Synchronous speed means the speed of the rotating magnetic field in the stator. Squirrel cage rotor and slip ring rotor squirrel cage vs wound rotor. Types, construction and principle of operation, 3 phase induction motor, general phasor diagram, equivalent circuit, power and torque. Instead of a series of rotor bars, a set of insulated rotor coils is used to accept external impedances.
The slip rings are mounted on the shaft with brushes resting on them. The rotor is separated from the stator by a small airgap which ranges from 0. We can react very quickly due to a comprehensive stock of slip ring motors in a power range up to 15000 kw. But the rotor construction differs with respect to the type of motor. The rotor of the slip ring induction motor is also cylindrical or constructed of lamination. The two brushes are connected to a single phase starconnected rheostat as. This rings attached with high resistance acts as an external circuit for the rotor. When motor attains normal speed, three brushes are short circuited. Compared to squirrel cage rotor the rotor construction is not simple. The video tutorial is essentially a part of the basic electrical and electronics engineering. Properly, it is an electric communication device that permits the flow of energy among two electrical rotating elements in a motor. Squirrel cage rotor wound type rotor or slip ring type rotor squirrel cage rotor in this type.
Diagnostics of rotor and stator problems in industrial induction motors by fang duan b. The value of slip in induction motor is can never be zero. Advantages and disadvantages of squirrel cage induction motor. A wound rotor or slip ring motor has a 3phase winding, similar to the stator. Wound rotor induction motors ac motors electronics. Slip ring induction motor over squirrel cage induction motor. In the case of a squirrel cage induction motor, the rotor is inaccessible and rotor circuit. 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.
Its starting torque is somewhat inferior to that of a d. Cylindrical laminated core rotor is wound like winding on the stator. One end of each of the three windings connects through carbon brushes to an insulated slip ring that mounts on the rotor shaft. However, the most important difference between them is the first one can convert ac to dc or dc to ac but the other cannot. Or they can be divided according to type of rotor i squirrel cage motor and ii slip ring motor or wound type basic working principle of an induction motor in a dc motor, supply is needed to be given for the stator winding as well as the rotor winding. It is possible to speed control by regulating rotor resistance. Squirrel cage motors are widely used due to their rugged construction and simple design. Slip ring motor fundamentals brighthub engineering. There is no difference between squirrel cage and slip ring motors. Induction motor seminar ppt, pdf report study mafia. A wound rotor induction motor is also known as slip ring induction motor.
Free download induction motor seminar ppt, pdf report. The function of the slip rings and the brushes is to provide a means of connecting external resistors in the rotor circuit. The rotor is the rotating part of the induction motor and is mounted on the shaft of the motor to which any mechanical load can be connected. In squirrel cage induction motors the rotor is simplest and most rugged in construction. Electric motor construction of induction motors britannica. The main difference in a slip ring induction motor is on the rotor construction and usage.
Squirrel cage wound rotor with slip rings the rotating magnetic field. Speed control of wound rotor induction motor using rotor. The slip rings brushes allow external resistors to be connected in series with the winding. What is the difference between slip ring and commutator. Slip ring induction motor or wound induction motor or phase wound induction motor. Construction of three phase induction motor electrical4u. The slip ring motor has very little application in industries. Slip ring induction motor construction, working and its. Pdf rotor side control of high power slip ring induction 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. This article is devoted to slip ring induction motors.
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 3 phase induction motor can be used for different applications with various speed and load requirements. In the slip ring type,the rotor consists of three phase winding similar to that of the stator winding. A 3 phase induction motor has two main parts i stator and ii rotor. It is mostly used in industrial drives because it is very reasonable and vigorous, economical and reliable. Electric motor electric motor construction of induction motors. Oct 10, 2016 a wound rotor induction motor is also known as slip ring induction motor. Slip ring induction motor fundamentals pnpntransistor. Their sole purpose is to allow resistance to be placed in series with the rotor windings while starting figure below. The slip ring rotor chamber has two modification openings.
Slip ring induction motor is made up from wound rotor and squirrel cage induction motor is made up from the squirrel cage rotor. Thus, we modify the construction of the present mechanism by exclusively. The construction of the slipring induction motor is exactly similar to the construction of squirrel cage induction motor. Wound rotor induction motor the engineering projects.
Slip in induction motor is the relative speed between the rotating magnetic flux and rotor expressed in terms of per unit synchronous speed. In slip ring induction motors the rotor is wound type. By far the most commonly used ac motor is the induction motor. Slip ring induction motors utilize a wound rotor that features steel laminations with slots that hold three singlephase windings.
The stator frame consists of laminations of silicon steel, usually with a thickness of about 0. Commutator and slip ring both are used to maintain electrical circuit continuity between a rotating and a static system. The brushes are connected to the variable resistor. Motors employing this type of rotor are widely known as phasewound motors or wound motor or slip ring motors. 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 construction of a stator for both of the kinds of three phase induction motors is identifcal, and is discussed briefly below. The construction of the present mechanism has been exclusively. 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. The slip ring induction motor is shown in the figure below. Starting andcontrol of slipring 5 electrical engineering book. 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. This article discusses about what is a slip ring induction motor, its construction, working, diagram, speed control, advantages. Diagnostics of rotor and stator problems in industrial.
There basically 2 types of induction motor depending upon the type. Depending upon the type of rotor construction used the three phase induction motor are. Three phase induction motor construction your electrical guide. The rotor windings are similar to those found on a dc armature, with the coils connected together to a set of rings. Slip ring induction motor working principle electrical mastar. The 3phase set of currents, each of equal magnitude and with a phase. Construction of induction motor posted by electrical edition. Slip ring induction motor construction and operation. The rotor will constantly be turning to align its magnetic field with that of the stator field.
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. 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. Pdf design and analysis of drive system with slip ring induction. Pdf three phase slip ring induction motor drive with. Control of motorcharacteristics by squirrelcage rotordesign. In this article, we shall discuss this motor s construction, working, speed control, advantages, disadvantages, and applications. An induction motor is an alternating current motor in which the primary winding on one member.
Construction of squirrel cage induction motor explained. The construction of stator of the induction motor is almost the same as other motors. It is very commonly used in industries because it is very cheap, robust, efficient, and reliable. This will ensure 100% reliability in operation of the locomotive. The slip ring commutator construction is, consists of immobile graphite otherwise brush which is known as metal contact which wipes on the exterior diameter of a revolving metal ring. Production of high starting torque with slip ring 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. To overcome this problem, the slip ring induction motor comes into the picture. 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 motors require external resistors to have high starting torque. Induction motors are the most commonly used motors in many applications. Rotor side control of high power slip ring induction motor using a. Almost 90% of induction motors have squirrel cage rotors. 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 however, no power is applied to the slip rings. Low starting current of the order of 250 to 300% of the full load current. This can be used in starting a slipring induction motor, for example. This arrangement in slip ring induction motors also reduces the high inrush currents during starting of induction motor. This final thesis will mostly be dedicated to induction motors but also to synchronous permanent magnet and reluctance motors. In previous articles i have discussed the construction, operation, starting, speed control, and classes of squirrel cage induction motors. 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 slip ringsbrushes allow external resistors to be connected in series with the winding. An asynchronous motor with wound rotor is used as traction.
This article encompasses the working principle of slip ring induction motor, construction, speed control, resistance calculation and its applications. Almost 90 percentage of induction motors are squirrelcage type, because this type of rotor has the simplest and most rugged construction imaginable and is almost indestructible. Slip ring induction motor application, construction, working principle, advantages and disadvantages, speed control of slip ring induction motor, the difference between slip ring i. Squirrel cage induction motor vs slip ring induction motor. Slip ring induction motor are used where high starting torque is required i. If you want to add any further topic related to this article. Based on the construction of the rotor, induction motors are broadly classified in two categories. Sketch of a crosssection of slip rings for an electric motor. The construction of slip ring induction motor is quite different compared to other induction motor.
If you want to add any further topic related to this article comment. This means that the state of the carbon brushes and the slip ring rotor can be monitored, and cleaning can take place. Learn more about the construction and operation of a slip ring induction motor. Why are there two different designs of rotor construction for induction motors. The most basic ways to control the speed of a slip ring induction motor is either from. In slip ring induction motors, higher starting torque can be attained by providing an external resistance in the rotor circuits during starting of the slip ring induction motor. Photograph your local culture, help wikipedia and win. Depending upon the type of rotor construction used the three phase induction motor are classified as. Lamination is necessary since a voltage is induced along the axial length.
Nov 27, 2019 the three phase induction motor is the most widely used electrical motor. What is the difference between a slip ring and a squirrel. The other three winding terminals are brought out and connected to three insulated slip rings. In this example, the slip rings have a brushlifting device and a sliding contact bar, allowing the sliprings to be shortcircuited when no longer required. The stator construction is the same in both motors. These are of two types, squirrel cage and slip ring motors. Slip rings induction motor provides some advantages like provides high starting torque, low starting current and it improves the power factor. Slip ring rotor or wound rotor or phase wound rotor. And in the previous article on types of electrical motors, we have classified induction motors based on the type of rotor used. We can add external variable resistance to the rotor of this type of motor. There are two types of induction motors, one with wound type rotor, also called slip ring motor and another one with squirrelcage rotor. The stator consists of 3ph winding forms wound poles that carry the supply current to induce a.
High starting torque of 200 to 250% of full load voltage. A squirrelcage motor with this type of rotor construction is called nemadesign class d. 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. The basic idea of an electric motor is to generate two magnetic fields. Thyristor, slip ring induction motor srim, stator and rotor. 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.
Construction of induction motor electrical edition. The working principles and stator construction of the slip ring induction motor are exactly the same as that of the squirrel cage motor. Sep 18, 2018 induction motors have been ruling the industrial world for many decades. The construction of a stator is the same for both the squirrel cage and slip ring induction motor.
It is also called asynchronous motor because it does not run at a synchronous speed. Because of the large rotor resistance, this motor has a pullout torque occurring at a high slip, and its starting torque is quite high. Threephase ac induction motors are widely used in industrial and commercial applications. Basic construction and operating principle like most motors, an ac induction motor has a fixed. Pdf this work has developed a steadystate and dynamic mathematical model of three phase slipring induction motors with external impedance find, read.
Wound rotor induction motors ac motors electronics textbook. 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. Slip ring motor manufacturer menzel provides shortterm availability and adaptation, applicationspecific requirements and worldwide logistics. These are also called as asynchronous motors, because an induction motor always runs at a speed lower than synchronous speed. It is a type of motor where its external circuit is connected using some rings. The slip ring induction motor working in the induction principle. Construction of induction motor the three phase induction motor is a preferable type of motor. Brushes are used to take connection from these slip rings at starting high external resistances are usually included to improve starting torque and reduce starting current. If you want to know about the slip ring induction motor. Slip ring induction motor working principle electrical. The induction motor are of two types based on the construction of rotor.
What makes the wound rotor motor a unique induction machine is its rotor. I will tell you about the construction of wound rotor induction motor in the first section. Learn a brief history of the electrical power systems construction. 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. The applications of electrical motor mainly include blowers, fans, machine tools, pumps, turbines, power tools, alternators, compressors, rolling mills, ships, movers, paper mills. The rotor winding terminals are connected to three slip rings which turn with the rotor. Generally, it is known as the asynchronous motor because its running speed is less than its synchronous speed. Slip ring induction motor construction, working, speedcontrol. Construction an induction motor consists essentially of two main parts.