Mainly we discuss a threephase squirrel cage induction motor. Wound rotor induction motor the engineering projects. An induction motor is an electrical device that converts electrical energy into mechanical energy. Introduction to induction motor the engineering knowledge. The rotor of a squirrel cage induction motor is shor. The field windings in the stator of an induction motor set up a rotating magnetic field through the rotor. The threephase induction motor the squirrelcage induction motor the woundrotor induction motor 3 4. Thus, the basic induction motor becomes an induction generator.
All questions related to transistor will be clear here by blogs. Before understanding the working of a threephase induction motor, let us look into the necessary constructional details of the engine because the actual working principle of an induction motor lies behind its construction. The rotor is constructed using a number of single bars shortcircuited by end rings and arranged in a hamsterwheel or squirrelcage. Slip ring induction motor construction, working and its. In order to provide high starting torque at low starting current, double cage construction is used. The construction and functions of various parts in a three phase squirrel. In simple words, the type of 3 phase induction motor which uses a squirrel cage rotor is called squirrel. 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. Starting torque is directly proportional to the rotor resistance. Squirrel cage induction motors are cheaper in cost compared to slip ring induction motors. Now let us discuss in detail, the most common form of induction motor, the squirrel cage induction motor. Some of the advantages, disadvantages and applications of squirrel cage induction motor compared with slipring induction motor are discussed below.
Single phase induction motor working, construction. The construction of this motor is similar to that of a squirrel cage motor. The slip ring induction motor working in the induction principle. When a 3 phase supply is given to the stator winding it sets up a rotating magnetic field in space. Squirrel cage induction motor an overview sciencedirect topics.
In this section, i will share the working of a squirrel cage induction motor with you guys. Squirrel cage wound rotor with slip rings the rotating magnetic field. It is most widely used for industrial applications due to its selfstarting attribute. The reason for the name squirrel cage is because of the type of rotor used in these motors. Induction motors are the most commonly used motors in many applications. A squirrelcage induction motor is one in which the secondary circuit consists of a. 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. 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. One or 2 fans are attached to the shaft in the sides of rotor to cool the circuit. Slip ring induction motor working principle electrical. All about squirrel cage induction motor you can find here basic ac motor principle, constructions, maintenance and frequently asked questions. Construction of squirrel cage induction motor explained. Squirrel cage construction, the rotor winding consists of a number of rotor bars, shortcut by rings from both side, see figure below. An induction motors rotor can be either wound type or squirrel cage type.
Most of 3 phase induction motors use squirrel cage rotor as it has a remarkably simple and robust construction enabling it to operate in the most adverse. A simple explanation of squirrel cage induction motors. Principle of operation the basic difference between an induction motor and a synchronous ac motor is that in. How are squirrel cage induction motors constructed. The stator of a double cage rotor of an induction motor is same as that of a normal induction motor.
These are also called as asynchronous motors, because an induction motor always runs at a speed lower than synchronous speed. We saw the working principle of squirrel cage induction motor which is the same in all induction motor. Here we will discuss the induction motor s construction and working in detail. Also lets get to know the methods which are used to control the speed of squirrel cage. The construction of stator for any induction motor is almost the same. The stationary part in single phase induction motors is stator and the rotating part is rotor. An ac motor starts through an exterior source however it needs an extra space of about 30% than a threephase motor.
Here we will learn how does single phase induction motor work. The stampings are lotted on its periphery to carry the winding called stator winding or main winding. However, such a procedure cannot be adopted for a squirrel cage motor because its cage is permanently shortcircuited. Know how the speed control is easily achieved by changing the number of. A squirrelcage rotor is the rotating part of the common squirrel cage induction motor. Afterwards i will cover the working principle and features of squirrel cage induction motor. If the speeds become equal, there would be no such relative speed, so no emf induced in the rotor, and no current would be flowing, and therefore no torque would be generated. When threephase stator winding of an induction motor is energized from a 3 phase supply, a rotating magnetic field is set up which rotates around the stator at synchronous speed n s. We need to give double excitement to make a machine turn. Here lets have a look at the 3d structure of squirrel cage rotor. In the last sections, i will share some advantages and uses.
Due to this flux rotor current induced and rotor flux also generated. If instead of taking mechanical power from the rotor, the rotor is driven by a prime mover such as the wind, it can be moved faster than the synchronous speed and starts producing electrical power instead of consuming it. A wound rotor induction motor is also known as slip ring induction motor. The rotor of shaded pole induction motors is the squirrel cage type rotor. There are 2 main types of the induction motor according to the construction of the rotor of the motor, first one is the squirrel cage motor because its rotor structure is like the squirrel and 2 nd wound rotor motor in industries, homes or for power generation purposes the 3phase squirrel induction motor is mostly used, due to its reliability, less cost, and selfstating property. Construction of three phase squirrel cage induction motor. Advantages and disadvantages of squirrel cage induction motor. However, the starting torque of this motor can be improved by employing another cage on the rotor, and the motor is called double squirrel cage induction motor.
It is very commonly used in industries because it is very cheap, robust, efficient, and reliable. For example, if we consider a dc motor, we will provide a supply to the stator and another to the. 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. The auxiliary winding is also known as starting winding. Comparison between squirrel cage and slip ring induction motor. Pdf this article tells detail about three phase squirrel cage induction motor construction, working principle, and calculations, after reading this. A capacitor start capacitor run induction motor is a single phase motor consists of a stator and a single cage rotor. The three phase induction motors are simple in construction, rugged, low cost and easy to maintain. Thus from the working principle of three phase induction motor, it may be observed that the rotor speed should not reach the synchronous speed produced by the stator. Three phase squirrel cage induction motor, construction, working. The majority of commercial and industrial applications usually involve the use of a threephase squirrelcage induction motor. Induction motor works on the principle of electromagnetic induction. These motors can operate at any working conditions. Synchronous speed means the speed of the rotating magnetic field in the stator.
In the second section, i would be throwing light on the operation and working principle of wound rotor induction motor. Construction of three phase squirrel cage induction motor youtube. The working of the threephase induction motor is based on the principle of electromagnetic induction. 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. It consists of a cylinder of steel laminations, with aluminum or copper conductors embedded in its surface. When rotor winding is shortcircuited with no resistance in series, it is called a squirrel cage induction motor and when rotor winding is shorted through a resistance in series, it is.
Induction motor drive has three distinct operating regions. 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. Or they can be divided according to type of rotor i squirrel cage motor and ii slip ring motor or wound type. Slip ring induction motor is one of the types of 3phase induction motor and is a wound rotor motor type. In this video you will learn about construction difference between squirrel cage and slip ring induction motor, for notes visit. Instead of a frame with a current inside an asynchronous motor is used a shortcircuited rotor resembling a squirrel cage in construction. Introduction to induction motor instrumentation and. Slip rings are made of high quality phosphor bronze and are of molded construction.
Some of them are even fractional horsepower motors, which are used in applications like small toys, small fans, hairdryers etc. Here you will know the squirrel cage induction motor working principle, construction, application and advantages of the squirrel cage induction motor. Squirrel cage induction motor the engineering projects. Most of single phase induction motors have squirrel cage rotor. The absence of slip ring and brushes make the construction of squirrel cage three phase induction motor very simple, robust, requires less. Firstly, i am going to tell you about the structure of squirrel cage induction motor. Thus, principle of 3 phase induction motor also explains why rotor rotates in same direction as the rotating field and why induction motor is self starting. This rotating magnetic field has a speed which is known as the synchronous speed. Double squirrel cage induction motor your electrical guide. This type of construction of bars and end rings is similar to a squirrel cage.
The principle of working of squirrel cage and slip ring induction motor is based on faradays law of electromagnetic induction. The rotor is separated from the stator by a small airgap which ranges from 0. Construction of squirrel cage induction motor any induction motor has a stator and a rotor. In short, the working principle of any induction motors involves stator flux and squirrel cage rotor flux. Induction motor working principle single phase and three.
Lets first talk about stator of squirrel cage induction motor. 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. The torque of the induction motor depends on the rotor resistance. The design and construction of the stator and rotor of an induction generator are similar to that of a. This article explains the construction, working principle of singlephase induction motors. Normally, we use the motors in industrial drives because they are rugged, reliable and economical. This rotor setup looks like a squirrel cage at a closer look and hence it is called a squirrel cage induction motor. An induction motor can therefore be made without electrical connections to the rotor. What are the specific applications of squirrel cage and.
The squirrel cage induction motor rotor is shorted and so there is no rotor excitation, the rotor voltage. The stator has laminated construction, made up of stampings. The relative motion between this field and the rotation of the rotor induces electric current in the conductive bars. Power inverters explained how do they work working principle igbt duration. Learn the working principle and applications of a squirrel cage induction motor, as well as. The principal advantages of the squirrelcage induction motor are its simplicity.
This arrangement is used for obtaining high starting torque at a low value of starting current. I will tell you about the construction of wound rotor induction motor in the first section. In operation, the nonrotating stator winding is connected to an alternating current power source. Shaded pole induction motors working and construction.
Working principle of 3 phase squirrel cage induction motor. C supply to stator winding flux generated in the stator winding. A 3 phase induction motor has two main parts i stator and ii rotor. When three phase supply is given to the stator winding, a rotating magnetic field of constant magnetic field is produced. The rotating magnetizing field represented by the space vector b m or, equivalently by the magnetizing current i m moves at the synchronous speed. In squirrel cage type, we use rotor bars but inring type, we use windings that are connected in star.
310 411 1393 51 409 1020 578 923 110 194 101 54 979 1115 1380 782 816 330 943 1120 420 552 1062 163 473 462 679 428 281 33 472 357 1527 791 836 1473 184 1335 7 313 1370 731 1358