A wound rotor or slip ring motor has a 3phase winding, similar to the stator winding. Ac induction motors are the most common motors used in industrial motion control systems, as well as in main powered home appliances. An induction motor also known as an asynchronous motor is a commonly used ac electric motor. What are the applications of a slipring induction motor. The rotor of the slip ring induction motor is also cylindrical or constructed of lamination. In all singlephase induction motors, the rotor is the squirrel cage type.
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. The terminals of the polyphase winding are connected to slipring which are mounted on the shaft of rotor. Generally, induction motor provides low starting torque as compared to d. The stator construction is the same in both motors. A slip ring is an electromechanical device that allows the transmission of power and electrical signals from a stationary to a rotating structure. Single phase induction motor, theory of operation double revolving field theory, equivalent circuit, determination of. In the case of a squirrel cage induction motor, the rotor is inaccessible and rotor circuit resistance is xed, whereas the woundrotor machines are provided with slip rings. Simulation of 3ph induction motor in matlab with direct and. Explain the various schemes of starting squirrel cage induction motor.
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. So, this motor is used in applications like lifts, pumps, mills where we require high starting torque. Wound rotor induction motors chapter ac motors pdf version. 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. An887, ac induction motor fundamentals microchip technology. Type of induction motor for ac in which the rotor has wire winding. Apr 11, 2017 induction motors generally will have low starting torque compared to dc series motor.
Xd is the synchronous reactance of armature coil offered to the flow of direct axis. Starting andcontrol of slipring 5 electrical engineering book. The slip ring rotor chamber has two modification openings. Download slip ring induction motors basics book pdf free download link or read online here in pdf. The main disadvantage of an induction motor is that the speed of the motor varies with the applied load. This article is devoted to slip ring induction motors. The slip ring induction motor working in the induction principle. The theoretical principle behind production of mechanical force by the.
In the case of a squirrel cage induction motor, the rotor is inaccessible and rotor circuit. Sketch of a crosssection of slip rings for an electric motor. With the help of slip ring, one can add an external resistance into the circuit because of. Three phase slip ring induction motor my tech info. 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. C series motors but this disadvantages of the induction motor can be overcome by slip ring induction motor. Read here to know about the starting arrangement and the role played by the external resistances in obtaining better starting characteristics. The slip ring motor has very little application in industries. This final thesis will mostly be dedicated to induction motors but also to synchronous permanent magnet and reluctance motors. Portland slip ring induction motorsbrush holder problems and. With neat diagrams explains the working of any two types of starters used for squirrel cage type 3 phase induction motor. The two ends of the loop are connected to slip rings. Higher maintenance of brushes and slip rings compared to squirrel cage motor.
Oct 04, 2017 3 phase motor with resistance type starter. The rotor winding terminals are connected to three slip rings which turn with the rotor. There are two types of induction motors, one with wound type rotor, also called slip ring motor and another one with squirrelcage rotor. Slip ring induction motor application slip ring induction motor provides high starting torque. Percent slip is a way to measure the speed performance of an induction motor. Single phase induction motor double revolving field theory the threephase induction motor starting torque inversely depends on the slip this implies that a small positive slip 0.
A slip ring can be used in any electromechanical system that requires rotation while transmitting power or signals. Wound rotor induction motors ac motors electronics. 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. Slip ring induction motor working principle electrical mastar. Pdf three phase slip ring induction motor drive with. In my last article, we have discussed everything on squirrel cage induction motors including its disadvantages. Squirrel cage motors have a rotor with short circuited bars whereas slipring motors have wound rotors having three windings each connected in star. As we know, the slip speed is the difference between the synchronous and rotor speed of the induction motor. The singlephase stator winding produces a magnetic field that pulsates in strength in a sinusoidal manner.
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. The stator is the outer component of the motor which can be seen. Speed control of threephase slip ring induction motor by rotor. Wound rotor with slip rings the rotating magnetic field the basic idea of an electric motor is to generate two magnetic fields. Read online slip ring induction motors basics book pdf free download link book now. Another type is squirrel cage motor that has no wire winding and has no slip rings.
The armature reactance varies from xq to xd periodically. The slip ringsbrushes allow external resistors to be connected in series with the winding. 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. With over 35 years of experience, our business development specialist will introduce you to the basics of slip rings and how they are designed and.
Pdf the use of squirrel cage motor for traction has revolutionised the motive. Slip ring induction motor fundamentals pnpntransistor. Slip ring induction motors are usually started by connecting starting resistance in the secondary circuit, which are shorted out as the motor speed up. Stator winding can be either star or delta connected depending upon the design. When the stator windings are connected to a threephase balanced network, a rotating magnetic field is generated due to current passage through its coils in a speed that corresponds to the electrical source. The induction motor model is created according to a group of standard equations current, voltage, power, efficiency, speed 1, p 388 or 2, p 167p 200 and values developed and edited in the laboratory. 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. Do you know what happens to slip ring motor when external resistance is added.
Nov 03, 2019 due to the various advantages of an induction motor, there is a wide range of applications of an induction motor. Slip ring motor manufacturer menzel provides shortterm availability and adaptation, applicationspecific requirements and worldwide logistics. State the steps to draw the equivalent circuit of 3phase induction motor. Write the classification of 3phase induction motor. What is common to all the members of this family is that the basic physical process involved in their operation is the conversion of electromagnetic energy. Pdf design and analysis of drive system with slip ring induction. This module explains the theory of operation of ac motors and discusses the various types of ac motors and their application. The induction motor is made up of the stator, or stationary windings, and the rotor. Squirrel cage motor almost 90% of induction motors are squirrel cage motors. The three phase induction motors are simple in construction, rugged, low cost and easy to maintain. All books are in clear copy here, and all files are secure so dont worry about it.
As discussed earlier, a slip ring induction motor is an asynchronous motor, as the rotor never runs in synchronous speed with the stator poles. A 3 phase induction motor can be used for different applications with various speed and load requirements. Terms used in wound rotor slip the difference between a motors synchronous speed and its speed at full load. The rotor of an induction motor can be a squirrel cage rotor or wound type rotor. Squirrel cage induction motor slip ring induction motor 2. Ysalient features y robust and nonflammable construction. Slip rings a conductive device attached to the end of a wound rotor that conducts current to the brushes. The singlephase ac induction motor best fits this description. The slip ring induction motor could be used for industrial wires where variable speed and high starting torque are prime requirements. But how does external resistance aid in better starting characteristics. Also know about the qualities of slip ring induction motors.
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. State the condition for maximum torque of 3phase induction motor. 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. A stator is in all the motor only winding on the stator is vary with types of motor. 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. One of their biggest advantages is their high efficiency which can go as high as 97%. The construction of a stator is the same for both the squirrel cage and slip ring induction motor.
Slip ring motor fundamentals brighthub engineering. Slip in induction motor is the relative speed between the rotating magnetic flux and rotor expressed in terms of per unit synchronous speed. Speed control of wound rotor induction motor using rotor. The rotor winding terminals are connected to three slip rings which turn with. Hence slip ring motors are used where one or more of the above requirements are to be met. Discuss the various starting methods of induction motors. What is the working principle of slip ring induction motor. In a dc motor, supply is needed to be given for the stator winding as well as the rotor winding. We can react very quickly due to a comprehensive stock of slip ring motors in a power range up to 15000 kw. If the ohmic values of these resistances are properly chosen and if the resistors are designed for. This portable document format \ pdf \ file contains bookmarks, thumbnails, and hyperlinks to help you navigate through the document. Slip ring induction motor is made up from wound rotor and squirrel cage induction motor is made up from the squirrel cage rotor. Also appreciate the external resistances and carbon brush arrangements with the slip rings and advantages of slip ring induction motor.
One of the advantages of the slip ring motor is that resistance may be inserted in the rotor circuit to obtain high starting torque at low starting current and then cut out to obtain optimum running conditions. Design and analysis of drive system with slip ring induction motor for electric traction in india. So obviously the speed of an induction motor can be controlled by varying any of three factors namely supply frequency f, number of pole p or slip s. Why slip ring induction motor is preferred for high. But in an induction motor only the stator winding is fed with an ac supply. It is very commonly used in industries because it is very cheap, robust, efficient, and reliable. An induction motor can therefore be made without electrical connections to the rotor. The slip of the induction motor varies from 5 percent for small motors to 2 percent for large motors. Speed control of induction motors the speed of an induction motor is given as n 120fp 1s. Why slip ring induction motor is preferred for high starting torque application. Dec 19, 2017 in this video you will learn connection of slip ring motor with starter panel now you can join our whatsapp group. One of the main classifications of asynchronous motors are the slip ring induction motors. Also know about the special constructional features of the rotor.
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. Starting of slip ring induction motor explained in an easy. Simulation of 3ph induction motor in matlab with direct. Learn more about the construction and operation of a slip ring induction motor. Coming to practical world, many industries operate with slip ring induction motor for high starting torque application. The value of slip in induction motor is can never be zero. The main methods employed for speed control of induction motors are as follows. What is common to all the members of this family is that the basic physical process involved in their operation is the conversion of electromagnetic energy to mechanical energy, and vice versa. Theory polyphase induction motors are mainly of two types by construction, squirrel cage and woundrotorwith slip rings. 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. Induction machines, which have these kinds of windings and terminals that are brought out, are called slip ring machines.
By putting resistance in series with the rotor windings, the starting current can be kept low while mainta. In general, the induction motor is cheaper and easier to maintain compared to other alternatives. A single phase induction motor has two types of rotor. To use variable resistance in the rotor circuit to control wound rotor induction motor speed theory polyphase induction motors are mainly of two types by construction, squirrel cage and woundrotorwith slip rings. A wound rotor induction motor has a stator like a squirrel cage induction motor, but a rotor with insulated windings brought out via slip rings and brushes. Slip ring motor fundamentals bright hub engineering.
Slip ring motor conversion to vsd driven standard squirrel. A slip ring induction motor can be started with external resistance added in its rotor circuit. Induction motor types based on the construction of the rotor, induction motors are broadly classified in two categories. Explain the rotor rheostat control of 3 phase slip ring induction motor. Explain the rotor rheostat control of 3 phase slip ring. As the name suggests, this type of motor has only one stator winding main winding and operates with a singlephase power supply. 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. The slip rings brushes allow external resistors to be connected in series with the winding. By far the most commonly used ac motor is the induction motor.
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