Advantages of 3 phase induction motor generally easy to build and cheaper than corresponding dc or synchronous motors induction motor is robust. The motor with national specifications is of heatproof class 120 e. Pdf electromagnetism lecture notes university of cambridge. The locked rotor test is made at 15 hz to minimize the errors due to saturation and skin effects. 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. The induction motor essentially consists of two parts. The alternating current ac induction motor is one of the most rugged and most widely used machines in industry. Introduction this application note describes the design of a 3phase ac induction motor drive with volts per hertz control in closedloop vhz cl. The electromagnetism lecture notes is a book to provide an introduction to electromagnetism for electrical and electronics engineers. The rotor of the squirrel cage three phase induction motor is cylindrical in shape and have slots on its periphery. An induction motor im is a type of asynchronous ac motor where power is supplied to. Induction motor works on the principle of induction where electromagnetic field is induced into the rotor when rotating magnetic field of stator cuts the. In an induction motor, the electric current in the rotor needed to produce torque is obtained via electromagnetic induction from the rotating magnetic field of the stator winding.
It is logical that the least expensive, lowest maintenance type. Synchronous and asynchronous electromechanicalsystems dr. It is logical that the least expensive, lowest maintenance type motor should be used most often. Apr 02, 2008 lecture series on basic electrical technology by prof. If an induction motor with certain ratio of rotor to stator slots, runs at 17 of the normal speed, the phenomenon will be termed as. Umanand, principal research scientist, power electronics group, cedt, iisc bangalore for more detail. Types, construction and principle of operation, 3 phase induction motor, general phasor diagram, equivalent circuit, power and torque. Induction motor notes electrical components electric power. Singlephase induction motor threephase induction motor singlephase induction motor there are probably more singlephase ac induction motors in use today than the total of all the other types put together. The singlephase induction motor is the most frequently used motor for refrigerators, washing machines, clocks, drills, compressors, pumps, and so forth. The stator separate from rotor by small air gap have ranges from 0. Several additional components are necessary to operate the singlephase motor.
Speed control of an induction motor there is a various method of speed control of an induction motor. It is available from fractional horsepower ratings to. Uses soft magnet rotor that is magnetized by the application of current in the stator coils 3. This application note also covers the basics of induction motors and different types of induction motors. A 3 phase induction motor can be used for different applications with various speed and load requirements. All we need to do is to keep daxis stator current constant.
It is this feature that makes induction machine suitable for use even in hazardous environments and reliable operation is achieved. There are two major components of an ac induction motor. A rotating magnetic field is set up on the stator by using distributed windings and a 3phase ac. Note that the torque exerted upon the motor by the dynamometer is indicated by the appropriate scale on the dynamometer circumference. Siemens circuit breakers siemens switch rotary 3pole siemens motor siemens induction motor shunt trip cqda2 shunt trip breaker siemens circuit breaker nema three phase induction motor text. Induction motors and transformers both im and transformer works on the principle of induced voltage transformer. An843, speed control of 3phase induction motor using. The ac induction motor is the most used electrical motor in industrial applications worldwide. There are two basic reasons for the use of singlephase motors rather than 3phase motors.
Starting method for induction motors a 3phase induction motor is theoretically self starting. 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. Three phase induction motor model design and performance analysis in ansys rmxprt. Short question answers for 3 phase induction motor. Squirrel cage wound rotor with slip rings the rotating magnetic field the basic idea of an electric motor is to generate two magnetic fields. Simplified steadystateequivalent circuit of induction motor. Other motors that are included are 1phase induction motors, permanent synchronous motors and synchronous reluctance motors.
The 3phase set of currents, each of equal magnitude and with a phase. Rewinding of motors pdf the information in this report and the good practice guide to maintain motor efficiency part 2 was. Woundrotor induction motors are more expensive they require much more maintenance because of the. If an induction motor with certain ratio of rotor to stator slots, runs at 17 of the normal. The induction motor cannot make a quickreversal run because of.
Following data is taken from no load, locked rotor, and dc tests of a 3phase, wye connected 40 hp, 60 hz, 460 v, induction motor with a. Right from its inception its ease of manufacture and its robustness have made it a very strong candidate for electromechanical energy conversion. Induction motors despite the fact that the threephase motor has more phases than the singlephase motor, the singlephase motor is a much more complex machine. Induction motor theory jerry bednarczyk, pe course content introduction the ac induction motor is well suited to applications requiring constant speed operation. 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.
The disadvantage of this type of rotor is that the motor behavior cannot be altered by connecting anything to the rotor there are no rotor terminals. Syllabus of bachelor of technology in electrical engineering 4th semester electrical machinesii. The induction motor is made up of the stator, or stationary windings, and the rotor. This will link and cut the rotor conductors which in turn will induce a current in the rotor conductors and. Determine the motor parameters and the total core, friction and windage losses. This final thesis will mostly be dedicated to induction motors but also to synchronous permanent magnet and reluctance motors.
Record all nameplate information for the induction motor. Three phase induction motor introduction the induction machine was invented by nikola tesla in 1888. An induction motor can therefore be made without electrical connections to the rotor. Lecture notes electrical machine ii bee 1401 page 1. The rotor has salient poles and a cage so that it starts like an induction motor, and runs like a synchronous motor. By far the most commonly used ac motor is the induction motor. These are compiled by david tong, department of applied mathematics and theoretical physics, university of cambridge. If the induction motor is operating in the linear magnetic region, the lm is constant. Lecture series on basic electrical technology by prof. The induction machine behaves like a transformer, transferring electrical energy from the stator to the rotor. Principle of operation of single phase induction motor. Fall 2005 ee595s electric drive systems 2 overview of strategies voltsperhertz control constant slip control fieldoriented control. The three phase induction motors are simple in construction, rugged, low cost and easy to maintain.
The supply is connected to the stator and the rotor received power by induction caused by the stator rotating flux, hence the motor obtains its name induction motor. The induction motor cannot make a quickreversal run because of the torque acting in the opposite. The electric energy generated purchased by consumers for different needs. Singlephase motors have only two power source supply lines connected. The rotor speed of an induction motor is given by the equation shown below. The major difference between them is that transformer is static in nature i. Synchronous and asynchronous electricmotors the electric motor is an electromechanical continuous energy conversion equipment that converts electrical energy into electrical energy mechanical energy. The stator of an induction motor consists of 3phase windings, which when connected to a 3phase supply creates a rotating magnetic field. Department of electrical engineering dit, university, dehradun, uttarakhand references.
An843, speed control of 3phase induction motor using pic18 mcus. The maximum torque that the motor can develop typically 2. Induction motor basics, single phase and three phase. The stator works as the primary while the rotor works as the secondary. Fall 2005 ee595s electric drive systems 3 voltsperhertz control. You should also make a dc measurement of stator winding linetoline resistance using a dmm. Applications of single phase induction motor these are used in low power. Draw the approximate equivalent circuit for the motor lockrotor noload dc test v line 36.
Scalar control is the term used to describe a simpler form of motor control, using nonvectorcontrolled. An induction motor also known as an asynchronous motor is a commonly used ac electric motor. The rotor will constantly be turning to align its magnetic field with that of the stator field. In general, the induction motor is cheaper and easier to maintain compared to other alternatives. A motor with only armortisseur windings is called an induction motor. Ac induction motors are also the most common motors used in main powered home appliances.
Starting of 3 phase induction motors, high starting torque motors, speed. Fall 2005 ee595s electric drive systems 36 the plan continued achieving 14. Syllabus of bachelor of technology in electrical engineering 4th semester. There are two types of induction motors, one with wound type rotor, also called slipring motor and another one with squirrelcage rotor. The basic idea of an electric motor is to generate two magnetic fields. For reason of economy, most houses, offices and also rural areas are supplied with single phase a. Extending binary properties to nary properties 12 8. The rotor of an induction motor can be a squirrel cage rotor or wound. This application note discusses the basics of an ac induction motor. It is based on freescales 56f800e microcontrollers. An induction motor is the most modest electrical machine from constructional point of view, in the majority of the cases.
Then, equation 1 can be shown in terms of magnitude as. Nov 03, 2019 an induction motor also known as an asynchronous motor is a commonly used ac electric motor. The threephase induction motor is the extensively used for various kinds of industrial drives. In this application note, we will generate a third pwm in software, using a general purpose timer and an io pin resource that are readily available on the picmicro microcontroller. Physical layout of induction motor in an induction motor induction refers the field in the rotor is induced by the stator currents and asynchronous refers that the rotor speed is not equal to the stator speed. From the equation 1 it is clear that the motor speed can be changed by a change in frequency f, a number of poles p, and slip s. An887, ac induction motor fundamentals microchip technology. Induction machines notes from jane courtney operation the induction machine behaves like a transformer, transferring electrical energy from the stator to the rotor. Induction motors are referred to as asynchronous motors because they operate at a speed less than their synchronous speed. Moduleiv 10 hours single phase induction motor, theory of operation double revolving field theory, equivalent circuit, determination of parameters methods of starting, split phase starting, repulsion starting, shaded pole starting, performance characteristics. The theory used in the work was collected by studying literature on how electrical motors work, and by simplifying the.
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