Speed control of vector controlled induction motors using. Induction motor theory jerry bednarczyk, pe course content introduction the ac induction motor is well suited to applications requiring constant speed operation. An experimental control system is built and tested. Detailed design of the chopper control circuit and the circuits associated with the control system are reported. Squirrel cage induction motor is used in lathes, drilling machine, fan, blower printing machines etc. This article will highlight the important concepts for wound rotor motors that must be understood before purchasing one of these but know it is not allinclusive. You need to select at least 1 product to add in your comparison list. The construction of a stator is the same for both the squirrel cage and slip ring induction motor.
This slip speed depends upon the mechanical load on the motor shaft. High quality wound rotor induction motor from huapu motor, made by a reliable manufacturer from china. Wound rotor tecowestinghouse motor company, a world leader. A plant process is shut down for maintenance once every two years. Apr 05, 2017 a wound rotor induction motor is built for heavy load frequent starts and or limited speed control motoring or generating at large power loads above a few hundred kw. Speed regulation of induction motors with wound rotor. Threephase squirrelcage induction motors are widely used as industrial drives because they are selfstarting, reliable and economical. What makes the wound rotor motor a unique induction machine is its rotor. Vsi with a dynamic capacitor is connected in the rotor circuit for controlling the reactive current in the rotor.
Slip ring induction motor fundamentals pnpntransistor. Rotor resistance speed control similar to rotor resistance starting, this method consists of varying the effective resistance in the rotor of a wound rotor induction motor to vary the speed. Starting method for induction motors a 3phase induction motor is theoretically self starting. Rotor as the name suggests it is a rotating part of an electrical machine, in which current is induced by transformer action from rotating magnetic field. Speed control of wound rotor induction motor pdf objective. Nov 20, 2003 speed control of wound rotor induction motors by ac regulator based optimum voltage control abstract. An induction motors rotor can be either wound type or squirrel cage type. The torque developed in this method is proportional to the square of the supply voltage.
The advent of vector control techniques has solved induction motor control problems. I will tell you about the construction of wound rotor induction motor in the first section. Torque speed characteristics of induction motor slip. Different methods of speed control of threephase asynchronous motor. Speed control of 3phase induction motor using pic18. Jul 17, 2017 the stator of a wound rotor motor is the same as a typical induction motor, but the rotor has a threephase winding, with each of the winding terminals connected to separate slip rings. This paper presents design and analysis of a three phase induction motor drive using igbt.
Refer to appendix c for glossary of technical terms. Slip power recovery system for variable speed operation of. The rotor of the squirrel cage motor has no winding, and there is no need for the rotor to be electrically connected to any electricity. Today i will discuss very important topic speed control of induction motor. In this paper the torque and speed of an induction motor are controlled using a chopper circuit on the rotor side. Speed control we have seen that to operate eyciently an induction motor must run with a small slip. It follows that any eycient method of speed control must be based on varying the synchronous speed of the weld, rather than the slip. This method is applicable to squirrel cage induction motor only. Post glover wound rotor motor resistors wound rotor motors, as opposed to ac induction motors, generate the same torque in both forward and reverse. Controllers for wound rotor motors include for the.
They are commonly used on fans, pumps, conveyors and crane systems. In general, the induction motor is cheaper and easier to maintain compared to other alternatives. Three phase slip ring induction motor my tech info. Squirrel cage rotor wound type rotor or slip ring type rotor squirrel cage rotor in this type. Rotor induction motor at noload and fullload to observe speed control using an. Torquespeed control of wound rotor induction motors using. Jan 09, 2017 this method is applicable to squirrel cage induction motor only. The stator construction is the same in both motors. Here we insist on the classical starting method used for such motors. Speed control kit for induction motors jaycar electronics. Abstract control of induction motor im is well known to be difficult owing to the fact the mathematical models of im are highly nonlinear and time variant.
Speed control of three phase induction motor electrical4u. If the external controller is set at zero resistance, the motor operates almost exactly the same as the squirrelcage motor, since the rotor is shortcircuited. The 3phase set of currents, each of equal magnitude and with a phase. Oct 03, 2016 what are the methods to control speed of wound rotor motors. Speed control of induction motor 7 ways to control. Request pdf speed control of wound rotor induction motors by ac regulator based optimum voltage control wound rotor induction motors are generally used for high torque and adjustable speed. What are the methods to control speed of wound rotor motors. Speed control of wound rotor induction motor using rotor resistance control aim to use variable resistance in the rotor circuit to control wound rotor induction motor speed theory polyphase induction motors are mainly of two types by construction, squirrel cage and wound rotor with sliprings. The speed of a pair of slipring motors can be controlled by a cascade. Large wound rotor induction motors wrim have been used in industries for decades. Variants of this method include rotor power recovery systems using a second machine or. Torquespeed control of wound rotor induction motors using a dc. Speed control of wound rotor induction motor using rotor. Wound rotor motors can be started with low inrush current, by inserting high resistance into the rotor circuit.
Rotor resistanc e control of an induction motor rotor resistance control is also one of the methods by which we can control the speed of the induction motor. With a liquid rheostat, or a static secondary speed control, the wound rotor is an important alternative drive where limited range adjustable speed. The merit of using wound rotor induction motor is to control speedtorque characteristics by inserting external resistance. Learn more about the construction and operation of a slip ring induction motor. The rotor will constantly be turning to align its magnetic field with that of the stator field. The speed torque curves of the wound rotor induction motor. Wound rotor induction motors are generally used for high torque and adjustable speed conditions. Wound rotor induction motors chapter ac motors pdf version.
The motors are rated according to their primary and secondary windings. Operating characteristics of a woundrotor slipring. The technique of starting wound rotor motors with resistance in the rotor circuit is also used for speed control applications. In this paper the speed control problem for a wound rotor induction motor is considered. The slip ring in duction motor has a number of disadvantages compared to squirrel cage motor such as 1. Wound rotor tecowestinghouse motor company, a world. Speed control of induction motor is possible in two sides. Continuous power flowing to the rotor resistor is a considerable heat loss. Speed control of induction motor through the rotor. Oct 10, 2016 a wound rotor induction motor is also known as slip ring induction motor. Historically, it has been used for hardtostart, high inertia fans, or where power system requirements demand a soft start.
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. Since the speed of a wound rotor induction motor may be controlled over a. Maintenance and reliability problems due to brushes and slip rin gs however, a wound rotor srim. Various induction motor speed control methods advantages. An induction motor or asynchronous motor is an ac electric motor in which the electric current. Pdf torque and speed control of wound rotor induction motor. Wound rotor induction motor the engineering projects. Wound rotor motors deliver speed control of heavy and hightorque loads. Diagnostics of rotor and stator problems in industrial. Speed control of wound rotor motors electric motors. Speed control of wound rotor induction motor using.
The stator of an induction motor consists of 3phase windings, which when connected to a 3phase supply creates a rotating magnetic field. The control of dc machines are found to be more expensive over the rotating machines and expected to have frequent maintenance. The wound rotor induction motor has some distinct application advantages. We can achieve speed control of induction motors of the wound rotor type by inserting additional rotor. Speed of 3 phase induction motor needs to varied according to requirement. Speed control of 3 phase induction motor electrical idea. The most commonly used controller for the speed control of. As discussed earlier, a slip ring induction motor is an asynchronous motor, as the rotor never runs in synchronous speed with the stator poles.
This final thesis will mostly be dedicated to induction motors but also to synchronous permanent magnet and reluctance motors. Speed control at the rotor side we can change the speed at the rotor by,by adding some external resistance in the rotor circuitby cascade connection of the motor. The slip ring induction motor could be used for industrial wires where variable speed and high starting torque are prime requirements. Starting of woundrotor induction motors electric equipment. This will link and cut the rotor conductors which in turn will induce a current in the rotor conductors and.
A wound rotor induction motor has a stator like a squirrel cage induction motor, but a rotor with insulated windings brought out via slip rings and brushes. In recent advancements in electric machine and drives, wound rotor motor is extensively used. The speed of a threephase induction motor driving a given load is determined by matching the torquespeed characteristics of the motor and load, as shown in fig. Power supply, dai, wound rotor induction motor 8231, electrodynamometer 8960, timing belt. The speed control of 3 phase induction motor depends on various factors like supplied voltage, frequency, number of poles. The rotor of a wound rotor induction motor is constructed by winding three separate windings in the rotor figure 44 1. In this type of three phase induction motor the rotor is wound for the same number of poles as that of stator but it has less. A wound rotor induction motor is also known as slip ring induction motor. Adjusting the resistance allows control of the speed torque characteristic of the.
The technique of starting wound rotor motors with resistance in the rotor circuit is also used for speed control. The induction motor is made up of the stator, or stationary windings, and the rotor. The rotor of the latter, however, as the name implies, has windings. The three phase induction motors are simple in construction, rugged, low cost and easy to maintain. An843, speed control of 3phase induction motor using pic18 mcus. At lower speeds, either power is wasted in rotor resistances or power is pumped back from the rotor circuit to grid using different standard energy. The closed loop constant vf speed control method is most. Speed control of induction motor 7 ways to control induction.
A wound rotor induction motor has a stator like the squirrel cage induction motor. The squirrel cage rotor is so called because its construction is reminiscent of the rotating. Dec 10, 2015 the rotor of a squirrel cage motor is constructed of bars connected together at each end by shorting rings. Full form kit includes case, doublesided silkscreened pcb, heatsink, cooling fan, hardware and electronics including parts from revised article in august 20. There are two types of induction motors, one with wound type rotor, also called slipring motor and another one with squirrelcage rotor. Select at least one product to add to your shopping list. Speed control of wound rotor induction motors by ac regulator. Their sole purpose is to allow resistance to be placed in series with the rotor windings while. One type is called squirrel cage motor and the other is called wound rotor induction motor wrim. This type of 3phase induction motor has high starting torque, which makes it ideal for applications where standard nema design motors fall short. The stator of slip ring induction motor is very much the same as that of the squirrel cage induction motor, but the construction of its rotor is very much different. The wound rotor motor is particularly effective in applications where using a squirrelcage motor may result in a starting current thats.
Introduction is there ever enough information at hand to analyze a motor problem. Induction motors combine outstanding performance with an advanced longlife design. Therefore the efficiency of three phase induction motor is reduced by this method of speed control. The wellknown multiphase wound rotor asynchronous or induction doublyfed electric machine wridf is the only electric machine system that stations multiphase separately winding sets on the rotor and stator assemblies, respectively. Power factor correction in wound rotor induction motor drive. Wound rotor induction motors and starters powell industries. Adjusting the resistance allows control of the speedtorque characteristic of the motor. Jun 30, 2015 speed control of three phase induction motor 1.
Torque and speed control of wound rotor induction motor by adjusting the rotor resistance with a microcontroller. Home operating characteristics of a woundrotor slipring induction motor fig. The speed of induction motor can be varied by changing supply voltage. Dec 17, 2019 when the speed control of three phase induction motor is done by adding resistance in rotor circuit, some part of power called, the slip power is lost as i 2 r losses. The two factors that determine the speed of the weld, are the supply.
When the speed control of three phase induction motor is done by adding resistance in rotor circuit, some part of power called, the slip power is lost as i 2 r losses. Exercise 1 threephase woundrotor induction machine with a. The basic idea of an electric motor is to generate two magnetic fields. Slip ring induction motor is also known as wound rotor induction motor. This article is devoted to slip ring induction motors. The speed is controlled by changing the external resistance in the rotor circuit. It is a 16 bit highperformance digital signal controller dsc. The speed is controlled by changing the external resistance in the rotor. Induction motors mainly consists of two types rotors which are wound rotor and squirrel cage rotor with similar stator construction.
Speed controls from stator side as well as rotor side are also. Speed control of wound rotor induction motors by ac. Controllers for wound rotor motors include for the stator the same protection and switching functions that are used for squirrel cage motors. A woundrotor motor, also known as slip ring rotor motor, is a type of induction motor where the rotor windings are connected through slip rings to external resistance. In the second section, i would be throwing light on the operation and working principle of wound rotor induction motor. As induction motors are widely used, we will present the cheaper technique to control these motors. A woundrotor motor, also known as slip ringrotor motor, is a type of induction motor where the rotor windings are connected through slip rings to external resistance.
The speed of the wound induction motor can be controlled by connecting an external resistance in the rotor circuit through slip rings. Instead of a series of rotor bars, a set of insulated rotor coils is. The regulation of speed is required in many applications of induction motors, including in electric locomotives and electric driving vehicles. Rotor resistance controls the speed of wound rotor induction motor. If the voltage injected opposes the rotor voltage, the effective rotor current decreases, which instantly affects the torque.
We can change the speed at the stator by, changing the supply frequency, changing the supply voltage and changing the number of stator poles. A special type of ac induction motor, known as wound rotor motors, will be the main. Slip ring induction motor is induction motor where there is 3phase winding on rotor and slip rings are connected with each phase winding. Their sole purpose is to allow resistance to be placed in series with the. Recently the performance of wound rotor induction motor has been greatly enhanced by combination of input voltage control and rotor resistance control simultaneously 9, 10. Winding rotor arrangements for 3 phase induction machine three phase slip ring induction motor a wound rotor or slip ring motor has a 3phase winding, similar to the stator winding. Determination of the losses in induction machines due to harmonics pdf. Speed control of induction motor detailed explanation. In contrast, a traditional induction motor aka squirrel cage motor has windings that are permanently shortcircuited by an end ring. Abstract in this paper the torque and speed of an induction motor are controlled using a chopper circuit on the rotor side. Traditionally, speed control of slip ring induction motor was achieved through varying the rotor resistance. A wound rotor induction motor has a stator like a squirrel cage induction.
An induction motor s rotor can be either wound type or squirrelcage type. What are the methods to control speed of wound rotor. The rotor winding terminals are connected to three slip rings which turn with the rotor. Wound rotor induction motors ac motors electronics textbook. Brushless woundrotor synchronous doublyfed electric.
To use variable resistance in the rotor circuit to control wound rotor induction motor speed. Stator winding can be either star or delta connected depending upon the design. By far the most commonly used ac motor is the induction motor. A major difference between the wound rotor motor and the squirrel cage rotor is that the. Instead of a series of rotor bars, a set of insulated rotor coils is used to accept external impedances. An induction motor can therefore be made without electrical connections to the rotor. Wound rotor induction motors ac motors electronics. As induction motors are widely being used, their speed control may be required in many applications. A wound rotor motor, also known as slip ring rotor motor, is a type of induction motor where the rotor windings are connected through slip rings to external resistance.
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