Speed control of wound rotor induction motor using rotor. Electrical interview questions which motor is best. Vem threephase motors with slipring rotor combine the general benefits of this drive solution with vems extraordinary manufacturing knowhow. Telecommunication engineering, southwest jiaotong university, china, 2005 thesis. Generally, it is known as the asynchronous motor because its running speed is less than its synchronous speed. Ger4212 ge generator rotor design, operational issues. Michigan scientific designs and manufactures rotor adapters to convert standard sseries slip ring rotors to a different size. 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. Slip power recovery system for variable speed operation of. It is also necessary to be able to drive the rotor. Abb slipring modular motors abb high voltage induction motors. Menzel elektromotoren gmbh uses cookies on this website to enhance the user experience and provide the best possible service.
Terminals box of the motor contains 3 terminals for stator and 3 for rotor and 2 cable entries. It is also necessary to be able to drive the rotor by an auxiliary motor or power supply and when possible to. Installation, operating and maintenance instructions translation english 4 the key in the shaft end is secured by the shaft protective sleeve for transport and storage only. Rotor supply frequency with respect to rotor frame. Slipring motors are still used in many branches of industry, and their particular properties are decisive in determining the efficiency of countless processes. Depending on the weight and size of the rotor, in addition to lifting equipment certain winding, cutting, straightening and taping machines may be applied. The windings have two endings the inside of the slip ring holds one end and the other end is placed on the rotary part. Understanding the alternator two slip rings are located on one end of the rotor assembly. Download fulltext pdf three phase slip ring induction motor drive with slip power control analysis for different load torque using microsoft excel as software tool. The brushes make sliding electrical contact with the slip rings. An increase in load will cause the rotor to slow down or increase slip.
Slip ring motor manufacturer menzel provides shortterm availability and adaptation, applicationspecific requirements and worldwide logistics. Lot of research work has been carried out to improve its power factor and to achieve suitable methods of speed control. These slip rings allow for speed and torque control and are the defining feature of wound rotor motors it is also why these motors are often referred to as slip ring. Slip ring assemblies are electromechanical components used to transmit. To slip ring rotor is applied a second supply voltage u2 and rectifier sr is incorporated in rotor. One slip ring is attached to each end of the rotating loop. The truing of commutators or slip rings can be carried out with. The slip ring rotor is made of steel laminations and it has either 2single phase winding slots or 3single phase winding slots. The rotor runs slower than the speed of the stator field. Fault identification of 3phase slip ring induction.
The rotor will constantly be turning to align its magnetic field with that of the stator field. The operating coil of an instantaneous relay is connected on one side to the field circuit through a currentlimiting resistance r and on the other side a small dc power source is connected with polarity as indicated. An operating and maintenance manual, a terminal plan and a safety data sheet. Thus, speed variable operation is possible, from zero to one and half times rated motor speed. The slip ring rotor construction of the rotor windings is exactly equal to the stator. We also have custom design solutions for applications requiring more than our standard line can offer. The slip and brushes allow external resistors to be connected in. Senring single channel large current slip ring with many structures, below are the two most popular structures, installtion guide as following. Introduction a gridconnected slip ring induction motor with current injection on the rotor.
The ac motor comprises slip ring rotor lf and wound stator st providing first supply voltage u1. Machines for small rated power levels are designed as roundwire windings, whereas for medium and large rated power levels bar windings are applied. In this article, i will discuss which motor is best to use, the squirrel cage motor is best or slip ring induction motor is best. A slip ring motor also requires a larger space for the motor and its controls. Consider an earth fault in the rotor circuit, f as shown in fig. Slip ring assemblies are electromechanical components used to transmit electrical signals e. Wound rotor induction motors ac motors electronics textbook. Because of the danger that the key may be thrown aside, a startup or a trial run with the key protected by the shaft sleeve only is strictly forbidden. As a leading designer and manufacturer of slip rings.
If the slip ring induction motor is started with all the slip rings or the rotor. Slipring induction motors in conjunction with rotor resistanceswitching contactors are widely used for ancillary mechanical. Each end of the rotor field winding is attached to a slip ring. Slipring motors are built using proven standardized motor design. Historically, slip rings were initially intended for use in blade deice and tiplight applications where electrical power was required for the main and tail rotor. Abb induction motors for the mining industry english pdf. Moflon has been manufacturing and supplying slip rings and rotary unions to companies, contractors, and other endusers for more than 30 years now. In a slip ring induction motor, the rotor resistance is a. The apparatus includes an annular end bell, a carbon brush assembly coupled to the end bell including a housing coupled to the end bell inner peripheral surface, at least a conduit formed in the housing, and a springloaded carbon brush disposed in the conduit, and a slip ring assembly. Evaluate the new system design under rotor icing conditions at the aerts facility. Rotor induction motor an overview sciencedirect topics. Free download induction motor seminar ppt, pdf report. Their sole purpose is to allow resistance to be placed in series with the rotor windings while starting figure below. Diagnostics of rotor and stator problems in industrial induction motors by fang duan b.
In the case of a squirrel cage induction motor, the rotor is inaccessible and rotor circuit resistance is xed, whereas the wound rotor machines are provided with slip rings by which additional resistance can be connected in series with the machine rotor. Cage induction motor an overview sciencedirect topics. Vem threephase motors with slipring rotor combine the general benefits of. The motor whose rotor is wound type such type of motor is called slip ring induction motor, whereas the squirrel cage motor, has a squirrel cage type rotor.
Slip rings a conductive device attached to the end of a wound rotor. A wound rotor, has a 3phase winding similar to the stator winding. How to calculate the slip ring induction motor rotor current. Introduction a gridconnected slip ring induction motor with current injection on the rotor side can be operated in supersynchronous mode to produce up to two times the rated nominal power. The moflon slip rings are designed to endure harsh environmental conditions like acidic and salty media and extreme vibrations. The black arrow, pointing left, indicates an increasing rotor winding resistance in the pointed direction. Percent slip is a way to measure the speed performance of an induction motor. The dependence of torquespeed characteristics on rotor resistance is shown in figure 7. A decrease in load will cause the rotor to speed up or decrease slip. The slip ring induction motor could be used for industrial wires where variable speed and high starting torque are prime requirements. A squirrel cage motor is thus preferred to a slip ring motor. In the induction motors used in lift and hoists, you will see a type of rotor called a slip ring.
A slip ring in electrical engineering terms is a method of making an electrical connection through a rotating assembly. The cage rotor consists of copper or aluminum bars which are uninsulated called rotor conductors, in slots bars are placed. 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. Three notable applications have been helicopter rotor deicing slip rings, radar pedestal slip rings, and wind turbine slip rings. Slipring motors are still used in many branches of industry. Us6448735b1 controller for a wound rotor slip ring. Welcome to the electric motor catalogue download portal of menzel. These unique electrical slip rings come in miniature slip ring capsules to large separates. Find the amount of resistance to be inserted in each rotor phase to obtain fullload torque at starting. The 3phase set of currents, each of equal magnitude and with a phase difference of 120o, flow in the stator windings and generate a rotating. Full scale testing of a centrifugally powered pneumatic. The slip ring rotor was developed after a decade or so. Us7095243b1 ac generator exciter rotor slipring test. A 4pole, 50hz, 3phase induction motor has a slipring rotor with a resistance and standstill reactance of 0.
Ht motor rotor resistance starter calculation resistance. There is some testing to be done before shorting the slip rings, including verifying that your motor runs with some rotor resistance at full speed or not. In an induction motor, torque is equal to the power crossing the air gap divided by the synchronous mechanical speed. High reliability slip ring design for wind turbines. Slip ring motors are still used in many branches of industry. Aluminum alloy condal windings were incorporated on some generator rotors, enabling the rotor size and ratings to increase and still allow conventional. Installation, operating and maintenance instructions three. These slip rings are attached to brushes and variable power resistor banks, where operators can change the speed of the motor by varying the resistance through the rotor coils. This is only possible if a lathe slide can be mounted on the frame of the machine. Squirrel cage wound rotor with slip rings the rotating magnetic field the basic idea of an electric motor is to generate two magnetic fields. Rather than experiment with expensive high voltage inverters, it makes much more sense to use the motor the way it was designed, with a variable resistance connected to the rotor.
Traditionally, speed control of slip ring induction motor was achieved through varying the rotor resistance. We can react very quickly due to a comprehensive stock of slip ring. Thereby, allowing current to flow through the field winding. The external resistors are mainly used during start up and under. Hairpin rotor stator catalog partsinline shanghai l. A slip ring is an electromechanical device that allows the transmission of power and electrical signals from a stationary to a rotating structure. What is the role of the slip rings and brushes in the. Instalation guide for slip ring with internal thread on rotor side and external thread on stator side. An induction motor can be defined as the ac electric motor device in which a power source fed by the alternating current with the. Slip ring motors are still used in many branches of industry, and their particular properties are decisive in determining the efficiency of countless processes.
Pdf rotor side control of high power slip ring induction motor. Terms used in wound rotor slip the difference between a motors synchronous speed and its speed at full load. It is their properties which are decisive in determining the efficiency of production. Slip ring induction motor is induction motor where there is 3phase winding on rotor and slip rings are connected with each phase winding. Before testing the rotor,inspect the brushes and slip rings.
Overview and application of rotating electrical slip ring. The difference between n s and n b is called the slip. Diagnostics of rotor and stator problems in industrial. A slip ring assembly comprises of brush blocks, which are accurately harmonized and usually available as a set of a ring and a brush. Do not use any metallic grit to clean up slip rings. Induction motors have been ruling the industrial world for many decades. Two stationary carbon brushes ride on two rotating slip rings. The rotor terminals are connected to three slip rings which turn with the. The principle of a slipring motor is that external rotor resistance provides the necessary motor torque during acceleration to full speed. The squirrel cage rotor is cylindrical in shape and slotted on its periphery. The current injection can be achieved using either a. Wound rotor induction motors with three rotor slip rings have been used in adjustable speed drives for many years. A test apparatus assembly is provided for testing an ac generator having an exciter rotor mounted to a shaft. The direct torque control dtc principle is used to control the torque of a wound ring rotor slip induction machine, also known as a doubly fed or cascade machine, by utilizing a solid state inverter on the rotor.
Threephase asynchronous motor with slip ring rotor. Vem threephase motors with slip ring rotor combine the general benefits of this drive solution with vems extraordinary manufacturing knowhow. Three phase slip ring induction motor drive with slip. Slip ring induction motor is also known as wound rotor induction motor. Since then a lot of improvement has taken place on the design of these two types of induction motors. Rotary systems also offers sealed, capsule, packaged, and industrial slip rings along with separate parts for design. Slip rings can also be called swivels, rotary joints, collectors, or commutators.
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. Here you can find regularly updated motor catalogues, broschures, data sheets and pdfs. As its name indicates stator is a stationary part of induction motor. Slip ring induction motor as an extension to the available non slip power recovery mechanisms available for. The aim behind the development of the project is to limit the current at starting of motor and to develop the high starting torque. Three phase slip ring induction motor my tech info. To test the rotor with a voltohmmilliameter vom,set the vom to its ohm scale and zero the meter. Electrical slip rings are used in helicopter, tiltrotor and rotorcraft applications for a variety of applications. The output voltage is taken from the rotor by the sli p rings and brushes. Fault identification of 3phase slip ring induction motor free download as powerpoint presentation. Formally, it is an electric transmission device that allows energy flow between two electrical rotating parts, such as in a motor. Pdf three phase slip ring induction motor drive with slip power. Pdf three phase slip ring induction motor drive with.
The mechanism employed here is to control the speed via a single thyristor acting as an onoff switch at the rotor side of this slip ring induction motor. Power control analysis for different load torque using. Difference between slip ring and squirrel cage rotor, what is. I will also discuss the advantages and disadvantages of squirrel cage and slip ring induction motor, and conclusion. The fixed brushes make a sliding contact with the conductor ring, creating the rotating electrical connection. Design a centrifugally powered pneumatic deicing system without the use of inflatable rubberized structures. In a wound rotor induction motor, external resistance can be connected to the rotor windings through slip rings as shown in fig. Slip ring induction motor fundamentals pnpntransistor. Asynchronous slipring motor synchronized with permanent magnets. Induction motor seminar ppt, pdf report study mafia.
Jun 26, 2017 michigan scientific designs and manufactures rotor adapters to convert standard sseries slip ring rotors to a different size. An electrical slip ring consists of five main components the brush sliding contact, conductor ring, ball bearings, rotor, and housing. There are different methods of starting of 3phase slip ring 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. Thus a satisfactory performance in both the starting and running conditions can be obtained by varying the value of the external resistance with the rotor. The rotor, acting as the armature, rotates in the field, cutting the lines of force and producing the desired output voltage.
The threelayered windings are separately laid in 120degrees. Using a slipring motor for vfd operation cr4 discussion. Starting andcontrol of slipring 5 electrical engineering book. We can react very quickly due to a comprehensive stock of slip ring motors in a power range up to 15000 kw. Rotor clip is the manufacturer of retaining rings, snap rings, circlips, wave springs, single turn wave springs, multi turn wave springs, spiral rings, nonthreaded fasteners, pliers, dispensers, applicators, hose clamps, axial rings, radial rings, selflocking rings, constant section ring, metric rings, din rings, ansi ring, jis ring, band clamps, gateway page with links to facilities in the. M line slip ring rotor horizontal installation, operation and maintenance manual. Wai serving the parts needs of the automotive, heavy duty, power sports aftermarket wai is the preferred parts manufacturer and supplier of alternators, starters, electronics and. Wound rotor induction motors with three rotor slip rings. Calculation table for slip ring induction motor used for crane hoisting application calculation table for slip ring induction motor used for crane hoisting application result contain approximate values for crosschecking only inputs power rating p2 100 hp speed n 980 rpm stator voltage e1 415 v stator current is 8 a rotor voltage e2 380 v. Integration of the selected system to the outer tip region of a fullscale kmax rotor. To slip ring rotor is applied a second supply voltage u2 and rectifier sr is incorporated in rotor circuit, variably controlling rotoro current i. Pdf design and analysis of drive system with slip ring induction. Design and analysis of drive system with slip ring induction motor for electric traction in india.
Pdf the use of squirrel cage motor for traction has revolutionised the motive power of a locomotive. Pdf performance characteristics of variablespeed slipring. Replace brushes if they are worn excessively,or if they are cracked or damaged. A stator winding is placed in the stator of induction motor and the three phase supply is given to it.
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