Development of the induction motor equivalent circuit. 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. A threephase induction motor problem enginuity systems. Along with variable frequency ac inverters, induction motors are used in many adjustable speed applications which do not. The induction motor is made up of the stator, or stationary windings, and the rotor. Applications of threephase induction motors of size varying from half a kilowatt to thousands of kilowatts are numerous. The capacitor motor, which belongs to the singlephase induction motor, is explained in this video. Ac induction motors are also the most common motors used in main powered home appliances. A 3phase induction motor uses current delivered in three phases in a sequence into the coils of a stator to create a rotating magnetic field. Horizontal squirrel cage mediumvoltage induction motor. Induction motor is one of the most important motor used in industrial applications. A three phase supply is given to the stator of the induction motor. Squirrel cage wound rotor with slip rings the rotating magnetic field. The singlephase ac induction motor best fits this description.
Squirrel cage wound rotor with slip rings the rotating magnetic field the basic idea of an electric motor is to generate two magnetic fields. Motor speed relationship the synchronous speed of an ac motor is the speed of the rotating magnetic field set up by the stator winding synchronous speed rpm 120 x frequency divided by the number of poles. Safety information 1 description 2 transport, assembly, and connection 3 startup 4 operation 5 faults 6 maintenance 7 spare parts 8 notes 9 threephase induction motor ac compact drives 1ph728 operating instructions edition 032008. So obviously the speed of an induction motor can be controlled by varying any of three factors namely supply frequency f, number of pole p or slip s. Advantages of 3 phase induction motor generally easy to build and cheaper than corresponding dc or synchronous motors induction motor is robust. The basic idea of an electric motor is to generate two magnetic fields. The torque the motor produces changes proportionally to roughly. The threephase induction motor is the extensively used for various kinds of industrial drives. With the singlephase motor, the starting torque is generally smaller than the operating torque, while the threephase motor features a relatively greater starting torque. The induction motor, which is the most widely used motor type in the industry, has been favored because of its good selfstarting capability, simple and rugged structure, low cost and reliability, etc.
In general, the induction motor is cheaper and easier to maintain compared to other alternatives. The rotor has salient poles and a cage so that it starts like an induction motor, and runs like a synchronous motor. The model created by rmxprt will then be used as an input for empulse as a basis for performing more detailed analysis and for increasing the accuracy of the performance pre. The equation that relates motor load to measured current values is shown in equation 4. Zone 1 hazardous area 2 the objective of this handbook is to provide a thorough and concise source of information concerning p type motors manufactured at electric machinery em. Multiplemotor ac crane drives with the use of a source of opposed voltage in the rotor circuit of an induction motor are examined. Induction machines are considered relatively reliable and robust due to their simple design and welldeveloped manufacturing technology. In an induction motor, the electric current in the rotor needed to produce torque is obtained via electromagnetic induction.
The main methods employed for speed control of induction motors are as follows. Stator winding spreading the coil in this manner creates a sinusoidal flux distribution per pole, which improves performance and makes the motor less noisy sound and electrically. Its starting torque is somewhat inferior to that of a d. Fall 2005 ee595s electric drive systems 2 overview of strategies voltsperhertz control constant slip control fieldoriented control. According to the type of rotor, an induction motor is divided into two types. Speed control of induction motors the speed of an induction motor is given as n 120fp 1s. It is estimated that more than 50 billion dollars could be saved annually by replacing all dumb motors with controlled ones. Introduction to induction motor the engineering projects. The most common type of ac motor being used throughout the work today is the induction motor. Coordination and standards tesys motor starters open version d. Our main office which is located in singapore, sits on an area of 90,000 square feet. Simulink model of three phase induction motor file.
You should also make a dc measurement of stator winding linetoline resistance using a dmm. As the name suggests, this type of motor has only one stator winding main winding and operates with a singlephase power supply. The synchronous speed of an induction motor depends on the frequency of the power supply and on the. Induction motor theory jerry bednarczyk, pe course content introduction the ac induction motor is well suited to applications requiring constant speed operation. An induction motor also known as an asynchronous motor is a commonly used ac electric motor. They are found everywhere from a small workshop to a large manufacturing industry. This induces an electric field in a coil or squirrel cage to drive a rotor. A threephase induction motor problem this application note describes how to set up, solve, and analyze the results of a twopole, threephase induction motor using rmxprt. 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. Differentiate between the various types of power electronics. However, control of induction machines is a much more challenging task than control of dc motors. Asplitphase induction motor the stator of a splitphase induction motor is provided with an auxiliary or starting winding s in addition to the main or running winding m. Uses soft magnet rotor that is magnetized by the application of current in the stator coils 3.
Single phase and three phase are the two types of an ac induction motor. The most common type of ac motor being used throughout the work today is the induction. The three phase induction motors are simple in construction, rugged, low cost and easy to. Motor technologies for higher efficiency in applications.
Like any other electrical motor, induction motors have two main parts the rotor and the stator. In all singlephase induction motors, the rotor is the squirrel cage type. In traditional designs of 60 hz linefed induction machines, skin effect is represented by correction coefficients k r and k x for bar resistance and slot leakage inductance. Single phase motors are used for smaller loads while 3 phase motors are used in high load applications. Types of ac induction motor rotors there are twotypes of rotor windings. However, should the motor require service, this manual includes a section that assists the.
Record all nameplate information for the induction motor. An induction motor is based on the principle of induction of voltages and currents. Model number m800006 outline dimension drawing see figure 4 nameplate data 1 see figure 5 rated frequency 50 hz motor location indoor altitude less than meters relative humidity less than 90% ambient temp 40 degrees c max duty type continuous weight approx. Threephase induction motor ac compact drives type 1pl622. Equivalent circuit of an induction motor enables the performance characteristics which are evaluated for steady state conditions. The squirrel cage induction motor was designed for an extended service life under very demanding conditions. Equation 4 the slip method the slip method for estimating motor load is recommended when only operating speed measurements are available. This paper aims to represent routine test performing in three phase induction motor.
An induction motor is also called asynchronous motor as it runs at a speed other than the synchronous speed. Do not lift both the motor and driven equipment with the motor lifting means. Construction an induction motor consists essentially of two main parts. Dq based modeling of three phase induction motor is presented in this model. Squirrel cage induction motor is used in lathes, drilling machine, fan, blower printing machines etc. Solution air handling units ac induction motor data supersedes. Each motor type has its own torque speed relationship which. Effects of vfds on induction motors the nonsinusoidal variable frequency output of pwm drives has several effects, including increased motor losses, inadequate ventilation at lower speeds, increased dielectric stresses on motor windings, magnetic noise, and shaft currents. A new system of twinmotor electric drive has been proposed for the traveling mechanisms of cranes. As the name indicates stator is a stationary part of induction motor.
Control and complementary technical tesys p c rotection. The voltage and current is induced in the rotor circuit from the stator circuit for the operation. Lecture 6 three phase induction motors cairo university. The good power factor of an induction motor can be achieved if the average flux density in the air gap is a absent b small c large d infinity ans. When frictional torque in a motor equals the morque from the lorentz force inside the motor, the net torque is zero and a steady operation is achieved. The speed of an ac motor depends on the frequency of the input power and the number of poles for which the motor is wound. The difference in speed between rotor, the synchronous speed and the rotating magnetic field is called the slip. In this type of three phase induction motor the rotor is wound for the same number of. Maintenance safe maintenance practices performed by qualified personnel are imperative. Safety information 1 description 2 transport, assembly, and connection 3 startup 4 operation 5 faults 6 maintenance 7 spare parts 8 notes 9 threephase induction motor ac compact drives 1pl622 operating instructions edition 032008. Threephase induction motor ac compact drives type 1ph728. L starters with fuse protection nf c or din fuses, type am, contactor and thermal overload relay 0. 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. P type induction motor rated 2950 hp, 6000 v, 880 rpm, 8 pole, 60 hz, 3phase.