Slip compensation of induction motor using sensorless control ieice. This final thesis will mostly be dedicated to induction motors but also to synchronous permanent magnet and reluctance motors. A 3 phase induction motor can be used for different applications with various speed and load requirements. You also come to know about the law on which the motor works, the types of field induces on the rotor, and. In fact, an induction motor can be treated as a rotating transformer i. Electrical interview questions which motor is best. Threephase induction motors are the most common and. The 3phase set of currents, each of equal magnitude and with a phase.
That is why such motors are known as induction motors. A 480v, 60 hz, 6pole, threephase, deltaconnected induction motor has the following parameters. As previously, we have covered a lot of important topics. Mar 11, 2017 what is slip in an induction motor, how it is calculate and all the details about slip in an induction motor is given in this video watch other videos. Slip is defined as difference between synchronous speed speed of rotation of magnetic field and rotor speed speed of rotatory part of induction motor. Introduction types of electrical machines types of 3ph induction motor basic principle working principle compnents of induction motor application comparision between 1ph i.
Construction of three phase induction motor electrical4u. No contacts on rotor shaft high powerweight ratio compared to dc motor lower costpower easy to manufacture almost maintenance free, except for bearing and other mechanical parts disadvantages essentially a fixedspeed machine speed is determined by. How an induction motor works by equations and physics. According to the type of rotor, an induction motor is divided into two types. The three phase induction motor is the most widely used electrical motor. What are four possible causes if the brushes for a slip. Fault identification of 3phase slip ring induction motor free download as powerpoint presentation. Motion and temperature heat control are paramount in energy.
The basic idea of an electric motor is to generate two magnetic fields. Electrical motor electric motor electromagnetic induction. 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 a humming b hunting c crawling d cogging ans. A variable frequency ac induction motor servo control system wherein slip is generated as a function of stator current. How do the new ie efficiency classes compare with the old eff efficiency classes. Protection of induction motor free download as powerpoint presentation.
Induction motor seminar ppt, pdf report study mafia. If slip is zero then their is no relative speed between stator and rotor. An induction motor also known as an asynchronous motor is a commonly used ac electric motor. Stator winding can be either star or delta connected depending upon the design. In turn, a current is produced in the rotor bars and shorting ring and another magnetic field is. Previously we shared the book on ac motors which explains all these properties briefly, this post is focused on the induction motor formulas and calculation examples. Induction motor equations engn1931f spring 2017 2 let. When a motor starts to rotate the slip is 100 % and the motor current is at maximum. Fullload slip varies from less than 1 % in high hp motors to more than 56 % in minor hp motors. The rotor and stator are separated by an air gap which allows free rotation of the rotor. The singlephase induction motor is the most frequently used motor for refrigerators, washing machines, clocks, drills, compressors, pumps, and so forth. For your splitphase motor lab, you may assume the free running current and power represent the zeroslip. Jun 01, 2018 slip in induction motor is the relative speed between the rotating magnetic flux and rotor expressed in terms of per unit synchronous speed. Lecture notes electrical machine ii bee 1401 page 1.
Download 3 phase induction motor powerpoint presentation. 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. So, now principle of induction motor right so, the operation of three phase induction. To start induction motor by rotor resistance starter 8. The slip ring induction motor could be used for industrial wires where variable speed and high starting torque are prime requirements.
The difference multiplied with hundred and divisible by the synchronous speed is called the slip percentage. 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. In this article, i will discuss which motor is best to use, the squirrel cage motor is best or slip ring induction motor is best. But producing goods and services is strongly related to the use of energy in an intelligent way. By far the most commonly used ac motor is the induction motor. Fall 2005 ee595s electric drive systems 36 the plan continued achieving 14. Free download induction motor seminar ppt, pdf report. Formula to calculate ac induction motor slip speed.
The stator of slip ring induction motor is very much the same as that of the squirrel cage induction motor, but the construction of its rotor is very much different. An induction motor can be defined as the ac electric motor device in which a power source fed by the alternating current with the help of a primary winding. It is logical that the least expensive, lowest maintenance type motor should be used most often. The construction of stator of the induction motor is almost the same as other motors. Number of poles, frequencies and synchronous induction motor speed. I will also discuss the advantages and disadvantages of squirrel cage and slip ring induction motor, and conclusion. What happens in the value of a slip from noload to a full. Therefore, the rotor thus cannot reach the synchronous speed ns it will slip. It is a maintenance free, less noisy and efficient motor. Induction motor equations engn1931f spring 2017 5 for low slip frequencies, the power of the motor is simply proportional to the product of the square of the gap field strength with the volume of the rotor and the noload speed of rotation.
As discussed earlier, a slip ring induction motor is an asynchronous motor, as the rotor never runs in synchronous speed with the stator poles. It is logical that the least expensive, lowest maintenance type. The value of slip in induction motor at full load varies from about 6% for small motors to about 2% for large motors. You should also make a dc measurement of stator winding linetoline resistance using a dmm. But the rotor construction differs with respect to the type of motor. S l r the flux in the singleturn coil on the rotor surface is. The rotor will constantly be turning to align its magnetic field with that of the stator field. Jan 11, 2018 such properties include a number of poles, speed, frequency, slip, starting current and rated horsepower.
It seems very odd that you want exactly four answers. The stator is the outer component of the motor which can be seen. Slip in electrical induction motors engineering toolbox. 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. This curve provides us with information about the operation of an induction motor. If the emf in the rotor of an 8 poles induction motor has a frequency of 1.
Electrical motor free download as powerpoint presentation. When a three phase induction motor connected to a single phase power supply using the steinmetz connection operates in a practical noload condition, not all windings consume active power. Slip ring induction motor is made up from wound rotor and squirrel cage induction motor is made up from the squirrel cage rotor. If the slip is zero, what is the speed of a induction motor. The value of slip in induction motor is can never be zero. L r s and be the angular velocities of the magnetic field line frequency, rotor, and slip respectively. In this video, i will explain you about the working of the threephase induction motor. The performance calculation by means of finding torque, slip and efficiency. An induction motor, 3 phase 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. Speed control of induction motor detailed explanation. Squirrel cage rotor wound type rotor or slip ring type rotor squirrel cage rotor in this type. Induction motor 1 induction motor why induction motor im.
Malagoli and others published optimal volume and slip of a three phase induction motor using differential. The maximum torque that the motor can develop typically 2. A 4 pole, 3 phase induction motor is supplied from hz supply. There are two types of induction motors, one with wound type rotor, also called slipring motor and another one with squirrelcage rotor. Pdf optimal volume and slip of a three phase induction motor. The rotor of the slip ring induction motor is also cylindrical or constructed of lamination.
Menzel 3phase slip ring induction motors in protection class ip 55 are designed in the ic 411 cooling class. Motor runs smoothly as the magnetic hum is reduced b. Nov 27, 2019 the three phase induction motor is the most widely used electrical motor. Rotor induction motor an overview sciencedirect topics. Generally, it is known as the asynchronous motor because its running speed is less than its synchronous speed. Slips can be defined as the difference between the flux speed ns and the rotor speed n. Now, if the conducting ladder is free to move now you are allowing to move. A stator is in all the motor only winding on the stator is vary with types of motor. When a three phase induction motor connected to a single phase power supply using the.
Such properties include a number of poles, speed, frequency, slip, starting current and rated horsepower. The torque produced by the induction motor is directly proportional to induction motor slip. Introduction to induction motor the engineering projects. Today we are going to made available a powerpoint presentation file for all. Slip of induction motor plays an important role in the operation of the induction motor. Slip, which varies from zero at synchronous speed and 1 when the rotor is at. The tendency of the rotor teeth to remain under the stator teeth due to direct magnetic attraction is reduced. Ppt induction motor powerpoint presentation free to. Rotor as the name suggests it is a rotating part of an electrical machine, in which current is induced by transformer action from rotating magnetic field. Concluding, advantage of induction motor is its simple operation, reliability and low cost. Electric energy and induction motors the level of prosperity of a community is related to its capability to produce goods and services. To understand the torque slip characteristics of induction motor we should focus on mathematics relations. S nsnrnsx100% ns synch speed nr rotor speed sslip slip increase with increase of mechanical load. Slip of induction motor electrical engineering interview.
In early slipring induction motor drives, power was transferred through the motor to be dissipated in external resistances, connected to the slip ring terminals of the rotor. As we know, the slip speed is the difference between the synchronous and rotor speed of the induction motor. The most popular type is the 3phase, squirrelcage ac induction motor. No slip, no torque because there will be no current in the rotor cage. In these types of motors the start winding can have a series capacitor andor a. As we know the speed of induction motor, torque of induction motor, so, the speed of induction motor can be changed by changing synchronous speed or by changing the slip of induction motor and then parameter r2 and x2 are changed then torque remain constant and change in slip is affected in speed control.
An induction motor can therefore be made without electrical connections to the rotor. The construction of a stator is the same for both the squirrel cage and slip ring induction motor. 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 slip of the induction motor varies from 5 percent for small motors to 2 percent for large motors. More than selection from electrical machine design book. Speed of the rotor of an induction motor is always less than its synchronous speed. Slip of an induction motor is negative when a magnetic field and rotor rotate in opposite direction. The speed of an ac motor depends on the frequency of the input power and the number of poles for which the motor is wound. Squirrel cage motors have a rotor with short circuited bars whereas slipring motors have wound rotors having three windings each connected in star. Slip s can be defined as the difference between the flux speed ns and the rotor speed n.
In an induction motor, torque is equal to the power crossing the air gap divided by the synchronous mechanical speed. Typical induction motor rotors the magnetic field generated in the stator induces an emf in the rotor bars. The stator works as the primary while the rotor works as the secondary. Slip speed of an ac induction motor is a small difference between the synchronous speed of the rotating magnetic field and actual speed of the rotor, generally measured in rpm. In a preferred embodiment the slip per ampere ratio is constant in the range from zero to approximately base speed and thereafter increases exponentially as. Record all nameplate information for the induction motor.
Nov 11, 2017 torque slip characteristics of induction machine pull out torque, breakdown torque, motoring mode, generating mode, breaking mode of induction motors, electric motor torque curve torque speed. Learn more about the construction and operation of a slip ring induction motor. Fall 2005 ee595s electric drive systems 2 overview of strategies voltsperhertz control constant slip control fieldoriented control. Protection of induction motor relay fuse electrical.
There are two types of induction motors, one with wound type rotor, also called slip ring motor and another one with squirrelcage rotor. The most commonly used is the squirrel cage induction motor. Torque slip characteristics of induction motor full guide. Slip in induction motor is the relative speed between the rotating magnetic flux and rotor expressed in terms of per unit synchronous speed. All we need to do is to keep daxis stator current constant. Higher protection classes can be realized on request at any time. The slip corresponding to full load speed of th motor is called full load slip. The generally humidityprotected motor winding is designed to be in thermal class f and is impregnated using the vpi process. To explain clearly when there is relative speed between stator and rotor ample amount of emf is induced in th. Squirrel cage rotor wound type rotor or slip ring type rotor squirrel cage rotor in this type rotor as the name suggests it is a rotating part of an electrical machine, in which current is induced by transformer action from rotating magnetic field. Three phase slip ring induction motor my tech info.
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