The construction of stator of the induction motor is almost the same as other motors. 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 highspeed squirrelcage induction machine requires totally different design compared to the traditional squirrel cage industrial motor because of mechanical limitations caused by the high speed. This paper highlights the design issues of high power induction motors for traction applications. Section 2 presents internal dynamics of the induction motor in state space form.
Y2 series three phase asynchronous motor is a kind of totally enclosed fancooled tefc squirrelcage induction motor. Motors of this type employ squirrel cage having relatively low resistance and reactance. Now let us discuss in detail, the most common form of induction motor, the squirrel cage induction motor. In this design the motors are built from doublecage rotors. Control of motor characteristics by squirrelcage rotor design. Induction motors are the most widely used in domestic, commercial and various industrial applications. Starting of squirrel cage induction motors485 an induction motor can be regarded as a transformer with a small air gap in the magnetic circuit. The software technologies used are visual basic 6 for form design and coding, database of space to iron, copper, insulation and air ideveloped in microsoft access comprising information. Design of a three phase squirrel cage induction motor for. These bars are shorted at each end with shorting rings. They are more expensive than motors of class a and b classes.
Designing squirrel cage rotor slots with high conductivity. Recall that leakage reactance is the reactance due to the rotor flux lines that do not also couple with the stator windings. 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. Impact of skin effect for the design of a squirrel cage induction motor on its starting performances md.
Analysis and design of ac induction motors with squirrel. However, should the motor require service, this manual includes a section that assists the. It consists of a cylinder of steel laminations, with aluminum or copper conductors embedded in its surface. Pdf squirrel cage induction motor design and the effect of. Kanpur, india design of a three phase squirrel cage induction motor for electric propulsion system ravi prakash,mohammad junaidakhtar, r. After the maximum torque point which is three to four times the fullload torque, the decrease in rotor p. The singlephase induction motor is not selfstarting. Y2 series 3phase induction motors are characterized with high efficiency and energy saving, large starting torque. Rating considerations dimensions of a machine depend on torque at a specific speed how intensively the magnetic circuit is used.
Know about the most popular and almost unbreakable construction of squirrel cage induction motor. Design of speed controller for squirrelcage induction. Section 4 presents the design of fuzzy logic controllers i. Squirrel cage induction motors menzel elektromotoren. 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. These motors are very robust in construction and very cheap. Pdf squirrel cage rotor design and manufacturing for.
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. How are squirrel cage induction motors constructed. Almost 70% of the industrial motors and drives comes under these category. A single phase induction motor is very similar to a 3phase squirrel cage induction motor. When a 3 phase supply is given to the stator winding it sets up a rotating magnetic field in space. The reason for the name squirrel cage is because of the type of rotor used in these motors. Pdf design of outer rotor single phase squirrel cage induction motor. The reactance x2 in an induction motor equivalent circuit represents the referred form of the rotors leakage reactance. The rotor will constantly be turning to align its magnetic field with that of the stator field.
A 3 phase squirrel cage induction motor is a type of three phase induction. The basic idea of an electric motor is to generate two magnetic fields. The squirrel cage induction motor was designed for an extended service life under very demanding conditions. Traditional design of cage rotor induction motors ronald g. Closedform analysis of squirrelcage induction motors with. S l r the flux in the singleturn coil on the rotor surface is. The maximum torque of a squirrel cage induction motor is also called pullout torque because of the way the motor reacts to an overload. The use of copper as the conductor of induction motor rotors would typically lead to improvements in efficiency, relative to motors. Although ac induction motors are easier to design than dc motors, the speed and the torque. Also lets get to know the methods which are used to control the speed of squirrel cage. In traditional designs of 60 hz linefed induction machines, skin effect is represented by correction coefficients k. Record all nameplate information for the induction motor. Harley and yao duan georgia institute of technology november, 2009.
An induction motors rotor can be either wound type or squirrelcage type. A simple explanation of squirrel cage induction motors. The same basic design is used for both singlephase and threephase motors over a. Teco totally enclosed fan cooled squirrelcage induction motors are designed, manufactured and tested to meet or exceed the latest nema, ieee, csa and. Pdf design of a threephase squirrelcage induction motor. Induction motor equations engn1931f spring 2017 2 let. Working principle of 3 phase squirrel cage induction motor. Unlike a 3phase induction motor, a singlephase induction motor is not self starting but requires some starting means.
Low and high voltage three phase induction motors m line squirrel cage rotor horizontal date. In this type of three phase induction motor the rotor is wound for the same number of poles as that of stator but it has less. 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. Squirrel cage induction motor the engineering projects. The singlephase stator winding produces a magnetic field that pulsates in strength in a sinusoidal manner. In this approach, the direct connection from geometry to performance is suppressed. Design of squirrel cage induction motors for traction applications. Information guide for general purpose industrial ac small. Parida department of electrical engineering national institute of technology, silchar,assam, india email. Pdf this paper introduces the design of an outer rotor single phase squirrel cage induction motor orspscim which is basically a single. Almost 95% of the induction motors used is of squirrel cage type. Construction of squirrel cage induction motor explained.
Firstly, i am going to tell you about the structure of squirrel cage induction motor. What is the difference between a squirrel cage motor and a. Almost 90% of induction motors have squirrel cage rotors. This paper presents the design of threephase induction motor im for high speed with torque speed curve suitable for vehicle propulsion applications. The torquespeed characteristics of the most common designs are shown in fig. During the design, according to the parameters given as input, there are many situations that are contradictory to each other in order to. Squirrel cage induction motor is used in lathes, drilling machine, fan, blower printing machines etc. The principal advantages of the squirrelcage induction motor are its simplicity of design and robust construction.
You should also make a dc measurement of stator winding linetoline resistance using a dmm. Third international conference on advances in control and optimization of dynamical systems march 15, 2014. But the rotor construction differs with respect to the type of motor. Horizontal squirrel cage mediumvoltage induction motor. When oversized, most of these motors operate in low efficiency. Pdf improving squirrel cage induction motor efficiency. The electrical circuit of the rotor is of the following nature squirrel cage rotor consists of a set of copper or aluminium bars installed. Control of motorcharacteristics by squirrelcage rotordesign. Slip ring induction motor is made up from wound rotor and squirrel cage induction motor is made up from the squirrel cage rotor. This motor should be mounted on the motor bench, wherein the motor shaft may be coupled to the dynamometer for taking the measurements. In a squirrel cage induction motor, the rotor has conductive bars embedded in slots in the laminations, running the length of the rotor. Classes of squirrel cage motors to cater to the different starting and running requirements of a various industrial applications, several standard designs of squirrelcage motors are available in the market.
The 3phase set of currents, each of equal magnitude and with a phase. Analysis and design of ac induction motors with squirrel cage rotors. Menzel squirrel cage induction motors are manufactured for various industries and industrial applications of all kinds. The rotor also consists of a set of slotted silicon steel laminations pressed together to form of a cylindrical magnetic circuit and the electrical circuit. For this reason, the design of the induction motor is of great importance. Also appreciate the rugged construction of squirrel cage rotor and know the spectacular reasons for the skewed arrangements of the rotor conductors. The winding terminals are brought out to three slip rings.
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. Analysis and design of ac induction motors with squirrel cage rotors by shine ho university of new hampshire, september, 1996 the traditional approach to modelling the ac induction motor revolves around the wellknown equivalent t circuit model. Pdf squirrel cage induction motor design and the effect. Maxwells equations in squirrelcage induction motors. Squirrel cage induction motor and wound rotor induction motor. A 3 phase induction motor has two types based on the rotor construction, named as. In addition, singlephase motors also have domestic use. The squirrel cage induction motors are 90% used in various industrial, domestic and commercial applications. Design of a threephase squirrelcage induction motor based on efficiency maximization using fem software mucet2008paper no here. The latter is of a form similar to that of the stator winding. Out of total electrical motors 80% are threephase squirrelcage induction motors which are widely used in industrial and domestic applications because of the relatively low cost and high reliability. There is no electrical connection between these bars. The rotor cage is similar in appearance to pet rodent exercise wheels from over a century ago, thus the name squirrel cage. The stator winding is assumed to be yconnected with the access to the phase terminals.
Deep bar and multiple cage effects are useful in design of such machines. Design of squirrel cage induction motor matlab examples. A primary consideration for induction motor designer is the. And in the previous article on types of electrical motors, we have classified induction motors based on the type of rotor used. There were many attempts to design the rotor bar shape to increase the starting torque in squirrel cage induction motor, and it is well known that deep slot of rotor bar increases the starting torque. Design of a three phase squirrel cage induction motor for electric. Particularly, the squirrel cage type is characterized by its. The larger the motor power, the more severe this phenomenon. The design of y2 series induction motor absorbed the advanced technology of electric motors around the world. Shamimul haque choudhury1,2, muhammad athar uddin1,2, md. Torquespeed characteristics of three phase squirrel cage. In operation, the nonrotating stator winding is connected to an alternating current power source. L r s and be the angular velocities of the magnetic field line frequency, rotor, and slip respectively.
Pdf optimal design of rotor slot geometry of squirrel. Control of motorcharacteristics by squirrelcage rotordesign the reactance x2 in an induction motor equivalent circuit represents the referred form of the rotors leakage reactance. The design features of an induction motor are classified as constructional wise and performance wise and results are combined. Former is cheaper and broadly used as it requires less maintenance than later one.
These induction motors require special attention during its design process boldeo and nasar. In squirrel cage induction motors, rotor windings wound in squirrel cage. There are other types of rotors used in ac motors such as synchronous and wound rotor, however, the focus here will be on the squirrel cage induction rotor. Know about the different winding slots, lamination of the stator and its construction. In section 3, the different speed control techniques of an ac motor are discussed.
Designing of three phase squirrel cage induction motor for. How an induction motor works by equations and physics. Squireel cage induction motors are widely used in industries. Normally, we use the motors in industrial drives because they are rugged, reliable and economical. 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. This allows an eternal threephase resistor to be connected to the rotor winding for the purpose of providing. 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. A squirrelcage rotor is the rotating part of the common squirrelcage induction motor.