If the operating slip of the motor with respect to fundamental component voltage is 0. This flux links with the rotor conductors and due to transformer action e. A three phase induction motor runs on a three phase ac supply. This article concentrates only on a threephase induction motor and its protection. However, recently, it has been increasingly used as variable speed motors driven by an inverter. These types of motors are known as selfstarting induction motors. Frequency of supply to the induction motor f pn120 12. It is the diagrammatic representation of the performance of the induction motor. Video lecture on need of three phase supply of chapter three phase circuits of subject basic electrical engineering for firstyear engineering students. Craig 4 in rotational electromechanical devices other than dc machines, torque is produced as a result of one or more magnetic fields which rotate about the air gap of the device. Fall 2005 ee595s electric drive systems 2 overview of strategies voltsperhertz control constant slip control fieldoriented control. Although single phase induction motor is more simple in construction and is cheaper than a 3phase induction motor of the same frame size, it is less efficient and it operates at lower power factor. Threephase induction motor protection systems and its. The power circuit is designed using 25a, 1200v igbt.
A passive filter at the output of power circuit is used to filter the harmonics. Air gap length is a major part of induction motor design. This torque produced by fifth harmonic which works as a braking action is small in quantity, so it can be neglected. It supplies an induction motor ich has a full load speed of 144wh 0 rpm. Chapter 3 induction motor and different speed control methods page no 3. A simple method for operating the threephase induction motor on. Three phase induction motors mcqs with explanatory answers 1. Abstract this research is purposed to establish a new method is good and simple to operate the 3phase induction motor on singlephase power by using the capacitors. The machine designer first assumes the efficiency and power factor at.
Brushless dc motors nyu tandon school of engineering. Find the starting current of 10 hp, three phase 220 v a class motor. Difference is that transformer is an alternating flux machine while induction motor is rotating flux machine. Induction motor is an ac electric motor, having a stator and a rotor just like other motors, but the working principle is a little different which would be discussed further. The torque produced by the 5 th harmonic rotates in the backward direction. Circle diagram of an induction motor its construction. Single phase induction motors electrical engineering info. A synchronous motor is defined by the period of the rotor being synchronized with the frequency of the stator windings current. Circle diagram of an induction motor the circle diagram of an induction motor is very useful to study its performance under all operating conditions. These igbts are protected against surge voltages using snubber circuit. If the load torque on the motor exceeds this value, the motor will stall, i,e. Here we consider only 5 th and 7 th harmonics and rest are neglected. Matlab simulation for speed control of three phase. Design strategy for a 3phase variable frequency drive vfd.
One singlephase wattmeter plus miscellaneous apparatus as needed. The rotor winding terminals are connected to three slip rings which turn with the rotor. Lecture 6 three phase induction motors cairo university. The maximum torque is also termed as pullout torque. The research was conducted at the laboratory of the electrical engineering of the.
The slip ringsbrushes allow external resistors to be connected in series with the winding. If the frequency of 3phase supply to the stator of 3phase induction motor is increased, then. Rotating flux is only possible when 3 phase voltage or poly phase which is 120 degree apart in time is applied to a three phase winding or poly phase winding 120 degree apart in space then a three phase rotating magnetic flux is. Of all ac motor available, a poly phase induction motor is one which is most used in several kinds of industrial drives. Record all nameplate information for the induction motor.
Induction motors have been traditionally used as constant speed motors supplied by the ac power source. Working principle of 3phase induction motor electrical. Fall 2005 ee595s electric drive systems 3 voltsperhertz control history. Because these motors typically only have an onoff state of operation, a vfd is needed if multiple operation speeds are desired. May 15, 2020 ppt threephase induction motor electrical engineering ee notes edurev is made by best teachers of electrical engineering ee. As i mentioned earlier in my article on introduction to induction motors, there are two types of induction motors, single phase induction motor and 3 phase induction motor 3 phase induction motor is the one which operates on three phase ac supply. A single phase induction motor is inherently not selfstaring can be shown easily. Threephase or polyphase motors are of mainly two types. A three phase, 12 pole, salient pole alternator is coupled to a diesel engine running at 500 rpm. 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. Introduction types of electrical machines types of 3ph induction motor basic principle working principle compnents of induction motor application comparision between 1ph i. Need of three phase supply three phase circuits basic. This document is highly rated by electrical engineering ee students and has been viewed 2567 times.
The 3phase induction motor is connected to 3phase bridge inverter as shown in fig. These currents act to produce mmf and ux along the axes of the respective coils. This circuit 3 phase induction motor starter is one such starter. Crawling and cogging of induction motor electrical4u. Find the percentage slip and number of poles of the induction motor.
Reluctance machines, induction machines, synchronous machines, stepper motors, and. Construction and principle of operation of singlephase transformer, emf equation, singlephase autotransformer. Design of a three phase squirrel cage induction motor for. Speed control of induction motor using pwm technique. The construction of the circle diagram is based on the approximate equivalent circuit shown below. Working principle of 3phase induction motor eduction motor works on the principle of electromagnetic induction. When a three phase supply is given to the three phase stator winding, a rotating magnetic field of constant magnitude is produced as discussed earlier. Let us consider the space around b0 and ccoil sides.
It is verylow cost but highly reliable gadget, besides being foolproof. Design methodology the design process of induction motor is an iterative process. Induction machines guru nanak dev engineering college. Introduction to induction motor the engineering projects. In a conventional round rotor induction motor the behavior of the machine is only needed to be calculated ov er one pole pi tch. There are two types of induction motors, one is named as single phase induction motor, while the second one is named as 3 phase induction motor. Three phase induction motors mcqs with explanatory answers. His document describes the design road taken when looking at a 3phase variable frequency drive vfd. The stator winding carries an alternating current which produces the flux which is also alternating in nature. The vsi line voltage has a dominant 5 th harmonic component. Electrical machines electrical engineering ee gate. The major difference between them is that transformer is static in nature i. A synchronous motor can be a type of 3phase ac motor, or not. A 3phase 50 hz square wave 6step vsi feeds a 3phase, 4 pole induction motor.
Speed control of three induction motor by vf method for batching motion system. In the case of three phase ac alternating current operation, the most widely used motor is a 3 phase induction motor, as this type of motor does not require an additional starting device. Construction and operating principle of three phase induction machines. These motor drives are designed to be used in conjunction with a 3phase induction motor. Today, i am going to write about 3 phase induction motor. An electrical motor is an electromechanical device which converts electrical energy into mechanical energy.
667 852 182 1055 1239 1055 65 426 1437 705 269 947 440 59 1248 798 22 478 1288 474 589 1235 233 1350 1317 842 172 1362 1255