Dec 10, 2015 the rotor of a squirrel cage motor is constructed of bars connected together at each end by shorting rings. Induction motor by thyristor control on rotor side. Slippower recovery scheme is an efficient method of speed control of wound. The 3phase set of currents, each of equal magnitude and with a phase. Improve the speed characteristics of slip ring induction motor by. The speed of induction motor can be varied by changing supply voltage.
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. The proposed drive system uses a matrix converter to transfer the slip energy from the rotor into the mains instead of using acdcac converter whilst the stator side is fixed to the grid. The speed is controlled by changing the external resistance in. Wound rotor motors are an old system for providing relatively efficient operation of a relatively large e. An electric motor is an electrical machine that converts electrical energy into mechanical. In the second section, i would be throwing light on the operation and working principle of wound rotor induction motor. The rotor connections are not brought out at the outside, it is shortcircuited inside of the motor. I will tell you about the construction of wound rotor induction motor in the first section. Speed control of vector controlled induction motors using. Compared squirrelcage induction motor to slipring wound.
Historically, it has been used for hardtostart, high inertia fans, or where power system requirements demand a soft start. To observe the rotor and stator currents at different motor speeds. The advantage to troubleshooting the wound rotor motor is that you can isolate the three basic components from each other to quickly isolate the root cause of any electrical anomaly. Their sole purpose is to allow resistance to be placed in series with the rotor windings while starting figure below. Since the speed of a wound rotor induction motor may be controlled over a. In three phase induction motor, the power is transferred from stator to. We can change the speed at the stator by, changing the supply frequency, changing the supply voltage and changing the number of stator poles.
This last aspect is highlighted in the results of the simulation of the 2. In the case of a squirrel cage induction motor, the rotor is inaccessible and rotor circuit resistance is xed, whereas the wound. 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. Request pdf speed control of wound rotor induction motors by ac regulator based optimum voltage control woundrotor induction motors are generally used for high torque and adjustable speed. 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. 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 however, no power is applied to the slip rings. The rotor of a wound rotor induction motor is constructed by winding three separate windings in the rotor figure 44 1. In previous articles i have discussed the construction, operation, starting, speed control, and classes of squirrel cage induction motors. In this study, the speed and torque of a wound rotor induction motor wrim have been controlled by adjusting the rotor resistance using a microcontroller. Are there single phase wound rotor induction motors. What are the methods to control speed of wound rotor motors. The technique of starting woundrotor motors with resistance in the rotor circuit is also used for speedcontrol applications. Induction motors combine outstanding performance with.
Pdf speed control of multiple induction motors of electromagnetic. Household blenders that advertise many speeds frequently combine a field. Operating characteristics of a woundrotor slipring. The rotor receives its power from an induction process and uses some form of variable external resistance to adjust startup current and speed. Wound rotor induction motors ac motors electronics textbook.
This paper investigates rotorside field oriented control of a woundrotor induction motor using the slip energy recovery principle. Ac induction motor speed control so what can we do to control the speed of an ac induction motor. The same motor action of rotating magnet field in the stator trying to pull the rotor at syn. A 3phase induction motor runs at almost rpm at noload and 950 r. A wound rotor motor regulator is a device that contains highwattage resistors designed to control the speed of a wound rotor motor and to operate in variable speed mode. Post glover wound rotor motor resistors wound rotor motors, as opposed to ac induction motors, generate the same torque in both forward and reverse. A wound rotor induction motor has a stator like the squirrel cage induction motor.
Induction motor is an economical and reliable choice as generator in many wind and running water power turbines where its rotational speed, performance, and. 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. Brushless woundrotor synchronous doublyfed electric. Wound rotor motors sound complex, but fundamentally are the same as your standard ac induction motor. Let us call this procedure additional voltage to the rotor. Speed control works well with variable speed loads like elevators and printing presses. The traditional way to control the speed of a wound rotor induction motor is to increase the slip by adding resistance in the rotor circuit. The motor whose rotor is wound type such type of motor is called slip ring induction motor, whereas the squirrel cage motor, has a squirrel cage type rotor. Featuring a rugged design, these machines provide the unique ability to gradually bring up to speed highinertia equipment and large loads smoothly and easily. The wound rotor motor is particularly effective in applications where using a squirrelcage motor may result in a starting current thats. The wound rotor induction motor has some distinct application advantages. 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 woundrotorwith sliprings.
The advantage to troubleshooting the wound rotor motor. The rotor of the slip ring motor has a cylindrical core with parallel slots, and each slot consists each bar. 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. 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. Various induction motor speed control methods advantages. The wound rotor induction motor sometimes called a slipring motor is a variation on the standard cage induction motors. When a large induction motor is running at its rated load and speed the slip will be only. Wound rotor induction motors are generally used for high torque and adjustable speed conditions. A wound rotor motor is a three phase induction variant that features speed control capacity and greatly reduced current and increased torque values during start up. Wound rotor motors also can develop high starting torque at standstill while maintaining low inrush. The regulation of speed is required in many applications of induction motors, including in electric locomotives and electric driving vehicles. Jan 10, 2019 the rotor conductors of the scim is shortcircuited by end rings. Speed regulation is poor with respect to changing torque loads. Performance parameters control of wound rotor induction motor using ann controller.
This document was uploaded by user and they confirmed. Rotor resistance controls speed of wound rotor induction motor. Why is the rotor resistance method of speed control not. 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 most basic ways to control the speed of a slip ring induction motor is either from the stator or rotor side. The motors are rated according to their primary and secondary windings. Wound rotor motors deliver speed control of heavy and hightorque loads. The simplest speed control scheme for wound rotor induction motors is. Speed is the same rotating magnet field trying to brake the secondary motor to syn speed exactly to prove it, connect a watt meter to the over driven motor and watch the kilo watts being pushed back into the system.
Speed control of induction motor detailed explanation. 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. Is there any advice or similar applications out there that could be helpful. Speed control of wound rotor induction motors by ac regulator based optimum voltage control abstract. Speed control methods for wound rotor ims electric equipment. Adjusting the resistance allows control of the speed torque characteristic of the motor. What makes the wound rotor motor a unique induction machine is its rotor.
Woundrotor induction motors are generally used for high torque and adjustable speed conditions. Performance analysis of double inverter fed wound rotor induction. How to troubleshoot wound rotor motors reliable plant. A wound rotor induction motor is also known as slip ring induction motor. Pdf torque and speed control of wound rotor induction motor.
Abstract experts theorized that a brushless multiphase woundrotor synchronous doublyfed electric machine system bwrsdf, which can symmetrically motor or generatewith variable speed, provides higher efficiency, higher power density, higher torque density, and lower cost than any other electric. On control of backtoback converters and sensorless induction. The researchers have developed various speed control techniques in the recent years for wrim. This speed control technique is only useful over a range of 50% to 100% of full speed. 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.
Conventional induction or squirrelcage motors have a rotor made up of laminated steel bars joined at one end. Stator frequency control as with a cage rotor machine. The proposed drive system uses a matrix converter to transfer the slip energy from the rotor into the mains instead of using acdcac. Speed control of wound rotor motors electric motors. Wound rotor induction motor, fuzzy logic controller, field.
The rotor of a squirrel cage motor is constructed of bars connected together at each end by shorting rings. Speed regulation of induction motors with wound rotor. Instead of a series of rotor bars, a set of insulated rotor coils is used to accept external impedances. The three phase supply is connected to the stator of wound rotor induction motor wrim through uncontrolled rectifier and pwm. Nov 20, 2003 speed control of wound rotor induction motors by ac regulator based optimum voltage control abstract. Wound rotor tecowestinghouse motor company, a world. That is why it is not possible to connect external resistances to rotor conducto. If the slip ring induction motor is started with all the slip rings or the rotor. Compared squirrel cage induction motor to slipring wound. In this paper the speed control problem for a wound rotor induction motor is considered. If you wish to get a much better result, consider using an active front end variable speed controller with the rotor resistors shorted out. I am involved in converting a ball mill, which requires a large amount of starting torque, from a slip ring motor driven application to a vfd driven appl. Speed is the same rotating magnet field trying to brake the secondary motor to syn speed exactly to prove it, connect a watt meter to the over driven motor.
This method is applicable to squirrel cage induction motor only. The speed of slipring induction motor can be controlled by. In contrast, a traditional induction motor aka squirrel cage motor has windings that are permanently shortcircuited by an end ring. The speed torque curves of the wound rotor induction motor. Oct 10, 2016 a wound rotor induction motor is also known as slip ring induction motor. Jan 09, 2017 this method is applicable to squirrel cage induction motor only.
The woundrotor induction motor sometimes called a slipring motor is a variation on the standard cage induction motors. Polyphase induction motors are mainly of two types by construction, squirrel cage and woundrotorwith sliprings. Computer simulation and mathematical modelling of static rotor. This article is devoted to slip ring induction motors. Simplified model of the ivcim drive with conventional pi controller where ref is the reference rotor angular speed, r is the rotor angular speed, e ref r is the tracking speed error, kp is the proportional gain. Almost 80% of the mechanical power used by industries is provided by three phase induction motors because of its simple and rugged construction, low cost, good operating characteristics, the absence of commutator and good speed regulation. The technique of starting wound rotor motors with resistance in the rotor circuit is also used for speed control applications. With a liquid rheostat, or a static secondary speed control, the wound rotor is an important alternative drive where limited range adjustable speed is required. If you wish to use the rotor resistors to control the speed of the motor going down, then you must have the motor trying to drive the load up but with insufficient torque, i. They are commonly used on fans, pumps, conveyors and crane systems. Pdf the proposed method is used to predict the efficiency and power factor of three phase wound rotor. Rotor resistance controls the speed of wound rotor induction motor.
When the rotor of ims is provided with a wound rotor, speed control is performed by adding a variable resistor to the rotor circuit connecting a power converter to the rotor to introduce or extract power from the rotor. Wound rotor induction motors ac motors electronics. Speed control methods for wound rotor ims electric. Woundrotor motors have a threephase winding wound on the rotor, which is terminated to slip rings. Pdf torque and speed control of wound rotor induction. 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. 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. Active and reactive power control of wound rotor induction. Rotor induction motor an overview sciencedirect topics.
One of reliable wound rotor induction motor manufacturer and supplier, contact us, here you can find much competitive prices of high quality wound rotor motor. The torque developed in this method is proportional to the square of the supply voltage. What are the methods to control speed of wound rotor. If the xaxis lies along the line joining the centres of poles rr. When used in this way, a woundrotor motor is called a doublyfed induction generator. High quality wound rotor induction motor from huapu motor, made by a reliable manufacturer from china.
As discussed earlier, a slip ring induction motor is an asynchronous motor, as the rotor never runs in synchronous speed with the stator poles. Construction of three phase induction motor electrical4u. The basic idea of an electric motor is to generate two magnetic fields. The rotor will constantly be turning to align its magnetic field with that of the stator field. Wound rotor motors can be started with low inrush current, by inserting high resistance into the rotor circuit.
Variablespeed electric machine drives are nowadays used various kinds of. Discussion in the previous experiment, we saw that a considerable voltage appears across the rotor windings on open circuit, and that this voltage varies linearly with rotor. Wound rotor motors have a threephase winding wound on the rotor, which is terminated to slip rings. Adjusting the resistance allows control of the speedtorque characteristic of the motor. Performance parameters control of wound rotor i nduction motor using ann controller.
The three phase induction motor is the most widely used electrical motor. Sep 28, 2016 the speed torque curves of the wound rotor induction motor, 2892016 lutfi alsharif. Instead of a series of rotor bars, a set of insulated rotor coils is. Their sole purpose is to allow resistance to be placed in series with the rotor windings while starting. This speed control technique is only usefull over a range of 50% to 100% of full speed. In this thesis, control of the backtoback converter squirrelcage induction ma. With a liquid rheostat, or a static secondary speed control, the wound rotor is an important alternative drive where limited range adjustable speed. In certain applications, such as in regenerative braking with traction motors. Since the slip of an induction motor increases as the rotor resistance increases, some speed control is possible using a wound rotor motor and varying the rotor resistance while running. Where speed of the motor to be controlled from zero. Oct 03, 2016 what are the methods to control speed of wound rotor motors. Speed control of wound rotor induction motors by ac.
The speed regulation is poor with respect to changing torque loads. Controllers for wound rotor motors include for the stator the same protection and switching functions that are used for squirrel cage motors. In that case, both stator and rotor are connected to active sources of power. A wound rotor induction motor has a stator like the squirrel cage induction motor, but a rotor with insulated windings brought out via slip rings and brushes. The speed torque curves of the wound rotor induction motor, 2892016 lutfi alsharif. The operation of the motor can be summarized as follows. Wound rotor tecowestinghouse motor company, a world leader. The speed is controlled by changing the external resistance in the rotor circuit. The rotor conductors of the scim is shortcircuited by end rings. Speed control of wound rotor induction motor using rotor. A woundrotor motor can also be used as a generator by connecting ac to the rotor.
Squirrelcage motors are simpler and cheaper, but harder to control than wound rotor. This paper proposes some design approaches combining pi control technique and fuzzy. We have sent the motor to our motor guy to refurbish and interconnect the rotor windings. Apr 06, 2017 when the rotor of ims is provided with a wound rotor, speed control is performed by adding a variable resistor to the rotor circuit connecting a power converter to the rotor to introduce or extract power from the rotor. This type of 3phase induction motor has high starting torque, which makes it ideal for applications where standard nema design motors fall short. Wound rotor induction motor the engineering projects. Simplified block diagram of the speed control of induction motor using a pi controller 21. Woundrotor motors can be started with low inrush current, by inserting high resistance into the rotor circuit. Speed control of wound rotor induction motor using.