Nov 03, 2019 there are basically two types of induction motor. Introduction types of electrical machines types of 3 ph induction motor basic principle working principle compnents of induction motor application comparision between 1ph i. Understanding motor nameplate information nema vs iec. Although single phase induction motor is more simple in construction and is cheaper than a 3 phase induction motor of the same frame size, it is less efficient and it operates at lower power factor. The most common type of ac motor being used throughout the work today is the induction motor. The frame of three phase induction motor should be strong and rigid as the air gap length of three phase induction motor is very small.
Thus the rotor rotates in the same direction as that of stator flux to minimize the relative velocity. 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. The types of induction motor depend upon the input supply. Induction motor basics, single phase and three phase induction. An induction motors rotor can be either wound type or squirrel cage type. This article concentrates only on three phase induction motor and its protection. The rotor is separated from the stator by a small airgap which ranges from 0. Explain starting methods of 3 phase induction motor. Types of single phase induction motors electronics hub.
The vertical mounting type motors should be transported in the vertical position. The threephase motor design was also worked on by the swiss engineer charles. Since the rotor is of squirrel cage type, there is no rotor insulation and hence the rotor structure is more robust. Threephase ac induction motors are widely used in industrial and commercial applications. Consider the working of a motor for a better understanding of these indicators. Dec, 2018 electrical engineering three phase induction motor objective types question and answer in hindi in this video we know about 25 important 25 objective questions with their answer in hindi which. The single phase induction motor resembles, three phase, squirrelcage motor except that, single phase induction motor has no starting torque and some special arrangement have to be made to make it as self starting. Both types have similar constructed rotor, but they differ in construction of rotor. Rotating flux is only possible when 3 phase voltage or poly phase which is 120 degree apart in time is applied to a three phase winding or poly phase winding 120 degree apart in space then a three phase rotating magnetic flux is. This induces an electric field in a coil or squirrel cage to drive a rotor. It acts as a covering and provides protection and mechanical strength to all the inner parts of the machine. The stator carries a 3 phase winding called stator winding while the rotor carries a shortcircuited winding called rotor winding only the stator winding is fed from the 3 phase supply. They run at a constant speed from noload to the full load.
Jan 02, 2020 polyphase induction motor mcq with explanation in case of 3 phase induction motors the ratio of core length to pole pitch for minimum cost is taken as. The three phase induction motors are simple in construction, rugged, low cost and easy to. Types of electric motors electric motors dc motors other motors h ac motors s unt motor separately excited. Dec 19, 2015 single phase induction motors are used primarily for domestic and lightindustrial applications where three phase supply is generally not available. One single phase wattmeter plus miscellaneous apparatus as needed. An ac motor is an electric motor driven by an alternating current ac. Single phase motors will last for years as well, and usually, most failures from single phase motors are a result of an inappropriate application rather. The singlephase induction motor is much the same in construction as the threephase motor. Induction motor basics, single phase and three phase. The threephase induction motor is the extensively used for various kinds of industrial drives. Like any electric motor, a 3 phase induction motor has a stator and a rotor.
Induction motor totallyenclosed fancooled nema standard epact three phase induction motors sdesign versatility teco totally enclosed fan cooled squirrelcage induction motors are designed, manufactured and tested to meet or exceed the latest nema, ieee, csa and. Different types of fault in three phase induction motor. For this motors, we require three phase power supply, whereas thus three phase power must be supplied in. The frame is either made up of diecast or fabricated steel.
Designation explanation of induction motor type 160 m operating conditions 1 3. Types of single phase induction motors as mentioned above that, due to the rotating magnetic field of the stator, the induction motor. Hello everyone, i am niko and, in this instructables i will show you, how to rewind and renew old three phase electric motor. The induction motor stator resembles the stator of a revolving field, three phase alternator. The stator of an induction motor consists of 3 phase windings, which when connected to a 3 phase supply creates a rotating magnetic field. Applications of single phase induction motor pnpntransistor. Methods of starting three phase induction motors as we know, once a supply is connected to a three phase induction motor a rotating magnetic field will be set up in the stator, this will link and cut the rotor bars which in turn will induce rotor.
Advantages of 3 phase induction motor generally easy to build and cheaper than corresponding dc or synchronous motors induction motor is robust. The frame of an induction motor is usually made of. This final thesis will mostly be dedicated to induction motors but also to synchronous permanent magnet and reluctance motors. The single phase induction motor is not selfstarting. The rotor composes of concentric strips of magnetic iron isolated from each other. Some single phase induction motors are also called squirrel cage motors because of the rotors similarity to a circular animal exercise wheel. Just like any other motor, a 3 phase induction motor also consists of a stator and a rotor.
Types and construction of three phase induction motor. Different types of motors used in electric vehicles. There are two types of induction motors, one with wound type rotor, also called slipring motor and another one with squirrelcage rotor. Squirrel cage induction motors a stator construction. You should also make a dc measurement of stator winding linetoline resistance. Flexible 5 ratings correspondence 220380415v50hz,220440v60hz is standard. In this chapter, we shall focus our attention on the construction. Home category electrical engineering mcq questions and answers 3 phase induction motors. Different types of electric motors and their applications. Three phase squirrelcage induction motors are widely used as industrial drives because they are selfstarting, reliable and economical. Generally, two types of induction motors are used in our industry such as wound rotor and squirrel cage rotor, but their faults are almost same. Squirrel cage induction motor and slip ring or wound rotor induction motor. The magnet is spun by a 3 phase ac motor with no rotor voltage 4. However, the rotor never succeeds in catching up the synchronous speed.
As mentioned above that, due to the rotating magnetic field of the stator, the induction motor becomes self starting. An induction motor can be, squirrel cage induction motor. Determination of the losses in induction machines due to harmonics pdf. There are three types of capacitor motors, as follows. There are two different types of the structure and similar in electrical properties. The two main types of ac motors are induction motors and synchronous motors. Frame size 180m and above, 380660v50hz is standard. Single phase induction motors are used extensively for smaller loads, such as household appliances like fans. This is the basic working principle of induction motor of either type, single phase of 3 phase. Single phase induction motors are used primarily for domestic and lightindustrial applications where three phase supply is generally not available. In the case of three phase ac alternating current operation, the most widely used motor is a 3 phase induction motor, as this type of motor does not require an additional starting device.
When the 3 phase stator windings are fed by 3 phase supply, a magnetic flux of constant magnitude which is rotating at synchronous speed is set up. Induction motors are generally two types as we see in the previous article. As discussed in chapter 16, the squirrel cage comprises the bars and. An induction motors rotor can be either wound type or squirrelcage type. Differentiate between the various types of generating electric power stations.
The single phase induction motor is much the same in construction as the three phase motor. Unit 16 electric motors objectives after studying this unit, the student will be able to state the purpose of an electric motor. An electrical motor is a device that has brought about one of the biggest advancements in the fields of engineering and technology ever since the invention. Starting method for induction motors a 3 phase induction motor is theoretically self starting. The basic idea of an electric motor is to generate two magnetic fields.
Induction motor 1 chapter 3 induction motor bee23 electrical machine power system 2 learning outcomes. Refer back to this diagram as the operational requirements of the singlephase motor are discussed. It is the outer part of the three phase induction motor. If you are searching for rewinding of one phase motor you can find it here. This elearning module provides a basic understanding of three phase induction motors. A 3 phase induction motor can be used for different applications with various speed and load requirements. Single phase induction motors arenot a selfstarting motor, and three phase induction motor are a selfstarting motor. When the motor is connected to a single phase power supply, the main winding carries an alternating current. Electrical engineering three phase induction motor objective. There are two basic reasons for the use of single phase motors rather than 3 phase motors. Ac induction motors are also the most common motors used in main. The stator of the threephase induction motor consists of three main parts. Three phase induction motor for industrial general purpose toshiba. Threephase induction motor protection systems and its.
Three phase induction motor faults and their causes. Ac induction motors are also the most common motors used in main powered home appliances. There are single phase induction motors and three phase induction motors. For three phase induction motors frames 143t 449t 18060 109 ave edmonton, ab t5s 2k2. Unit 16 electric motors washington state university. An induction motor also known as an asynchronous motor is a commonly used ac electric motor. The three phase induction motors are simple in construction, rugged, low cost and easy to maintain. The difference in speed between rotor, the synchronous speed and the rotating. A 3 phase induction motor uses current delivered in three phases in a sequence into the coils of a stator to create a rotating magnetic field.
The construction of stator for both the kind of three. A 3 phase induction motor has two main parts i stator and ii rotor. Three phase induction motors are constructed into two major types. The 3phase set of currents, each of equal magnitude and with a phase. Mostafa elshahed objectives learn a brief history of the electrical power systems construction. For reason of economy, most houses, offices and also rural areas are supplied with single phase a. Perform an analysis on induction machines which is the most rugged and the most. The types of induction motors can be classified depending on whether they are a single phase or three phase induction motor. An electrical motor is an electromechanical device which converts electrical energy into mechanical energy. Motor starters are types switches either electromechanical or solid state that are designed to start and stop the motors by providing the necessary power to the motor and preventing the. Squirrel cage wound rotor with slip rings the rotating magnetic field. Understand the principle and the nature of single phase and 3 phase induction machines. When the 3 phase supply is provided to the stator, a magnetic field is produced which rotates the rotor and motor starts.
But at the starting of the induction motor, starting current is very large which may damage motor windings. Generally 3 phase induction motors have a high starting torque, high power factor, high efficiency, and low current. Since the three phase induction motors have been widely employed in industrial, commercial and residential systems, the supplied. Phase induction motors capacitorstart induction motor dynamic and steadystate performance of a capacitorstart singlephase induction. Slip ring induction motor or wound rotor induction motor or phase wound induction motor. Applications of three phase induction motors of size varying from half a kilowatt to thousands of kilowatts are numerous. These types of motors are known as selfstarting induction motors. Introduction this application note describes the design of a 3phase ac induction motor drive with volts per hertz control in closedloop vhz cl. The induction motor is started by itself that we know. A capacitor motor is a single phase induction motor with a main winding arranged for a direct connection to a source of power and an auxiliary winding connected in series with a capacitor. These are of two types, squirrel cage and slip ring motors. Three phase or poly phase motors are of mainly two types.
Uses soft magnet rotor that is magnetized by the application of current in the stator coils 3. Y2 series 3 phase induction motors are widely used as drive mechanism in various kinds of machineries like machine tools, pumps, fans, compressors, gear boxes, etc. Some singlephase induction motors are also called squirrel cage motors because of the rotors similarity. Please refer to this link to know more about induction motor types and advantages. Construction of three phase induction motor electrical4u. Star delta starter for 3phase motor electronics hub. Figure 1 three phase induction motor with all their essential parts. It is based on freescales 56f800e microcontrollers. Induction motor mainly uses electromagnetic induction for changing the energy from electric to mechanical. The first ac commutatorfree threephase induction motors were. At the end of the lecture, student should be able to. Record all nameplate information for the induction motor. The 3 phase induction motor is usually called according to the type of its rotor to distinguish between the two types wound rotor type.
A single phase induction motor is inherently not selfstaring can be shown easily. Understanding motor nameplate information nema vs iec standards. Difference is that transformer is an alternating flux machine while induction motor is rotating flux machine. Its main function is to support the stator core and the field winding. There are two types of 3 phase induction motors based on the type of construction of rotor. Below are some of the types of motors that may be encountered. Phase wound induction motor slipring induction motor.
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