage induction motors using. Closedform analysis of squirrelcage induction motors with. Almost 95% of the induction motors used is of squirrel cage type. Rational systems for the drives of hoisting cranes, roller conveyors, and elevators are solved taking into account specific features of the operation of inductions motors with the squirrel cage rotor in a frequency regulation system. What are the advantages of a squirrelcage induction motor. Low and high voltage three phase induction motors m line squirrel cage rotor horizontal date. Cage induction generators for wind turbines with power. The ordinary squirrel cage induction motor has excellent running characteristics, but it suffers from the drawback that due to its very low rotor resistance, its starting torque is poor. The relative motion between this field and the rotation of the rotor induces electric current in the conductive bars. Pdf on may 26, 2004, claudio bruzzese and others published improved squirrel cage induction motor phase model for accurate rotor fault simulations and parameters identification by f. Kanpur, india design of a three phase squirrel cage induction motor for electric propulsion system ravi prakash,mohammad junaidakhtar, r. 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. 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.
Mainly we discuss a threephase squirrel cage induction motor. Oct 09, 2016 a 3 phase induction motor has two types based on the rotor construction, named as. It is called a squirrel cage motor because the rotor inside of it known as a squirrel cage rotor looks like a squirrel cage. This article will explain the principles of squirrel cage motors, how they. The rotor is constructed using a number of single bars shortcircuited by end rings and arranged in a hamsterwheel or squirrelcage configuration. Pdf improved squirrel cage induction motor phase model for. 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. Slip ring induction motor is made up from wound rotor and squirrel cage induction motor is made up from the squirrel cage rotor. Starting of squirrel cage induction motors485 an induction motor can be regarded as a transformer with a small air gap in the magnetic circuit. A squirrelcage rotor is the rotating part of the common squirrelcage induction motor. This arrangement is used for obtaining high starting torque at a low value of starting current.
Three phase squirrel cage induction motor with inverter section model 0100hz. Squirrel cage construction, the rotor winding consists of a number of rotor bars, shortcut by rings from both side, see figure below. We introduce ourselves as an eminent manufacturer and trader of 3phase squirrel cage induction motor. It is very commonly used in industries because it is very cheap, robust, efficient, and reliable. Parida department of electrical engineering national institute of technology, silchar,assam, india email. The main disadvantage of a squirrelcage motor is its poor starting torque, because of its low rotor resistance. Standard squirrel cage motors also have a fixed nominal rating that is almost always based on s1 duty. The 3phase set of currents, each of equal magnitude and with a phase. Our test motor with squirrel cage has a circumferential speed of 40 ms. Horizontal squirrel cage mediumvoltage induction motor.
The starting torque could be increased by having a cage of high resistance, but then the motor will have poor efficiency under normal running conditions because there will be more rotor cu losses. Starting torque is directly proportional to the rotor resistance. Each serves approximately the same purpose but is dependent upon the number of contactors provided. A squirrel cage induction motor therefore draws a very high starting. Oct 19, 20 three phase squirrel cage induction motor with inverter section model 0100hz. May 20, 2015 the threephase induction motor the squirrel cage induction motor the woundrotor induction motor 3 4. It consists of a sextant of a motor composed of six concentric cylinders as follows. The number of poles depends upon the electrical build two, four, six or eight pole motors are available, however the. The construction of stator of the induction motor is almost the same as other motors. A wide variety of squirrel cage motor options are available to you, there are 897 suppliers who sells squirrel cage motor on, mainly located in asia. If the standard squirrel cage motor is selected purely on nominal power, for example a 37 kw to replace a 37 kw slip ring motor, then. 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 rotor is constructed using a number of single bars shortcircuited by end rings and arranged in a hamsterwheel or squirrel cage configuration.
586 196 527 1274 20 665 1425 648 173 106 856 1523 66 1364 1552 482 783 719 386 1066 98 449 1541 1071 1004 344 385 16 160 1624 346 1379 972 1141 761 86 306 1492 485 252 571 736