Slip ring induction motor are used where high starting torque is required i. Teco totally enclosed fan cooled squirrelcage induction motors are designed, manufactured and tested to meet or exceed the latest nema, ieee, csa and other international standards. Scribd is the worlds largest social reading and publishing site. The rotor winding terminals are connected to three slip rings which turn with the rotor. Fullload slip varies from less than 1 % in high hp motors to more than 56 % in minor hp motors. Also know about the qualities of slip ring induction motors. For load sharing to take place automatically, the motor speed should drop considerably as the load increases and this is ensured by using a motor having a high fullload slip, say for example 10%. Nov 03, 2019 an induction motor also known as an asynchronous motor is a commonly used ac electric motor. Read here to know about the starting arrangement and the role played by the external resistances in obtaining better starting characteristics. Induction motors generally will have low starting torque compared to dc series motor.
Squirrel cage motors have a rotor with short circuited bars whereas slipring motors have wound rotors having three windings each connected in star. The slipring motor or woundrotor motor is a variation of the. In slip ring induction motors, the shape of the torquespeed curve can be changed by introducing extra resistance into the rotor of the motor. Woundrotor motors can be started with low inrush current, by inserting high resistance. Figure 4 shows the torquespeed characteristics of slip ring induction motor in modified static kramer drive. A photograph of a wound rotor for an induction machine is shown in fig. Pdf the use of squirrel cage motor for traction has revolutionised the motive power of a locomotive. Percent slip is a way to measure the speed performance of an induction motor. Condition monitoring of slipring induction motor nanopdf. Pdf design and analysis of drive system with slip ring induction. But in an induction motor only the stator winding is fed with an ac supply. By putting resistance in series with the rotor windings, the starting current can be kept low while mainta.
Slip ring induction motor working principle electrical mastar. Low and high voltage three phase induction motors m line slip ring rotor date. It is very commonly used in industries because it is very cheap, robust, efficient, and reliable. The aim behind the development of the project is to limit the current at starting of motor and to develop the high starting torque. Rotor side control of high power slip ring induction motor using a. Squirrelcage rotor almost 90 per cent of induction motors are squirrelcage type. To understand the performance such as torque, speed, current, powerfactor, slip, and efficiency of 3phase slip ring induction motor in loaded configuration. Possibility of adding additional resistance to control speed.
Slipring induction motor connection and testing youtube. 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. The rotor of the slip ring induction motor is also cylindrical or constructed of lamination. Slip in electrical induction motors engineering toolbox. Ppt induction motor powerpoint presentation free to. Severe arcing between the brushes and collector rings. 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. So, it is not advised to start a slip ring induction motor with its rotor terminals shorted. These motors are suitable for all general applications where an open machine is not applicable due to severe environments such as excessive dirt, dust andor moisture. Slip ring motors contents product description 62 overview of technical data 64 motor selection data series srspr variablespeed slip ring motors, continuous duty s1 65 series shsph version for crane applicationsiron and steel works, duty types s3, s4s5 67 bearings 626 terminal boxes 631. This method depends on having a huge starting torque and a small starting current and slip.
This motor is much heavier than the 22kw slip ring motor and resistor bank so the crane had to be rerated as well. This article is devoted to slip ring induction motors. The rotor core is made up of steel laminations which have slots to accommodate formed 3single phase windings. Starting of slip ring induction motor explained in an easy. A slip ring is an electromechanical device that allows the transmission of power and electrical signals from a stationary to a rotating structure. Slip power recovery system in three phase slip ring. As the rotor rotates the brushes slip over the rings and provide means of connecting stationary external circuit elements to the rotating windings. How an squirrel cage motor can be converted to a slip ring. As its name indicates stator is a stationary part of induction motor.
Portland slip ring induction motorsbrush holder problems and. Motors employing this type of rotor are known as squirrelcage inductionmotors. Smooth starting of slip ring induction motors article pdf available in ieee transactions on energy conversion 124. The ac cage induction to the motor or the charthe slip ring motor is the mainstay of acteristics of the motor electrical drive systems.
This regulation specifies the eco design requirements for 2, 4 and 6pole lowvoltage threephase asynchronous motors in the output range from 0. In a dc motor, supply is needed to be given for the stator winding as well as the rotor winding. The rotor of an induction motor can be a squirrel cage rotor or wound. Fault identification of 3phase slip ring induction motor. Kirloskar brothers limited an overview of manufacturing units of kbl k i r l o s k a r va d i, m a h a r a s h t r a s h ri v a l, m a h a r a s h t r a d e w a s, m a d h y a p r a d e s h k o n d h a p u r i, m a h a r a s h t r a 02. The terminals of the rotor windings of the slipring motors. Number of poles, frequencies and synchronous induction motor speed. They are especially suitable for heavy load inertia applications. Stator winding can be either star or delta connected depending upon the design. Objectives to understand the load characteristic of 3phase slip ring induction motors. Sep 09, 2017 first of all, both the motors are different from the construction and design point of view.
All motors comply with the following indian and international standards. Slip ring induction motor application slip ring induction motor provides high starting torque. Advantages and disadvantages of slip ring 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. Adjusting the resistance allows control of the speedtorque characteristic of the motor. Generally, it is known as the asynchronous motor because its running speed is less than its synchronous speed. Installation, operating and maintenance instructions three.
C series motors but this disadvantages of the induction motor can be overcome by slip ring induction motor. There is a high risk that partial discharge will break down the winding isolation material causing flashover if it is not designed for vfd. Slip power recovery system in three phase slip ring induction. Starting torque of slip ring motor and induction motor. 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. Slip ring motor fundamentals bright hub engineering. A slip ring can be used in any electromechanical system that requires rotation while transmitting power or signals. Construction of three phase induction motor electrical4u. Generally we all are know induction motor is most widely used motor in industrial. Most of the application of industrial as well as domestic are this type of induction motor. As discussed earlier, a slip ring induction motor is an asynchronous motor, as the rotor never runs in synchronous speed with the stator poles.
The rotor terminals are connected to three slip rings which turn. Wound rotor with slip rings the rotating magnetic field. Learn more about the construction and operation of a slip ring induction motor. Squirrel cage induction motor slip ring induction motor 2. A slip ring induction motor can be started with external resistance added in its rotor circuit. Depending upon the type of rotor construction used the three phase induction motor are. A slip ring motor is normally not designed for the extreme high dudt values stressing the winding insulation at vfd drive fast switching. The construction of a stator is the same for both the squirrel cage and slip ring induction motor. Lecture 6 three phase induction motors cairo university. Slip rings a conductive device attached to the end of a wound rotor that conducts current to the brushes. Threephase ac induction motors are widely used in industrial and commercial applications. The three phase induction motors are simple in construction, rugged, low cost and easy to maintain.
Abb library is a web tool for searching for documents related to abb products and services. Sketch of a crosssection of slip rings for an electric motor. Aim to understand the function of the 3phase slip ring induction motors and how it is work when its characteristic getting changes. The induction motor stator resembles the stator of a revolving field, three. The slip ring induction motor could be used for industrial wires where variable speed and high starting torque are prime requirements. 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. You have most likely difficulties to get a slip ring motor replaced when it cant be no longer reworked. Adding external resistance to the rotor of a slip ring induction motor, makes the rotor resistance high. Terms used in wound rotor slip the difference between a motors synchronous speed and its speed at full load. So, this motor is used in applications like lifts, pumps, mills where we require high starting torque. If the motor slip is known, the rotor speed can be expressed by the equation. This paper describes a new form of polyphase induction motor, the series hysteresis motor, which derives most of its. When a motor starts to rotate the slip is 100 % and the motor current is at maximum.
Sometimes 2 additional for shunt field terminals cabinet type and position dc field supply required. 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. Wound rotor induction motor variable speed three phase windings in stator rotating magnetic field three phase windings in rotor three phase variable frequency current induced in rotor rotor current brought out to variable resistanceelectronic controls through brushes on three slip rings to control speed. Slip ring induction motor working principle electrical. Slip ring modular motors from abb, availability for heavy load inertia applications. The squirrel cage induction motor is the most popular type of ac motor. Design and analysis of drive system with slip ring induction motor for electric traction in india.
Three phase induction motors electric motors bharat bijlee. Starting andcontrol of slipring 5 electrical engineering book. Even by replacing the rotor if you find a way to use the same stator for the new rotor slip ring type there would be a difference in the power rating an. Generally, induction motor provides low starting torque as compared to d. Slip ring rotor or wound rotor or phase wound rotor. Already since 1927, we are a global manufacturer, supplier, and distributor of large slip ring motors up to 15000 kw and,8 kv. Slip ring motors with resistor starter have been a standard solution to achieve a kind of soft start, when either reduction of start motor current or torque is required, used for 50 years or so. Woundrotor motors can be started with low inrush current, by inserting high resistance into the rotor circuit. Vibrations amplifications on the unsupported shaft extensions of the rotors. Manual for induction motors and generators, french.
This type of rotor is provided with a 3phase, doublelayer, distributed winding consisting of coils used in alternators. Short out the slip rings and the motor will run just like a standard induction motor. Slip in induction motor is the relative speed between the rotating magnetic flux and rotor expressed in terms of per unit synchronous speed. Cad library electric motors 2d3d drawings cad library automation 2d. The slip ring rotor chamber has two modification openings. General purpose slipring induction motors product catalogue. Dec 01, 2017 slipring induction motor also known as rotor resistance start motor. Some changes in the stator may be encountered when a slip ring motor is used in a cascaded system, as the supply for the slave motor is controlled by the supply from the rotor of the other slip ring motor with external resistance mounted on its rotor. Pdf this work has developed a steadystate and dynamic mathematical model. Motors employing this type of rotor are variously known asphasewound motors or wound motors or as slip ring motors. Keywords artificial intelligence techniques for fault diagnosis, condition monitoring, fault detection and diagnosis. Three phase slip ring induction motor my tech info. Slip ring induction motor have big advantage of having high starting torque compared to squirrel cage motor.
This means that the state of the carbon brushes and the slip ring rotor can be monitored, and cleaning can take place. In previous articles i have discussed the construction, operation, starting, speed control, and classes of squirrel cage induction motors. Slip ring motor conversion to vsd driven standard squirrel. Thyristor, slip ring induction motor srim, stator and rotor, polyphase motor, universal. Starting torque of slip ring motor and induction motor with. Slip ring motor 5 frame size rated power duty cycle rated speed stator current rotor voltage rotor current pn kw % ed nn min1 i1 a u2 v i2 a 3en315sg 04 90 100 1478 171 310 177. Low and high voltage three phase induction motors slip ring rotor fixed brushholderm line date. It can improve mechanical performance, simplify system operation and eliminate damageprone wires dangling from movable joints.
Therefore slip ring induction motors are generally employed where load requires high starting torque or good speed control. 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. The main difference in a slip ring induction motor is on the rotor construction and usage. Carbon brush performance on slip rings mining electrical. The slip ringsbrushes allow external resistors to be connected in series with the winding. Induction motor seminar ppt, pdf report study mafia. Pdf rotor side control of high power slip ring induction motor. The individual eco design requirements are scheduled as follows. The slip ring motor has very little application in industries.
Dec 19, 2016 this motor is much heavier than the 22kw slip ring motor and resistor bank so the crane had to be rerated as well. Lecture notes institute of aeronautical engineering. The value of slip in induction motor is can never be zero. Slipring induction motor also known as rotor resistance start motor. But how does external resistance aid in better starting characteristics. There are different methods of starting of 3phase slip ring induction motor.
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. Fault identification of 3phase slip ring induction motor free download as powerpoint presentation. An887, ac induction motor fundamentals microchip technology. Slip ring induction motor fundamentals pnpntransistor. Free download induction motor seminar ppt, pdf report. 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. Advantages of slip ring induction motor it has high starting torque and low starting current. 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. These are of two types, squirrel cage and slip ring motors. For existing synchronous motors to be applied to vfd operation, the synchronous motor must have its dc.
The slip rings brushes allow external resistors to be connected in series with the winding. This can be used in starting a slip ring induction motor, for example. Slip ring motors are normally used where additional torque is required to overcome the inertia of the. Slip ring motors are the motors of choice whenever high starting torque or low starting current are required.
The slip ring induction motor has two distinctly separate parts, one is the stator and other is the rotor. Rarely 5% 10% slip ring motors are used in industries because it has several disadvantages like it required. 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. Feb 20, 2014 terms used in wound rotor slip the difference between a motor s synchronous speed and its speed at full load. Cheap copare to slipring im maintainance is easy cost is less compare to slipring im can use at explosive area starting torque is low compare to slip ring im application. A stator winding is placed in the stator of induction motor and the three phase supply is given to it. Abb library is a web tool for searching for documents related to abb products and. Some sections may explain explicitly between the three configurations, but have different requirements for each.
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