Menzel squirrel cage motors are available in all standard motor cooling and protection types for lowvoltage from 75 kw as well as medium. Torquespeed characteristics of three phase squirrel cage. This paper highlights the design issues of high power induction motors for traction applications. 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. A simple explanation of squirrel cage induction motors. Almost 95% of the induction motors used is of squirrel cage type. In a squirrel cage induction motor, the rotor has conductive bars embedded in slots in the laminations, running the length of the rotor. Particularly, the squirrel cage type is characterized by its. Unlike a 3phase induction motor, a singlephase induction motor is not self starting but requires some starting means. Design of squirrel cage induction motors for traction applications. Recall that leakage reactance is the reactance due to the rotor flux lines that do not also couple with the stator windings. 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.
They are more expensive than motors of class a and b classes. The basic idea of an electric motor is to generate two magnetic fields. Rating considerations dimensions of a machine depend on torque at a specific speed how intensively the magnetic circuit is used. Impact of skin effect for the design of a squirrel cage induction motor on its starting performances md. 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. 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. However, should the motor require service, this manual includes a section that assists the. 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. The use of copper as the conductor of induction motor rotors would typically lead to improvements in efficiency, relative to motors. The singlephase stator winding produces a magnetic field that pulsates in strength in a sinusoidal manner. 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.
Standard types of squirrel cage motors are as explained below. What is the difference between a squirrel cage motor and a. Analysis and design of ac induction motors with squirrel. A 3 phase squirrel cage induction motor is a type of three phase induction. Induction motors are the most widely used in domestic, commercial and various industrial applications.
Normally, we use the motors in industrial drives because they are rugged, reliable and economical. Third international conference on advances in control and optimization of dynamical systems march 15, 2014. In this design the motors are built from doublecage rotors. Pdf squirrel cage induction motor design and the effect of. 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 stator winding is assumed to be yconnected with the access to the phase terminals. Design of speed controller for squirrelcage induction. Squireel cage induction motors are widely used in industries.
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. Analysis and design of ac induction motors with squirrel cage rotors. Design of a three phase squirrel cage induction motor for. The rotor will constantly be turning to align its magnetic field with that of the stator field. These motors are very robust in construction and very cheap. Advantages and disadvantages of squirrel cage induction motor. Record all nameplate information for the induction motor. This motor should be mounted on the motor bench, wherein the motor shaft may be coupled to the dynamometer for taking the measurements. Maxwells equations in squirrelcage induction motors. The torquespeed characteristics of the most common designs are shown in fig. How are squirrel cage induction motors constructed.
The squirrel cage induction motors are 90% used in various industrial, domestic and commercial applications. The reason for the name squirrel cage is because of the type of rotor used in these motors. Designing squirrel cage rotor slots with high conductivity. Now let us discuss in detail, the most common form of induction motor, the squirrel cage induction motor. S l r the flux in the singleturn coil on the rotor surface is. The larger the motor power, the more severe this phenomenon. 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. Deep bar and multiple cage effects are useful in design of such machines.
Know about the different winding slots, lamination of the stator and its construction. Induction motor equations engn1931f spring 2017 2 let. 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. Although ac induction motors are easier to design than dc motors, the speed and the torque. Harley and yao duan georgia institute of technology november, 2009. The design features of an induction motor are classified as constructional wise and performance wise and results are combined.
In traditional designs of 60 hz linefed induction machines, skin effect is represented by correction coefficients k. In this approach, the direct connection from geometry to performance is suppressed. Y2 series three phase asynchronous motor is a kind of totally enclosed fancooled tefc squirrelcage induction motor. Squirrel cage induction motors menzel elektromotoren. Design of squirrel cage induction motor matlab examples. 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. 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. This allows an eternal threephase resistor to be connected to the rotor winding for the purpose of providing. 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.
Former is cheaper and broadly used as it requires less maintenance than later one. Section 2 presents internal dynamics of the induction motor in state space form. 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. A single phase induction motor is very similar to a 3phase squirrel cage induction motor.
Motors of this type employ squirrel cage having relatively low resistance and reactance. Control of motor characteristics by squirrelcage rotor design. The construction of stator of the induction motor is almost the same as other motors. Low and high voltage three phase induction motors m line squirrel cage rotor horizontal date. In operation, the nonrotating stator winding is connected to an alternating current power source. Control of motorcharacteristics by squirrelcage rotordesign. During the design, according to the parameters given as input, there are many situations that are contradictory to each other in order to. The latter is of a form similar to that of the stator winding. Menzel squirrel cage induction motors are manufactured for various industries and industrial applications of all kinds. Design of a three phase squirrel cage induction motor for electric. Starting of squirrel cage induction motors485 an induction motor can be regarded as a transformer with a small air gap in the magnetic circuit. 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. These bars are shorted at each end with shorting rings. Firstly, i am going to tell you about the structure of squirrel cage induction motor.
The principal advantages of the squirrelcage induction motor are its simplicity of design and robust construction. Pdf squirrel cage rotor design and manufacturing for. It consists of a cylinder of steel laminations, with aluminum or copper conductors embedded in its surface. Section 4 presents the design of fuzzy logic controllers i. Pdf improving squirrel cage induction motor efficiency.
These induction motors require special attention during its design process boldeo and nasar. Kanpur, india design of a three phase squirrel cage induction motor for electric propulsion system ravi prakash,mohammad junaidakhtar, r. Parida department of electrical engineering national institute of technology, silchar,assam, india email. Traditional design of cage rotor induction motors ronald g. 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 primary consideration for induction motor designer is the. The singlephase induction motor is not selfstarting. Shamimul haque choudhury1,2, muhammad athar uddin1,2, md. But the rotor construction differs with respect to the type of motor. In addition, singlephase motors also have domestic use. There is no electrical connection between these bars. When oversized, most of these motors operate in low efficiency. The winding terminals are brought out to three slip rings.
And in the previous article on types of electrical motors, we have classified induction motors based on the type of rotor used. Pdf design of outer rotor single phase squirrel cage induction motor. Know about the most popular and almost unbreakable construction of squirrel cage induction motor. Almost 70% of the industrial motors and drives comes under these category. 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 design of y2 series induction motor absorbed the advanced technology of electric motors around the world. After the maximum torque point which is three to four times the fullload torque, the decrease in rotor p. A squirrelcage rotor is the rotating part of the common squirrelcage induction motor. 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. Also lets get to know the methods which are used to control the speed of squirrel cage. Information guide for general purpose industrial ac small. The electrical circuit of the rotor is of the following nature squirrel cage rotor consists of a set of copper or aluminium bars installed.
The reactance x2 in an induction motor equivalent circuit represents the referred form of the rotors leakage reactance. Also appreciate the rugged construction of squirrel cage rotor and know the spectacular reasons for the skewed arrangements of the rotor conductors. An induction motors rotor can be either wound type or squirrelcage type. You should also make a dc measurement of stator winding linetoline resistance using a dmm. Closedform analysis of squirrelcage induction motors with. Pdf squirrel cage induction motor design and the effect.
Pdf this paper introduces the design of an outer rotor single phase squirrel cage induction motor orspscim which is basically a single. The same basic design is used for both singlephase and threephase motors over a. This paper presents the design of threephase induction motor im for high speed with torque speed curve suitable for vehicle propulsion applications. When a 3 phase supply is given to the stator winding it sets up a rotating magnetic field in space. L r s and be the angular velocities of the magnetic field line frequency, rotor, and slip respectively. Design of a threephase squirrelcage induction motor based on efficiency maximization using fem software mucet2008paper no here. Squirrel cage induction motor is used in lathes, drilling machine, fan, blower printing machines etc. Designing of three phase squirrel cage induction motor for. 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. The rotor cage is similar in appearance to pet rodent exercise wheels from over a century ago, thus the name squirrel cage. Slip ring induction motor is made up from wound rotor and squirrel cage induction motor is made up from the squirrel cage rotor.
In squirrel cage induction motors, rotor windings wound in squirrel cage. The squirrel cage induction motor was designed for an extended service life under very demanding conditions. The 3phase set of currents, each of equal magnitude and with a phase. Working principle of 3 phase squirrel cage induction motor. Squirrel cage induction motor and wound rotor induction motor. Almost 90% of induction motors have squirrel cage rotors. For this reason, the design of the induction motor is of great importance. An induction motor can therefore be made without electrical connections to the rotor. Squirrel cage induction motor the engineering projects. Pdf design of a threephase squirrelcage induction motor.
In section 3, the different speed control techniques of an ac motor are discussed. 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. Teco totally enclosed fan cooled squirrelcage induction motors are designed, manufactured and tested to meet or exceed the latest nema, ieee, csa and. Y2 series 3phase induction motors are characterized with high efficiency and energy saving, large starting torque. How an induction motor works by equations and physics. Horizontal squirrel cage mediumvoltage induction motor. A 3 phase induction motor has two types based on the rotor construction, named as.
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