The induction motor is made up of the stator, or stationary windings, and the rotor. Rotor side control of high power slip ring induction motor. Moflon have been manufacturing fiber optic rotary joints and photoelectric hybrid slip rings for more than 10 years, standard 12346812 channels fiber in stock mz rotor flange slip rings. A slip ring motor also requires a larger space for the motor and its. 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. But the rotor construction differs with respect to the type of motor. Slipring induction motors utilize a wound rotor that features steel laminations with slots that hold three. Induction motors have been ruling the industrial world for many decades. Slip ring induction motor as an extension to the available non slip power recovery. A slip ring motor is expensive, as are its controls, compared to a squirrel cage motor. By putting resistance in series with the rotor windings, the starting current can be kept low while mainta.
Rotor is flangemounting,standard rotating electrical connectors. A slip ring motor is normally not designed for the extreme high dudt values stressing the winding insulation at vfd drive fast switching. What are slip rings and why do some motors use them. We develop appropriate solution with characteristic lines that match precisely your specifications and demands for your application.
A 400 v, 50hz, induction motor, when started directly from the mains takes 4 times the fullload current and the torque produced is twice the fullload torque. Induction motor theory jerry bednarczyk, pe course content introduction the ac induction motor is well suited to applications requiring constant speed operation. Slip ring induction motor as an extension to the available non slip power. Because the torque curve of the motor is effectively modified by the resistance. Adopted the advanced military surface processing technique and goldgold contact, such capsule slip rings are perfectly suitable for application where weak signal transmission is dominated advantages. Differentiate between the various types of generating electric power stations. Construction of a synchronous machine circuit globe. 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. Its robust and simple construction as well as its high degrees of protection. They are especially suitable for heavy load inertia applications. In general, the induction motor is cheaper and easier to maintain compared to other alternatives. It also requires meticulous and periodic maintenance of the brushes, brush gear, slip rings, external rotor resistances etc. Slipring motors are still used in many branches of industry, and their. With regard to its construction and winding connection of its passive.
The rotor of the motor consists the cylindrical laminated core having semiclosed circular slots and short circuit. The slip ring induction motor could be used for industrial wires where variable speed and high starting torque are prime requirements. Lamination is necessary since a voltage is induced along the axial length of the steel as well as in the stator conductors. As a result of the simple construction, the motor provides long. An induction motor also known as an asynchronous motor is a commonly used ac electric motor. Characteristic for the threephase motor is the high current load on the mains supply. Construction of three phase induction motor electrical4u. Rotor side control of high power slip ring induction motor using a single thyristor.
I will tell about the construction of a wound rotor later in this article. Three phase slip ring induction motor my tech info. The construction of the present mechanism has been exclusively. Essentially, the motor consists of a rotor and a stator which make no physical contact at any time, due to a carefully maintained air gap. 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. Construction, working, advantages, disadvantages, characteristics and applications single phase unexcited synchronous motor the characteristic of single phase unexcited synchronous motor in which excitation does not necessary is given below. Electric motor electric motor construction of induction motors. The rotor is separated from the stator by a small airgap which ranges from 0. Thus, we modify the construction of the present mechanism by exclusively. The main difference between slip ring induction motor is in rotor construction and usage. This simple construction makes the squirrel cage motor the most rugged and the least.
The slip ring motor has very little application in industries. A commutatorbrushes arrangement helps in achieving unidirectional torque in a typical dc motor. Pdf rotor side control of high power slip ring induction motor. The rotor of an induction motor can be a squirrel cage rotor or wound type rotor.
The laminations are insulated from each other usually by a varnish layer. Starting and control of threephase asynchronous motors eaton. This means that the state of the carbon brushes and the slip ring rotor can be monitored, and cleaning can take place. A squirrel cage motor is thus preferred to a slip ring motor. The construction of stator of the induction motor is almost the same as other motors. Therefore slip ring induction motors are generally e. Lpc series is a group of capsule slip rings of compact design with the outer diameter of 2254mm.
Smooth starting of slip ring induction motors article pdf available in ieee transactions on energy conversion 124. In normal conditions, the slip ring motor functions like a squirrel cage motor. Note that the motor has no brushes, commutators, belts or slip rings. It is very commonly used in industries because it is very cheap, robust, efficient, and reliable. There is a high risk that partial discharge will break down the winding isolation material causing flashover if it is not designed for vfd. Typically, this construction includes the use of an aluminum inlet cone and an aluminum rub ring. Portland slip ring induction motorsbrush holder problems. Crompton greaves crane duty motors are designed and manufactured with carefully selected and tested insulating materials to ensure long services. The life of the motor mostly depends upon the life of the insulating materials since bearings, brush gears, slip rings. Slip ring induction motor operation motion industries.
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. A 3 phase induction motor has two main parts i stator and ii rotor. In three phase induction motor, the power is transferred from stator to. The squirrel cage induction motor is the most popular type of ac motor. The aluminum inlet cone will be the first point of fan wheel contact if there is a mechanical failure. Crane duty motors, slip ring crane duty motors, squirrel. Slip ring motor 3 with their solid construction and special design in cast iron or steel akh slip ring motors still have a big resonance in numerous industry sectors. Dc motor principle a machine that converts dc power into mechanical energy is known as dc motor. Induction motors generally will have low starting torque compared to dc series motor.
Starting and control of threephase asynchronous motors. It carries the armature winding in which the voltage is generated. Today, i am going to tell you about a wound rotor induction motor, which is also a type of 3 phase induction motor. Woundrotor motors can be started with low inrush current, by inserting high resistance into the rotor circuit. Mostafa elshahed objectives learn a brief history of the electrical power systems construction. Wound rotor induction motors ac motors electronics. A woundrotor motor, also known as slip ringrotor motor, is a type of induction motor where the.
Therefore slip ring induction motors are generally employed where load requires high starting torque or good speed control. Stator winding can be either star or delta connected depending upon the design. Its operation is based on the principle that when a current carrying conductor is placed in a. 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. The three phase induction motor is the most widely used electrical motor. Slipring induction motor construction and operation.
The slip ring rotor chamber has two modification openings. In small machines the conductor bars and end rings are sometimes made of aluminium with the bars and rings cast in as part of the rotor core. They are employed in hoists, elevators, compressors, printing presses, large ventilating fans, loads requiring. Rarely 5% 10% slip ring motors are used in industries because it has several disadvantages like it required. The construction of the rotor is rugged and simple. 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. The construction of a stator is the same for both the squirrel cage and slip ring induction motor. Squirrel cage wound rotor with slip rings the rotating magnetic field the basic idea of an electric motor is to generate two magnetic fields. Using the values of the starting resistors used, actual starting torque can be calculated. Slip rings are devices that can transmit power, electrical signals, or data between a rotatating component and a stationary component.
Dc motors although ac motors are used in most of the cases, dc motors have many applications and used for multipurpose applications. A brushless dc motor or bldc motor is a type that is most suitable for applications that require high reliability, high efficiency, more torque per weight, etc. 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. Be specially designed for energy saving purpose which is totally enclosed and fancooled type. Lecture 6 three phase induction motors cairo university. 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. In the induction motors used in lift and hoists, you will see a type of rotor called a slip ring. What is the working principle of slip ring induction motor. Slip ring motors are the motors of choice whenever high starting torque or low starting current are required.
Slip ring induction motor is made up from wound rotor and squirrel cage induction motor is made up from the squirrel cage rotor. The main motor is necessarily a slip ring induction motor but the auxiliary motor can be slip ring or squirrel cage induction motor. The construction of slip ring induction motor is quite different compared to other induction motor. What are the applications of a slipring induction motor. The output of the machine is taken from the stator. Know how to control the speed of slip ring motors bright. This does not involve the power from on rotor side be fed back to the source. A secondary use of the slip ring motor, is to provide a means of speed control. Speed control of wound rotor induction motor using rotor. A wound rotor induction motor is also known as slip ring induction motor. The construction of slip ring induction motor is same as other induction motors. General purpose slipring induction motors product catalogue. The main difference in a slip ring induction motor is on the rotor construction and usage.
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 develop a high starting torque with. 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. Adjusting the resistance allows control of the speedtorque characteristic of the motor. Effects of rotor asymmetry conference paper pdf available june 1997 with 3,082 reads how we measure reads. Carbon brush performance on slip rings mining electrical. Actually the entire construction bars and end rings resembles a squirrel cage, from which the name is derived. Slip ring induction motor have big advantage of having high starting torque compared to squirrel cage motor. For satisfactory operation, motor a must be phase wound slip ring type with the stator to rotor winding ratio of 1. Slip ring induction motor advantages disadvantages and. Almost 80% of the mechanical power used by industries is provided by three phase induction. Electric motor construction of induction motors britannica. 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.
The value for k is different for each slip ring motor. Each slip ring motor has a resistance value that when connected to the rotor will result in a starting torque of 100%. Why are there two different designs of rotor construction for induction motors. Slip ring motor conversion to vsd driven standard squirrel. 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 stator frame consists of laminations of silicon steel, usually with a thickness of about 0. Wound rotor induction motor the engineering projects.
Their sole purpose is to allow resistance to be placed in series with the rotor windings while starting figure below. Similarly figure shows the disassembled view of a slip ring motor a stator b rotor c bearing. Rotor side control of high power slip ring induction motor using a. Slip ring motor fundamentals bright hub engineering. 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.
930 917 818 1345 1501 284 1071 629 1249 525 75 76 1374 1418 421 194 1260 163 145 549 727 1346 1301 260 842 324 511 188 919 1500 895 786 748 243 262 36 261 1081 1180 304 952 1026 187 983 504 150