It consists laminated cylindrical core which has a semiclosed slot at the outer periphery and carries threephase insulated winding. So, this motor is used in applications like lifts, pumps, mills where we require high starting torque. Oct 04, 2017 3 phase motor with resistance type starter. Good performance, such as high safety, energy saving, compact design, low noise, little vibration, high torque big breakaway torque, reliable operation, stable running and convenient maintenance. Fuzzy logic allows combining fuzzy information from different signals together to. Slip ring induction motor operation motion industries. Terms used in wound rotor slip the difference between a motors synchronous speed and its speed at full load. Slip of induction motor plays an important role in the operation of the induction motor. The slip ring motors in our mebsgr series that are described in the following text are in the ic 411 cooling class, known as surfacecooled or ribbedcooled. Fault identification of 3phase slip ring induction motor.
Dec 19, 2016 the torque speed curves are completely different between an induction motor and slip ring motor. Abb induction motors for the mining industry english pdf leaflet application note. The value of slip in induction motor at full load varies from about 6% for small motors to about 2% for large motors. Y designed to give equal resistance in each phase with special profile of fixed and moving electrodes.
A squirrel cage motor is thus preferred to a slipring motor. A stator is in all the motor only winding on the stator is vary with types of motor. The ac cage induction to the motor or the charthe slip ring motor is the mainstay of acteristics of the motor electrical drive systems. Starting and speed control of 3phase slipring induction. Slip in induction motor is the relative speed between the rotating magnetic flux and rotor expressed in terms of per unit synchronous speed. 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.
It is logical that the least expensive, lowest maintenance type motor should be used most often. But how does external resistance aid in better starting characteristics. Why we need to start induction motor using a starter or with one of starting methods. Portland slip ring induction motorsbrush holder problems and. Three phase slip ring induction motor is also known as a. Sketch of a crosssection of slip rings for an electric motor. Learn more about the construction and operation of a slip ring induction motor. Higher is the inertia, higher has to be the accelerating torque, otherwise the start will be very long and the motor can be damaged by the heating.
The slip ring induction motors usually have a phasewound rotor. Users occasionally inquire as to the feasibility of converting an existing woundrotor moto. Slip ring induction motor application slip ring induction motor provides high starting torque. The above block diagram shows the controlling of a three phase slip ring induction motor using programmable logic controller. Slip ring induction motor fundamentals pnpntransistor. Slip ring motor conversion to vsd driven standard squirrel cage ac motor by j van niekerk, zest weg group over a number of years slip ring motors have largely been replaced by standard squirrel cage ac induction motors, often in conjunction with ac variable speed drives vsds.
Pdf design and analysis of drive system with slip ring induction. This work has developed a steadystate and dynamic mathematical model of three phase slip ring induction motors with external impedance. Record all nameplate information for the induction motor. Slip ring induction motors are usually started by connecting starting resistance in the secondary circuit, which are shorted out as the motor speed up. 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. A slip ring can be used in any electromechanical system that requires rotation while transmitting power or signals. The slip ring induction motor has two distinctly separate parts, one is the stator and other is the rotor. What are the applications of a slipring induction motor. The starting of an induction motor does not relate to simple switching alone. In this example, the slip rings have a brushlifting device and a sliding contact bar, allowing the slip rings to be shortcircuited when no longer required. Free download induction motor seminar ppt, pdf report. Induction motor the downside of the slip ring motor is that slip rings and brush assemblies need regular maintenance, which is a cost not applicable to the standard cage motor.
Diagnostics of rotor and stator problems in industrial induction motors by fang duan b. Y provides smooth and stepless cutting of resistance in rotor circuit of the motor, reducing starting current and increasing starting torque of slipring induction motor. Dec 19, 2017 in this video you will learn connection of slip ring motor with starter panel now you can join our whatsapp group. Stator winding can be either star or delta connected depending upon the design. The bearing oil ring maintains lubrication when forcefeed oil supply fails, allowing the motor to come safely to a standstill. This means that the state of the carbon brushes and the slip ring rotor can be monitored, and cleaning can take place. Induction motors combine outstanding performance with an advanced longlife.
The catalogue covers slip ring induction motors called also wound rotor induction motors that are applied to start a high inertia load or a load that requires a very high starting torque across the full speed range. Torquespeed characteristics of three phase squirrel cage induction motor aim to obtain the torquespeed characteristics tn r of a three phase squirrel cage induction motor using 1. Scribd is the worlds largest social reading and publishing site. Induction motors have been ruling the industrial world for many decades. In slip ring induction motors the rotor is wound type. 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.
As discussed earlier, a slip ring induction motor is an asynchronous motor, as the rotor never runs in synchronous speed with the stator poles. Squirrel cage motors have a rotor with short circuited bars whereas slip ring motors have wound rotors having three windings each connected in star. How to maintain carbon brushes, brushholders, commutators and slip rings a major player in the industry worldwide, mersen o. If the external controller is set at zero resistance, the motor operates almost exactly the same as the squirrelcage motor, since the rotor is shortcircuited. If you have selected your slip ring motor to limit starting currents you can short out the slip rings and run your motor but the starting torque is reduced unless you use some features on the vfd to boost starting torque.
Construction of three phase induction motor electrical4u. In order to start a slip ring motor, the accelerating torque has to be sufficiently higher than the resisting torque. The most basic ways to control the speed of a slip ring induction motor is either from the. Generally, it is known as the asynchronous motor because its running speed is less than its synchronous speed. A slip ring, three phase induction motor rotates at a speed of 1440rpm, when a supply of 400v, 50hz is applied across the stator terminals. Differential equations are solved using computer simulation. Slip and motor current are reduced when the rotor begin turning. Maruthi prasad and others published rotor side control of high power slip ring induction motor using a single. The rotor will constantly be turning to align its magnetic field with that of the stator field. Woundrotor motors can be started with low inrush current, by inserting high resistance into the rotor circuit. Therefore slip ring induction motors are generally e. Slip ring motors are the motors of choice whenever high starting torque or low starting current are required.
The rotor winding terminals are connected to three slip rings which turn with the rotor. Inductive reactance depends on the frequency and the slip. The slip ring motor the motor has only one motor is the major moving part and if example of an induction the induction motor can designed and used motor which can offer be shown to have a. Carbon brush performance on slip rings mining electrical. A slipring motor also requires a larger space for the motor and its controls. Slip rings a conductive device attached to the end of a wound rotor that conducts current to the brushes. We can react very quickly due to a comprehensive stock of slip ring motors in a power range up to 15000 kw. Induction motor seminar ppt, pdf report study mafia. Pdf design and analysis of drive system with slip ring. Already since 1927, we are a global manufacturer, supplier, and distributor of large slip ring motors up to 15000 kw and,8 kv. It also requires meticulous and periodic maintenance of the brushes, brush gear, sliprings, external rotor resistances etc. The slip ring rotor chamber has two modification openings. Improve the speed characteristics of slip ring induction motor by.
Slip ring motor conversion to vsd driven standard squirrel. The slip ring motor has very little application in industries. Slip ring induction motor have big advantage of having high starting torque compared to squirrel cage motor. 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. The rotor will constantly be turning to align its magnetic field with the stator field. The motor which employing the wound rotor is known as a slip ring induction motor or phase wound motor.
This guide is designed for the use of all professionals in indus. Cylindrical laminated core rotor is wound like winding on the stator. Abb slipring modular motors abb high voltage induction motors. These motors can be also applied in drives where limited speed regulation is required. Fault identification of 3phase slip ring induction motor free download as powerpoint presentation.
Pdf the use of squirrel cage motor for traction has revolutionised the motive power of a locomotive. Nov 27, 2019 the three phase induction motor is the most widely used electrical motor. Home category electrical engineering mcq questions and answers 3 phase induction motors 1 the frequency of the induced emf in an induction motor is a. The rotor core is made up of steel laminations which have slots to accommodate formed 3single phase windings.
Slip ring motor manufacturer menzel provides shortterm availability and adaptation, applicationspecific requirements and worldwide logistics. The construction of a stator is the same for both the squirrel cage and slip ring induction motor. Abstract condition monitoring of slipring induction motor have been a challenging. The rotor is wound for the same number of poles as that of the stator. Starting of slip ring induction motor explained in an easy manner. If the rotor windings are shorted and a start is attempted i. Tuesday, october 25, 2016 the main difference between slip ring and cage types is that the slip ring rotor generally has a much lower slip at full speed than the cage rotor if it is properly shorted directly at the rings.
Squirrel cage wound rotor with slip rings the rotating magnetic field. Induction motor as an extension to the available non slip power recovery mechanisms available for. The slip ring induction motor working in the induction principle. A woundrotor motor, also known as slip ring rotor motor, is a type of induction motor where the rotor windings are connected through slip rings to external resistance. Induction motors generally will have low starting torque compared to dc series motor. Y available in various sizes for motors upto 5000 kw. Also know about the qualities of slip ring induction motors. Slip ring motor fundamentals brighthub engineering. This article is devoted to slip ring induction motors. If the slip ring induction motor is started with all the slip rings or the rotor.
The works of the stator is common in all motor to develop a magnetic field. Percent slip is a way to measure the speed performance of an induction motor. Rotor induction motor an overview sciencedirect topics. The slip ring rotor chamber of the ic 411 slip ring induction motor is separated by what is known as a labyrinth seal, which prevents contamination from coal dust. The stator is the outer component of the motor which can be seen.
Slip ring induction motors slip ring motor starter moflon. Cage induction motor an overview sciencedirect topics. Wound rotor with slip rings the rotating magnetic field the basic idea of an electric motor is to generate two magnetic fields. Slipring induction motors utilize a wound rotor that features steel laminations. Design and analysis of drive system with slip ring induction motor for electric traction in india article pdf available in international journal of power electronics and drive systems 53. If the 3phase slip ring induction motor is started as a normal motor with the slip rings shorted, due to low starting torque of slip ring motor, the motor will draw high current i. You should also make a dc measurement of stator winding linetoline resistance using a dmm. The torque produced by the induction motor is directly proportional to induction motor slip. Wound rotor induction motors with three rotor slip rings have been used in adjustable speed drives for many. A slip ring is an electromechanical device that allows the transmission of power and electrical signals from a stationary to a rotating structure.
The difference is that, in the case of the induction motor, the secondary windings can move due to the rotation of the rotor the secondary winding of the im, the induced voltage in it does not have the same frequency of the stator the primary voltage 3192014 emdii induction motor design. This final thesis will mostly be dedicated to induction motors but also to synchronous permanent magnet and reluctance motors. How to convert a slip ring motor into squirrel cage motor quora. They are especially suitable for heavy load inertia applications. Figure 4 shows the torquespeed characteristics of slip ring induction motor in modified static kramer drive. Slip ring induction motor is also known as wound rotor induction motor.
The construction of the slipring induction motor is exactly similar to the construction of squirrel cage induction motor. Telecommunication engineering, southwest jiaotong university, china, 2005 thesis submitted for the degree of masters of engineering science in school of electrical and electronic engineering the university of adelaide, australia august 2010. 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. The slip ring induction motor could be used for industrial wires where variable speed and high starting torque are prime requirements. Makwana and others published three phase slip ring induction motor drive with slip power control analysis for different load torque using microsoft excel as software.
It is very commonly used in industries because it is very cheap, robust, efficient, and reliable. This can be used in starting a slipring induction motor, for example. The scheme is somewhat analogous to a primitive kramer system, where a dc motor is coupled to the induction motor shaft and is fed by the rectifier slip power through a diode rectifier. Torquespeed characteristics of three phase squirrel cage. Compared to squirrel cage rotor the rotor construction is not simple. Adjusting the resistance allows control of the speedtorque characteristic of the motor.
If the slip of 3 phase induction motor is increases, the current in its stator winding a. The basic idea of an electric motor is to generate two magnetic fields. Y requires minimum initial investment and negligible maintenance. There is no difference between squirrel cage and slip ring motors. Read here to know about the starting arrangement and the role played by the external resistances in obtaining better starting characteristics. Hence, the three phase wound rotor slip ring induction motor competes favourably with the squirrel cage induction motor counterpart as the most widely used threephase induction motor for industrial applications.
Home operating characteristics of a woundrotor slipring induction motor fig. Slip ring induction motor working principle electrical mastar. Transient analysis of threephase wound rotor slipring. Be specially designed for energy saving purpose which is totally enclosed and fancooled type. If the ohmic values of these resistances are properly chosen and if the resistors are designed for continuous operation, they can serve dual purpose i. Three phase slip ring induction motor my tech info. Generally, induction motor provides low starting torque as compared to d. There is no difference between squirrel cage and slip ring. 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. To prevent oil vapor ingress into the motor enclosure, the inner side of bearing endshield is provided with additional motor seal. Pdf three phase slip ring induction motor drive with.
Slip in electrical induction motors slip is the differentiation between synchronous and asynchronous speed. The stator circuit is rated as same in the squirrel cage motor, but the rotor is rated in frame voltage or short circuit current. Condition monitoring of slipring induction motor ijirae. Diagnostics of rotor and stator problems in industrial. Operating characteristics of a woundrotor slipring. C series motors but this disadvantages of the induction motor can be overcome by slip ring induction motor. The stationary part of the motor is called stator and rotary part of the motor is called rotor. Slip power recovery system in three phase slip ring. Slip in electrical induction motors engineering toolbox. Introduction types of electrical machines types of 3ph induction motor basic principle working principle compnents of induction motor application comparision between 1ph i.
There are two types of induction motors, one with wound type rotor, also called slip ring motor and another one with squirrelcage rotor. It consists of plc board which has input and output ports, contactors which are used for either to close or to openthe terminals and one three phase slip ring induction motor. When a motor starts to rotate the slip is 100 % and the motor current is at maximum. Pdf rotor side control of high power slip ring induction motor. Most important mcq or objective questions on induction motor are discussed in this page. Starting of squirrel cage induction motors contents 4. Squirrelcage rotor almost 90 per cent of induction motors are squirrelcage type, because this type of rotor has the simplest and most rugged construction imaginable and is almost indestructible. Can a slip ring motor run through a variable frequency drive. Apr 11, 2017 induction motors generally will have low starting torque compared to dc series motor. An ac alternating current induction motor consists of a stator and a rotor and the interaction of the currents flowing in the rotor bars and the rotating magnetic field in the stator generates the torque that turns. By far the most commonly used ac motor is the induction motor.
A slip ring induction motor can be started with external resistance added in its rotor circuit. A slipring motor is expensive, as are its controls, compared to a squirrel cage motor. This type of rotor is provided with a 3phase, doublelayer, distributed winding consisting of coils used in alternators. The value of slip in induction motor is can never be zero.
1463 1440 444 1022 606 314 244 354 1059 574 1317 712 1123 597 271 87 1353 871 726 1435 116 1480 912 1457 1405 611 911 453 367 859 77 97 102 220 495