Dc machines 1 dc machines transformsmechanicalenergyintoelectric energywithdc voltage and current dc generatoror dynamo, or conversely dc motor. Let us now solve some problems on shunt, separately excited and series motors. These notes has been made by me after watching nptel lectures given by dr. Time response analysis of dc motor using armature control. This excessive current would operate the overload device, disconnect the motor from the supply, and thus protect the motor. Mod01 lec31 lecture31starting of dc shunt motors 32. Electrical machines i online course video lectures by. Dc shunt motor speed control and analysis using ziegler. This paper discusses the speed and torque control of a shunt dc motor through matlab simulink simulations. It is a machine which converts electrical energy into mechanical energy. Principles and working of dc and ac machines bits pilani. Pdf basic electrical engineering 1st year ebook, notes. This document is highly rated by students and has been viewed 852 times.
Download nptel handwritten notes of dc machine download nptel handwritten notes of induction machine. Shunt wound dc motor or dc shunt motor is a selfexcited dc motor whereas we said before at previous article types of dc motor that it operates on direct current and the field winding is connected in parallel to the armature winding so both windings exposed to the same power supply voltage, and this motor able to maintain at a. Though there are separate branches for the flow of armature current and field current. In this lesson aspects of starting and speed control of d. To limit i a, a resistance is inserted in series with r a then removed after the development of e c a t a r v i.
In order to measure the time response of a dc motor it is necessary to obtain transfer function of the dc motor. Hence the armature current differs and the speed of a dc shunt motor will continue constant which is shown in the fig dotted line ab. So back emf is a controlling factor of armature current. It directly provides rotary motion and, coupled with wheels or drums and cables, can provide translational motion. That is the reason behind naming it a dc shunt motor. Debaprasad kastha, department of electrical engineering, iit kharagpur. Dc machines in dc machines, the field winding is wound onto the stator, while the armature winding is located on the rotor. A 10 hp, 230v dc shunt motor has an armature resistance of 0.
A rotating armature coil passes through a magnetic field that develops between the north and. A common actuator in control systems is the dc motor. On the other hand, back emf reduces marginally more than that the. There are three main varieties of dc motors, all of which make use of the relations above. In mechanical system, speed varies with number of task so speed control is necessary to do mechanical work in a proper way. A 440v dc shunt motor draws 40a while supplying the rated load at 1500rpm. You learn how to commission a direct current shunt motor. Equipment set or individual components direct current shunt motor, direct current series motor laboratory safety cables set of laboratory equipment. Hi friends, this playlist contains dc machinery fundamentals, dc generator and dc motors, these videos cover most of the concept that will need in understand the dc machines, the material used for. 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. Dec 11, 2016 history of dc motor michael faraday u. So, both the w indin gs are supplied w ith same mag nitude of. Equivalent circuit parameters are armature resistance ra 110 ohms, field resistance rf 2.
The armature current can be written as tb a a v e i r where r a is armature resistance, p zn e b 60a i armature current is proportional to back emf. Types of dc motor a direct current motor, dc is named according to the connection of the field winding with the armature. 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. A shunt dc motor connects the armature and field windings in parallel or shunt with a common d. Oct 22, 2018 hi friends, this playlist contains dc machinery fundamentals, dc generator and dc motors, these videos cover most of the concept that will need in understand the dc machines, the material used for. The dc shunt wound motor, running on direct current, has its field windings placed in parallel to the armature. In electrical terms, parallel is generally denoted as shunt. When the motor is connected to the dc supply mains, a direct current passes through the brushes and commutator to the armature winding while it passes through the commutator it is converted into ac so that the groups of conductors under successive field poles carry currents in the opposite directions. In a shunt motor, the field and armature windings are connected in parallel. To limit i a, a resistance is inserted in series with r a. The shunt and series windings are wound on the same pole pieces.
Dc machine are the electromechanical energy conversion devices which converts either dc power to mechanical power or mechanical power to dc power. 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. Selfexcited dc motor is further divided into shunt wound, and series wound motor. V and 1 nd or i f 1 nd where n is the speed, v is applied voltage, ia is the armature current, and ra is the armature resistance and. You learn the significance of the data included on the rating plate of a dc motor. Dec 29, 2015 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. The terminal voltage of the armature, v the external resistance in armature circuit, r a the flux per pole. Separately excited and shunt generator characteristics. Hi friends, this playlist contains dc machinery fundamentals, dc generator and dc motors, these videos cover most of the concept that will need in. The characteristics of a shunt motor reveal that it is an approximately constant speed motor. You become familiar with the measuring circuit for commissioning a direct current shunt motor. First, one is separately excited dc motor and selfexcited dc motor. In dc shunt motor the armature and field winding are connected in parallel across the supply voltage the resistance of the shunt winding. Characteristics of dc compound motor dc compound motors have both series as well as shunt winding.
May 10, 2020 dc machines nptel notes edurev is made by best teachers of. Current is supplied to the rotating armature winding through commutator segments. The aim is to establish relationship between the speed of dc motor and the load torque at different voltages as well as investigating the performance of closedloop systems when different voltages are applied to the. Jul 11, 2019 by this method a dc shunt motors speed is controlled through a field rheostat. Speed control of dc shunt motor with field and armature. Shunt motor is a special type of dc motor which runs at. Dc machine are the electromechanical energy conversion devices which converts. Dc machines complete course includes fundamentals, motors. Solution as usual let us begin the solution by drawing the shunt motor. Dc motors plays an important role in energy conversion process. Dc motors may be termed as shunt, series, compound or separately excited. Lathes, drills, boring mills, shapers, spinning, and weaving machines series motor.
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. Types of dc motors dc motor are of 3 types they are 1. This parallel configuration allows independent path of current for field winding and armature. 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. Jul 11, 2019 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. Dc shunt motor armature the parallel combination of two windings is connected across a common dc power supply. The shunt motors are used where constant speed is required and starting conditions are not severe. If the field resistance is increased by 5%, calculate the new steady state armature current and speed of the motor.
The change in back emf is very small due to small voltage drop in the armature and series field resistance therefore the speed is inversely proportional to flux as constant supply voltage. Whenever the shunt motor load is increased e b vi a r a and flux reduces as a result drop in the armature resistance and armature reaction. Dc machines 1 dc machines transformsmechanicalenergyintoelectric energywithdc voltage and currentdc generatoror dynamo, or converselydc motor. A 20hp, 250v dc shunt motor has an armature resistance of 0. Since they are connected in parallel, the armature and field windings are exposed to the same supply voltage. Transfer function is obtained by conducting the speed control test on the dc shunt motor 2. 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. The principle of operation of a dc generator is similar to that of the ac generator, which was discussed previously. Motor starters 3 point and 4 point starters protective devicescalculation of starter steps for d. The armature current is large at heavy load condition this will result in increase of field flux and reduces the speed as a result back emf decreases and more armature current allow to flow. Armature reaction, separately excited and self excited generators, load characteristics of shunt, principle of operation, speed control of d. It is typically used for industrial, adjustable speed applications, such as machine.
The dc shunt motor is well suitable for lathes, machine tools, driving, shafting, milling machine, conveyors etc. In this method, speed variation is accomplished by means of a variable resistance inserted in series with the shunt field. Other members of the family are the directcurrent dc motor or generator, the induction motor or generator, and a number of derivatives of all these three. The dc shunt motor is useful for moderate speed control. What is a dc shunt motor and its advantage and disadvantage. The dc shunt motor is 120vdc with rated speed of 1800 revolutions per minute. Download notes,take a printout then watch nptel lecture and then go. Construction and principle of operation of the shunt dc motor.
Each commutator segment also located on the rotor is connected to an armature winding coil. In a compound motor, if series and shunt windings are connected such that series flux is in direction as that of the shunt flux then the motor is said to be cumulatively compounded. What is common to all the members of this family is that the basic. The electric equivalent circuit of the armature and the freebody diagram of the rotor are shown in the following figure. The shunt motor runs at a speed defined by the expressions. The shunt winding has a large number of turns so that it has appreciable inductance.
Dc series motor cannot be run at no load condition. As the name implies selfexcited, hence, in this type of motor, the current in the windings is supplied by the machine or motor itself. 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. Different types, principle of operation of dc generator, emf equation, methods of excitation. Characteristics of dc shunt motor, dc series motor, dc. Electrical machines 1 pdf notes em 1 pdf notes smartzworld. Construction and principle of operation of singlephase transformer, emf equation, singlephase autotransformer. C is applied to a shunt motor, the large inductive reactance of shunt winding will reduce the field current too much. The aim is to establish relationship between the speed of dc motor and the load torque at different voltages as well as investigating the performance of closedloop systems when different voltages are applied to the armature circuit of the motor when a constant voltage. Mod01 lec30 lecture30characteristics of dc shunt motors. An increase in controlling resistances reduces the field current with a reduction in flux and an. Dc shunt motor pdf april 2, 2020 by masuzi pdf sd and torque control of a dc shunt motor dc shunt motor dc shunt motor ar in dc shunt motor the field winding and ar is connected parallel cur remains fairly constant.
The electric braking of a dc motor is of three types, i rheostatic or dynamic braking, ii plugging or reverse current braking and iii regenerative beaking. Be it motor or generator operations, the analysis of d. The field winding is connected in parallel with the armature. Same voltage is applied to both shunt winding and armature in this motor. In this paper speed control of the dc motor by armature control method is proposed. The compound motors are used where higher starting torque and fairly.
To know how to estimate and predict efficiency of a d. For this example, we will assume that the input of. Dc shunt motor shunt wound dc motor principle, construction. Pdf sd and torque control of a dc shunt motor dc shunt motor dc shunt motor ar in dc shunt motor the field winding and ar is connected parallel cur remains fairly constant. Mod01 lec32 lecture32speed control of dc shunt motors 33. Modelling and simulation of armaturecontrolled direct. Consequently, shunt motor will not usually run on a.
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