Modeling of linear induction machines for analysis and control. The linear induction launcher lil is an aircored electromagnetic coil launcher operating on the principle of the induction motor. Because duty cycles less than 100% allow time for the motor to cool, a lower duty cycle allows all linear. Induction motor seminar ppt, pdf report study mafia. What is a linear induction motor and how does it work. The result is a flat stator, or upper section, of iron laminations.
Nov 04, 2016 vivek brahmbhatt already has explained very nicely the construction of lim. Singlesided linear induction machines featuring secondary conductive coating pdf. Mec design and construction of a pulsed linear induction motor. Calculating linear motor requirements baldor motion. The rotor will constantly be turning to align its magnetic field with that of the stator field. The linear induction motor science publishing group. It has three phase winding housed in slots in a field system. Motion and temperature heat control are paramount in energy. Each aircored linear induction motor has a primary winding consisting of a linear array of coaxial circular coils, and a secondary which is a cylindrical conductive sleeve concentric with the primary. Electric energy and induction motors the level of prosperity of a community is related to its capability to produce goods and services. The shape and operation of a linear induction motor can be visualized as depicted in the figure by making a radial cut in a rotating induction machine and flattening it out. A linear motor is an electric device that provides an electromagnetic force by causing a direct and linear movement to a subject, and a structure in which a cylindrical rotary motor is developed linearly can be considered.
Construction of a pulsed linear induction motor induction launc hers feasible within the scop e of a small undergraduate pro ject. If another type of motor was used for the same purpose, being used for that purpose instead of another purpose wouldnt cause it to be called a linear induction motor. Numerous applications of lims can be found in industry today, one of the most interesting being high speed magnetic levitation railway systems. Multiobjective optimization of singleslide linear induction motors using kriging surrogate model. View linear induction motor research papers on academia.
A finite length of the primary part of a linear induction motor lim contributes to nonuniform magnetic field distribution in an airgap. For singlesided assemblies, the reaction plate consists of 18in. Simple method of linear induction motor redesign sciencedirect. First of all mentions linear induction machines in 1890, only two years after the discovery of the rotary induction principle. In a traditional electric motor, the rotor rotating part spins inside the stator static part in a linear motor, the stator is unwrapped and laid out flat and the rotor moves. They may replace a traditional lift hill and brakes. Most linear motors are used in the machine construction industry and for production automation purposes. Induction motor theory jerry bednarczyk, pe course content introduction the ac induction motor is well suited to applications requiring constant speed operation. The simplest form of construction of a linear motor is as simple as a three phase induction motor. A parallel history of linear induction motors with applications in linear. Perphase equivalent circuit of a linear induction motor lim.
Electric motor electric motor linear induction motors. Design of a single sided linear induction motor slim using a user interactive computer program a thesis presented to the faculty of the graduate school university of missouricolumbia in partial fulfillment of the requirements for the degree master of science by sarveswara prasad bhamidi dr. A linear induction motor or lim is a special type of induction motor used to achieve rectilinear motion rather than rotational motion as in the case of conventional motors. It explains what linear induction motors are used for but the definition of a linear induction motor doesnt state that its used for a certian purpose. Motorsector induction motorlinear induction motorproperties of a linear induction motormagnetic. A linear induction motor lim is an alternating current ac, asynchronous linear motor that works by the same general principles as other induction motors but is typically designed to directly produce motion in a straight line. They have since been superseded by linear synchronous motor technology. I would just like to add some practical applications of lim. Thus the leakage reactance of the linear motor is decreased and.
Linear induction motor background alternating current ac electric motor powered by a three phase voltage scheme force and motion are produced by a linearly moving magnetic field used in industry for linear motion and to turn large diameter wheels 6 4. The duty cycle of a motor is defined as the time the motor receives power during a cycle divided by the total time of the cycle. A linear induction motor lim is a form of electromagnetic propulsion containing no moving parts. The linear induction motor offers considerable advantage at high speeds, it is not limited by centrifugal force and is independent of adhesion. The linear induction motor is designed for high speed operation. Nov 11, 2011 the linear induction motor is designed for high speed operation. Allows you online search for pdf books ebooks for free downloads in one place.
When a linear motor receives power for more than thirty 30 seconds, it is operating at a duty cycle of 100%. The aim this researc h pro ject is to dev elop a linear induction motor system capable of op erating at 400 v olts with an initial energy of 25 j to in v estigate the lo w feasibilit y op erating concept and erify. They are capable of speeds up to 1800 insec 45 ms and are typically used in applications where accurate positioning is not required. It causes the current asymmetry if the primary winding is supplied from a symmetrical voltage source. An induction motor can be used as an induction generator, or it can be unrolled to form a linear induction motor which can directly generate linear motion. A linear induction motor comprises an inductor, which has a magnetic circuit comprised of first and second groups of laminated cores and also has a multiphase concentrated winding, and a secondary element having an electrically conductive member disposed on a magnetically conductive base. Linear induction motors lim are used extensively in industrial applications, especially in transportation systems. Pdf construction of three phase linear induction motor. Calculation method of linear induction motor supplied from. Free download induction motor seminar ppt, pdf report. Theory of linear induction motors yamamura, sakae on. The basic idea of an electric motor is to generate two magnetic fields. A linear induction motor lim is a specific type of alternating current ac, multiplephase machine that provides force and movement in a linear direction.
May 31, 2016 linear induction motor lim is an asynchronous motor, working on the same principle an induction motor works, but is designed to produce the rectilinear motion, unlike the rotary movement produced by a motor. The aim of this paper is to present the redesign method of an electromechanical actuator linear induction motor lim and to show advantages of the redesign. A linear motor is similar to a rotary motor but is linear. An ac motors synchronous speed, is the rotation rate of the stators magnetic field. A linear induction motor provides linear force and motion rather than rotational torque. The 3phase set of currents, each of equal magnitude and with a phase. A linear induction motor lim is an alternating current ac, asynchronous linear motor that.
To size a linear motor for a horizontal application you need to know. Typically lim systems launch the roller coaster train from the station extremely quickly. But producing goods and services is strongly related to the use of energy in an intelligent way. Linear induction motor lim is an asynchronous motor, working on the same principle an induction motor works, but is designed to produce the rectilinear motion, unlike the rotary movement produced by a motor. Linear induction motors are less efficient than permanent magnet linear motors, and thus produce more heat for a given continuous force output. This is obtained if we cut the stator of an induction motor from. Performance optimization of linear induction motor by eddy current 771 journal of engineering science and technology december 2011, vol. Linear motors are electric induction motors that produce motion in a straight line rather than rotational motion.
Lim is an advanced version of rotary induction motor which gives a linear translational motion instead of. The induction motor is made up of the stator, or stationary windings, and the rotor. They have since been superseded by linear synchronous motor technology the first use of linear induction motors for launching a train was in 1996. Characteristically, linear induction motors have a finite primary or secondary length, which generates endeffects. Power is nothing without control and whether it is for a roller coaster, a public transportation system or an industrial use, projects that require linear motion often have diverse and in many cases complex control requirements. This video demonstrates the working model of using linear induction motor in movement of train. Construction of three phase linear induction motor. It is simply the primary winding on a stator in case of an induction motor. Engineers who design electric machines need simulation tools that can be employed for quick, accurate product development. Developing an efficient yet powerful linear induction motor lim is key to swissloops future as a sustainable hyperloop transportation company. The lims 3phase coil assembly can be directly connected to the ac line for single speed applications or to an adjustable frequency drive for variable speed control. Design, analysis of linear induction motor based on. Simplified steadystateequivalent circuit of induction motor.
Then, equation 1 can be shown in terms of magnitude as. A polyphase linear induction motor comprising a primary member having magnetic material formed with a polyphase winding and, for cooperating with the primary member, a secondary member comprising electrically conductive material backed by further magnetic material is so arranged that the working flux passes in low reluctance paths lying substantially in planes directed transversely of the motor. Induction motor classification of ac motorsinduction 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. A conducting rod moving in a uniform magnetic field. The laminated cores of the first group are arranged in a perpendicular relation to the direction of. The basic design and construction of a linear induction motor is similar to a three phase induction motor, although it does not look like a conventional induction motor. A finite length of the primary part of a linear induction motor lim contributes to nonuniform magnetic field distribution in.
Linear induction motors can be manufactured in a wide range of force outputs, speeds, and footprints. In this type of motor, the stator and rotor are called primary and secondary respectively. An exhibit at the university of illinois at urbanachampaign engineering open house. In general, the induction motor is cheaper and easier to maintain compared to other alternatives. The direction of any magnetic induction effect is such as to oppose the cause of the effect. Pdf on jan 1, 1994, jacek f gieras and others published linear induction drives find, read and cite all the. Mechanical power and rotor outputlnduction motor equationsynchr0nous wattvariation in rotor with a mechnical clutchanalogv with a d. Pdf electric machines by dp kothari and ij nagrath pdf download. The maximum speed for urban transit is about 70 kmh, with the trains repeatedly performing powering, coasting, and braking operations within relatively short distances between stations. Ac induction linear induction open closed loop polynoid open loop, low duty cycle b stage type preferred. Ppt linear induction motor powerpoint presentation. Linear induction motor lim for hyperloop pod prototypes. Linear induction motor a linear induction motor lim is an advanced version of rotary induction motor which gives a linear translational motion instead of the rotational motion. Passenger and cargo capsules need to be accelerated via some form of a highspeed linear accelerator and a.
But producing goods and services is strongly related to the. A maximum weights of moving load b length of move and overall travel. Each primary is installed along the entire length of the launch structure, but is divided into sections. If the induction motor is operating in the linear magnetic region, the lm is constant. Passenger and cargo capsules need to be accelerated via some form of a highspeed linear accelerator and a lim is believed to be one of the best options for such a system. Vivek brahmbhatt already has explained very nicely the construction of lim. Mar 12, 2007 an exhibit at the university of illinois at urbanachampaign engineering open house. In this leaflet the following information can be found. A linear motor is an electric device that provides an electromagnetic force by causing a direct and linear movement to a subject, and a structure in which a cylindrical. This paper presents a calculation method of the lim performance. This paper explores the construction process of a linear induction motor lim, the basic concepts behind key aspects of linear induction machines construction and the testing process of a working.
The linear motor has a long history similar to that of a rotating machine. Generally, it is known as the asynchronous motor because its running speed is less than its synchronous speed. Chapter 29 electromagnetic induction induction is critical to modern industrial life. The changes are made keeping the original flavor of the book intact, that is, indepth coverage of fundamental concepts. Pdf electric machines by dp kothari and ij nagrath pdf. Characteristically, linear induction motors have a finite primary or secondary length, which generates endeffects, whereas a conventional induction motor is arranged. Were the power required to overcome air resistance and achieve adequate acceleration provided by conventional means, bulk and mass would be excessive. As a result, they often require forced air or watercooling to achieve published specifications. In this thesis, the analysis of the dynamic response of a linear induction motor as an electromechanical system is done, accounting for all the governing equations implied in. Normally lim is used to make a motion frictionless absolutely. High velocity linear induction launchers sciencedirect.564 425 178 371 613 1209 169 452 756 609 998 113 190 1094 1397 1227 882 1030 952 1127 288 799 452 968 1239 322 160 109