Characteristics of induction motors nidec corporation. Lecture series on basic electrical technology by prof. This document is highly rated by electrical engineering ee students and has been viewed 2516 times. One bench mounted multirange dc power supply psw 2504. Understand the principle and the nature of single phase and 3 phase induction machines. Noload and blocked rotor test on an induction machine. The motor then runs as a singlephase induction motor. 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. They are found everywhere from a small workshop to a large manufacturing industry. Three phase ac induction motors are widely used in industrial and commercial applications. View notes l29nkdet ee nptel from eso 203 at iit kanpur. Gradually apply three phase voltage across motor stator terminals via the autotransformer d.
The basic idea of an electric motor is to generate two magnetic fields. Speed control of a three phase induction motor using pwm. Module 8 threephase induction motor version 2 ee iit, kharagpur lesson 29 rotating magnetic field in threephase induction. Stator frame it is the outer most part of the three phase induction motor. In this module, containing six lessons 2934, mainly, the study of induction motors, fed from balanced threephase supply, will be described. And on the other hand, when designed to have a high impedance, the motor has an increased amount of torque in a lowspeed range. Induction motor works on the principle of induction where electromagnetic field is induced into the rotor when rotating magnetic field of stator cuts the stationary rotor.
Frequency of supply to the induction motor f pn120 12. Pdf basic electrical engineering 1st year ebook, notes. Rotating magnetic field in threephase induction motor nptel. In this case, power flows from the mechanical system, to the rotor circuit, then across the air gap to the stator circuit and external electrical system. For the latter two technologies, we consider the case of threephase power, which is generally preferred over singlephase because of much higher power density. Equivalent circuit of an induction motor enables the performance characteristics which are evaluated for steady state conditions. Record all nameplate information for the induction motor. The advantages of threephase ac induction motor are listed below. List and describe the more commonly used equipment in. The most popular type is the 3phase, squirrelcage ac induction motor. Induction motor basics, single phase and three phase.
Introduction types of electrical machines types of 3ph induction motor basic principle working principle compnents of induction motor application comparision between 1ph i. Its main function is to support the stator core and the field winding. Constructional details of a practical single phase transformer, core, winding. Single phase induction motor the singlephase induction machine is the most frequently used motor for refrigerators, washing machines, clocks, drills, compressors, pumps, and so forth. When a motor is designed in such a way that impedance of the aluminum conductor of the rotor is reduced, its efficiency is increased in a highspeed range. The rotor will constantly be turning to align its magnetic field with that of the stator field. Differentiate between the various types of generating electric power stations. Induction motors have been traditionally used as constant speed motors supplied by the ac power source. In three phase induction motor the magnitude of induced emf in rotor depends upon on the slip of induction motor.
The three phase induction motor is the extensively used for various kinds of industrial drives. Noload and blocked rotor test on an induction machine aim theory. These types of motors are known as selfstarting induction motors. Mostafa elshahed objectives learn a brief history of the electrical power systems construction. Synchronous motors are special types of motors used in constant speed applications, whereas most of the motors used in the industrial applications are of induction type. The voltage and current is induced in the rotor circuit from the stator circuit for the operation. Induction generators are also called as asynchronous generators.
Difference is that transformer is an alternating flux machine while induction motor is rotating flux machine. The stator circuit model of an induction motor consists of a stator phase winding resistance r 1, stator phase winding leakage reactance x 1 as shown in the circuit diagram below. Ppt threephase induction motor electrical engineering ee. Introduction induction motors are employed in textile mills, agriculture and almost all the manufacturing industries to drive the loads because of its rugged construction and ease operation. Construction of three phase induction motor electrical4u. It consists dc source amplitude is 500, three phase pwm inverter and three phase induction motor. The threephase induction motor is the extensively used for various kinds of industrial drives. Be careful it can hurt to tangle with a threephase motor. Find the percentage slip and number of poles of the induction motor. Induction machines guru nanak dev engineering college. Refer back to this diagram as the operational requirements of the singlephase motor are discussed.
It is very important that this brace be reinstalled exactly as it was originally, before the motor is moved from storage or any time when the motor is being transported. Three phase induction motor using written pole technology, main winding, exciter winding, control circuit for optimum utilization. Threephase induction motor, cage and wound slipring rotor, synchronous and rotor speed, slip, induced voltages in stator winding and rotor bar. Threephase or polyphase motors are of mainly two types. The rotor is either a wound type or consists of copper bars shortcircuited at each end, in which case it is known as squirrelcage rotor.
Shortcircuit rings are often combined with ventilating fans for cooling the motor. Before starting to explain how an induction asynchronous generator works, i assume that you know the working principle of an induction motor. Apr 30, 2020 ppt threephase induction motor electrical engineering ee notes edurev is made by best teachers of electrical engineering ee. 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 currents and create a rotor field which will interact with the stator field and produce rotation. The bars forming the conductors along the rotor axis are connected by a thick metal ring at the ends, resulting in a short circuit as shown in figure 1. This article concentrates only on a threephase induction. The drive shaft is located in the centre of the rotor. An electrical motor is an electromechanical device which converts electrical energy into mechanical energy. Ac induction motors are also the most common motors used in main powered home appliances. Almost 80% of the mechanical power used by industries is provided by three phase induction motors because of its simple and rugged construction, low cost, good operating characteristics, the absence of commutator and good speed regulation. 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. The rotor resistance and stand still reactance per phase are 0.
In figure 1 a cross section of the stator of a three phase, two pole induction. This would result in a balanced three phase current. These are of two types, squirrel cage and slip ring motors. The singlephase motor stator has a laminated iron core with two windings arranged perpendicularly. Nov 27, 2019 the three phase induction motor is the most widely used electrical motor.
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. A three phase, 12 pole, salient pole alternator is coupled to a diesel engine running at 500 rpm. There are two basic reasons for the use of singlephase motors rather than 3phase motors. This rotating magnetic field sweeps across the rotor conductors and hence an electromagnetic force emf. Equations 1 3 represent the currents that ow in the three phase windings. The conductors are heavy copper or aluminum bars fitted in each slot and shortcircuited by the end rings. Umanand, principal research scientist, power electronics group, cedt, iisc bangalore for more detail. Disconnect any mechanical load connected to the induction motor. Advantages of 3 phase induction motor generally easy to build and cheaper than corresponding dc or synchronous motors induction motor is robust. This paper presents design and analysis of a three phase induction motor drive using igbt. The singlephase induction motor is much the same in construction as the threephase motor. The 3phase set of currents, each of equal magnitude and with a phase.
One single phase wattmeter plus miscellaneous apparatus as needed. The motor then produces a constant torque and not a pulsating torque as in other singlephase motors. In an induction motor, the rotor rotates because of slip i. Threephase induction motor, cage and wound slipring rotor, synchronous and rotor speed, slip, induced voltages in stator winding and rotor barwinding.
Nov 27, 2019 an electrical motor is an electromechanical device which converts electrical energy into mechanical energy. Note down the machine ratings and calculate rated current of the machine noload test. Different types of starters for induction motor nptel. This pdf ebook notes on basic electrical engineering contains brief concise notes and will help you in your studies for your first year semester examination. The most common type of ac motor being used throughout the work today is the induction motor. Lecture 6 three phase induction motors cairo university.
Umanand, principal research scientist, power electronics group, cedt, iisc bangalore. General theory of induction motors nptel one, used for threephase induction motor will be presented. A three phase, 50 hz, 4 pole slip ring induction motor has a star connected rotor. You should also make a dc measurement of stator winding linetoline resistance. The three phase induction motor with written pole technology consists of two three phase stator windings and the ferrite layer on the rotor periphery.
It supplies an induction motor ich has a full load speed of 144wh 0 rpm. In a three phase induction machine, there are three sets of windings phase a winding, phase b and phase c windings. These are excited by a balanced three phase voltage supply. The principle of operation of a three phase induction motor using written pole technology depends on one set of.
The stator or the stationary part consists of three phase winding held in place in the slots of a laminated steel core which is enclosed and supported by a cast iron or a steel frame as shown in fig. Configuration of a motor with unequal number of stator and rotor poles. To this end, it will be assumed that the motor is a balanced three phase wye connected load and that you will therefore need to measure only one lineneutral voltage, only one line current, and only one phase power to characterize p in completely. Perform an analysis on induction machines which is the most rugged and the most.
Induction motor 1 chapter 3 induction motor bee23 electrical machine power system 2 learning outcomes. This paper proposes an alternative methodology for estimating the speed of a three phase induction motor driven by a voltage source inverter, using space vector modulation under the scalar control. Induction machines are by far the most common type of motor used in industrial, commercial or residential settings. 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. The induction motor stator resembles the stator of a revolving field, three phase alternator. Electrical machines i video course electrical engineering nptel. Module 8 threephase induction motor version 2 ee iit, kharagpur lesson 29 rotating magnetic field in. Threephase induction motor protection systems and its.
Circuit diagram for noload and blockedrotor test on 3 phase induction motor a. A successful salesman for general electrics motor division once remarked to one of your instructors that, when asked by a customer how a motor. The open circuit voltage on open circuit between the slip rings 0 volts. The three phase induction motor carries a three phase winding on its stator. At the end of the lecture, student should be able to. Dc source is connected to the dc side of the converter. This strange behavior of single phase induction motor can be explained on the basis of doublefield revolving theory. A three phase induction motor runs on a three phase ac supply. Here are the pdf lecture notes for the first year engineering subject basic electrical engineering. The rotor of the squirrel cage three phase induction motor is cylindrical in shape and have slots on its periphery. This three phase motor is accountable for larger load operations in several applications like goods and lifts hoists, conveyors, compressors, pumps, ventilation systems, industrial fan controllers, etc.
Applications of three phase induction motors of size varying from half a kilowatt to thousands of kilowatts are numerous. Dc motor, the ac induction motor, and the ac synchronous motor. Just like a dc machine, a same induction machine can be used as an induction motor as well as an induction generator, without any internal modifications. The three phase induction motor is also known as squirrelcage rotor due to its construc tion. They run at a constant speed from noload to the full load. The most popular type is the 3 phase, squirrelcage ac induction motor. The rotor of three phase induction motor consists of a cylindrical laminated core with parallel slots that can carry conductors. Theory and analysis of three phase induction motor using. However, recently, it has been increasingly used as variable speed motors driven by an inverter. These motors are selfstarting and use no capacitor, start winding, centrifugal switch or other starting device. Some singlephase induction motors are also called squirrel cage motors because of the rotors similarity.
The no load current i 0 is simulated by a pure inductive reactor x 0 taking the magnetizing component i and a noninductive resistor r 0 carrying the core loss. There are two basic reasons for the use of single phase motors rather than 3 phase motors. The three phase induction motors are simple in construction, rugged, low cost and easy to maintain. Starting of 3 phase induction motors, high starting torque motors, speed. Three phase induction motor drive using igbts and constant v. Vf speed control of 3 phase induction motor using space. Pdf speed control of induction motor using pi and vf. The sinusoidal stator phase currents fed in the stator coils create a magnetic field. For reason of economy, most houses, offices and also rural areas are supplied with single phase a. Due to the robust construction and ease of control, three phase asynchronous motors are widely preferred over many other motors for the ac motor driven applications. 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. This induced emf effectively decides the magnitude of rotor current. Ppt threephase induction motor electrical engineering.