Nspeed control of slip ring induction motor pdf

The power drawn from the rotor terminals could be spent more usefully. Therefore the efficiency of three phase induction motor is reduced by this method of speed control. From the equation 1 it is clear that the motor speed can be changed by a change in frequency f, a number of poles p, and slip s. This system cordinates with the motor during the motor startup and makes it available for process control. The aim behind the development of the project is to limit the current at starting of motor and to develop the high starting torque. Dec 17, 2019 when the speed control of three phase induction motor is done by adding resistance in rotor circuit, some part of power called, the slip power is lost as i 2 r losses. An induction motor is practically a constant speed motor, that means. The entire mechanism of a slip ring motor or a wound rotor motor depends on the speed control system. Slip ring motor characteristics a slip ring motor or a phase wound motor is an induction motor.

There are four possible speeds can be obtained by this arrangement. This means that the state of the carbon brushes and the slip ring rotor can be monitored, and cleaning can take place. 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. A three phase, 12 pole, salient pole alternator is coupled to a diesel engine running at 500 rpm. Woundrotor motors can be started with low inrush current, by inserting high resistance into the rotor circuit. What are the applications of a slipring induction motor. Where f supply frequency p1 no of poles in slip ring motor p2 no of poles in other motor.

Speed of a dc shunt motor can be varied very easily with good efficiency, but in case of induction motors, speed reduction is accompanied by a corresponding loss of efficiency and poor power factor. Where, s slip, nspeed of the motor in rpm, f frequency in hz and p no. Speed control of an induction motor there is a various method of speed control of an induction motor. Here in this experiment we perform the speed control of a 3 phase slip ring induction motor by adding external resistance to the rotor circuit. Slip ring induction motor have big advantage of having high starting torque compared to squirrel cage motor. Slip ring induction motor working principle electrical mastar. Slip and motor current are reduced when the rotor begin turning. There are two mechanisms to control speed, the first is through rotor rheostat control and the second is through cascade control. Pdf performance characteristics of variablespeed slip.

A slip ring is an electromechanical device that allows the transmission of power and electrical signals from a stationary to a rotating structure. 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. Slip energy recovery of an induction motor slip energy recovery is one of the methods of controlling the speed of an induction motor. A c machines gscheme connect to start and reverse direction of rotation of single phase induction motor. We know that a motor uses an external high resistance circuit for producing high starting torque. A woundrotor motor, also known as slip ringrotor motor, is a type of induction motor where the rotor windings are connected through slip rings to external resistance. Following are the various methods of speed control of induction motor achieved from rotor side. 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. Ysalient features y robust and nonflammable construction. The motor can be started using grid rotor resistor.

How to control the speed of an induction motor quora. Inductive reactance depends on the frequency and the slip. At lower speeds, slip ring motors lose efficiency because the output is proportional to the speed. Slip ring induction motor speed control using a thyristor. When the speed control of three phase induction motor is done by adding resistance in rotor circuit, some part of power called, the slip power is lost as i 2 r losses. Pdf three phase induction motor tests squirrel cage induction motor load test sd control you schematic diagram for load test on three phase induction motor what is no load test of an induction motor circuit globe pdf experiment no 3 load and blocked rotor test on three what is no load test of slipring motor quora. A slip ring can be used in any electromechanical system that requires rotation while transmitting power or signals. The three ends of three phase windings are permanently connected to these slip rings.

In this article, we will learn about the speed control of slip ring induction motors and will appreciate that the speed control of slip ring motors are so flexible when compared to the squirrel cage induction motors. This work has developed a steadystate and dynamic mathematical model of three phase slip ring induction motors with external impedance. The change in speed depends upon both rotor circuit resistance and load. Ring induction motor for indian railways which is switching over to fully. Stator winding can be either star or delta connected depending upon the design. With the advancement in control mechanism 3ph squirrel cage motor is being. The value of slip in induction motor at full load varies from about 6% for small motors to about 2% for large motors. Rotor side control of high power slip ring induction motor.

In this project we are going to start and control the speed of 3phase slip ring induction motor. By putting resistance in series with the rotor windings, the starting current can be kept low while mainta. Compared to squirrel cage rotor the rotor construction is not simple. Design and analysis of drive system with slip ring induction motor for electric traction in india. Wound rotor induction motors ac motors electronics. Adjusting the resistance allows control of the speed torque characteristic of the motor. This manual covers squirrel cage rotor motor where the rotor consists. 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. Matlabsimulink based design and simulation of speed control. Slip ring motor fundamentals brighthub engineering. Today i will discuss very important topic speed control of induction motor. Pdf design and analysis of drive system with slip ring.

Cr this pap er presents the analysisand design of all improvised rotor chopper circuit, which can be used to cont rol the speed of slip ring induction motors. Pdf matlabsimulink based design and simulation of speed. That permits control of the current induced in the armatures, giving variable control of the motor output. Slip ring induction motor as an extension to the available non slip power recovery mechanisms available for low power srims. To study the speed control of induction motor by varying supply frequency vf control. 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 important characteristics normally shown by a squirrel cage induction motors are crawling and cogging. If the 3phase slip ring induction motor is started as a normal motor with the slip rings shorted, due to. Starting and control of threephase asynchronous motors eaton. All slip rings are connected with variable resistance. The slip ring rotor chamber has two modification openings. Figure 3 shows the relation between the voltage and. Polyphase induction motors are mainly of two types by construction, squirrel cage and woundrotorwith sliprings. 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.

Their sole purpose is to allow resistance to be placed in series with. Induction motor types based on the construction of the rotor, induction motors are broadly classified in two categories. When a motor starts to rotate the slip is 100 % and the motor current is at maximum. Why we need to start induction motor using a starter or with one of starting methods. By applying the vf control we can get the large operating range by keeping vf ratio constant. By adding external resistance to rotor winding starting current will low but it has high starting torque. The airgap induced emf in an ac machine is given by. Squirrel cage wound rotor with slip rings the rotating magnetic field the basic idea of an electric motor is to generate two magnetic fields. We can react very quickly due to a comprehensive stock of slip ring motors in a power range up to 15000 kw.

How to control the speed of 3 phase slip ring induction. Percent slip is a way to measure the speed performance of an induction motor. Slip of induction motor plays an important role in the operation of the induction motor. Slip in electrical induction motors engineering toolbox. This makes constant vf the most common speed control of an induction motor. This method is generally used for squirrel cage induction motors, as squirrel cage rotor adapts itself for. The slip ring induction motor could be used for industrial wires where variable speed and high starting torque are prime requirements. The slip ring in duction motor has a number of disadvantages compared to squirrel cage motor. Motors specification of electric motors marshall wolf automation.

An induction motor is practically a constant speed motor, that means, for the entire loading range, change in speed of the motor is quite small. Portland slip ring induction motorsbrush holder problems and. The copper losses are very high due to high content of harmonics at the output of the rectifier. The torque produced by the induction motor is directly proportional to induction motor slip. Experimental results are given and compared with the analytical results. The starting of an induction motor does not relate to simple switching alone. But please keep in mind that this method is applicable for squirrel cage rotor as here number of poles change with and are always equal to the number of stator. Adjusting the resistance allows control of the speedtorque characteristic of the motor.

Slip ring motor conversion to vsd driven standard squirrel. The issues related to control techniques with emphasis on induction. As discussed earlier, a slip ring induction motor is an asynchronous motor, as the rotor never runs in synchronous speed with the stator poles. 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. Jun 30, 2015 in case of squirrel cage induction motor the slip cannot be increase above certain limit, the operating speed range is very less. 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. Slip rings a conductive device attached to the end of a wound rotor that conducts current to the brushes. Speed control of wound rotor induction motor using rotor. Research the research of speed control for induction motor based on dynamic recurrent neural network. External resistance control by using three rheostats doubly fed machine speed control by rotor. Find the percentage slip and number of poles of the induction motor. Package solution for slip ring induction motor with variable speed control sprs is part of the complete package for motor starting process. A closedloop speed control scheme for a slip ring induction motor is described in this paper. Pillai department ofelectrical engineering, indian institute of technology, bombay, powai, bombay 400076, india abstra.

Induction motors generally will have low starting torque compared to dc series motor. Therefore slip ring induction motors are generally employed where load requires high starting torque or good speed control. An843, speed control of 3phase induction motor using pic18 mcus. Slip ring induction motor working principle electrical. This article is devoted to slip ring induction motors. Cascade control speed control of three phase induction. Advantages and disadvantages of slip ring induction motor. What is the working principle of slip ring induction motor.

So, by varying resistance after the motor has attained rated speed, the slip value can. Based on the construction of the rotor, induction motors are broadly classified in two categories. Introduction the technology of slip power recovery controlled by chopper for slip ring induction motor has been widely applied in highvoltage largecapacity motor because of higher power factor, higher efficiency and lower control voltage than those without chopper. There are different methods of starting of 3phase slip ring induction motor. In addition to handling heavier loads, slip ring motors allow easy speed control and tolerate variations in speed up to 25% of the rated speed. Figure shows the disassembled view of an induction motor with squirrel cage rotor. Apr 11, 2017 induction motors generally will have low starting torque compared to dc series motor. The external resistance can be easily connected through the brushes and slip rings and hence used for speed control and improving the starting torque of three. The loss of efficiency occurs through increased slip loss. Differential equations are solved using computer simulation. Speed control of wound rotor induction motor using.

Apart from using the heat generated in meaning full ways, the slip ring output could be connected to another induction machine. Slip power recovery system in three phase slip ring. However, in their case, the initial in rush of current is controlled by applying a. The resistance of this motor depends upon the slip, and independent of the torque.

The slip ring motor has very little application in industries. The speed control of the slip ring induction motor by chopper is shown in the figure a. Speed control of slip ring induction motor by chopper. Apart from the high starting torque, it also has some other advantages, and although slip ring induction motors have some disadvantages, they play a very important role in elevators, cranes, hoists and in industrial uses such as printing presses. The remaining two contactors are used to control the speed of a motor by cutting the resistance of rotor of a motor. Generally, it is known as the asynchronous motor because its running speed is less than its synchronous 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.

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. The first two contactors are used to change the phase sequence of power supply tochange the direction of a motor as per our requirement. This method is applicable to threephase slip ring induction motor only. The stator construction is the same in both motors. A slip ring motor or a phase wound motor is an induction motor which can be started with full. It should be noted that, speed control from rotor side is only applicable for slip ring induction motor. Slip energy recovery of an induction motor circuit globe.

By introducing external resistance in the rotor circuit, the speed of the motor can be reduced. Pdf three phase slip ring induction motor drive with. A modified rotor chopper for speed control of slip ring. Speed control of slip ring induction motors part ii. In this paper, the performance characteristics of a variable speed drive system with a slip ring induction motor incorporating a rectifierchopper system in the rotor circuit were studied. Cylindrical laminated core rotor is wound like winding on the stator. Speed control of threephase slip ring induction motor by rotor resistance control. Jan 09, 2017 the starter of slip ring induction motor is connected to threephase supply and its rotor is connected to stator of the other machine. Be specially designed for energy saving purpose which is totally enclosed and fancooled type. Three phase slip ring induction motor my tech info. It also involves its switchgears to control its starting inrush current. In slip ring induction motors the rotor is wound type.

Various induction motor speed control methods advantages. The construction of a stator is the same for both the squirrel cage and slip ring induction motor. Speed control of three phase induction motor electrical4u. Crawling and cogging of induction motor electrical4u. This method is also known as static scherbius drive. Induction motor seminar ppt, pdf report study mafia. The speed of a threephase induction motor driving a given load is determined by matching the torquespeed characteristics of the motor and load, as shown in fig. Speed control of 3 phase slip ring induction motor youtube. Slipring induction motor connection and testing youtube. 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. Starting and speed control of 3phase slipring induction. An alternative to squirrel cage induction motor for.

Modeling and analysis of slip power recovery controlled. When the injected voltage is in phase opposition with the induced rotor e. Speed control of wound rotor induction motor using rotor resistance control aim 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. Methods of speed control of induction motor electrical. Because of more advantages, squirrel cage motor is always preferred. Free download induction motor seminar ppt, pdf report. The rotor speed of an induction motor is given by the equation shown below. An843, speed control of 3phase induction motor using. Speed control of induction motor 7 ways to control induction. However, it reduces substantially in a slip ring motor due to the high impedance of the rotor circuit. Learn more about the construction and operation of a slip ring induction motor.

Squirrel cage motor almost 90% of induction motors are squirrel cage motors. But there is no restriction for the direction of phase rotation. A modified rotor chopper for speed control of slip ring induction motors s. This method is also called the tandem control and obsolete now. The on and off time of chopper is adjusted in order to get desirable speed of the motor.

Terms used in wound rotor slip the difference between a motor s synchronous speed and its speed at full load. In the same way, the synchronous speed of the differentially cascaded motor can be given by the expression. It supplies an induction motor ich has a full load speed of 144wh 0 rpm. The speed control is achieved through slip power recovery with the aid of static power devices. The most basic ways to control the speed of a slip ring induction motor is either from the stator or rotor side. It is very commonly used in industries because it is very cheap, robust, efficient, and reliable. Speed control of 3phase induction motor using pic18 microcontrollers. Slip ring motor manufacturer menzel provides shortterm availability and adaptation, applicationspecific requirements and worldwide logistics. Dec 01, 2017 slipring induction motor also known as rotor resistance start motor. Slip power recovery system for variable speed operation of. Slip ring induction motor fundamentals pnpntransistor. These characteristics are the result of improper functioning of the motor that means either motor is running at very slow speed or it is not taking the load. The mechanism employed here is to control the speed. In the rotor resistance control method, the slip power in the rotor circuit is wasted as i 2 r losses during the low speed operation.

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