It is a machine which converts electrical energy into mechanical energy. This paper describes the speed control of a dc shunt motor using conventional controllers pid, imc and fuzzy logic controller based on matlab simulation program. The resulting torquespeed characteristic of a shunt dc motor is shown in fig. Speed control of dc shunt motor your electrical guide. Speed control of shunt dc motor johurul islam academia. Cwdc motors have higher torque than a shwdc motor while offering better speed control than a swdc motor.
As such, the field windings and armature are connected in a parallel combination, and in electrical terminology a parallel combination is known as a shunt. Lathes, drills, boring mills, shapers, spinning, and weaving machines series motor. A simple explanation of how to control the speed of a dc motor. This system is used where very sensitive speed control of motor is required e. Selfexcited field motors can be series, shunt, or compound wound connected to the armature. Since they are connected in parallel, the armature and field windings are exposed to the same supply voltage. Speed control of dc shunt motor electric motor direct current.
Speedcontrolofdcshuntmotor page 1 experiment no 9 aim. Speed control can be achieved using dc drives in a number of ways. By means of this method, the motor can be worked at any speed up to its maximum speed. A thyristor bridge is a technique commonly used to control the speed of a dc motor by varying the dc voltage. By decreasing the flux, the speed can be increased and vice versa. Many dc motors use an electromagnet for the stator, as illustrated in figure 27. In this article we are going to discuss about brake test on d. Speed control methods of dc motor speed control of. The arrangement of this system is as shown in the figure at right. Speed control of dc shunt motor using microcontroller and. This paper discusses the speed and torque control of a shunt dc motor through matlab simulink simulations.
Previously, you saw that a dc motor is made up basically of a fixed magnet stator and a rotating magnet rotor. With some products, velocity mode operation can include capacity for regeneration. In order for a dc motor to run, current mu st flow in the armature winding and the stator must develop a magnetic field flux, either by means of a shunt winding or a series winding or both. This is also well known that the dc machines can be used as a generator as well as as a motor, their is the difference of operation in both case i. Pulsewidth modulation pwm or dutycycle variation methods are commonly used in speed control of dc motors. This type of dc motor is only used for direct coupling and other work where the load or part of the load is permanently coupled to the motor this will be seen from the speedtorque characteristic, which shows that on no load or light load the speed will be very high and therefore dangerous.
Ward leonard control smooth variation of voltage, on the other hand, produces a flat characteristic with. The dc motor converts the mechanical power into dc electrical power. Speed control methods of dc shunt motor my tech info. The torque developed by a dc motor is directly proportional to the armature current and the stator flux. And the armature winding is connected to external supply voltage hence it plays the role of current carrying. Though there are separate branches for the flow of. The terminal voltage of the armature, v the external resistance in armature circuit, r a the flux per pole. Working principle of dc shunt motor your electrical guide. When a current carrying conductor is placed in a magnetic field, it experiences a force. The speed of a shunt motor can be changed by flux control method.
A dc shunt motor also known as a shunt wound dc motor is a type of selfexcited dc motor where the field windings are shunted to or are connected in parallel to the armature winding of the motor. Though there are separate branches for the flow of armature current and field current. M1 may be any ac motor or dc motor with constant speed. The flux of a dc motor can be changed by changing ish with help of a shunt field rheostat.
Pdf this paper discusses the speed and torque control of a shunt dc motor through matlab simulink simulations. The dc shunt motor is 120vdc with rated speed of 1800 revolutions per minute. Therefore speed of the 3 types of dc motors shunt, series and compound can be controlled by changing the. The flux is dependent on the current through the shunt field winding. Speed control of dc shunt motor with field and armature rheostat control 79 2. Apparatus type range quantity 1 voltmeter mc 0300v 1 2 ammeter mc 020a 1 3 rheostat 1250. The actual values for a given load, speed, and motor vary. He has 8 years of experience in customer support, operations and. Speed control of dc motor using pulse width modulation, 555.
Thus flux can be controlled by adding a rheostat variable resistance in series with the. Speed control of dc motor shunt motor and series motor. The voltage applied to the motor may be reversed by backing the field current of generator through controller fc. The high number of turns allows a strong magnetic field to be generated, but the smaller gauge wires provide a high resistance and limit the current flowing through the shunt coil. I discuss the field resistance methos of speed control of dc shunt machinesthis lecture is a bit longbut it is worth it i have also put a summary of the lecture in pdf. Simplified dc motor with an electromagnet as stator. Thus the speed of dc motor is given by, eb v i a r a. The brushed dc electric motor generates torque directly from dc power supplied to the motor by using internal commutation, stationary magnets permanent or electromagnets, and rotating electromagnets advantages of a brushed dc motor include low initial cost, high reliability, and simple control of motor speed. The simple rheostatic method provides a speed torque characteristic dc shunt motor with little hardness and little stability. In this project, i will show how speed control of dc motor can be implemented using 555 and pulse width modulation pwm. Tarun agarwal is the chief customer support officer at edgefx technologies pvt ltd. This type of motor has good speed regulation even as the load varies, but does not have the starting torque of a series dc motor. Speed control of dc shunt motor with field and armature. Motors plays an important role in energy conversion process.
The voltage equation of a dc motor is where e b is the back emf, v is the supply voltage, i a the armature current, and r a is the armature resistance again, the expression of back emf in a dc motor is where. Voltage values given in these examples are used for explanation only. Electrical machinel dc laboratory manual grietelectrical and. In the armature control method, the speed of the dc motor is directly proportional to the back emf eb and eb v iara. For example, cpu fans, fume extinguishers, toy cars etc. Brake test also called as direct loading test of testing the motor. The concept of the speed regulation is different from the speed control. Speed control of dc shunt motor free download as pdf file. The armature of the shunt motor m whose speed is to be controlled is connected directly to a d. To study the methods of controlling the speed of shunt dc motor. A shunt dc motor connects the armature and field windings in parallel or shunt with a common d.
To control the speed of dc shunt motor by armature control method and field control method apparatus requirred. Therefore speed of the 3 types of dc motors shunt, series and compound can be controlled by changing the quantities on the righthand side of the equation above hence the speed can be varied by changing. Dc shunt motor speed control and analysis using ziegler. Speed control of dc motor shunt, series and compound. Ac induction motor speed control so what can we do to control the speed of an ac induction motor. Speed control of dc shunt motor with field and armature rheostat. This equation is called the dc motor speed equation and is just a straight line with a negative slope. The characteristics of a shunt motor reveal that it is an approximately constant speed motor. Before discussing the speed control of dc motor, let us first establish the expression of the speed of a dc motor. Disadvantages are high maintenance and low lifespan for high. As resistance increased, the value of the field current will reduce. We use dc motors in many systems in our day to day life. Working principle from the above circuit diagram, we can conclude that if we want to increase the speed of the shunt motor, we will vary the field resistance.
Dc drives offer the ability to control the speed and torque of heavyduty dc motors in various industrial and other similar applications. Brake test is also a method of finding efficiency of dc motors. Dc shunt motor speed control and analysis using ziegler nichols algorithm with pid controller yogesh sharma l,a shis patra 2 1, 2 electrical engineering department, m. In the case of a dc motor, the magnetic field is produced by the field winding. Theory the back emf for a dc motor is given by, p nz back emf, e b 60 a the number of poles, p the armature conductors, z and the number of parallel paths, a are constant for a particular machine. Working principle of dc shunt motor, dc series motor and all other dc motors can be stated as follows. Brushed dc motor fundamentals microchip technology. A dc motors speed and torque characteristics vary according to three different magnetization sources, separately excited field, selfexcited field or permanentfield, which are used selectively to control the motor over the mechanical loads range. As you know that the construction of any type of dc motor is very similar to a dc generator. Speed control of a dc motor using controllers science.
The dc shunt motor construction is the same as any type of dc motor. Dc starter face plate type suitable for above motor. On occasion, a field regulator is contained within the field circuit of dc shunt motor for additional speed adjustment. Therefore the voltage drops i a r a will be negligible as compared to the external supply voltage v. The field of the shunt motor is supplied from a constantvoltage exciter e. One of the most important features of the dc motor is that their speed can easily be control according to the requirement by using simple methods. Examples of how a dc rectifier bridge operates are given on the next few pages.
Voltage can be applied to the terminals of the dc motor or external resistance can be applied in the armature. Speed control of dc motor using pulsewidth modulation. The shunt motor runs at a speed defined by the expressions. Because loading will be applied directly on shaft of the motor by means of a belt and pulley arrangement.
When supply voltage v and armature resistance ra are kept constant, the speed is directly proportional to armature current ia. A mathematical model of the process has been developed using real plant data and then conventional controllers and fuzzy logic controller has been designed. The duty cycle is defined as the percentage of digital high to digital low plus digital high pulsewidth during a pwm period. Compoundwound dc motors basic drive circuits drive circuits are used in applications where a controller of some kind is being used and speed. Control of motor torque and velocity or speed are operating mode selections available to most basic dc drives and to some flux vector type ac drives. The shunt field windings of a dc shunt motor are made of smaller gauge wire, but they have many more turns than a serieswound dc motor. In this type figure 1 the field is in series with the armature.
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