The slip ring induction motor working in the induction principle. The torque of the induction motor depends on the rotor resistance. It consists of a cylinder of steel laminations, with aluminum or copper conductors embedded in its surface. The majority of commercial and industrial applications usually involve the use of a threephase squirrelcage induction motor. The auxiliary winding is also known as starting winding. A squirrelcage induction motor is one in which the secondary circuit consists of a.
The absence of slip ring and brushes make the construction of squirrel cage three phase induction motor very simple, robust, requires less. Know how the speed control is easily achieved by changing the number of. Comparison between squirrel cage and slip ring induction motor. The stator has laminated construction, made up of stampings. Due to this flux rotor current induced and rotor flux also generated.
It is most widely used for industrial applications due to its selfstarting attribute. These are also called as asynchronous motors, because an induction motor always runs at a speed lower than synchronous speed. In the last sections, i will share some advantages and uses. 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. It is very commonly used in industries because it is very cheap, robust, efficient, and reliable. 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. When three phase supply is given to the stator winding, a rotating magnetic field of constant magnetic field is produced. The reason for the name squirrel cage is because of the type of rotor used in these 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. Advantages and disadvantages of squirrel cage induction motor. Construction of squirrel cage induction motor any induction motor has a stator and a rotor. We saw the working principle of squirrel cage induction motor which is the same in all induction motor. Most of single phase induction motors have squirrel cage rotor.
The rotor is constructed using a number of single bars shortcircuited by end rings and arranged in a hamsterwheel or squirrelcage. 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. Double squirrel cage induction motor your electrical guide. A squirrelcage rotor is the rotating part of the common squirrel cage induction motor.
What are the specific applications of squirrel cage and. Here we will learn how does single phase induction motor work. The construction of stator for any induction motor is almost the same. The rotor is separated from the stator by a small airgap which ranges from 0. In the second section, i would be throwing light on the operation and working principle of wound rotor induction motor.
C supply to stator winding flux generated in the stator winding. The rotor of shaded pole induction motors is the squirrel cage type rotor. All about squirrel cage induction motor you can find here basic ac motor principle, constructions, maintenance and frequently asked questions. The stator of a double cage rotor of an induction motor is same as that of a normal induction motor. Some of the advantages, disadvantages and applications of squirrel cage induction motor compared with slipring induction motor are discussed below. Afterwards i will cover the working principle and features of squirrel cage induction motor.
Principle of operation the basic difference between an induction motor and a synchronous ac motor is that in. A 3 phase induction motor has two main parts i stator and ii rotor. Synchronous speed means the speed of the rotating magnetic field in the stator. 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.
Induction motor working principle single phase and three. 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. Induction motors are the most commonly used motors in many applications. Now let us discuss in detail, the most common form of induction motor, the squirrel cage induction motor. Construction of squirrel cage induction motor explained. Construction of three phase squirrel cage induction motor. But there is a small difference in the construction of its rotor. All questions related to transistor will be clear here by blogs. This rotating magnetic field has a speed which is known as the synchronous speed. 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. How are squirrel cage induction motors constructed. Squirrel cage wound rotor with slip rings the rotating magnetic field. Squirrel cage construction, the rotor winding consists of a number of rotor bars, shortcut by rings from both side, see figure below. Squirrel cage induction motors are cheaper in cost compared to slip ring induction motors.
Here we will discuss the induction motor s construction and working in detail. The relative motion between this field and the rotation of the rotor induces electric current in the conductive bars. Squirrel cage induction motor an overview sciencedirect topics. Here you will know the squirrel cage induction motor working principle, construction, application and advantages of the squirrel cage induction motor. In operation, the nonrotating stator winding is connected to an alternating current power source. Slip rings are made of high quality phosphor bronze and are of molded construction. The field windings in the stator of an induction motor set up a rotating magnetic field through the rotor. When a 3 phase supply is given to the stator winding it sets up a rotating magnetic field in space. 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. 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.
An induction motor is an electrical device that converts electrical energy into mechanical energy. Also lets get to know the methods which are used to control the speed of squirrel cage. The rotor of a squirrel cage induction motor is shor. Construction of three phase squirrel cage induction motor youtube.
However, such a procedure cannot be adopted for a squirrel cage motor because its cage is permanently shortcircuited. Induction motor drive has three distinct operating regions. In order to provide high starting torque at low starting current, double cage construction is used. 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. The principle of working of squirrel cage and slip ring induction motor is based on faradays law of electromagnetic induction. 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. Thus, the basic induction motor becomes an induction generator. Mainly we discuss a threephase squirrel cage induction motor.
The construction of this motor is similar to that of a squirrel cage motor. We shall discuss what is a singlephase induction motor, construction, working, types, starting methods, why it is not selfstarting, advantages, and applications. The stationary part in single phase induction motors is stator and the rotating part is rotor. Single phase induction motor working, construction. This article explains the construction, working principle of singlephase induction motors. Squirrel cage induction motor working principle when a 3 phase supply is given to the stator winding it sets up a rotating magnetic field in space.
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. I will tell you about the construction of wound rotor induction motor in the first section. The three phase induction motors are simple in construction, rugged, low cost and easy to maintain. As you can see, the 3 phase squirrel cage induction motor could achieve the electromechanical energy conversion simple and straight forward. The rotating magnetizing field represented by the space vector b m or, equivalently by the magnetizing current i m moves at the synchronous speed.
Starting torque is directly proportional to the rotor resistance. This rotor setup looks like a squirrel cage at a closer look and hence it is called a squirrel cage induction motor. Pdf this article tells detail about three phase squirrel cage induction motor construction, working principle, and calculations, after reading this. In this section, i will share the working of a squirrel cage induction motor with you guys. A wound rotor induction motor is also known as slip ring induction motor. In squirrel cage type, we use rotor bars but inring type, we use windings that are connected in star.
A simple explanation of squirrel cage induction motors. This type of construction of bars and end rings is similar to a squirrel cage. The construction and functions of various parts in a three phase squirrel. 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. The principal advantages of the squirrelcage induction motor are its simplicity. Slip ring induction motor construction, working and its. Three phase squirrel cage induction motor, construction, working. Learn what a three phase induction motor is, how it is constructed, and its working. Lets first talk about stator of squirrel cage induction motor. In short, the working principle of any induction motors involves stator flux and squirrel cage rotor flux. Firstly, i am going to tell you about the structure of squirrel cage induction motor. Normally, we use the motors in industrial drives because they are rugged, reliable and economical.
Wound rotor induction motor the engineering projects. 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. Working principle of 3 phase squirrel cage induction motor. Introduction to induction motor the engineering knowledge. 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. An induction motor can therefore be made without electrical connections to the rotor. The working of the threephase induction motor is based on the principle of electromagnetic induction. Here lets have a look at the 3d structure of squirrel cage rotor. Induction motor works on the principle of electromagnetic induction. The design and construction of the stator and rotor of an induction generator are similar to that of a.
The threephase induction motor the squirrelcage induction motor the woundrotor induction motor 3 4. Introduction to induction motor instrumentation and. Shaded pole induction motors working and construction. Or they can be divided according to type of rotor i squirrel cage motor and ii slip ring motor or wound type. An induction motors rotor can be either wound type or squirrel cage type. The working principle of a threephase induction motor is quite simple to understand. Learn the working principle and applications of a squirrel cage induction motor, as well as. An ac motor starts through an exterior source however it needs an extra space of about 30% than a threephase motor. The squirrel cage induction motor rotor is shorted and so there is no rotor excitation, the rotor voltage. Some of them are even fractional horsepower motors, which are used in applications like small toys, small fans, hairdryers etc. Squirrel cage induction motor the engineering projects. 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. Instead of a frame with a current inside an asynchronous motor is used a shortcircuited rotor resembling a squirrel cage in construction. This arrangement is used for obtaining high starting torque at a low value of starting current.
In simple words, the type of 3 phase induction motor which uses a squirrel cage rotor is called squirrel. A capacitor start capacitor run induction motor is a single phase motor consists of a stator and a single cage rotor. These motors can operate at any working conditions. We need to give double excitement to make a machine turn. The stampings are lotted on its periphery to carry the winding called stator winding or main winding. Power inverters explained how do they work working principle igbt duration.
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