For reason of economy, most houses, offices and also rural areas are supplied with single phase a. Due to its simplicity, robustness and low cost, this type of motor is the most widely used and, in practical terms, is quite suitable for almost all types of machines. Determination of the losses in induction machines due to harmonics pdf. 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. 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. Manual on induction motors used as generators volume 10 skat. Slip in induction motor is the relative speed between the rotating magnetic flux and rotor expressed in terms of per unit synchronous speed. An887, ac induction motor fundamentals microchip technology.
The stator of an induction motor consists of 3phase windings, which when connected to a 3phase supply creates a rotating magnetic field. Selection of induction motors for industrial applications part 1 photo credit. An induction motor or asynchronous motor is an ac electric motor in which the electric current. Speed control of induction motor using pwm technique. This paper presents a methodology to compute the inductances of the abc induction motor model considering mixed eccentricity. This tutorial will introduce the user to the fundamental electrical and mechanical principles of ac electric induction motor design and application. The induction motor is made up of the stator, or stationary windings, and the rotor.
We thank you for making this choice, and would ask you to read the contents of this manual. Threephase or polyphase motors are of mainly two types. In high performance drive systems, the motor speed should clo sely follow a. When describing a three phase induction motor by a system of non linear equations, following assumptions are made. The value of slip in induction motor is can never be zero. Induction motor equations engn1931f spring 2017 2 let. This motor always uses both auxiliary winding and condenser not only when starting but also during operation. An induction motor also known as an asynchronous motor is a commonly used ac electric motor. 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. Motor marking for iecex will have a nameplate with the iecex logo, iecex. The sinusoidal stator phase currents fed in the stator coils create a. Find the synchronous speed of 4 pole induction motor which operates at 60 hz.
The induction motor stator resembles the stator of a revolving field, three phase alternator. Introduction this manual provides information on how to safely install, couple to the driven equipment, and maintain the toshiba squirrel cage mediumvoltage induction motor. Induction motors derive their name from the way the rotor magnetic field is created. In this project paper microcontroller based system to control speed of induction motor is developed using pulse width modulation technique 2. Abstract recent trends indicate the use of permanent magnet pm motors because of its energy savings over induction motors. The important characteristics normally shown by a squirrel cage induction motors are crawling and cogging. An induction motor is based on the principle of induction of voltages and currents. S l r the flux in the singleturn coil on the rotor surface is. Premium efficiency motor selection and application guide i acknowledgments the premium efficiency motor selection and application guide and its companion publication, continuous energy improvement in motor driven systems, have been developed by the u. Understanding permanent magnet motor operation and. Differentiate between the various types of generating electric power stations. It is logical that the least expensive, lowest maintenance type motor.
There is no ongoing power associated with a fixed magnetic field, just some fixed energy to hold it there. These motors are suitable for all general applications where an open machine is not applicable due to severe environments such as excessive dirt, dust andor moisture. Manual on inductionmotors used as generators volume 10 published. Crawling and cogging of induction motor electrical4u. The induction motor is classified into a singlephase motor and a threephase motor according to the using power source. Diagnostics of rotor and stator problems in industrial. Synchronous speed, frequency, and poles of the induction motor are related by the formula. Threephase induction motor protection systems and its. That is why such motors are known as induction motors. Most important mcq or objective questions on induction motor are discussed in this page.
Mostafa elshahed objectives learn a brief history of the electrical power systems construction. Manual on induction motors used as generators volume 10 published. Department of energy doe office of energy efficiency and renewable energy eere with support from the copper. List and describe the more commonly used equipment in an electric substation. A portion of rotating magnetic field in a threephase induction motor. Induction implies causing current thru a magnetic field.
The electric motor speed is fixed when ac motor is connected to ac line. The singlephase motor stator has a laminated iron core with two windings arranged perpendicularly. This will link and cut the rotor conductors which in turn will induce a current in the rotor conductors and. An electrical motor is a device that has brought about one of the biggest advancements in the fields of engineering and technology ever since the invention. The motor is mounted in a test rig that allows one to control the torque applied to the motor shaft and to measure both rpm and torque. The stator voltages will be formulated in this section from the motor. Single phase induction motor the singlephase induction machine is the most frequently used motor for refrigerators, washing machines, clocks, drills, compressors, pumps, and so forth. Equivalent circuit of an induction motor enables the performance characteristics which are evaluated for steady state conditions. A 3 phase induction motor can be used for different applications with various speed and load requirements. This article concentrates only on a threephase induction motor and its protection.
Starting method for induction motors a 3phase induction motor is theoretically self starting. Additions to the various factors influencing the selection of. By observing a few essential rules, you will ensure problemfree. By default, the block sets the simulation type parameter to continuous to use a continuous sample time during simulation. The stator or the stationary part consists of three phase winding held in place in the slots of a laminated steel core which is enclosed and supported by a cast iron or a steel frame as shown in fig. In fact, an induction motor can be treated as a rotating transformer i.
Chapter 3 induction motor and different speed control methods page no 3. Selection of induction motors for industrial applications. P number of poles for more details about rotating magnetic field, read production of rotating magnetic field this rotating field passes through the air gap and cuts the rotor conductors, which are stationary. The voltage and current is induced in the rotor circuit from the stator circuit for the operation. Record all nameplate information for the induction motor. Introduction types of electrical machines types of 3ph induction motor basic principle working principle compnents of induction motor application comparision between 1ph i. This paper deals with the basic knowledge for technicians to study about the concept of maintenance of induction motor. This is also the same reason that transformers dont pass dc.
Synchronous motors are special types of motors used in constant speed applications, whereas most of the motors used in the industrial applications are of induction type. L r s and be the angular velocities of the magnetic field line frequency, rotor, and slip respectively. There are two basic reasons for the use of singlephase motors rather than 3phase motors. Dynamic model in space vector form mathematical description of induction motor is based on space vector notation. You should also make a dc measurement of stator winding linetoline resistance using a dmm. Teco totally enclosed fan cooled squirrelcage induction motors are designed, manufactured and tested to meet or exceed the latest nema, ieee, csa and other international standards. Hence, an utmost care should be exercised in selection of most appropriate type of motor considering number of technical factors for each application, so that the motor would provide desired and. The block uses the threephase input voltages to regulate the individual phase currents, allowing control of the motor torque or speed. A threephase ac induction motor is the only type where the rotating magnetic field is created naturally in the stator because of the nature of the supply. The induction motor block implements a threephase induction motor. Crosssection of an elementary symmetrical threephase machine. The squirrel cage induction motor was designed for an extended service life under very demanding. Threephase induction motors are also called asynchronous motors. How an induction motor works by equations and physics.
The induction machine is used in wide variety of applications as a means of. Ggm america is the sales office and authority of ggm co. As a voltage and a current is applied to the stator winding terminals. Understanding permanent magnet motor operation and optimized filter solutions june 15, 2016 todd shudarek, principal engineer mte corporation n83 w330 leon road menomonee falls wi 53154. 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. In addition induction motor types, main parts were discussed. 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. Horizontal squirrel cage mediumvoltage induction motor.