For induction motor, 0 three phase power supply is connected to the three phase stator winding of induction motor, a rotating magnetic field is produced in the air gap. Different types of fault in three phase induction motor. The difference in speed between rotor, the synchronous speed and the rotating. The stator of an induction motor is in principle, the same as that of a synchronous motor or generator. For better understanding, the basic operation and control principle of 3 phase ac induction motors is described in section 2. One single phase wattmeter plus miscellaneous apparatus as needed. The stator in the electric motor generates the field current which rotates in a stable speed based on the ac frequency.
A three phase induction motor runs on a three phase ac supply. Servicing usually requires that the motor be sent to a motor repair shop for rewinding. It requires least maintenance as compared to other electrical motors. An induction motor essentially consists of two main parts. Three phase induction motor faults and their causes. Compare the rotation of this motor with that in figure 164. Methods of starting three phase induction motors as we know, once a supply is connected to a three phase induction motor a rotating magnetic field will be set up in the stator, this will link and cut the rotor bars which in turn will induce rotor currents and create a rotor field which will interact with the stator field and produce rotation. Induction motor different types of duties in motor construction how induction motor as a rotating transformer how to run three phase motor on single phase power supply induction motor interview question slip ring induction motor srim vs squirrel cage induction motor scim synchronous watt types of encloser employed in induction motor types of insulation class.
In this application note, the methods to generate different pwm waveforms for 3 phase ac induction motor using an infineon 16bit microcontroller xc164cs are introduced. Generally, two types of induction motors are used in our industry such as wound rotor and squirrel cage rotor, but their faults are almost same. Here we have classified these faults in three types, but these are further sub divided. The working of the synchronous motor mainly depends on the 3 phase supply. Today we are going to made available a powerpoint presentation file for all. The induction motor is the most widely used motor in the industry due to its simple and rugged construction. The starting methods of three phase induction motor generally are directonline starting, reducedvoltage starting and soft starter. A 3 phase induction motor can be used for different applications with various speed and load requirements. Perform an analysis on induction machines which is the most rugged and the most. An induction motor can therefore be made without electrical connections to the rotor. In this case, power flows from the mechanical system, to the rotor circuit, then across the air gap to the stator circuit and external electrical system. As previously, we have covered a lot of important topics.
Induction motor totallyenclosed fancooled nema standard epact three phase induction motors sdesign versatility teco totally enclosed fan cooled squirrelcage induction motors are designed, manufactured and tested to meet or exceed the latest nema, ieee, csa and. The induction motor stator resembles the stator of a revolving field, three phase alternator. Safe running speed for the squirrelcage induction motors. An induction motor also known as an asynchronous motor is a commonly used ac electric motor. The stator carries a 3 phase winding and is fed from a 3 phase supply. An843, speed control of 3phase induction motor using pic18 mcus. The singlephase induction motor is much the same in construction as the threephase motor. The rotor is separated from the stator by a small airgap which ranges from 0. You should also make a dc measurement of stator winding linetoline resistance. The rotor is connected to the mechanical load through the shaft. Types of single phase induction motors electronics hub. Record all nameplate information for the induction motor. A 3 phase induction motor uses current delivered in three phases in a sequence into the coils of a stator to create a rotating magnetic field.
Three phase induction motors are further divided into two types. Induction motor seminar ppt, pdf report study mafia. Both types are popular but for larger sizes the induction motor is the most highly. The squirrel cage motor is mostly started by stardelta stater and hence the stator of squirrel cage motor are delta connected. Understand the principle and the nature of single phase and 3 phase induction machines. Uses soft magnet rotor that is magnetized by the application of current in the stator coils 3. These types of motors are known as selfstarting induction motors. Squirrel cage wound rotor with slip rings the rotating magnetic field. Slip ring rotor or wound rotor or phase wound rotor.
Synchronous speed is determined by the number of poles p and frequency f of power supply. A wound rotor, has a 3phase winding similar to the stator winding. In an induction motor, the electric current in the rotor needed to produce torque is obtained via electromagnetic induction. A 3 phase, y connected, 460 volt line to line, 25 horsepower, 60 hz, 8 pole induction motor has the following constants, in ohms per phase referred to the stator.
Squirrel cage induction motors a stator construction. Rotates a number of degrees with each electric pulse. In a good preventive maintenance program with detailed checks, the person in charge should have a record card on file for every motor in the plant. Three phase induction motors draw six or more times rated current when started at rated voltage. Types of single phase induction motors as mentioned above that, due to the rotating magnetic field of the stator, the induction motor. 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. Unit 16 electric motors washington state university. For this example, refer to the motor equivalent circuit and calculations described above.
Threephase motors have fewer components that may malfunction than other motor types. The slip ring three phase induction motor are started by inserting resistances so, the stator winding can be connected either in star or delta. Difference between single phase and three phase induction. An induction motors rotor can be either wound type or squirrel cage type. The winding wound on the stator of three phase induction motor is also. Systematic and periodic inspections of motors are necessary to ensure best operating results. If a 3o motor is the problem, the motor is serviced or replaced. Free download induction motor seminar ppt, pdf report. 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.
The rotor winding terminals are connected to three slip rings which turn with the rotor. For slip ring induction motor, by providing external resistance in rotor circuit we can also limit starting current. There are two types of rotors which are employed in 3 phase induction motor. Unless otherwise the name plate specifies, all the squirrelcage, 3 phase, induction motors lower than v and smaller than 315 frame size can safely run continuously at the speed in the table below. Figure 3 5 shows a basic alternator with its single phase output voltage. Consequently, the rated output of 100 horsepower should be derated to approximately 82 hp to reduce the possibility of damage to the motor. The single phase motor stator has a laminated iron core with two windings arranged perpendicularly. Therefore, induction motor protection plays an important role in its long life service. In this application note, we will generate a third pwm in software, using a general purpose timer and an io pin resource that are readily available on the picmicro microcontroller.
The stator of an induction motor consists of 3 phase windings, which when connected to a 3 phase supply creates a rotating magnetic field. The threephase induction motor is the extensively used for various kinds of industrial drives. Types and construction of three phase induction motor. Types of electric motors electric motors dc motors other motors h ac motors s unt motor separately excited. My original aim was to bridge the gap between specialist textbooks which are pitched at a level too academic for the average user and the more prosaic handbooks, which are full of useful detail but provide. What is the operating principle of a 3ph induction motor. There are two types of 3 phase induction motors based on the type of construction of rotor. The conductors are heavy copper or aluminum bars fitted in each slot and shortcircuited by the end rings. Three phase induction motor for industrial general purpose toshiba. To get a good understanding of the working principle of a three phase. Single phase induction motor the single phase induction machine is the most frequently used motor for refrigerators, washing machines, clocks, drills, compressors, pumps, and so forth.
The rotor of three phase induction motor consists of a cylindrical laminated core with parallel slots that can carry conductors. Generally, it is known as the asynchronous motor because its running speed is less than its synchronous speed. Principle of operation of single phase induction motor. The very first thing that you should do before starting any type of maintenance on a motor is a visual inspection, a lot of times the trouble can be found just by looking, because if the problem is that bad then it should be very obvious by observation. One way to reduce the starting current is to start the motor at reduced voltage.
Y2 series 3 phase induction motors are widely used as drive mechanism in various kinds of machineries like machine tools, pumps, fans, compressors, gear boxes, etc. Designation explanation of induction motor type 160 m operating conditions 1 3. Determination of the losses in induction machines due to harmonics pdf. When we connect the primary winding, or the stator to a 3 phase ac source. It is true that single phase motors are less efficient substitute for 3 phase motors but 3 phase power is normally. Directonline starting this kind of starting mode is the most basic and simplest in the motor starting. Explain starting methods of 3 phase induction motor. Induction motor 1 chapter 3 induction motor bee23 electrical machine power system 2 learning outcomes. Rfoc of a single phase induction motor im with two asymmetrical main and auxiliary windings. Nov 27, 2019 an electrical motor is an electromechanical device which converts electrical energy into mechanical energy. Download 3 phase induction motor powerpoint presentation. After looking at some of the considerations for fullvoltage starting, we will consider several. Just like any other motor, a 3 phase induction motor also consists of a stator and a rotor. Two types of induction motors single phase induction motor.
At the end of the lecture, student should be able to. They can be used in control of motors used in conveyors and other machinery. The main difference between single phase induction motor and three phase induction motor is that single phase motors are not selfstarting so they require some starting mechanism while three phase motors are selfstarting. Squirrel cage induction motor and wound rotor induction motor based on the construction of rotor.
An induction motor im is a type of asynchronous ac motor where power is supplied to. Maintenance and troubleshooting three phase induction motor. The speed of this rotating magnetic field is called the synchronous speed. One is almost identical to that of the three phase induction motor while the other is of a form similar to that of the d. They run at a constant speed from noload to the full load. Windingrotor arrangements for 3 phase induction machine three phase slip ring induction motor. The effect of unbalanced voltages on polyphase induction motors is equivalent to the introduction.
The magnet is spun by a 3 phase ac motor with no rotor voltage 4. First of all, i am going to discuss about the construction of 3 phase induction motor and then i. Some singlephase induction motors are also called squirrel cage motors because of the rotors similarity. 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. The rotors of the three phase induction motor are further classified as. Advantages of 3 phase induction motor generally easy to build and cheaper than corresponding dc or synchronous motors induction motor is robust. The individual voltages, therefore, add to produce a single phase ac voltage. Unit 16 electric motors objectives after studying this unit, the student will be able to state the purpose of an electric motor. Single phase induction motors are used primarily for domestic and lightindustrial applications where three phase supply is generally not available. It is made up of a number of stampings, which are slotted to receive the windings. Therefore, 3o motors usually operate for many years without any problems. An induction motor or asynchronous motor is an ac electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding. It is desired to install a 3phase cage induction motor restricting the maximum line current drawn from a 400 v 3phase supply to 120 a.
This induces an electric field in a coil or squirrel cage to drive a rotor. Unlike a 3 phase induction motor, a single phase induction motor is not self starting but requires some starting means. 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. The three phase induction motors are simple in construction, rugged, low cost and easy to maintain. This application note also covers the basics of induction motors and different types of induction motors. Phase wound induction motor slipring induction motor. For instance, a 100 horsepower, three phase motor operating with voltages of 598, 575 and 552 applied at the motor terminals is running with a 4% voltage unbalance 100 x 23575.
Refer back to this diagram as the operational requirements of the singlephase motor are discussed. There are two basic reasons for the use of single phase motors rather than 3 phase motors. Such high currents may pose serious problems for the motor and the electrical system when large motors are started. Three phase induction motor provided with the different starter like stardelta starter, autotransformer starter and dol starter etc. Ap1609710 different pwm for three phase acim 060803 for pdf. An induction motor or asynchronous motor is an ac electric motor in which the electric current. The ideal motor maintenance program aims at preventing breakdowns rather than repairing them. Analysis of three phase induction motors controlled by thyristors. For reason of economy, most houses, offices and also rural areas are supplied with single phase a. Ac induction motors are also the most common motors used in main powered home appliances. The first ac commutatorfree threephase induction motors were. The major difference between them is that transformer is static in nature i. A 3 phase induction motor has two main parts i stator and ii rotor.
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